NASA Aeronautical NASA SP-7037 (142)Engineering December 1981A Continuing Bibliography with Indexes (NASA-SP-7037 (142)) AEECNAC11CAL N82-16041 ENGINEERING. A CONTINUING BIBLIOGRAPHY WITH INDEXES, SUPPLEMENT 142 (National Aeronautics and Space Administration) 114 p Uiiclas $5.00 CSCL 01A 00/01 05UJo National Aeronautics and ty~ £/kf Space Administration /tov^^A, "" ^4^, Aeronautical Engineering Aeron sring Aeronautical Engineering ngineering Aeronautical Engine ^al Engineering Aeronautical Er nautical Engineering Aeronaut! Aeronautical Engineering Aeror 3ring Aeronautical Engineering ngineering Aeronautical Engine sal Engineering Aeronautical Er lautical Engineering Aeronaut* Aeronautical Engineering Aeror sring Aeronautical Engineering https://ntrs.nasa.gov/search.jsp?R=19820008168 2020-03-21T09:49:45+00:00Z ACCESSION NUMBER RANGES Accession numbers cited in this Supplement fall within the following ranges. STAR (N-10000 Series) N81-30080 - N81-32113 IAA (A-10000 Series) A81-43983 - A81-47132 This bibliography was prepared by the NASA Scientific and Technical Information Facility operated for the Nat iona l Aeronaut ics and Space Administration by PRC Government Information Systems. NASA SP-7037(142) AERONAUTICAL ENGINEERING A Continuing Bibliography Supplement 142 A selection of annotated references to unclas- sified reports and journal articles that were introduced into the NASA scientific and tech- nical information system and announced in November 1981 in • Scientific and Technical Aerospace Reports (STAR) • International Aerospace Abstracts (IAA). Scientific and Technical Information Branch 1981 National Aeronautics and Space Administration Washington, DC This supplement is available as NTISUB/141/093 from the National Technical Information Service (NTIS). Springfield. Virginia 22161' at the price of $5.00 domestic; $10.00 foreign. INTRODUCTION Under the terms of an interagency agreement with the Federal Aviation Administration this publication has been prepared by the National Aeronautics and Space Administration for the joint use of both agencies and the scientific and technical community concerned with the field of aeronautical engineering. The first issue of this bibliography was published in September 1970 and the first supplement in January 1971. Since that t ime, m o n t h l y supplements have been issued. This supplement to Aeronautical Engineering - A Continuing Bibliography (NASA SP-7037) lists 398 reports, journal articles, and other documents originally announced in November 1981 in Scientific and Technical Aerospace Reports (STAR) or in International Aerospace Abstracts (IA A). The coverage includes documents on the engineering and theoretical aspects of design, construction, evaluation, testing, operation, and performance of aircraft (including aircraft engines) and associated components, equipment, and systems. It also includes research and development in aerodynamics, aeronautics, and ground support equipment for aeronautical vehicles. Each entry in the bibliography consists of a standard bibliographic citation accompanied in most cases by an abstract. The listing of the entries is arranged in two major sections, IAA Entries and STAR Entries, in that order. The citations, and abstracts when available, are reproduced exactly as they appeared originally in IAA and STAR, including the original accession numbers from the respective announcement journals. This procedure, which saves time and money, accounts for the slight variation in citation appearances. Three indexes - subject, personal author, and contract number — are included. An annual cumulative index will be published. in AVAILABILITY OF CITED PUBLICATIONS IAA ENTRIES (A81-10000 Series) All publications abstracted in this Section are available from the Technical Information Service. American Institute of Aeronautics and Astronautics. Inc. (AIAA), as follows: Paper copies of accessions are available at $7.00 per document up to a maximum of 40 pages. The charge for each additional page is $0.25. Microfiche of documents announced in IAA are available at the rate of $3.00 per microfiche on demand, and at the rate of $1.25 per microfiche for standing orders for all IAA microfiche. The price for the IAA microfiche by category is available at the rate of $1.50 per microfiche plus a $1.00 service charge per category per issue. Microfiche of all the current AIAA Meeting Papers are available on a standing order basis at the rate of $1.50 per microfiche. Minimum air-mail postage to foreign countries is $1.00 and all foreign orders are shipped on payment of pro-forma invoices. All inquiries and requests should be addressed to AIAA Technical Information Service. Please refer to the accession number when requesting publications. STAR ENTRIES (N81 10000 Series) One or more sources from which a document announced in STAR is available to the public is ordinarily given on the last line of the citation. The most commonly indicated sources and .their acronyms or abbreviations are listed below. If the publication is available from a source other than those listed, the publisher and his address will be displayed on the availability line or in combination with the corporate source line. Avail: NTIS. Sold by the National Technical Information Service. Prices for hard copy (HC) and microfiche (MF) are indicated by a price code followed by the letters HC or MF in the STAR citation. 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Avail: Fachinformationszentrum. Karlsruhe. Sold by the Fachinformationszentrum Energie, Physik, Mathematik GMBH, Eggenstein Leopoldshafen, Federal Republic of Germany, at the price shown in deutschmarks (DM). Avail: Issuing Activity, or Corporate Author, or no indication of availability. Inquiries as to the availability of these documents should be addressed to the organization shown in the citation as the corporate author of the document. Avail: U.S. Patent and Trademark Office. Sold by Commissioner of Patents and Trademarks, U.S. Patent and Trademark Office, at the standard price of 50 cents each, postage free. Other availabilities: If the publication is available from a source other than the above, the publisher and his address will be displayed entirely on the availability line or in combination with the corporate author line. GENERAL AVAILABILITY All publications abstracted in this bibliography are available to the public through the sources as indicated in the STAR Entries and IAA Entries sections. It is suggested that the bibliography user contact his own library or other local libraries prior to ordering any publication inasmuch as many of the documents have been widely 'distributed by the issuing agencies, especially NASA. A listing of public collections of NASA documents is included on the inside back cover. SUBSCRIPTION AVAILABILITY This publication is available on subscription from the National Technical Information Service (NTIS). The annual subscription rate for the monthly supplementsis$50.00domestic;$100 00 foreign. All questions relating to the subscriptions should be referred to NTIS, Attn: Subscrip- tions, 5285 Port Royal Road, Springfield Virginia 22161 ADDRESSES OF ORGANIZATIONS American Institute of Aeronautics and Astronautics Technical Information Service 555 West 57th Street. 12th Floor New York. New York 10019 British Library Lending Division. Boston Spa. Wetherby, Yorkshire, England National Technical Information Service 5285 Port Royal Road Springfield. Virginia 22161 Pendragon House. Inc. 899 Broadway Avenue Redwood City. California 94063 Commissioner of Patents and Trademarks U.S. Patent and Trademark Office Washington. D.C. 20231 Superintendent of Documents U.S. Government Printing Office Washington, D.C. 20402 Department of Energy Technical Information Center P.O. Box 62 Oak Ridge. Tennessee 37830 ESA-lnformation Retrieval Service ESRIN Via Galileo Galilei 00044 Frascati (Rome) Italy Fachinformationszentrum Energie. Physik. 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Colorado 80225 NTIS PRICE SCHEDULES Schedule A STANDARD PAPER COPY PRICE SCHEDULE (Effective January 1. 19811 Prico Cod* A01 A02 A03 ACM A05 A06 A07 A08 A 09 A10 Al l AI2 A13 AI4 A15 A16 A17 A18 A19 A 20 A21 A22 A23 A24 A25 P«0> Ran* Microfiche 001-025 026-050 051-075 076-100 101 125 126-150 151-175 176 200 201 225 226-250 251 275 276 300 301-325 326-350 351-375 376-400 401-425 426 450 451-475 476-500 501-525 526-550 551-575 576-600 601 -up Nonti American Pric. S 350 500 650 800 950 1100 1250 1400 15.50 17.00 1850 2000 21 50 2300 2450 2600 2750 2900 3050 3200 3350 3500 3650 3800 3950 - I/ Foreign Prie* $ 700 1000 1300 1600 1900 2200 2500 2800 3100 3400 3700 4000 4300 4600 4900 5200 5500 5800 61 00 6400 6700 7000 7300 7600 7900 A99 - Write for quote I/ Add SI.SO for each additional 25 page increment or portion thereof for 601 pages up. 2/ Add S3.OO for each additional 25 page increment or portion thereof for 601 pages and more. Schedule E EXCEPTION PRICE SCHEDULE Paper Copy & Microfiche E01 E02 E03 E04 EOS Price) S 550 650 850 1050 1250 S 1150 1350 17 50 21 50 2550 E06 E07 EOS E09 E10 1450 1650 18 SO 2050 2250 2950 3350 3750 41 50 4550 E11 E12 E13 E14 E15 2450 2750 30.50 3350 3650 4950 55.50 61 50 6750 7350 E16 E17 E18 E19 E20 3950 42.50 4550 5050 6050 7950 8550 91 50 10050 121 50 E99 - Write for quote N01 VIII TABLE OF CONTENTS IAA Entries 553 STAR Entries 579 Subject Index A-1 Personal Author Index B-1 Contract Number Index C-1 TYPICAL CITATION AND ABSTRACT FROM STAR NASA SPONSORED DOCUMENT NASA ACCESSION NUMBER -*- N81-10636*| FWG Associates. Inc.. Tullahoma. Tenn.-*- - AVAILABLE ON MICROFICHE TITLE- r AUTHORS- CONTRACT OR GRANT- REPORT NUMBER- PILOT-AIRCRAFT SYSTEM REPONSE TO WIND SHEAR lirtonm R0port Barry S. Turkel and Walter Frost Washington NASA Nov.. 1980 98 p refs (Contract NAS8-33458) (NASA-CR-3342) Avail: NTIS''HC A05/MF A01 CSCL04B- The nonlinear aircraft motion and automatic control model is expanded to incorporate the human pilot into simulations of aircraft response to wind to wind shear. The human pilot is described by a constant gains lag filter. Two runs are carried out using pilot transfer functions. Fixed-stick, autopilot, and manned computer simulations are made with an aircraft having characteristics of a small commuter type aircraft flown through longitudinal winds measured by a Doppler radar beamed along the glide slope. Simulations are also made flying an aircraft through sinusoidal head wind and tail wind shears at the phugoid frequency to evaluate the response of manned aircraft in thunderstorm wind environments. S.F. -CORPORATE SOURCE -PUBLICATION DATE -AVAILABILITY SOURCE -COSATI CODE TYPICAL CITATION AND ABSTRACT FROM IAA AIAA ACCESSION NUMBER TITLE- TITLE OF PERIODICAL- ' A81-10474 jf~n\e design of blowing-cooled aircraft electrical machines (Voprosy konstruktsii produvaemykh aviatsionnykh elek- tricheskikh mashin). V. I. Naumenko, O. G. Klochkov, and V. V. . • Bandurin (Akademiia Nauk Ukrainskoi SSR, Institut Elektrodina-. miki, Kiev, Ukrainian SSR). Tekhnicheskaia Elektrodinamika, July- ~AVAILABLE ON MICROFICHE "AUTHORS Aug. 1980, p. 81-87. In Russian. The current status of air-cooled aircraft electrical machines is reviewed. The possibility of reducing the weight and size of air-cooled machines is discussed, with particular emphasis on the design of cooling systems for synchronous ac-generators. B.J. AUTHOR'S AFFILIATION PUBLICATION DATE IX AERONAUTICAL ENGINEERING A Continuing Bibliography (Suppl. 142) DECEMBER 1981 IAA ENTRIES A81-43998 Challenges in alloy design • Titanium for the aerospace industry. D. Banerjee (Defence Metallurgical Research Laboratory, Hyderabad, India) and R. V. Krishnan (National Aeronautical Laboratory, Bangalore, India). Indian Academy of Sciences, Proceedings (Engineering Sciences), vol. 4, Apr. 1981, p. 21-39. 30 refs. This review describes the principles governing the design of titanium alloys for engine and airframe applications in the aeronauti- cal industry. The relationships between processing, microstructure and properties of the commonly used alpha + beta titanium alloys are described in some detail. The state of science is seen to be sufficiently advanced to enable the metallurgist to optimally design this class of alloys to meet specific requirements. The challenges to the alloy designer lie in increasing the temperature capability of titanium alloys, and in standardizing processing techniques which will decrease the high manufacturing costs of components. (Author) A81-44042 Boeing 767 - The new fuel saver. J. Marsden. Flight International, vol. 120, Aug. 8, 1981, p. 436-440, 442-448, 453. A detailed introduction is given for the 767 airliner, which is intended to yield an 8.5% fuel reduction in 100-2000 n. mi. flights by comparison with the A310. Attention is given to such aspects of the aircraft as passenger accommodations, the extensive use of CRT displays for both electronic flight instrumentation and engine indication/crew alerting systems in the cockpit, advanced hydraulic, environmental control and electrical systems, the use of carbon and Kevlar-reinforced plastics, the airframe assembly sequence, and engine performance characteristics. Detailed dimensional data are presented, and a tentative list of airline orders and options is given showing a total of 173 orders and 138 options. Airline orders will differ in their choice of JT9D or CF6-80 engines. A cut-away section of the aircraft is included. O.C. A81-44043 Ferranti mission managers. R. Whitaker. Flight International, vol. 120, Aug. 15, 1981, p. 505, 506, 509, 510. A description is given of the components and functions of a family of advanced inertial navigation/attack mission-management systems for employment in such ground attack aircraft as the Harrier, F-18, Tornado and Jaguar. The systems address problems arising from the need to coordinate terrain avoidance, navigation, target detection, weapon aiming and firing and evasive maneuvers. The following subsystems are incorporated in order to meet the demands of mission management: (1) inertial navigation; (2) a head-down multifunction display comprised of a moving map, sensor inputs and decisionmaking aids; (3) a laser ranger and marked target seeker; and (4) a computer-aided mission planning system with portable data storage. O.C. A81 -44074 The influence of aircraft operations on air quality at airports. H. Segal (FA'A, Washington, DC) and R. Yamartino (Argonne National Laboratory, Argonne, IL). Air Pollu- tion Control Association, Journal, vol. 31, Aug. 1981, p. 846-850. 9 refs. FAA-supported research. Results are presented of a study of the impact of aircraft emissions on air quality at airports. Air quality data was evaluated through the modeling and monitoring of aircraft emissions at four commercial and one general aviation airport by the statistical analysis of emission plume measurements, the submodeling of aircraft operations at airports, and the construction of Airport Vicinity Air Pollution models for aircraft operations at airports. It is found that the 1-hr average concentrations of CO do not exceed 7 ppm when concentrations are determined under conditions compatible with National Ambient Air Quality standards, which is small compared to the limiting standard of 35 ppm. For N02, annual average concentrations are found to be 10-20% of the limiting standard, while short-term concentrations represent 30-40% of the WHO health effects limiting level. Peak hourly hydrocarbon concentrations of 5 ppm are modeled. It is concluded that aircraft emissions have a smaller impact on air quality than had been estimated prior to the promulgation of aircraft engine emission standards in 1973. A.L.W. A81 -44076 Guidance and Control Conference, Albuquer- que, NM, August 19-21, 1981, Collection of Technical Papers. Conference sponsored by the American Institute of Aeronautics and Astronautics. New York, American Institute of Aeronautics and Astronautics, Inc., 1981. 544 p. Members, $65.; nonmembers, $75. The subjects considered are related to the effects of convective heat transfer on the performance of inertial systems, the improve- ment of aircraft specific range by periodic control, fuel optimal aircraft trajectories with fixed arrival times, effects of displacement and rate saturation on the control of statically unstable aircraft, a mode decomposition control logic for system performance enhance- ment, a fixed-trim re-entry guidance analysis, and maximum informa- tion trajectories for homing missiles. Attention is given to differential game guidance laws for intercept missiles, spin-controlled maneuver strategies using unbalanced precessions, synthesizing state-space models to realize given covariance functions, the analysis of aircraft longitudinal handling qualities, autopilot design via improved discrete modal control, adaptive control of flexible space structures, a Doppler aided low accuracy strapdown inertial navigation system, the reality of wheel speed modulation, a Voyager attitude control perspective on fault tolerant systems, the lower limits of seismic background noise levels, implications of improved reliability and maintainability upon digital flight control, and the attitude control of a flexible triangular truss in space. G.R. A31-44080 " The improvement of aircraft specific range by periodic control. E. G. Gilbert (Michigan, University, Ann Arbor, Ml) and D. T. Lyons (TRW, Inc., Redondo Beach, CA). In: Guidance and Control Conference, Albuquerque, NM, August 19-21, 1981, Collec- tion of Technical Papers. New York, American Institute of Aeronautics and Astronautics, Inc., 1981. p. 19-27. 21 refs. Grant No. AF-AFOSR-77-3158. (AIAA 81-1748) The possibility of improving aircraft cruise by periodic motion is investigated for subsonic aircraft with jet engines. A realistic point-mass model is formulated and the potential for improvement in specific range is studied using analytical and computational tech- niques. The methods of analysis, which are based on special classes of trajectories, give results which support those obtained previously using a less realistic energy-state model. Specifically, significant improvements are possible if a constraint is imposed on the maximum altitude. This conclusion is further substantiated by the computation of optimal periodic trajectories for a wide variety of aircraft characteristics and constraint altitudes. Conditions which favor significant improvement are: large thrust reserve at the constraint altitude, reasonably high lift-to-drag ratio, low constraint al'titude, and low wing loading. The trajectory optimization algo- 553 A81-44081 rithm, which is described in some detail, is especially efficient and may be useful in other applications. (Author) A81-44081 # Fuel optimal aircraft trajectories with fixed arrival times. J. W. Burrows (Boeing Computer Services, Inc., Seattle, WA). In: Guidance and Control Conference, Albuquerque, NM, August 19-21, 1981, Collection of Technical Papers. New York, American Institute of Aeronautics and Astronautics, Inc., 1981, p. 28-34. 7 refs. (AIAA 81-1749) A maximum principle application shows that a fuel optimal aircraft trajectory which arrives at an assigned time is also a direct operating cost-optimal trajectory for certain time cost. The time cost is minimum for maximum endurance cruise. Only for minimum time cost can an optimal trajectory contain a hold or path stretching segment. These concepts are illustrated for three aircraft: the Boeing 737, 747, and 767. Complete optimal trajectories are shown for the 747. Cruise control implications are investigated using the 767 model. Finally, optimal descents are compared to Mach/CAS descents for the 737. (Author) A81-44082 * ~ Effects of displacement and rate saturation on the control of statically unstable aircraft. G. D. Hanson and R. F. Stengel (Princeton University, Princeton, NJ). In: Guidance and Control Conference, Albuquerque, NM, August 19-21, 1981, Collec- tion of Technical Papers. . New York, American Institute of Aeronautics and Astronautics, Inc., 1981, p. 35-49. 9 refs. Grant No. NsG-1587. (AIAA 81-1752) Methodologies are presented for the analysis and design of stability augmentation control laws for aircraft in which 'hard' displacement and rate limiting are significant. Candidate control laws are derived using the linear-quadratic (LQ) regulator Analytical and computational estimates of the stability limits imposed by control saturation are presented using state trajectories with control limiting, as well as describing functions and eigenvalue computation. Analysis also includes an investigation of the interaction of the state-space saturation and stability boundaries for various choices of LQ weighting matrices. For minimum-energy control, the saturation and stability boundaries are shown to be parallel. In this case, there is a direct relation between the solution to the matrix Riccati equation and the aircraft's open-loop dynamics. (Author) A81-44083 ff A mode decomposition control logic for sys- tem performance enhancement. M. N. Wagdi (Riyadh, University, Riyadh, Saudi Arabia). In: Guidance and Control Conference, Albuquerque, NM, August 19-21, 1981, Collection of Technical Papers. ' New York, American Institute of Aero- nautics and Astronautics, Inc., 1981, p. 50-55. (AIAA 81-1753) The performance of controlled systems is enhanced by treating the system as interconnected subsystems representing different operational modes. Control vectors of one subsystem are preassigned in a feedback form of the states, enabling the specification of eigenvalues and eigenvectors of the subsystem modes. This is considered a prespecified external command input for remaining subsystems, and control vector regulator technique. Emphasis is on constructing a control logic that will optimally control subsystem X while subsystem Y is controlled by an external command input, yielding desired closed-loop eigenvalues. The resulting control strate- gy is found suboptimal with respect to the overall system, although the system overall performance is improved. D.L.G. A81-44092 * ff Analysis of aircraft longitudinal handling qual- ities. R. A. Hess (NASA, Ames Research Center, Moffett Field, CA). In: Guidance and Control Conference, Albuquerque, NM, August 19-21, 1981, Collection of Technical Papers. New York, American Institute of Aeronautics and Astronautics, Inc., 1981, p. 138-145. 11 refs. (AIAA 81-1771) The optimal control model (OCM) of the human pilot is applied to the study of aircraft handling qualities. Attention is focused primarily on longitudinal tasks. The modeling technique differs from previous applications of the OCM in that considerable effort is expended in simplifying the pilot/vehicle analysis. After briefly reviewing the OCM, a technique for modeling the pilot controlling higher order systems is introduced. Following this, a simple criterion for determining the susceptibility of an aircraft to pilot induced oscillations (PIO) is formulated. Finally, a model-based metric for pilot rating prediction is discussed. The resulting modeling procedure provides a relatively simple, yet unified approach to the study of a variety of handling qualities problems. (Author) A81 -44093 * # An analytical pilot rating method for highly elastic aircraft. R. L. Swaim (Oklahoma State University, Stillwater, OK) and S. Poopaka. In: Guidance and Control Conference, Albuquerque, NM, August 19-21, 1981, Collection of Technical Papers. . New York, American Institute of Aero- nautics and Astronautics, Inc., 1981, p. 146-152. 15 refs. Grant No. NsG-4018. (AIAA 81-1772) An analytical method was developed to predict pilot ratings for highly elastic aircraft subject to severe mode interactions between rigid body and elastic dynamics. An extension of the standard optimal control model of pilot response was made to include the hypothesis that the pilot controls the system with an internal model consisting of the slowly varying part of the aircraft dynamics. This modified optimal control model was analytically evaluated for a longitudinal pitch tracking task on a large flexible aircraft. Paramet- ric variations in the undamped natural frequencies of two symmetric elastic modes were made to induce varying amounts of mode interaction. The model proved successful in discriminating when the pilot can or cannot visually separate rigid from elastic pitch response in the turbulence excited tracking task. This method shows consider- able promise in making it possible to investigate such mode interaction effects on handling qualities in the preliminary design stage of new aircraft. (Author) A81-44094 H Longitudinal equivalent systems analysis of Navy tactical aircraft. D. E. Pischoff (U.S. Naval Material Command, Naval Air Development Center, Warminster, PA). In: Guidance and Control Conference, Albuquerque, NM, August 19-21, 1981, Collec- tion of Technical Papers. New York, American Institute of Aeronautics and Astronautics, Inc., 1981, p. 153-161. 12 refs. (AIAA 81-1775) The high order transfer functions representing the longitudinal dynamics of augmented aircraft were matched in the frequency domain with first over second order short period models. Matching of the pitch rate to pilot input transfer function is shown to yield excellent time history matches. However, the resulting numerator term (L-alpha) takes on very large, unrealistic values. Two methods are presented for extending the frequency matching technique to restrict the variation of L-alpha. First, the effect of simultaneously matching pitch rate and normal acceleration is demonstrated. Secondly, additional terms are introduced into the pitch rate low order system definition to account for specific control system configurations. A control anticipation parameter is developed which provides correlation between the high and various low order system descriptions. (Author) A81-44095 ff Autopilot design via improved discrete modal control. D. V. Stallard (Raytheon Co., Missile Systems Div., Bedford, MA). In: Guidance and Control Conference, Albuquerque, NM, August 19-21, 1981, Collection of Technical Papers. New York, American Institute of Aeronautics and Astronautics, Inc., 1981, p. 162-172. 43 refs. (AIAA 81-1777) The objective is to develop a computationally practical method of applying discrete modal control theory to the design of an improved pitch autopilot of an interceptor missile, with realistic modelling and constraints. A new discrete 'Mode Reckoner' algo- rithm is described, which can calculate deterministically the modes needed for feedback to achieve the desired eigenvalues; the algorithm also calculates the disturbance moment, which is cancelled by feedback. The six-state missile plant in the simulation has the rigid-body pitch dynamics, the first body-bending mode, actuator dynamics and measurements only from a conventional gyro and accelerometer. The desired step response and suppression of distur- bance moment are achieved. (Author) A81-44096 I: Boost-glide range-optimal guidance. H. J. Kelley, E. M. Cliff, and F. H. Lutze (Optimization, Inc., Blacksburg, VA). In: Guidance and Control Conference, Albuquerque, NM, August 19-21, 1981, Collection of Technical Papers. New York. American Institute of Aeronautics and Astronautics, Inc., 1981, p. 173-176. (AIAA 81-1781) A simple guidance scheme is proposed which optimizes approxi- mately the range of the glide phase of a boost-glide vehicle's 554 A81-44123 trajectory. The scheme requires only altitude, flight-path angle, and attitude measurements for implementation. The guidance law pro- vides an attitude command based on the actual flight-path angle and on a calculated flight-path angle associated with that of an equilibrium, constant dynamic pressure, glide of maximum lift-to- drag ratio. By proper weighting of these two inputs, an approximate- ly optimal guidance control is realized. Two examples are given which demonstrate the trajectory characteristics for a high- performance aircraft and for a missile-type vehicle. (Author) A81-44101 H Doppler aided low accuracy strapdown inertial navigation system. I. Y. Bar-ltzhack (Technion - Israel Institute of Technology, Haifa, Israel) and 0. Serfaty. In: Guidance and Control Conference, Albuquerque, NM, August 19-21, 1981, Collection of Technical Papers. New York, American Institute of Aeronautics and Astronautics, Inc., 1981, p. 206-216. 20 refs. Research supported by the Israel Aircraft Industries, Ltd. (AIAA 81-1798) This paper presents a covariance analysis of the performance of a Doppler aided low accuracy, coarsely aligned strapdown inertial navigation system (INS) whose fine alignment takes place automati- cally in flight. It is shown that the fine alignment in azimuth, which requires turns, consists of in-flight gyro calibration and in-flight gyrocompassing. The spacing of the turns is investigated. The influence of several position fixes is examined and it is shown that they can replace INS turns. It is also shown that the use of magnetic heading reference reduces system errors but is not necessary for the satisfactory performance of the augmented system. Two sub-optimal Kalman filters are designed and evaluated. Their small performance degradation with respect to that exhibited by the optimal filter and their low sensitivity to parameter changes is demonstrated by true covariance simulation runs. (Author) A81-44108 * ft Multiobjective insensitive design of airplane control systems with uncertain parameters. A. A. Schy (NASA, Langley Research Center, Hampton, VA) and D. P. Giesy (Kentron International, Inc., Hampton, VA). In: Guidance and Control Conference, Albuquerque, NM, August 19-21, 1981, Collection of Technical Papers. New York, American Institute of Aeronautics and Astronautics, Inc., 1981, p. 262-273. 13 refs. (AIAA 81-1818) A multiobjective computer-aided design algorithm has been developed which minimizes the sensitivity of the design objectives to uncertainties in system parameters. The more important uncertain parameters are described by a gaussian random vector with known covariance matrix, and a vector sensitivity objective function is defined as the probabilities that the design objectives will violate specified requirements constraints. Control system parameters are found which minimize the sensitivity vector in a Pareto-optimal sense, using constrained minimization algorithms. Example results are shown for lateral stability augmentation system (SAS) design for three Shuttle flight conditions. (Author) A81-44109 * S Motion-base simulator results of advanced supersonic transport handling qualities with active controls. J. B. Feather and 0. S. Joshi (Douglas Aircraft Co., Long Beach, CA). In: Guidance and Control Conference, Albuquerque, NM, August 19-21, 1981, Collection of Technical Papers. New York, American Institute of Aeronautics and Astronautics, Inc., 1981, p. 274-280. 8 refs. Contract No. NAS1-16147. (AIAA 81-1819) Handling qualities of the unaugmented advanced supersonic transport (AST) are deficient in the low-speed, landing approach regime. Consequently, improvement in handling with active control augmentation systems has been achieved using implicit model- following techniques. Extensive fixed-based simulator evaluations were used to validate these systems prior to tests with full motion and visual capabilities on a six-axis motion-base simulator (MBS). These tests compared the handling qualities of the unaugmented AST with several augmented configurations to ascertain the effectiveness of these systems. Cooper-Harper ratings, tracking errors, and control activity data from the MBS tests have been analyzed statistically. The results show the fully augmented AST handling qualities have been improved to an acceptable level. (Author) A81-44110 * ;7 Investigation of control, display, and crew- loading requirements for helicopter instrument approach. J. V. Lebacqz, R. M. Gerdes (NASA, Ames Research Center, Moffett Field, CA), R. D. Forrest (FAA, Moffett Field, CA), and R. K. Merrill (U.S. Army, Aeromechanics Laboratory, Moffett Field, CA). In: Guidance and Control Conference, Albuquerque, NM, August 19-21, 1981, Collection of Technical Papers. New York, American Institute of Aeronautics and Astronautics, Inc., 1981, p. 281-295. 19 refs. (AIAA 81-1820) A ground simulation experiment was conducted on a flight simulator for advanced aircraft to investigate the influence and interaction of flight-control system, flight-director display, and crew-loading situation on helicopter flying qualities during terminal- area operations in instrument conditions. Six levels of control complexity were implemented on a representative helicopter model. The six levels of augmentation were examined with display variations consisting of raw elevation and azimuth data only and of raw data plus one-, two-, and three-cue flight directors. Crew-loading situa- tions simulated for the control-display combinations were dual-pilot operation and single-pilot operation. Four pilots performed a total of 150 evaluations of combinations of these parameters for a represen- tative microwave landing system approach task. Pilot rating results indicated the existence of a control display trade-off for ratings of satisfactory, whereas ratings of adequate-but-unsatisfactory de- pended primarily on the control system; the control system required for ratings of adequate-but-unsatisfactory was clearly more complex for the single-pilot situation than that for the dual-pilot situation. (Author) A81-44111 ft IFFC flying qualities simulation. T. J. Cord (USAF, Wright Aeronautical Laboratories, Wright-Patterson AFB, OH). In: Guidance and Control Conference, Albuquerque, NM, August 19-21, 1981, Collection of Technical Papers. New York, American Institute of Aeronautics and Astronautics, Inc., 1981, p. 296-300. (AIAA 81-1821) A piloted simulation of an Integrated Flight/Fire Control (IFFC) automatic tracking system has been performed on the Flight Dynamics Laboratory LAMARS simulation facility. The main objectives were to assess the flying qualities of such a system and to gather information on how the pilot interacts with a high-gain, high-bandwidth automatic guidance system. Results are presented in terms of performance and pilot opinion ratings for aircraft configura- tions which include variations in visual display (lead-computing optical sight (LCDS), director, fixed sight and IFFC), and flight control system definition (level of IFFC application). (Author) A81-44122 /•' Control characteristics of a Buoyant Quad- Rotor Research Aircraft. B. L. Nagabhushan, D. W. Lichty, and N. P. Tomlinson (Goodyear Aerospace Corp., Defense Systems Div., Akron, OH). In: Guidance and Control Conference, Albuquerque, NM, August 19-21, 1981, Collection of Technical Papers. New York, American Institute of Aeronautics and Astronautics, Inc., 1981, p. 370-377. (AIAA 81-1838) Control characteristics of a Buoyant Quad-Rotor Research Aircraft are predicted by considering such a vehicle configuration based on preliminary design. Concepts for controlling the vehicle with or without its external sling load are evaluated by using a flight dynamics simulation of the configuration. Results are presented which show the vehicle response to control inputs, wind distur- bances, and power failure while hovering over a point on the ground. Typical control power and trim characteristics of the vehicle are also discussed. (Author) A81-44123 H Modern control synthesis applied to the longi- tudinal decoupled motion of an aircraft. J. L. Speyer, J. E. White, and D. G. Hull (Texas, University, Austin, TX). In: Guidance and Control Conference, Albuquerque, NM, August 19-21, 1981, Collec- tion of Technical Papers. New York, American Institute of Aeronautics and Astronautics, Inc., 1981, p. 378-389. 13 refs. Research supported by the General Dynamics Corp. (AIAA 81-1839) Multi-input/multi-output control synthesis for the longitudinal decoupled motion of an aircraft is developed -using the Linear- Quadratic Gaussian synthesis technique. The objective is to track commands of pitch rate and normal acceleration using the flap and the elevator. A completely controllable state space is developed which determines the structure of the compensator. With this robust compensator, the command is tracked with zero steady-state error. From pitch rate, acceleration and angle of attack measurements, this 555 A81-44126 state space is reconstructed from an observer. The controller gains are chosen to avoid stimulating the higher-order actuator modes while the observer gains are chosen to enhance robustness. In fact, acceptable, robust performance is obtained with only an acceleration measurement. (Author) A81-44126 # Use of atmospheric electric fields for vertical stabilization and terrain avoidance. M. L. Hill, T. R. Whyte, R. 0. Weiss (Johns Hopkins University, Laurel, MD), R. Rubio (U.S. Army, Atmospheric Sciences Laboratory, White Sands Missile Range, NM), and M. Isquierdo (Texas, University, El Paso, TX). In: Guidance and Control Conference, Albuquerque, NM, August 19-21, 1981, Collec- tion of Technical Papers. New York, American Institute of Aeronautics and Astronautics, Inc., 1981, p. 401-410. 17 refs. Army-supported research. (AIAA 81-1848) Using a light aircraft and mini-RPVs (remotely piloted vehicles), in-flight measurements of the quasi-electrostatic field which exists in the atmosphere have been made in various weather and terrain conditions. During flight tests of a mini remotely piloted vehicle near an 8000-ft high mountain peak, it was observed that favorable curvatures of the field lines exist and that such a stabilization system can provide for avoidance of collision with such protrusions. The heading of a mini RPV aimed towards the mountain peak was automatically changed to a heading directly away from the mountain by automatic commands generated by an electrostatic stabilization system. Signals in the roll axis loop of the electrostatic system show that in a region about 200 meters in front of a precipitous cliff the equipotential planes were favorably tilted downward to angles as large as 20 degrees. (Author) A81-44127 * # Flying qualities criteria and flight control design. D. T. Berry (NASA, Flight Research Center, Edwards AFB, CA). In: Guidance and Control Conference, Albuquerque, NM, August 19-21, 1981, Collection of Technical Papers. New York, American Institute of Aeronautics and Astronautics, Inc., 1981. p. 411-415. (AIAA 81-1823) Despite the application of sophisticated design methodology, newly introduced aircraft continue to suffer from basic flying qualities deficiencies. Two recent meetings, the DOD/NASA Work- shop on Highly Augmented Aircraft Criteria and the NASA Dryden Flight Research Center/Air Force Flight Test Center/AIAA Pilot Induced Oscillation Workshop, addressed this problem. An overview of these meetings is provided from the point of view of the relationship between flying qualities criteria and flight control system design. Among the items discussed are flying qualities criteria development, the role 'of simulation, and communication between flying qualities specialists and control system designers. (Author) A81-44133 ft Closed-loop criteria for assessing longitudinal- axis handling qualities of transports in final approach. W. H. Levison (Bolt Beranek and Newman, Inc., Cambridge, MA) and W. W. Rickard (Douglas Aircraft Co., Long Beach, CA). In: Guidance and Control Conference, Albuquerque, NM, August 19-21, 1981, Collec- tion of Technical Papers. New York, American Institute of Aeronautics and Astronautics, Inc., 1981, p. 470-479. 12 refs. (AIAA 81-1773) A methodology is demonstrated for assessing longitudinal-axis handling qualities of transport aircraft on the basis of closed-loop criteria. Six longitudinal-axis approach configurations were studied covering a range of handling quality problems that included the presence of flexible aircraft modes. Using closed-loop performance requirements derived from task analyses and pilot interviews, predictions of performance/workload tradeoffs were obtained using an analytical pilot/vehicle model. A subsequent manned simulation study yielded objective performance measures and Cooper-Harper pilot ratings that were largely consistent with each other and with analytic predictions. (Author) A81 44134 a Low-order approaches to high-order systems - Problems and promises. D. G. Mitchell and R. H. Hoh (Systems Technology, Inc., Hawthorne, CA). In: Guidance and Control Conference, Albuquerque, NM. August 19-21, 1981, Collection of Technical Papers. New York, American Institute of Aeronautics and Astronautics, Inc., 1981, p. 480-490. 18 refs. Contract No. F33615-80-C-3604. (AIAA 81-1774) Low-order equivalent system approaches to analysis of aircraft pitch dynamics are reviewed. Equivalent systems show promise for reducing the transfer functions of complex, highly-augmented aircraft into familiar and interpretable parameters. The merits of such approaches are discussed in light of the flying qualities military specification and the desire to retain the classical criteria for defining acceptable pitch characteristics. Several potential problems with interpreting the equivalent systems parameters are reviewed. Some high-order transfer functions are shown to produce low-order system parameters which may not be equivalent to their classical counter- parts and which may be difficult to physically interpret. (Author) A81-44135 * # Flight test results for the F-8 digital fly-by- wire aircraft control sensor analytic redundancy management tech- nique. J. C. Deckert (Charles Stark Draper Laboratory, Inc., Cambridge, MA). In: Guidance and Control Conference, Albuquer- que, NM, August 19-21, 1981, Collection of Technical Papers. New York, American Institute of Aeronautics and Astronautics, Inc., 1981, p. 491-499. 6 refs. Contract No. NAS4-2675. (AIAA 81-1796) This paper reviews the formulation and flight test results of an algorithm to detect and isolate the first failure of any one of twelve duplex control sensor signals being monitored. The technique uses like-signal differences for fault detection while relying upon analytic redundancy relationships among unlike quantities to isolate the faulty sensor. The fault isolation logic utilizes the modified sequen- tial probability ratio test, which explicitly accommodates the inevitable irreducible low frequency errors present in the analytic redundancy residuals. In addition, the algorithm uses sensor output selftest, which takes advantage of the duplex sensor structure by immediately removing a highly erratic sensor from control calcula- tions and analytic redundancy relationships while awaiting a defini- tive fault isolation decision via analytic redundancy. This study represents a proof of concept demonstration of a methodology that can be applied to duplex or higher flight control sensor configura- tions and, in addition, can monitor the health of one simplex signal per analytic redundancy relationship. (Author) A81-44268 # The influence of structural parameters and velocity on the shimmy of self-aligned wheels (Vliianie konstruktiv- nykh parametrov i skorosti dvizheniia na shimmi orientiruiushchikh- sia koles). L. G. Lobas and N. V. Nikitina (Akademiia Nauk Ukrainskoi SSR, Institut Mekhaniki, Kiev, Ukrainian SSR). Priklad- naia Mekhanika, vol. 17, July 1981, p. 127-131. In Russian. An analysis is presented of the integral curves of a dynamic system modeling landing gear with self-aligned wheels. A numerical solution is used to study the effect of structural parameters (e.g., the type of damper, the dry friction moment, and the stiffness of the elastic element of the damper) on the integral curves. B.J. A81-44299 New visual displays for the next generation of civil aircraft (Nouvelles visualisations pour la prochaine generation d'avions civils). J. P. Labc-rie (Societe Nationale Industrielle Aero- spatiale, Division Avions, Toulouse, France). L'Onde Electrique, vol. 61, June-July 1981, p. 11-16. In French. Visual display devices based on cathode ray tubes which will be installed on the next generation of civil aircraft are discussed with particular emphasis on those intended for the A 310 and A 300-600 Airbus. The new devices, in contrast to those currently in use to replace classical instrumentation, derive from preliminary definition studies for the redesign of the instrument panel and are destined for use on board civil aircraft currently in the design and preliminary realization stages, including the Boeing 767 and the A 310 Airbus. On the A 310, cathode ray tube applications include the Primary Flight Display, assuming functions of short-term control and medium-term guidance, the Navigation Display, for use in long-term navigation, an alarm display, and a systems display, which indicates the states of aircraft systems. A.L.W. A81 -44322 The selection of air radio navigation system for the post-1990 period (Le choix du systeme de radionavigation aerienne pour la periode posterieure a 1990). J. C. Heurtley and J. W. Bradley (FAA, Washington, DC). (Institute of Electrical and Elec- tronics Engineers, Position Location and Navigation Symposium, Atlantic City, NJ, Dec. 8-11, 1980.) Navigation (Paris), vol. 29, July 1981, p. 259-266. In French. The selection by the FAA of the air radio navigation system or 556 AS 1-44373 combination of systems best suited to meet the needs of the post-1990 period is discussed. The place of the FAA radio navigation system studies within the Federal Radionavigation Plan is outlined, and the elements of the short-term program undertaken by the FAA for meeting current needs with currently available equipment are indicated. The steps of the long-term planning for the 1990s and beyond are then examined in detail, with attention given to the technical, economic and institutional factors governing the selection of a future navigation system for civil aviation. Means for determin- ing the performances of present systems and future performance in the areas of precision, coverage, reliability and operational value are discussed, and the conformability of the systems currently under consideration, namely VOR/DME, LORAN C and Navstar/GPS, to these criteria is examined. It is pointed out that although the analyses of the FAA will be taken into account in the recommenda- tion of a future system, the final selection is up to the users. A.L.W. A81-44323 Aerial collisions with relief features (Les colli- sions aeriennes avec le relief). Navigation (Paris), vol. 29, July 1981, p. 288-311. In French. An analysis is presented of characteristics common to jet aircraft collisions with obstacles on the ground. Attention is given to the conditions of visibility, flight conVol responsibilities, knowledge of the terrain by the crew and predicted flight paths as possible factors contributing to collisions during the approach and landing phases of a flight. It is pointed out that such accidents are usually attributed to the lack of a precise determination of aircraft position and a closer cooperation between the flight commander and the other members of the crew in preparation for descent is recommended. The circumstances of two aircraft accidents classified as relief collisions are related as illustrations of these points. The accidents involved the collision of a SE 210 Caravelle with a hill upon a direct approach to Dubai airport in March, 1972, and the destruction of a B 727 upon approach to Washington Dulles International Airport in December, 1974. A.L.W. A81-44324 Automated celestial position determination (Le point astronomique automatise). Navigation (Paris), vol. 29, July 1981, p. 341-360. In French. Methods for the application of microprocessors in celestial position calculations are examined. Following a brief review of transformations of the four triangulation formulas which have been developed to simplify position calculations, the formulas of Guyou (1909), which are readily adaptable to machine calculations, are presented, and the determination of the celestial fix according to these formulas, which allow position determination at an estimated parallel, are analyzed. The application of the method under actual conditions in Cartesian coordinates is considered, with particular attention given to cases of elevation curves of the first, second and third types and culmination near the zenith. A.L.W. A81-44329 Advanced ultrasonic testing of aerospace struc- tures. R. J. Botsco (NOT Instruments, Inc., Huntington Beach, CA). In: Material and process applications - Land, sea, air, space; Proceedings of the Twenty-sixth National Symposium and Exhibi- tion, Los Angeles, CA, April 28-30, 1981. Azusa, CA, Society for the Advancement of Material and Process Engineer- ing, 1981, p. 24-33. Attention is given to two new and very diverse ultrasonic test methods which are especially well suited for inspecting aerospace structures. One method utilizes the ultrasonic impedance plane (BondaScope) for inspecting bonded structures. The other method involves high resolution pulsed ultrasound (NovaScope) which finds particular use for the thickness gaging of critical, complex structures. Actual test results obtained on a wide variety of typical structures are included to demonstrate the capabilities and versatilities of these ultrasonic methods. Applications of the test methods include the detection and depth location of unbonds in multi-layered metal laminates, the detection of unbonds between graphite layers bonded to other types of materials, the testing of Kevlar structures, and the inspection of boron fiber and fiberglass composites. G.R. A81-44341 Composite applications on Boeing commercial aircraft. V. S. Thompson (Boeing Commercial Airplane Co..Seattle, WA). In: Material and process applications - Land, sea, air, space; Proceedings of the Twenty-sixth National Symposium and Exhibi- tion, Los Angeles, CA, April 28-30, 1981. Azusa, CA, Society for the Advancement of Material and Process Engineer- ing, 1981, p. 194-201. An overview is presented of the application of such advanced composite materials as graphite, Kevlar and hybrid Kevlar/graphite- reinforced plastics to the 767/757 series aircraft, based on experience since the early 1960s with fiberglass-reinforced plastics. It is shown that the application of such materials to rudders, elevators, spoilers, ailerons, landing gear doors, fixed trailing edges, fairings and engine cowls represents a weight savings of about 1250 Ib by comparison with metallic alternatives. This 25-30% weight reduction factor has been demonstrated to yield annual fuel savings of $750,000 on 747 aircraft. Attention is given the details of manufacturing and their attendant cost savings, such as the 25% reduction in the cost of a 737 aircraft fiberglass rudder panel by comparison to a mechanically fastened aluminum structure. O.C. A81-44342 EF-111A graphite/epoxy Horizontal Stabilizer Trailing Edge, J. A. Suarez and S. J. Dastin (Grumman Aerospace Corp., Bethpage, NY). In: Material and process applications - Land, sea, air, space; Proceedings of the Twenty-sixth National Symposium and Exhibition, Los Angeles, CA, April 28-30, 1981. Azusa, CA, Society for the Advancement of Material and Process Engineering, 1981, p. 202-215. Contract No. F33615-78-C-5234. A production-suitable, vacuum-bag-cure manufacturing method for integrally stiffened graphite/epoxy sandwich structure has been verified for the EF-111A Horizontal Stabilizer Trailing Edge. Fabrication and static test of a structurally complete EF-111A Horizontal Stabilizer Trailing Edge has demonstrated the feasibility of constrained, vacuum pressure, oven-processing techniques for single integral cure exact molded (SICEM) assemblies. Cost and producibility analyses have been performed on the integrally-cured trapezoidal stiffener concept to determine production benefits and to project realistic total costs. (Author) A81 -44355 Development and hardware verification of an aeroelastically tailored forward swept composite wing. J. W. Ellis (Rockwell International Corp., North American Aircraft Div., Los Angeles, CA). In: Material and process applications - Land, sea, air, space; Proceedings of the Twenty-sixth National Symposium and Exhibition, Los Angeles, CA, April 28-30, 1981. Azusa, CA, Society for the Advancement of Material and Process Engineering, 1981, p. 362-373. The development, fabrication and testing of a divergence- and flutter-resistant subscale wing structure, representing a high perfor- mance forward-swept fighter wing, are described, with attention to an unorthodox unbalanced laminate composite ply wing skin design that provides special aeroelastic tailoring characteristics. Verification of the design was provided by wind tunnel testing of the 0.6-scale wing model at transonic speeds. Extensive details are given for the construction methods employed in the production of the subscale wing, along with performance-prediction computer studies of the structure. O.C. A81-44373 Utilization in industry of I CAM 'Manufac- turing Cost/Design Guide' /MC/DG/ for composite structures. D. S. Klivans (Rockwell International Corp., Los Angeles, CA) and 8. R. Nqton (Battelle Columbus Laboratories, Columbus, OH). In: Mate- rial and process applications - Land, sea, air, space; Proceedings of the Twenty-sixth National Symposium and Exhibition, Los Angeles, CA, April 28-30, 1981. Azusa, CA, Society for the Advancement of Material and Process Engineering, 1981, p. 593-600. Utilizing the MC/DG, trade-studies have been conducted on advanced composite fuselage shear-panels. The configurations in- cluded light weight/high complexity; moderate weight/moderate complexity; and high weight/low complexity configurations. The panels were of single curvature and were assembled using mechanical and cocuring methods. The graphite/epoxy selected was AS/3502-6. The configurations studied included hat and J-sections for the stringers, and J-sections for the frames, and the manufacturing man-hours were determined for each. The results are presented in diagrams indicating the weight and manufacturing man-hours for each configuration. The MC/DG formats were used to develop the design employing a step-by-step approach to support the cost of the 557 A81-44374 concept. The final cost was accurate, and the objectives of the MC/DG program were demonstrated. (Author) A81 -44374 Utilization in industry of I CAM 'Manufac- turing Cost/Design Guide' /MC/DG/ for metallic structures. A. J. Pillera (Lockheed-California Co., Burbank, CA) and B. R. Noton (Battelle Columbus Laboratories, Columbus, OH). In: Material and process applications - Land, sea, air, space; Proceedings of the Twenty-sixth National Symposium and Exhibition, Los Angeles, CA, April 28-30, 1981. Azusa, CA, Society for the Advancement of Material and Process Engineering, 1981, p. 601-606. The MC/DG has been utilized for structural performance/ manufacturing cost studies of seven titanium fuselage panel designs for an SST project. Various structural concepts with varying skin thicknesses, frames, and stringer count, were studied. An engineering team conducting the trade studies, included design, stress, weight, and producibility engineers. Detailed engineering drawings were utilized providing realistic applications of the MC/DG. The study enabled the selection of the most cost-effective concept by deter- mining the cost of weight saved for each panel. The use of the MC/DG was fully demonstrated in developing a cost/weight effective design by utilizing the manufacturing cost methodology developed. This provided program dollar costs (including materials, labor and tooling). (Author) A81-44375 The ICAM 'Manufacturing Cost/Design Guide' /MC/DG/ for Avionics. R. Remski (Honeywell, Inc., St. Louis Park, MN), J. G. Vecellio (Rockwell International Corp., Avionics and Missiles Group, Cedar Rapids, IA), and B. R. Noton (Battelle Columbus Laboratories, Columbus, OH). In: Material and process applications - Land, sea, air, space; Proceedings of the Twenty-sixth National Symposium and Exhibition, Los Angeles, CA, April 28-30, 1981. Azusa, CA, Society for the Advancement of Material and Process Engineering, 1981, p. 607-619. USAF- supported research. General and specific ground rules, which include specifications of electronic discrete parts, materials, assemblies, and manufacturing methods, are described. An overview is given of the aerospace electronic design processes, indicating the way in which the MC/DG will be used to conduct trade studies at the conceptual design phase, as well as the detailed design phases for the circuitry and the chassis. The numerous trade studies and data requirements to achieve affordable performance in avionic systems are surveyed. It is noted that these data must be presented to designers so that the cost-trade studies can be conducted with schedule limitations. C.R. A81-44378 Future applications of adhesive bonding in the U.S. Air Force. T. J. Reinhart (USAF, Materials Laboratory, Wright-Patterson AFB, OH). In: Material and process applications - Land, sea, air, space; Proceedings of the Twenty-sixth National Symposium and Exhibition, Los Angeles, CA, April 28-30, 1981. Azusa, CA, Society for the Advancement of Material and Process Engineering, 1981, p. 642-651. Service experience with structural adhesive bonding on fighter, transport and bomber aircraft is summarized. It is pointed out that bonded construction on the C-5, F-111, and F-15 and the new technology replacement components for the C-130 and C-141 have given outstanding performance. It is thought that the gradual switch to the Boeing-developed phosphoric acid anodize will permit even greater reliability to be built into the adhesive bonded components. Areas in which research is still required are indicated; these include: feed-back control of the cure process, life prediction methdology for adhesive bonded structures, techniques for automated inspection of treated adherend surfaces, and the automated application of the adhesive to the surfaces to be bonded. C.R. A81-44382 Maintenance and repair of advanced composite structure. C. E. Beck (USAF, Wright Aeronautical Laboratories, Wright-Patterson AFB, OH). In: Material and process applications - Land, sea, air, space; Proceedings of the Twenty-sixth National Symposium and Exhibition, Los Angeles, CA, April 28-30, 1981. Azusa, CA, Society for the Advancement of Material and Process Engineering, 1981, p. 689-694. 8 refs. DOD- USAF-Navy-supported research. It is shown that graphite/epoxy structures, designed in a variety of configurations and for a wide range of load intensities, can be effectively repaired to virtually full original strength. Among the composites using vehicle types considered are helicopters, space and missile systems, and fixed-wing aircraft, including such advanced military aircraft as the F-14, F-15, F-16, F-18 and AV-8B. Attention is given the portion of life cycle costs represented by structural maintenance and repair. It is shown that total operational and maintenance costs currently far exceed initial acquisition cost. O.C. A81-44383 Review of Navy composite repair program. A. Manno (U.S. Naval Material Command, Naval Air Development Center, Warminster, PA). In: Material and process applications • Land, sea, air, space; Proceedings of the Twenty-sixth National Symposium and Exhibition, Los Angeles, CA, April 28-30, 1981. Azusa, CA, Society for the Advancement of Material and Process Engineering, 1981, p. 695-704. 7 refs. Applications of composite materials to current and near-term Navy aircraft have necessitated the establishment of repair methods both for field and depot maintenance levels. Navy requirements are presented for field level repairs as they apply to current repair programs with emphasis on Navy facilities and capabilities. Repair concepts for damages up to 4 inches in diameter have been developed for field level applications for relatively thick wing skins. Results of this work are presented for both bonded and bolted concepts. Additional work is currently being performed as part of a recently initiated program for field level repairs in which a wide range of thicknesses and damage types is being addressed. A survey of existing materials is being made to select the best materials and processes available to meet the Navy requirements. An extensive test and evaluation program is being performed as part of this program. (Author) A81 -44384 Composite repair concepts for depot level use. J. D. Labor (Northrop Corp., Hawthorne, CA). In: Material and process applications - Land, sea, air, space; Proceedings of the Twenty-sixth National Symposium and Exhibition, Los Angeles, CA, April 28-30, 1981. Azusa, CA, Society for the Advancement of Material and Process Engineering, 1981, p. 705-715. Contract No. N62269-80-C-0232. A description is given of a Navy program being conducted to develop and validate repair procedures, at depot-level facilities, for the repair of graphite/epoxy structural components typical of emerging Naval aircraft. The structural configurations considered include: (1) monolithic skin panels up to 0.4 in. thick, (2) full-depth honeycomb sandwich construction, and (3) sine-wave spar or rib substructures. The realistic criteria to be met include the stipulation that autoclaves will not be used, and that repairs be made directly on the aircraft with access limited to one side of the structure. A separate investigation was made of the tendency of a parent laminate, having previously absorbed moisture, to delaminate or blister during the repair cure cycle. The criteria defined include such service requirements as operating temperature range, strength, fatigue loading and environmental exposure. O.C. A81 -44385 Advanced composite repair - Recent develop- ments and some problems. S. H. Myhre (Northrop Corp., Aircraft Div., Hawthorne, CA). In: Material and process applications - Land, sea, air, space; Proceedings of the Twenty-sixth National Symposium and Exhibition, Los Angeles, CA, April 28-30, 1981. Azusa, CA, Society for the Advancement of Material and Process Engineering, 1981, p. 716-727. 18 refs. Contract No. F33615-79C-3217. Attention is given to the maintenance and repair of advanced composite materials used in aircraft. The experience gained in the past decade is summarized. Emphasis is given to generic problems rather than to those related to particular types of hardware. Problems discussed include bonding on wet laminates, nondestructive inspection, environmental effects, simplified field repair, and joint repair. It is noted that the development of repair technology throughout the 1970's has demonstrated the repairability of compos- ite structure, as seen in at least five independent investigations. C.R. A81-44393 Advanced structural repair for lower cost. A. L; Sanders, Jr. (Rockwell International Corp., North American Aircraft Div., Los Angeles, CA) and H. C. Croop (USAF, Wright Aeronautical Laboratories, Wright-Patterson AFB, OH). In: Material and process applications - Land, sea, air, space; Proceedings of the 558 AS 1-44471 Twenty-sixth National Symposium and Exhibition, Los Angeles, CA, April 28-30, 1981. Azusa, CA, Society for the Advancement of Material and Process Engineering, 1981, p. 804-815. USAF-sponsored research. The objectives of defense department reliability and maintain- ability activities are considered. As a contribution to the achievement of these objectives, a study is being conducted regarding the possible applications of newer technologies to reduce structural maintenance costs of in-service Air Force aircraft. The program for the study is structured to be completed in four separate phases. The Phase I objective was to identify chronic high-cost structural maintenance problems of 16 operational Air Force aircraft. The activities of Phase II were related to the selection of a primary repair/replacement candidate, and the development of innovative cost-effective repair solutions or new designs, using advanced materials and/or processes. Phase III is to provide a feasibility demonstration. G.R. A81-44394 Repair of adhesive bonded structure on com- mercial aircraft. T. Seidl (United Air Lines, Inc., San Francisco, CA). In: Material and process applications - Land, sea, air, space; Proceedings of the Twenty-sixth National Symposium and Exhibi- tion, Los Angeles, CA, April 28-30, 1981. Azusa, CA, Society for the Advancement of Material and Process Engineer- ing, 1981, p. 816-824. Modern aircraft would be inconceivable without structural adhesives. Problems related to maintenance operations and bonding repairs are considered. One of the most common problems associated with bonded parts is their propensity to absorb water. The presence of water may be inferred if the unit weight has increased over a previously established weight, or it may be verified by an X-ray examination or, in the case of nonmetallic structure, by means of a moisture detector. Delaminations, often directly resulting from ingested water, may be identified by coin-tapping. Attention is given to physical damage, delaminations, corrosion removal, liquid remov- al, the replacement of structural members, the replacement of face sheets and core in nonmetallics, and the replacements of face sheets, doublers, and core materials. Finishes and sealants are discussed, taking into account polyurethane enamel, polysulfide sealants, and silicone sealants. It is pointed out that major repairs to bonded structure are impossible without proper fixtures, contour molds, and honeycomb cutters. G.R. A81-44395 Development of large-area damage repair pro- cedures for the F-14A horizontal stabilizer. Phase I - Repair development. J. Mahon (Grumman Aerospace Corp., Bethpage, NY) and J. Candella (U.S. Navy, Norfolk, VA). In: Material and process applications - Land, sea, air, space; Proceedings of the Twenty-sixth National Symposium and Exhibition, Los Angeles, CA, April 28-30, 1981. Azusa, CA, Society for the Advancement of Material and Process Engineering, 1981, p. 825-835. Many F-14A aircraft have been in active service for several years and, as a result, a number of the aircraft have sustained damage to the boron/epoxy stabilizer. Much of this damage has been less than 2-in. in diameter and was effectively repaired. The damage to the horizontal stabilizers of some aircraft, however, has been far more extensive, approaching 6-in. in diameter. The Large-Area Repair Program was initiated to develop structural repairs for damage up to 6 in. in diameter to the F-14 horizontal stabilizer boron/epoxy covers. The repair approach involves application of an autoclave cocured, adhesive bonded, boron/epoxy flush patch to the damage site. The Large-Area Repair Program is divided into four phases. A description is presented of the technical results of the Phase I effort. During Phase I, the large-area repair was developed and verified by the successful static testing of three unconditioned, damaged, and repaired test elements at ambient and elevated temperatures. G.R. A81-44396 Nonhoneycomb composite skin stabilization - A solution to high costs of maintenance. R. L. Miller and W. C. Cooper (Vought Corp., Dallas, TX). In: Material and process applications - Land, sea, air, space; Proceedings of the Twenty-sixth National Symposium and Exhibition, Los Angeles, CA, April 28-30, 1981. Azusa, CA, Society for the Advancement of Material and Process Engineering, 1981, p. 836-847. Contracts No. F33615-78-C-5108; No. F34601-77-A-0176-SA47. Problems with adhesively bonded metallic honeycomb sandwich structures are related to corrosion and debonding of metallic sandwich structures leading to excessive inspection, maintenance, and replacement costs. The operating costs attributed to deficiencies in metallic honeycomb structures have been, and continue to be of serious concern. An investigation was conducted with the objective to find a solution to these problems. The conclusion was reached that nonhoneycomb skin stabilized composite structures are a viable alternative to the continued high maintenance cost of many metallic honeycomb structures. The considered composite articles are direct replacements for their metallic counterparts. The composite struc- tures can be produced cost-competitively. Nonautoclave processing methods are applicable to this type of structure. Life cycle projections indicate a significant reduction in cost through lower replacement rates and less frequent and less complex inspection requirements. G.R. A81-44398 Skin-stabilized horizontal stabilizer for the T-38 aircraft. D. L. Stansbarger (Northrop Corp., Aircraft Div., Hawthorne, CA). In: Material and process applications - Land, sea, air, space; Proceedings of the Twenty-sixth National Symposium and Exhibition, Los Angeles, CA, April 28-30, 1981. Azusa, CA, Society for the Advancement of Material and Process Engineering, 1981, p. 861-873. USAF-sponsored research. Under an on-going program sponsored by the Air Force Materials Laboratory, Manufacturing Technology Division, Northrop Corporation is developing an innovative manufacturing/design ap- proach to the production of advanced composite empennage structures which utilize skin stiffened stabilization techniques in lieu of full depth honeycomb core. This technology will allow a direct replacement to be made for existing metallic honeycomb assemblies, resulting in a reduction in the current high maintenance cost (life cycle cost) associated with existing metallic honeycomb sandwich structures due to corrosion and water entrapment, as well as improving the durability and maintainability of the resulting struc- tures. (Author) A81-44424 * jj Effect of leading-edge vortex flaps on aero- dynamic performance of delta wings. C. S. Reddy (Old Dominion University, Norfolk, VA). Journal of Aircraft, vol. 18, Sept. 1981, p. 796-798. 8 refs. Grant No. NsG-1561. The effect of leading-edge vortex flaps on the aerodynamic characteristics of highly swept-back wings is analytically investigated, using the free vortex sheet method. The method, based on a three-dimensional inviscid flow model, is an advanced panel type employing quadratic doublet distributions to represent the wing surface, rolled-up vortex sheet and wake and is capable of computing forces, moments and surface pressures. O.C. A81-44447 *' Transonic dip mechanism of flutter of a sweptback wing. II. K. Isogai (National Aerospace Laboratory, Tokyo, Japan). AIAA Journal, vol. 19, Sept. 1981, p. 1240-1242. Possible mechanisms of the transonic dip phenomenon of sweptback wing flutter are investigated. A flutter analysis is performed using a two-dimensional wing having vibrational character- istics similar to a typical streamwise section of a sweptback wing, and a computer code is developed to solve the transonic small perturba- tion equation by a finite-difference method. The large negative peak value of the out-of-phase component in the load distribution at 0.825 is found to be due to the phase lag of the shock-wave motion, and it is concluded that the shock wave, especially in the phase delay of the shock-wave motion, plays the dominant role in the transonic- dip mechanism. D.L.G. A81-44471 Mi-26 - The first true heavy lift helicopter. M. Lambert. Interavia, vol. 36, Aug. 1981, p. 764-767. The Soviet helicopter Mi-26 can carry a 20.000 kg payload for a distance of 800 km. Its compact titanium rotor head is the first in the world to carry eight blades. Electric blade deicing is installed. The rotor diameter is 3 meters. Maximum use was made of airfoils to achieve a 50% payload to gross weight ratio. The Mi-26 is suited for operations in Siberia where the climate makes it almost impossible to maintain good roads, and heavy machinery and vehicles have to be moved by air. The cruising speed of the helicopter is 255 km/h. The Mi-26 is flown by a four-man crew, including two pilots, a navigator, and a flight engineer. All four crewmen have large domed windows which offer the only downward and rearward view. Aft of the big 559 A81 -44473 flight deck is a four-seat passenger compartment, and there are about 36 folding seats along the walls of the main cabin. G.R. A81-44473 The new generation of turboshaft and turbo- prop engines. M. Grangier. Interavia, vol. 36, Aug. 1981, p. 771, 772. General activities regarding the development of new turboprop and turboshaft engines are currently at a high level in connection with increasing demands for business aircraft, commuter airliners, and helicopters, and also as.a result of requirements for more efficient and economical engines. The new engines which are and have recently been developed by aerospace manufacturers in the Western World are considered. Attention is given to the development of a small turbine designed to be manufactured in both turboshaft and turboprop versions, turboshaft engines installed in Lynx helicop- ters operating with several navies and air forces, engines intended to power new-generation European helicopters with gross weights between 7 and 14 tons, and an engine specifically developed to power a Franco-German anti-tank helicopter. G.R. A81-44474 The 146 emerges from the shadows. B. Rek and D. Wood. Imeravia, vol. 36, Aug. 1981, p. 786-788. The emergence of the British Aerospace 146 airliner came nearly eighteen years after the appearance of the last new British jet airliner, the BAG One-Eleven. The project concerning the new aircraft was adopted in the early 1970s, only to be shelved in 1974 in the wake of the first Arab oil crisis. The 146 airframe is the subject of an extensive work- and risk-sharing program. The reasons for the slow sales progress are considered, taking into account the second fuel-price explosion and accompanying airline recession in 1979, and the remarkable transformation occurring this summer in the fortunes of the 146. There is now a unique product in the shape of the 146-200: a new 100-plus-seat jet airliner powered by fuel-efficient high-bypass-ratio turbofans. G.R. A81-44554 * # Kinematic properties of rotary-wing and fixed- wing aircraft in steady coordinated high-g turns. R. T. N. Chen (NASA, Ames Research Center, Moffett Field, CAI. American Institute of Aeronautics and Astronautics, Atmospheric Flight Mechanics Conference, Albuquerque, NM, Aug. 19-21, 1981, Paper 81-1855. 15 p. 24 refs. An analytical approach to the study of flight dynamics of aircraft operating in a high-angle-of-attack flight regime and of helicopters operating in extreme thrust conditions is presented. Steady coordinated high-g turns are used to establish the initial equilibrium flight conditions near stall angles of attack. The kinematic properties of the aircraft in steady coordinated turns are examined: in high-g turns, pitch rate (independent of the angle of attack) is of a much larger magnitude than roll and yaw rate; a substantial roll rate is found to develop in steep turns for all angles of attack; the angle of attack also has a significant effect on the pitch attitude, with decreasing influence as the normal load factor increases. The exact small disturbance equations of motion of the aircraft in general steady turns are also developed for application to both rotary-wing and fixed-wing aircraft in extreme conditions. These equations are in a first-order, vector-matrix format, and are thus compatible with many efficient software packages developed in modern system theory. J.F. A81-44556 * ;7 Automatic helical rotorcraft descent and land- ing using a Microwave Landing System. L. A. McGee, J. D. Foster, and G. Xenakis (NASA, Ames Research Center, Moffett Field, CA). American Institute of Aeronautics and Astronautics, Atmospheric Flight Mechanics Conference, Albuquerque, NM, Aug. 19-21, 1981, Paper 81-1857. 11 p. 5 refs. A helical-approach concept is presented for Instrument Flight Rules (IFR) operation of rotorcraft into congested terminal areas where separation from high-speed jet traffic is highly desirable and the airport-precision-approach aid is a Microwave Landing System (MLS). The concept takes advantage of the fact that rotorcraft need not land on the main runway but can operate from a pad that lies on an MLS radial offset from the centerline. The results of 48 flights using a UH-1H helicopter and a research avionics system are presented. Three levels of navigation sophistication were also investigated. It is shown that an approach helix can be contained in a relatively small volume and that being within the Instrument Landing System (ILS) Category II window at a 30-m (100-ft) altitude is not a requirement for a successful hover over a landing pad. Only two of the three navigation systems provided estimates that-allowed all flights to descend from hover to touchdown. (Author) A81-44557 ff Equivalent system analysis of translation rate command systems for hover and low speed flight. C. G. Carpenter and J. Hodgkinson (McDonnell Aircraft Co., St. Louis, MO). American Institute of Aeronautics and Astronautics, Atmospheric Flight Mechanics Conference, Albuquerque, NM, Aug. 19-21, 1981, Paper 81-18ti8. 10 p. 6 refs. A fixed-base handling qualities simulation was performed to investigate the characteristics of translation rate command systems in hover and low speed flight. Three types of translation rate command systems were investigated: (1) translation rate generated by attitude, (2) translation rate generated by direct force control and (3) translation rate generated by blended attitude/direct force control. The mission duplicated visual ship-board operation. The high order dynamics were analytically matched by equivalent low order systems, whose parameters were then used to evaluate flying qualities criteria. Pilot comments indicate a preference for a direct force control system. (Author) A81-44561 H Data analysis for aircraft parameter estimates. W. R. Wells (Wright State University, Dayton, OH) and S. S. Banda (USAF, Flight Dynamics Laboratory, Wright-Patterson AFB, OH). American Institute of Aeronautics and Astronautics, Atmospheric Flight Mechanics Conference, Albuquerque, NM, Aug. 19-21, 1981, Paper 81-1864. 6 p. 8 refs. Estimates of lateral stability and control derivatives of a single engine general aviation aircraft were obtained from a maximum likelihood estimation algorithm expressed in the frequency domain. The aircraft lateral equations of motion included some of the effects of unsteady aerodynamics. Measured data of the aircraft motion are converted into the frequency domain by a discrete form of the fast Fourier transform algorithm for use in the estimates. The sampling and packing theorems from discrete Fourier transform theory are used to reconstruct intermediate values of the sparsely sampled frequency data. Improvements in the estimates of the stability and control derivatives are noted whenever the interpolation schemes are included in the estimation algorithm. (Author) A81-44562 * « Determination of model structure and parame- ters of an airplane from pre- and post-stall flight data. V. Klein (Joint Institute for Advancement of Flight Sciences, Hampton, VA), J. G. Batterson, and P. C. Murphy (NASA, Langley Research Center, Hampton, VA). American Institute of Aeronautics and Astronautics, Atmospheric Flight Mechanics Conference, Albuquerque, NM, Aug. 19-21, 1981. Paper 81-1866. 11 p. 8 refs. A procedure for airplane model structure determination from flight data based on modified stepwise regression (MSR), several decision criteria and postulated aerodynamic model equations is presented. The MSR is constructed to force a linear model for the aerodynamic coefficient first, then select significant nonlinear terms and reject nonsignificant terms from the model. In addition to the statistical criteria in the stepwise regression, the prediction sum of squares (PRESS) criterion and analysis of residuals are examined for the selection of an adequate model. The procedure is used in examples with simulated and real flight data. It is shown that the MSR performs better than the ordinary stepwise regression and that the technique can be also applied to the large amplitude maneuvers. (Author) A81-44563 ff A model-following technique for insensitive aircraft control systems. G. C. Nield (U.S. Air Force Academy, Colorado Springs, CO) and J. D. Powell (Stanford University, Stanford, CA). American Institute of Aeronautics and Astronautics, Atmospheric Flight Mechanics Conference, Albuquerque, NM, Aug. 19-21, 1981, Paper 81-1867. 10 p. 11 refs. A new control-system design method is presented which uses model following and full-state feedback to keep the dominant roots of a system constant. Under favorable circumstances, it can accomplish this even in the presence of arbitrarily large parameter uncertainties. The method has the attractive feature that the parameter-insensitivity and disturbance-rejection characteristics of the system can be selected independently from the no-disturbance. 560 A81-44616 nominal-plant performance. Application is made to an aircraft flight control problem. (Author) A81-44570 * H A vortex-lattice method for calculating longi- tudinal dynamic stability derivatives of oscillating delta wings. D. Levin (NASA, Ames Research Center, Moffett Field, CA). American Institute of Aeronautics and Astronautics, Atmospheric Flight Mechanics Conference, Albuquerque, NM, Aug. 19-21, 1981, Paper 81-1876. 11 p. 23refs. A nonsteady vortex-lattice method is introduced for predicting the dynamic stability derivatives of a delta wing undergoing an oscillatory motion. The analysis is applied to several types of small oscillations in pitch. The angle of attack varied between + or - 1 deg, with the mean held at 0 deg when the flow was assumed to be attached and between + or - 1 deg and the mean held at 15 deg when both leading-edge separation and wake roll-up were included. The computed results for damping in pitch are compared with several other methods and with experiments, and are found to be consistent and in good agreement. (Author) A81 -44576 f, Stability characteristics of a forward swept wing aircraft at high angles of attack. R. A. Calico, jr. (USAF, Institute of Technology, Wright-Patterson AFB, OH) and S. G. Fuller (USAF, Wright Aeronautical Laboratories, Wright-Patterson AFB, OH). American Institute of Aeronautics and Astronautics, Atmo- spheric Flight Mechanics Conference, Albuquerque, NM, Aug. 19-21, 1981, Paper 81-1884. 8 p. 7 refs. The stability of an aircraft with a swept forward wing at high angles of attack and sideslip is determined analytically via two methods. The first of these considers an eigenvalue analysis of high angle of attack and sideslip trim conditions, and an alpha, beta stability envelope is determined. These results are compared with an approximate analysis which uncouples the translation and rotational motion of the aircraft and analyzes the stability of the latter. This method only requires the knowledge of static derivatives. This second approach reduces to the familiar, dynamic sideslip angle dimensionless yawing moment coefficient criteria for symmetric flight. The results of the two methods are shown to yield good agreement. (Author) A81-44577 # Stability of aircraft motion in critical cases. J. E. Cochran, Jr. and C.-S. Ho (Auburn University, Auburn, AL). American Institute of Aeronautics and Astronautics, Atmospheric Flight Mechanics Conference, Albuquerque, NM, Aug. 19-21, 1981, Paper 81-1885. 10 p. 9 refs. Research supported by Auburn University. Methods developed by Malkin (1959) and Liapunov (1950) for the analysis of critical equilibrium states of autonomous nonlinear dynamic systems have been described. The critical states considered are those in which either a single zero eigenvalue or a pair of imaginary eigenvalues of the associated linear system exist and the remaining eigenvalues have negative real parts. Application of the method results in either a single nonlinear, autonomous, ordinary, differential equation, or a pair of such equations, describing motion in the 'critical mode'. Two methods are also used to determine the stability of the motion of a rapidly rolling aircraft in the critical case of one zero eigenvalue and of an aircraft flying at a relatively high angle of attack when the associated linear system has a pair of pure imaginary eigenvalues. J.F. A81-44578 ;; Time-constrained maximum-energy turns. S. R. Petersen (USAF, Space Div., Los Angeles Air Force Station, CA) and C. E. Rader (USAF, Institute of Technology, Wright-Patterson AFB, OH). American Institute of Aeronautics and Astronautics, Atmospheric Flight Mechanics Conference, Albuquerque, NM, Aug. 19-21, 1981, Paper 81-1886. 10 p. 6 refs. . The object of this study is to find the trajectories which a high-performance aircraft would employ to maximize the change in specific energy during a turn. The turn is through 180 degrees and begins from two different velocities, one above and one below the corner velocity. The turning time is varied over three values in order to examine the effect of additional time on the final specific energy. The values of the change in specific energy during the turns are compared to the changes in specific energy which result from a minimum time turn. A suboptimal control approach, which uses both gradient and second-order parameter optimization techniques. is employed to find the maximum specific energy trajectories. The results show that turning times slightly greater than the minimum turning time allow large increases in aircraft specific energy, and that the trajectories can be flown with simple control inputs. (Author) A81-44579 II Lateral-directional flying qualities of transport aircraft. D. S. Joshi and W. W. Rickard (Douglas Aircraft Co., Long Beach, CA). American Institute of Aeronautics and Astronautics, Atmospheric Flight Mechanics Conference, Albuquerque, NM, Aug. 19-21, 1981, Paper 81-1887. 9 p. 10 refs. A piloted motion-base simulation test was conducted to evaluate several MIL-F-8785B and -8785C lateral-directional flying qualities criteria. Twenty-seven transport aircraft configurations were designed to span the spectrum of a number of lateral-direction parameters. The experiment was designed to study the effect of each criterion separately. Subjective and objective measures of flying qualities were analyzed using a combination of statistical and graphical methods. Several deficiencies in the criteria were identified and revisions have been proposed. (Author) AS 1-44580 // A unifying framework for longitudinal flying qualities criteria. R. F.Stengel (Princeton University, Princeton, NJ). American Institute of Aeronautics and Astronautics, Atmospheric Flight Mechanics Conference, Albuquerque, NM, Aug. 19-21, 1981, Paper81-1889. 13 p. 11 refs. Contract No. N62269-80-C-0720. The objective of this paper is to interpret existing flying qualities criteria in a multivariable format based upon state vectors and matrices of stability and control derivatives. State-space methods are shown to be entirely compatible with conventional flying qualities analysis. Furthermore, they lead to a new definition of the well-known control anticipation parameter that has potential utility in the evaluation of higher-order aircraft/control systems. (Author) A81-44581 ,-7 An investigation of the impact of aerodynamic lags on dynamic flight characteristics. R. W. Thomas (McDonnell Aircraft Co., St. Louis, MO). American Institute of Aeronautics and Astronautics, Atmospheric Flight Mechanics Conference, Albuquer- que.NM.Aug. 19-21, 1981, Paper 81-1892. 9 p. Investigations of an F-15 longitudinal response discrepancy have found evidence of aerodynamic lags influencing conventional dy- namic flight characteristics. Lags in an oscillating airfoil and the .lift response of the horizontal tails were included in the F-15 aerody- namic math model, reducing short-period damping and resulting in better agreement with flight test data. Effects of aerodynamic lags on the dynamic characteristics of a statically unstable configuration were also investigated. The primary effect was found to be a small decrease in the short period damping, with a larger decrease found with an unstable static margin. Results indicate the potential requirement to include unsteady aerodynamic effects in conventional handling qualities analyses, with emphasis on control system design to assure satisfactory flying qualities. D.L.G. A81-44615 H Pressure fluctuations on the surface of a small passenger aircraft. I - Periodic disturbances caused by the rotation of the propeller (Fluktuace tlaku na povrchu maleho dopravniho letounu. I - Periodicke rozruchy vyvolane rotaci vrtule). Z. Hujecek. Zpravodaj VZLU, no. 1, 1981, p. 7-20. 19 refs. In Czech. The level of internal noise in small passenger aircraft depends on the magnitude of pressure fluctuations on the external surface and the acoustic properties of the fuselage wall. In order to determine the optimal design of the fuselage wall from the viewpoint of acoustic properties, it is necessary to know the pressure fluctuation field on the fuselage surface. For the case of a small turboprop aircraft, the changing pressure fluctuation field is determined by the superposi- tion of the acoustic field caused by the rotating propeller, the pressure fluctuation field caused by the boundary layer on the fuselage wall, the pressure fluctuation field caused by vortices behind the propeller, the effect of flow separation behind irregularities of the surface, and the noise of the engine proper. The present study gives particular attention to periodic disturbances caused by the rotation of the propeller. B.J. A81-44616 a Philosophy of safety and reliability (Filozofie bezpecnosti a spolehlivosti). V. Kahanek. Zpravodaj VZLU, no. 1, 1981, p. 21-29. 13 refs. In Czech. The philosophy of modern approaches to reliability and safety 561 A81-44618 in aviation is discussed. Statistical data on aircraft accidents are analyzed, and differences in assumptions used for solving problems of reliability and safety are considered. Specific differences between small and large passenger aircraft from the point of view of accident investigation are described. Two tasks directed at the improvement of aircraft reliability and safety are examined: improvement of human factors engineering and the design of fail-safe structures. B.J. A81-44618 ff Pressure fluctuations on the surface of a small passenger aircraft. II - The effect of the turbulent boundary layer (Fluktuace tlaku na povrchu maleho dopravniho letounu. II - Vliv turbulentni mezni vrstvy). Z. Hujecek. Zpravoda/ VZLU, no. 2, 1981, p. 63-72. 24 refs. In Czech. In order to determine the optimal acoustic design of the fuselage wall of a small passenger aircraft, it is necessary to know the pressure fluctuation field on the fuselage surface. For the case of a small turboprop aircraft, the changing pressure fluctuation field is deter- mined by the superposition of the acoustic field caused by the rotating propeller, the pressure fluctuation field caused by the boundary layer on the fuselage wall, and other factors. The present investigation examines the role of the turbulent boundary layer in the generation of pressure fluctuations. B.J. A81-44623 A 7.5 GHz microstrip phased array for aircraft-to-satellite communication. F. W. Cipolla (Ball Corp., Ball Aerospace Systems Div., Boulder, CO). Microwave Journal, vol. 24, Aug. 1981, p. 75-78. Contract No. F30602-78-C-0329. A 7.5 GHz receive-only microstrip phased array, which achieves a gain of 19.8 dBic for the broadside beam, has been developed for the SHF SATCOM communications systems. The device is left-hand circularly polarized and has 3-bit digital PIN diode phase shifters for steering the beam. A microprocessor-based beam steering controller is provided for calculating the phase shifter settings for each beam position. The entire array, including radiating elements, quadrature hybrid, phase shifters, corporate feed, RF chokes, and dc bias, is in microstrip medium. V.L. A81-44648 * Clear air turbulence - An airborne alert system. L. P. Stearns, F. Caracena (NOAA, Environmental Research Labora- tories, Boulder, CO), P. M. Kuhn (Northrop Services, Inc., Moffett Field, CA), and R. L. Kurkowski (NASA, Ames Research Center, Flight Systems Research Div., Moffett Field, Cf^). Science, vol. 213, Aug. 28, 1981, p. 1007, 1008. 5 refs. An infrared radiometer system has been developed that can alert a pilot of an aircraft 2 to 9 minutes in advance of an encounter with clear air turbulence. The time between the warning and the clear air turbulence event varies with the flight altitude of the aircraft. In turbulence-free areas, the incidence of false alarms is found to be less than one in 3.4 hours of flight time compared to less than one per 10 hours of flight time in areas with turbulence. (Author) A81-44666 * ff Autoignition characteristics of aircraft-type fuels. L. J. Spadaccini and J. A. TeVelde (United Technologies Research Center, East Hartford, CT). Combustion Institute, Spring Technical Meeting, Warren, Ml, Mar. 23, 1981. Paper. 27 p. 19 refs. Contract No. NAS3-20066. An investigation was conducted of the ignition delay characteris- tics of five liquid hydrocarbon fuels in air. The test apparatus developed permitted independent variation and control of tempera- ture, pressure, air flow rate, and fuel/air ratio in order that the effects of each parameter could be investigated independently. All of the fuels tested behaved in a predictable manner, that is, ignition delay time decreased as temperature, pressure, and fuel/air ratio increased. The results for the different fuels tested (Jet-A, MP-4, No. 2 diesel, ERBS, and cetane) were directly comparable, since it can be shown that the fuel spray characteristics from the multiple conical tube injector are relatively insensitive to small changes in fuel properties (viscosity, surface tension, and density). G.R. Electrical and Electronics Engineers, Inc., 1981, p. 37-41. An optimal target oentroid estimator is essential to the performance of any sequential-lobing tracking radar. The considered investigation is concerned with a comparative analysis of three edge-point thresholding estimation techniques to determine the most accurate target centroid location estimator within a given set of operating parameters. This analysis was conducted using a software simulation of an automatic landing system which is capable of controlling the variation of certain parameters for the purpose of error isolation. Included in the comparison is an amplitude-weighted scan angle nonthresholding estimator to provide a contrast in the implementation and results of the techniques. It was found that the accuracy of all four estimators increased with the amount of information to be evaluated. The effect of turbulence alone was slight on the accuracy of the estimators. G.R. A81-44699 An aircraft landing system employing observ- ers. R. F. Wilson, C. L. Phillips, E. R. Graf, and S. A. Starks (Auburn University, Auburn, AL). In: SOUTHEASTCON '81; Proceedings of the Region 3 Conference and Exhibit, Huntsville, AL, April 5-8, 1981. Piscataway, NJ, Institute of Electrical and Electronics Engineers, Inc., 1981, p. 280-284. 5 refs. Preliminary results are presented of the effort to design an observer to estimate position and velocity for a proportional plus integral plus derivative (PID) controller. Here, the observer is used to reduce noise problems in the control system, which is an automatic aircraft landing system. It is shown that the noise problems are reduced and that adequate stability margins are maintained. The necessity of future work in order to determine the best pole locations for the observer is stressed. C.R. A81-44700 Image processing design for autonomous ac- quisition of targets. W. W. Boyd, C. A. MacPherson, J. L. Taylor, J. M. Taskett, and M. C. Lineberry (Texas Instruments, Inc., Dallas, TX). In: SOUTHEASTCON '81; Proceedings of the Region 3 Conference and Exhibit. Huntsville, AL, April 5-8, 1981. Piscataway, NJ, Institute of Electrical and Electronics Engineers, Inc., 1981, p. 285-290. Primary considerations in designing an image-processing system that can autonomously acquire high-value tactical targets are discussed. Attention is given to establishing requirements, and the implications of these requirements on the image-processing algo- rithms are analyzed. It is pointed out that through these steps, detection and acquisition times can be estimated and, hence, algorithm processing times established. The results of certain candidate algorithms that show promise of meeting mission goals are presented. The design process described takes account of the geographical and climatological features of the area of intended use. Aircraft maneuverability and human factor limits are also considered in establishing system requirements. Analysis shows the feasibility and desirability of employing the seeker and terrain features to cue the aircraft to the target. C.R. A81-44741 A comparison of actual and simulated horizon- tal flight paths - RNAV /Area Navigation/ system. A. Hargrove (Tuskegee Institute, Tuskegee, AL). In: SOUTHEASTCON '81; Proceedings of the Region 3 Conference and Exhibit, Huntsville, AL, April 5-8, 1981. Piscataway, NJ, Institute of Electrical and Electronics Engineers, Inc., 1981, p. 638-642. The Area Navigation (RNAV) System for aircraft now under development has unique capabilities. Foremost among these capabili- ties is an Automatic Guidance System which defines great circle flight paths and guides the aircraft along circular transitions at waypoints between these great circle paths. Control laws and philosophies have been developed that will enable the sensors, navigation computer unit and electronic displays of the RNAV system to compute and display current 'real world' positions and path of the aircraft. Simulation of a point mass aircraft model and the actual aircraft configuration is described. (Author) A81-44681 Three edge-point estimation schemes for track- ing airborne targets. R. J. Machuzak, E. R. Graf, C. L. Phillips, and S. A. Starks (Auburn University, Auburn, AL). In: SOUTHEASTCON '81; Proceedings of the Region 3 Conference and Exhibit, Huntsville, AL, April 5-8, 1981. Piscataway, NJ, Institute of A81-44849 ," Aeronautical engineering - A historical per- spective. J. D. Anderson, Jr. (Maryland, University, College Park, MD). AIAA Student Journal, vol. 19, Summer 1981, p. 22-31. 11 refs. Early concepts concerning mechanical, heavier-than-air designs for achieving flight were generally based on an imitation of the flight 562 A81-45539 of birds. The concept of the modern aircraft with its fixed wings, a fuselage, and a tail was invented by an English baron, George Cayley. After inscribing his idea on a silver disk in 1799, Cayley conducted aerodynamic research related to his invention during a 10-yr period and wrote three research papers. The further evolution of Cayley's idea is discussed, taking into account Henson's design for a fixed-wing aircraft powered by a steam engine driving two propellers, the first powered takeoff by a piloted full-sized aircraft achieved by Du Temple in 1874, contributions made by Lilienthal, the first successful flight of a heavier-than-air powered aircraft in history achieved by Langley, and the developments leading to the first powered, manned flight by the Wrights. G.R. A81-44850 H Project Bandit • An economical, high perfor- mance business aircraft for the 1990s. AIAA Student Journal, vol. 19, Summer 1981, p. 36-42. 7 refs. The considered project tries to satisfy the need for a single- engine jet aircraft for fast, long-range business trips. Bandit is a fast and economic jet aircraft and, compared to most existing aircraft, yields significantly higher seat-miles per gallon (88.1 seat-miles/gallon compared to 6-10 seat-miles/gallon for typical present-day general- aviation jet aircraft). Aspects of design philosophy and configuration selection are considered, taking into account the preliminary configurations investigated, a comparison of the Bandit with other aircraft, the fuselage structure of Bandit, the radome, mission-phase fuel weights, the canopy of laminated polycarbonate, the three fuel tanks, the turbofan engine design, the control systems, and perfor- mance data. G.R. A81-44898 *=' Numerical and classical analysis of V/STOL aircraft using selected propulsion systems. S. B. Wilson, III, G. H. Kidwell, Jr., and R. S. Christiansen (NASA, Ames Research Center, Moffett Field, CA). American Institute of Aeronautics and Astro- nautics, Aircraft Systems and Technology Conference, Dayton, OH, Aug. 11-13, 1981, Paper 81-1676. 9 p. 17 refs. The development needed for the evolution of selected V/STOL research vehicles into optimized antisubmarine warfare (ASW) aircraft configurations, using numerical procedures and traditional analytical methods, has been examined. Three propulsion systems, which represent state-of-the-art development aimed at solving the thrust-vectoring and attitude-control problems of V/STOL aircraft, are analyzed. The use of NASA computer programs for aircraft synthesis (ACSYNT), and for optimizing configurations (COMMIN), coupled with contractor-supplied propulsion system data provides for accurate performance prediction of the selected ASW configura- tions. Particular emphasis on the transition phase between the research vehicle and the optimized configuration demonstrates the strengths and weaknesses of using generic research aircraft instead of building prototypes to demonstrate new technology. (Author) A81 -44899 tf Aerodynamic integration of externally mount- ed engines on a long-range bomber. A. E. Schoenheit and W. J. Karger (Rockwell International Corp., North American Aircraft Div., Los Angeles, CA). American Institute of Aeronautics and Astronau- tics, Aircraft Systems and Technology Conference, Dayton, OH, Aug. 11-13, W81,Paper81-1693.Qp. The B-1 strategic bomber was designed as a multimission variable-sweep weapon system. The diverse aerodynamic require- ments of integrating the propulsion system into both an efficient subsonic cruising vehicle and a penetrating subsonic and supersonic weapon system have been achieved. The design process included numerous wind tunnel tests to refine the engine inlet and nozzle characteristics as well as integration of the nacelle package into the overall configuration. The performance bookkeeping process with- stood the development obstacles enountered, and the aerodynamic performance levels were substantiated by flight testing. Results are presented which can be useful in future design procedures. (Author) A81-45315 ,7 Self-oscillations of a self-aligned landing gear strut in the case of classical nonholonomic rolling constraints (Avtokolebaniia orientiruiushcheisia stoiki shassi v sluchae realizatsii klassicheskikh negolonomnykh sviazei kacheniia). L. G. Lobas (Akademiia Nauk Ukrainskoi SSR, Institut Mekhaniki, Kiev, Ukraini- an SSR). MatematicheJtaia Fizika, no. 29, 1981, p. 48-55. In Russian. The derivative-expansion method is used to determine the limit-cycle self-oscillation amplitude for a self-aligned landing gear strut under classical nonholonomic rolling constraints. Recommenda- tions are made on the choice of a damping factor for a square-law damper connected in parallel to the elastic element. The velocity dependences of self-oscillation amplitude and frequency are exam- ined. B.J. A81-45515* Practical solutions to the aircraft minimum fuel, fixed-range, fixed time-of-arrival trajectory optimization prob- lem. J. A. Sorensen and M. H. Waters (Analytical Mechanics Associates, Inc., Mountain View, CA). In: Joint Automatic Control Conference, San Francisco, CA, August 13-15, 1980, Proceedings. Volume 1. New York, Institute of Electrical and Electronics Engineers, Inc., 1980. 3 p. (WA10-D). 7 refs. Contract No. NAS1-15497. A practical scheme is presented for generating fixed range, minimum fuel vertical flight profiles that also satisfy time-of-arrival constraints. The resulting algorithm is suitable for incorporation into an on-board flight management system. Example results show that such a capability can save up to 6% of fuel burned in flights subject to delays because of terminal area congestion. (Author) A81-45518 * Pareto-optimal multi-objective design of air- plane control systems. A. A. Schy, K. G. Johnson (NASA, Langley Research Center, Hampton, VA), and D. P. Giesy (Kentron Inter- national, Inc., Hampton, VA). In: Joint Automatic Control Con- ference, San Francisco, CA, August 13-15, 1980, Proceedings. Volume 1. New York, Institute of Electrical and Electronics Engineers, Inc., 1980. 8 p. (WP1-A). 10 refs. A constrained minimization algorithm for the computer aided design of airplane control systems to meet many requirements over a set of flight conditions is generalized using the concept of Pareto- optimization. The new algorithm yields solutions on the boundary of the achievable domain in objective space in a single run, whereas the older method required a sequence of runs to approximate such a limiting solution. However, Pareto-optimality does not guarantee a satisfactory design, since such solutions may emphasize some objectives at the expense of others. The designer must still interact with the program to obtain a well-balanced set of objectives. Using the example of a fighter lateral stability augmentation system (SAS) design over five flight conditions, several effective techniques are developed for obtaining well-balanced Pareto-optimal solutions. For comparison, one of these techniques is also used in a recently developed algorithm of Kreisselmeier and Steinhauser, which replaces the hard constraints with soft constraints, using a special penalty function. It is shown that comparable results can be obtained. (Author) A81-45522 Optimal multirate flight control design. J. R. Broussard and D. P. Glasson (Analytic Sciences Corp., Reading, MA). In: Joint Automatic Control Conference, San Francisco, CA, August 13-15, 1980, Proceedings. Volume 1. New York, Institute of Electrical and Electronics Engineers, Inc., 1980. 7 p. (WP1-E). 9 refs. Contract No. N00014-79-C-0431. A new approach to multirate control synthesis based on optimal regulator theory is described in this paper. The present technique obviates dimensionality problems typical of classically based tech- niques and offers a systematic procedure for designing multirate controllers to meet continuous-time or real frequency domain specifications. Mathematical developments of the multirate regulator and proportional-plus-integral (PI) controllers are presented. An example system is designed and its properties are compared to those of an equivalent single-rate system. (Author) A81-45539* Generic multi-body formulation of heavy lift airship equations of motion. R. F. Ringland, M. B. Tischler, I. L. Ashkenas, and H. R. Jex (Systems Technology, Inc., Hawthorne, CA). In: Joint Automatic Control Conference, San Francisco, CA, August 13-15, 1980, Proceedings. Volume 1. New York, Institute of Electrical and Electronics Engineers, Inc., 1980. 10 p. (TA1-C). 26 refs. Contract No. NAS2-10330. This paper describes the formulation of a comprehensive set of equations which describe the dynamic behavior of a generic heavy lift airship (HLA). They are being used in a digital computer simulation to investigate the response dynamics and flying qualities of HLAs operating with various payloads in a variety of operational 563 A81-45540 environments. A key feature is the separate treatment of each component body making up the HLA. This allows the analyst to vary the configuration (e.g., number of lift-propulsion units, presence or absence of slung payload, etc.) without rewriting the equations. It further provides measures of key structural and control loads acting on the HLA and eases the task of modeling wind disturbances. (Author) A81-45540 Adaptive multivariable model following. E. G. Rynaski (Calspan Advanced Technology Center, Buffalo, NY). In: Joint Automatic Control Conference, San Francisco, CA, August 13-15, 1980, Proceedings. Volume 1. New York, Institute of Electrical and Electronics Engineers, Inc., 1980. 6 p. (TA2-A). Requirements for multivariable model following are investigated in this paper. A control law is specified that is independent of the dynamics of the model, allows for a model as low as first order regardless of the plant order and generally specifies a limited need to identify the plant stability and control parameters. If the plant transmission zeros are minimum phase, the model following system is stable. A method of eliminating initial transients between the model and the plant is presented. Two examples are given to show the efficacy of the design technique. In the first example, a model following control law is defined for the X-22A V/STOL research aircraft and demonstrates frequency-time domain relationships of the control law calculations. The second example presents flight data results for the USAF/Calspan Total In-Flight Simulator (TIPS) airplane. (Author) A81-45551 * Sensor/actuator failure detection and isolation for airbreathing propulsion systems. G. G. Leininger (Purdue University, West Lafayette, IN) and K. Behbehani (Toledo, Universi- ty, Toledo, OH). In: Joint Automatic Control Conference, San Francisco, CA, August 13-15, 1980, Proceedings. Volume 2. New York, Institute of Electrical and Electronics Engineers, Inc., 1980. 5 p. (TP4-B). 12 refs. Grant No. NsG-3084. In this paper, the Generalized Likelihood Ratio (GLR) test is used to detect and isolate sensor and/or actuator failures when a digital computer simulation model of the physical system is available. The input to the GLR detector is an innovation sequence formed by subtracting the model outputs from the sensed outputs. Application of the GLR detector to the General Electric QCSEE turbofan engine demonstrates the utility of the proposed procedure. (Author) A81-45553 Real-time estimation in advanced turbofan engines. R. K. Sahgal, B. A. Anderson, R. D. Hackney (United Technologies Corp., Pratt and Whitney Aircraft Group, West Palm Beach, FL), and G. T. McKee (Sanders Associates, Nashua, NH). In: Joint Automatic Control Conference, San Francisco, CA, August 13-15, 1980, Proceedings. Volume 2. New York, Institute of Electrical and Electronics Engineers, Inc., 1980. 7 p. (TP4-E). 12 refs. The feasibility of using an observer as an active part of an advanced turbofan control system to dynamically estimate engine parameters of interest is demonstrated. The observer estimates engine parameters that may be used for protection, direct control, analytical redundancy and/or diagnostic analysis. Turbine temperature, a prime protection parameter for jet engine control, is difficult to measure responsively and accurately. Analytical estimates based on informa- tion already available within the control system provide an alternate source for temperature information. This paper presents a practical method of calculating real time estimates, including turbine tempera- ture, required for engine control and diagnostics. (Author) A81-45573 Output predictive algorithmic control - Preci- sion tracking with application to terrain following. J. G. Reid, J. T. Silverthorn (USAF, Institute of Technology, Wright-Patterson AFB, OH), and D. E. Chaffin (USAF, Wright Aeronautical Laboratories, Wright-Patterson AFB, OH). In: Joint Automatic Control Confer- ence, San Francisco, CA, August 13-15, 1980, Proceedings. Volume 2. New York, Institute of Electrical and Elec- tronics Engineers, Inc., 1980. 8 p. (FA9-F). 13 refs. The output predictive digital control problem is formulated as an overdetermined linear least squares problem with considerable design flexibility. An efficient numerical technique is derived for its solution, and some 'rules of thumb' are given for the selection of the design parameters. The control switch time is seen to be an important factor affecting robustness, and a 'robust' design strategy for selection of this time is presented. The greatest power of the control technique is seen in the tracking task. A hypothetical terrain following example shows the digital, closed loop, predictive control- ler to be both extremely high in 'bandwidth' and to have a very short 'settling time'. (Author) A81-45588 General describing function method for sys- tems with many nonlinearities, with application to aircraft perfor- mance. J. H. Taylor (Oklahoma State University, Stillwater, OK). In: Joint Automatic Control Conference, San Francisco, CA, August 13-15, 1980, Proceedings. Volume 2. New York. Institute of Electrical and Electronics Engineers, Inc., 1980. 6 p. (FP9-A). 8 refs. Contract No. N00014-75-C-0432. It is shown that the Sinusoidal-Input Describing Functions (SIDFs) technique described is useful in the investigation of limit cycle conditions in completely general multivariable nonlinear systems. Restrictions on the type and number of nonlinearities, system configuration and the presence of constant inputs have been completely removed. In general, the results obtained bolster the expectation that the iterative LC analysis technique will be found to converge in such a way as to locate limit cycle conditions, provided that limit cycles exist. A major point of departure from previous SIDF analysis methods is the substitution of root locus-like plots of 'quasi-linear eigenvalues' in lieu of frequency domain SIDF tech- niques for multivariable systems. O.C. A81-45602 Output predictive algorithmic control - Preci- sion tracking with application to terrain following. J. G. Reid (Lear Siegler, Inc., Dayton, OH), D. E. Chaffin (USAF, Avionics Laborato- ry, Wright-Patterson AFB, OH), and J. T. Silverthorn (USAF, Institute of Technology, Wright-Patterson AFB, OH). Journal of Guidance and Control, vol. 4, Sept.-Oct. 1981, p. 502-509. 12 refs. The output predictive digital control problem is formulated as an overdetermined linear least-squares problem with considerable design flexibility. An efficient numerical technique is derived for its solution, and some 'rules of thumb' are given for the selection of the design parameters. The control switch time is seen to be an important factor affecting robustness, and a 'robust' design strategy for selection of this time is presented. The greatest power of the control technique is seen in the tracking task. A hypothetical terrain-following example shows the digital, closed-loop, predictive controller to be extremely high in 'bandwidth' and to have a very short 'settling time'. (Author) A81-46325 Limb restraint F 18 style. B. A. Miller (Martin Baker Aircraft Co., Ltd., Higher Denham, Middx., England). SAFE Journal, vol. 11, Summer 1981, p. 12-15. The need for good limb restraint is important whenever a high performance aircraft is likely to operate at lower altitudes exposing the pilot to the possibility of ejection at high indicated airspeeds. A review of various past restraint system designs is presented first; a detailed description of the current restraint systems applied to the Martin Baker SJU-5/A seat of the F-18 Hornet is then given. The review concentrates on the U.S. Navy torso harness and the combined harness, which provides advantages over the former in areas of single point donning and release, cost, attrition and comfort; leg and arm restraint systems are also discussed. It is concluded that although both the torso and leg restraint systems perform well, the arm restraint system needs some final refinement in design. The aim to incorporate restraint systems which demand little or no special actions by the pilot and which in no way hinder his normal flight operations has been realized. J.F. A81-46334 flB.199 - Compact Tornado power. F. Munger. Flight International, vol. 120. Aug. 22, 1981, p. 552-558. A development status report is presented for the RB.199 low-bypass turbofan powerplant of the Tornado fighter, of which 2,000 are scheduled for construction in a cooperative venture involving British, Italian and German manufacturers. In addition to reviewing the design features and both present and projected performance characteristics, the distribution of construction and development characteristics is described. It is believed that the basic design can reach the 20,000-lb thrust class, or 20-25% greater output than at present, through increases of airflow and hot section operating temperatures. A detailed cut-away drawing of the engine is included. O.C. A81-46340 H Soviet practice in designing and procuring military aircraft. R. D. Ward (General Dynamics Corp., Fort Worth, TX). Astronautics and Aeronautics, vol. 19, Sept. 1981. p. 24-38. A detailed historical review is presented of the changing organization of military aircraft design, development and production in the Soviet Union since the end of the Second World War. Attention is given the policy-making hierarchy of such ministries as Defense and Aircraft Production, and the distribution of responsibil- ities among the research institutes comprising the Ministry of Aircraft Production: (1) the Central Aero-Hydrodynamics Institute; (2) the Scientific Research Institute for Aircraft Equipment; (3) the All-Union Institute of Aviation Materials; (4) the Flight Research (Test) Institute; (5) the Scientific Research Institute for Aviation Technology and Organization of Production; (6) the Central Institute of Aviation Motor Building; and (7) the Central Design Office, which directs the eight experimental-design bureaus engaged in detail design and construction of prototype aircraft. Extensive differences be- tween fighter and bomber aircraft design methods are noted. O.C. A81-46345 Creep properties of single-crystal nickel-based superalloys. II - Creep at medium temperature 7760 C/ (Proprietes en fluage de monocristaux de superalliages a base de nickel. II - Fluage a moyenne temperature /760 C/). C. Carry (Lausanne, Ecole Polytech- nique Federale, Lausanne, Switzerland), C. Houis, and J. L. Strudel (Paris, Ecole Nationale Superieure des Mines, Evry, Essonne, France). Memoires et Etudes Scientifiques de la Revue de Metallurgie, vol. 78, July-Aug. 1981, p. 337-343. 12 refs. In French. Research supported by the Ministere des Armees and Ministere de ('Industrie et de la Recherche. A comparison is presented of the finely dentritic worked structures and those completely free of dendrites in MAR-M 200 single crystals under creep conditions at 760 C and under heavy loads (700 MPa). Each sample was subjected to two types of heat treatment (1350 C for one hour followed by 870 C for 64 hr; and 1350 C for one hr, followed by 760 C for 24 hr) prior to the occurrence of creep. It is shown that in the homogeneous structures total resolution of the gamma phase is possible in MAR-M 200 by treatment at 1350 C for one hour. Results can be applied to the study of aircraft gas turbines. K.S. A81-46352* Aircraft noise control in the 1980's. H. H. Hubbard and H. G. Morgan (NASA, Langley Research Center, Acoustics and Noise Reduction Div., Hampton, VA). In: Inter-noise 80: Noise control for the 80's; Proceedings of the Ninth Internation- al Conference on Noise Control Engineering, Miami, FL. December 8-10, 1980. Volume 1. Poughkeepsie, NY, Noise Control Foundation, 1980, p. 33-62. 35 refs. It is pointed out that a need exists for the orderly development of technology and engineering methods for noise control of all types of aircraft. The nature and scope of aircraft noise problems are reviewed, and a description is provided of noise control progress made to date. The most serious aircraft noise problems confronting communities in the past two decades have been associated with the subsonic air carrier jet transport. Operational trends related to traffic growth and operational constraints are examined, and noise level trends are considered, taking into account engine cycle develop- ments, the role of Federal noise certification, future noise exposures, and multiple noise sources. Advanced source noise reduction technology developments are discussed along with a noise impact assessment, and advanced operating procedures. Attention is also given to engine noise and sonic boom exposures in connection with supersonic air carrier aircraft, and exterior and interior noise control related to propeller/rotor aircraft. G.R. A81-46353 EPA proposed national strategy for further reduction of aviation noise. R. J. Koenig (U.S. Environmental Protection Agency, Washington, DC). In: Inter-noise 80: Noise 567 A81-46354 control for the 80's; Proceedings of the Ninth International Conference on Noise Control Engineering, Miami, FL, December 8-10, 1980. Volume 1. Poughkeepsie, NY, Noise Control Foundation, 1980, p. 123-126. Based on actions taken to date, in the year 2000 there would still be approximately 2.5-million people living in areas exposed to average outdoor noise levels, from aviation operations, of 65 dB or above. The EPA proposes a national strategy for dealing with these remaining cases of high noise exposure from aviation. To be fully successful this proposed strategy must receive the support and active involvement of the FAA, the aircraft manufacturers, the airlines, the pilots, the airports, elected officials, and airport neighbors. The strategy is focused on providing relief to airport neighborhoods as soon as possible but not later than the year 2000. Since the nature of the aircraft fleet is to a large extent already determined by actions previously taken, the strategy for this period is targeted on operation changes and compatible land-use actions. Attention is given to the optimization of aircraft flight procedures, airport noise abatement planning, off-airport land-use management, soundproofing, and relocation. G.R. A81-46354 Integrated noise model - The Federal Aviation Administration's computer program for predicting noise exposure around an airport. T. L. Connor (FAA, Office of Environment and Energy, Washington, DC). In: Inter-noise 80: Noise control for the 80's; Proceedings of the Ninth International Conference on Noise Control Engineering, Miami, FL, December 8-10, 1980. Volume 1. Poughkeepsie, NY, Noise Control Foundation, 1980. p. 127-130. The FAA believes that the method to be used for flexible and effective noise planning should suitably employ a computer-based mathematical model for producing standardized noise maps and predicting noise impacts. The continuing development of the Integrated Noise Model (INM) ensures that the goal of a standard airport noise planning tool is achievable. The INM determines the total impact of aircraft noise at or around airports. This impact can be given in terms of contours of equal noise exposure for a number of different noise measures. The INM is not only a set of computer programs, but an entire system of activites designed to promote and support the use of the airport noise analysis tool. The INM Development Program is the mechanism by which these activities are coordinated. The progress made with respect to each element of the INM Development Program is discussed. G.R. A81-46355 Airport noise control in the 1980s - FAA's plans and policies. J. E. Wesler (FAA, Washington, DC). In: Inter-noise 80: Noise control for the 80's; Proceedings of the Ninth International Conference on Noise Control Engineering, Miami, FL, December 8-10, 1980. Volume 1. Poughkeepsie, NY, Noise Control Foundation, 1980, p. 131-134. 9 refs. It is pointed out that aviation noise will remain a serious problem during the next decade. The steps taken by the FAA to control and reduce aircraft noise are briefly considered. It has been possible to reduce aircraft noise in connection with the design of new aircraft. Advisory procedures have been issued for noise abatement departure procedures. However, all actions taken together will not eliminate aircraft noise. A further reduction of noise emission at the source would require new technological developments, and is consequently at least some years away. For these reasons, the burden of airport noise control in the 1980s is going to fall on airport operators and local governments. In its Aviation Noise Abatement Policy statement, the Federal government stated the basic concept that aviation noise abatement is a shared responsibility among all elements of the aviation industry. Airport operators are primarily responsible for local actions to reduce the effects of noise on residents surrounding their airports. G.R. A81-46356 Remaining problems in the prediction, mea- surement, evaluation, and control of aircraft noise. N. Shapiro (Lockheed-California Co., Burbank, CA). In: Inter-noise 80: Noise control for the 80's; Proceedings of the Ninth International Conference on Noise Control Engineering, Miami, FL, December 8-10, 1980. Volume 1. Poughkeepsie, NY, Noise Control Foundation, 1980, p. 337-340. 8 refs. In 1972 the Society of Automotive Engineers published a list of aircraft noise problem areas needing investigation. Looking through that list now, it can be seen that some significant advances have been made, but there is little, if anything, that can actually be deleted. The renewed interest in energy-efficient propeller-powered aircraft, using the recently developed prop-fans, has revived propeller noise research. Of particular concern are the forward flight effects on far-field noise and the near-field noise characteristics of supersonic tip speed propellers. Control of fuselage transmission of the relatively low frequency propeller noise again needs attention. The noise sources of a jet engine are considered, taking into account the jet exhaust noise, particularly that from the coannular flow of a turbofan engine. Attention is also given to the desirability of a better understanding of 'flight effects', noise propagation, acoustic measure- ments, and an evaluation of noise impact. G.R. A81-46357 Investigation of the physical working environ- ment for cabin attendants within Scandinavian Airlines System /SAS/. U. Sundback and B. Tingvall (Lulea, Hogskola, Lulea, Sweden). In: Inter-noise 80: Noise control for the 80's; Proceedings of the Ninth International Conference on Noise Control Engineering, Miami, FL, December 8-10, 1980. Volume 1. Poughkeepsie, NY, Noise Control Foundation, 1980, p. 341-344. The considered investigation was conducted on board a number of aircraft during regular flights. The investigation was mainly concerned with noise conditions and the vibrations to which the entire body of a cabin attendant had been subjected. The types of aircraft studied included the Douglas 8, Douglas 9, Douglas 10, and Boeing 747. The noise was recorded with the aid of tape recorders at various locations in the cabin, taking into account different phases of the flight. Four cabin attendants were carrying noise dose meters during their entire working period in order to record the amount of noise they are exposed to. The vibration levels were found to be very low. In most cases the levels are below the reference curves for 'fatigue decreased proficiency' except for measurements conducted on a DC 8 at a jump seat at the back galley. G.R. A81-46363 Model for airport noise exposure on a national basis • 1960 to 2000. K. M. Eldred (Bolt Beranek and Newman, Inc., Cambridge, MA). In: Inter-noise 80: Noise control for the 80's; Proceedings of the Ninth International Conference on Noise Control Engineering, Miami, FL, December 8-10, 1980. Volume 2. Poughkeepsie, NY, Noise Control Foundation, 1980, p. 803-808. 11 refs. The effective perceived noise level and noise exposure forecast descriptors are used to calculate cumulative noise levels, which utilize perceived noise level frequency weighting and A-frequency weight- ing, respectively. The contour noise levels, sizes, shapes and populations encompassed for a specific airport depend on seven factors, including noise vs distance and number of operations by aircraft type, stage lengths, flight procedures, and spatial distribution of population. A simplified method for noise control analysis is discussed, based on two subsets of the seven factors, airport noise characteristics, and airport noise impact potential. The simplified method is also applied to estimate national impact with change in fleet mix and operations between 1975 and 2000. It is found that a long term solution for the impact of airport noise requires minimizing both the airport noise impact potential and airport noise characteristic levels. D.L.G. A81-46364 Plans for control of the noise exposure pro- duced by military aircraft in the 1980's - Aircraft noise. G. D. Vest (USAF, Environmental Div., Washington, DC). In: Inter-noise 80: Noise control for the 80's; Proceedings of the Ninth International Conference on Noise Control Engineering, Miami, FL, December 8-10, 1980. Volume 2. Poughkeepsie, NY, Noise Control Foundation, 1980. p. 809-812. 15 refs. Controlling noise exposure due to military aircraft in the 1980s is discussed, recognizing that combat performance and training requirements impose severe limitations on airborne noise source reduction alternatives. The DOD policy regarding aircraft noise is given, and several improvements with the latest generation of combat aircraft are presented, including the A-10, F-15 and F-16. Primary emphasis is on cooperative land use planning, formulized as the Air Installation Compatible Use Zone program, which contains a study of accident potential zone maps, noise and land use zone maps, and 568 A81-46372 flight track maps. The program to date has been successful, producing positive actions by other agencies, and adopting a balanced program focusing on the noise source, path and receiver. D.L.G. A81-46366 Noise control at general aviation airports. W. J. Critchfield and C. E. Nay (Torrance Municipal Airport, Torrance, CA). In: Inter-noise 80: Noise control for the 80's; Proceedings of the Ninth International Conference on Noise Control Engineering, Miami, FL, December 8-10, 1980. Volume 2. Poughkeepsie, NY, Noise Control Foundation, 1980, p. 827-830. Noise control at general aviation airports is illustrated by a program at the Torrance, CA Municipal Airport. Although in existence for 24 years, the plan became effective within the last four years at a cost of 3750,000. Effectiveness is based on the degree of political, economical, and professional commitments. Designing the noise abatement program is discussed, with emphasis on community cooperation and pilot education, and flight patterns are redefined, rather than limiting frequency of operations. Good results are produced, and include reduced noise in surrounding residential areas, and increased financial feasibility and operational capability. D.L.G. A81-46367 Airport noise contour predictions - Improving their accuracy. W. J. Galloway (Bolt Beranek and Newman, Inc., Canoga Park, CA). In: Inter-noise 80: Noise control for the 80's; Proceedings of the Ninth International Conference on Noise Control Engineering, Miami, FL, December 8-10, 1980. Volume 2. Poughkeepsie, NY, Noise Control Foundation, 1980, p. 835-838. A working group of SAE Committee A-21, Aircraft Noise, was formed to propose standards to derive data for use in airport noise computations and to specify algorithms to perform the computa- tions. An A-weighted sound exposure level is specified as the recommended measure for the noise from a single flyover, based on data obtained from airport monitoring equipment. The procedure is designed to reduce the levels at 10,000 feet, for example, by 4 dB relative to other procedures. Ground-to-ground and low angle propagations are also discussed, and flight path prediction obtained by observing a series of flight operations on radar, are found essential to predictions of accurate noise contours. It is concluded that good definitions of noise data and aircraft operating conditions provide substantial improvement in noise contour accuracy, although further attention is needed on predictions of start, take-off roll, and acceleration on the runway. D.L.G. A81-46368 Airbase induced community noise - Facilitat- ing the military/civil interface. R. E. Greene (Orange County, Environmental Management Agency, Santa Ana, CA). In: Inter-noise 80: Noise control for the 80's; Proceedings of the Ninth Internation- al Conference on Noise Control Engineering, Miami, FL, December 8-10, 1980. Volume 2. . Poughkeepsie, NY, Noise Control Foundation, 1980, p. 839-842. Noise/land-use compatibility planning is discussed to minimize airbase operational constraints and maximize development of noise compatible land use in the vicinity of bases. The military role is presented with emphasis on the Air Installation Compatible Use Zone (AICUZ) program and AICUZ officers approach of community leaders. The civil government role is also presented, and a military/ civil partnership is recommended to implement a noise control/noise compatible land use strategy. The program existing at Orange County, CA, is used to illustrate the implementation phase, where single event mitigation criteria is considered a partial solution to the problem of high variability of source noise emission from military jet aircraft. D.L.G. A81-46369 Optimizing complex runway use programs for airport noise abatement. R. L. Miller (Bolt Beranek and Newman, Inc.. Cambridge. MA). In: Inter-noise 80: Noise control for the 80's; Proceedings of the Nmth International Conference on Noise Control Engineering, Miami, FL, OecembeT~8-10. 1980. Volume 2. Poughkeepsie, NY. Noise Control Foundation. 1980, p. 843-846. Airport noise abatement at Logan International Airport in Boston is investigated to optimize a runway use program. A single priority system is found to often cause overutilization of a runway. and the noise exposed population is presented as a function of runway utilization to help establish priorities for alternate impact criteria. A definition of impact is made, based on health and welfare effects on complaint data or on political expedience, which is quantifiable in terms of exposure levels. Other factors influencing the set of optimum utilization are also presented, such as wind and weather constraints on runways. Minimum and maximum utilizations are established for Logan Airport, and a compromise is made which minimizes the number of residents in areas where the L(dn) exceeds 70 and 75 dB. but does not increase the high exposure levels for any group of residents. D.L.G. A81-46370 Aircraft noise and land use compatibility tradeoff, analyses. D. E. Bishop (Bolt Beranek and Newman, Inc., Canoga Park, CA). In: Inter-noise 80: Noise control for the 80's; Proceedings of the Ninth International Conference on Noise Control Engineering, Miami, FL, December 8-10, 1980. Volume 2. Poughkeepsie, NY, Noise Control Foundation, 1980, p. 847-850. Generalizations which extend the usefulness of basic airport noise exposure contour computations are investigated to plan studies that may be obtained from a limited set of noise contours. The basic relationship between day/night level (DNL), aircraft noise levels, and number of events is used in the analysis in addition to the noisemap airport noise modeling program. Different components of the aircraft fleet are layered in preparing the program input, and the contour areas are calculated. Examples are given which show the DNL contour areas for all airport operations, air carrier jets only, and business jets only. Two trends are demonstrated and the figures allow airport goals to be set in quantitative terms of targeted incompatible land use conversion, changes in noise exposure, and levels of air carrier passenger capacity. D.L.G. A81-46371 Optimization of takeoff flight paths with respect to FAR Part 36 noise using dynamic programming. A. P. Hays (Lockheed-California Co., Burbank, CA). In: Inter-noise 80: Noise control for the 80's; Proceedings of the Ninth International Conference on Noise Control Engineering, Miami, FL, December 8-10, 1980. Volume 2. Poughkeepsie, NY, Noise Control Foundation, 1980, p. 851J554. A method of scheduling the thrust and speed of a second generation supersonic transport (SST) to minimize takeoff noise on the ground is presented. Dynamic programming is selected as the optimization method, which is used for trajectory optimization and noise minimization. The number of decision-making stages is set to three, and sideline noise remains reasonably constant due to reduced ground attenuation on the sideline noise. The value of minimum traded noise is found from three computer runs, and the optimal control is selected based on minimum cumulative noise energy at the flyover noise microphone. The program can quickly evaluate changes of the aerodynamic propulsion or acoustic characteristics of an SST, and can be modified to determine optimal trajectories for different noise receiver distributions. D.L.G. A81 -46372 Airport Noise Control and Land Use Compati- bility Studies - A U.S. case. S. Romanoff (Landrum and Brown, Inc., Cincinnati, OH). In: Inter-noise 80: Noise control for the 80's; Proceedings of the Ninth International Conference on Noise Control Engineering, Miami, FL, December 8-10, 1980. Volume 2. Poughkeepsie, NY, Noise Control Foundation, 1980, p. 855-858. The Airport Noise Control and Land Use Compatibility (ANCLUC) Study, which provides a framework for the consideration of costs and benefits from various noise control strategies is investigated. The ANCLUC Study effort has five phases including noise analysis, identification of community land use/noise conflicts and options for mitigating noise impacts, formulizing recommended noise control and land use plans, and implementation. Each phase is discussed, presenting techniques to minimize airport noise/land use conflicts, maximize economic feasibility, and develop land use patterns for areas experiencing significant noise impacts. It is concluded that a comprehensive examination of social, economic and environmental costs and benefits is necessary for the co-existence of airports and surrounding communities. D.L.G. 569 A81-46373 A81-46373 A long range research programme of noise abatement at the airport of Beograd and its practical results. D. L. Zoric (Beograd, Univerzitet, Belgrade, Yugoslavia), M. R. Vuckovic (Jugoslovenski Aerotransport, Belgrade, Yugoslavia), and D. R. Lukic (Yugoslav Federal Government, Aviation Service, Belgrade, Yugosla- via). In: Inter-noise 80: Noise control for the 80"s; Proceedings of the Ninth International Conference on Noise Control Engineering, Miami, FL, December 8-10, 1980. Volume 2. Poughkeepsie, NY, Noise Control Foundation, 1980, p. 859-862. 6 refs. A brief review is presented of previous and current research on aircraft noise abatement in the Belgrade suburbs. Attention is given to a comparative analysis of data obtained in 1975 (which determined the existing noise level and the exposure of the inhabitants to the aircraft noise), a 1978 verification of the first results, and noise exposure forecasts for 1985 and 1990. Future plans include the construction of an additional runway. K.S. A81-46374 * A program to support the full utilization of data from existing social surveys of environmental noise. J. M. Fields (NASA, Langley Research Center, Hampton, VA). In: Inter-noise 80: Noise control for the 80's; Proceedings of the Ninth International Conference on Noise Control Engineering, Miami, FL, December 8-10, 1980. Volume 2. Poughkeepsie, NY, Noise Control Foundation, 1980, p. 937-940. 21 refs. A brief review is presented of a three-part project (partially supported by NASA), which promotes greater utilization of social survey data for gaining new information about human response to environmental noise. The goal is accomplished by (1) publishing a catalog of existing social surveys on environmental noise, (2) establishing a data archive for noise survey data sets, and (3) reanalyzing selected surveys to address substantial and methodologi- cal issues. A finding about annoyance scales illustrates the use of a comparative analysis. K.S. A81 -46375 Noise reduction test facilities at Douglas Air- craft. E. L. Zwieback (Douglas Aircraft Co., Long Beach, CAI. In: Inter-noise 80: Noise control for the 80's; Proceedings of the Ninth International Conference on Noise Control Engineering, Miami, FL, December 8-10, 1980. Volume 2. Poughkeepsie, NY, Noise Control Foundation, 1980, p. 1093-1096. A brief review is presented of several aircraft noise reduction test facilities, ranging from units used for evaluating the basic acoustic characteristics of materials to a large array of field instruments used to determine aircraft flyover noise characteristics. The facilities described include an anechoic acoustic test facility, acoustic test laboratory facilities, an engine noise test facility, and an acoustics/vibration data center. Future trends are indicated. K.S. A81-46376 Aircraft noise identification system - Applica- tion for inflight position detector. F. Sasaki (Japan Broadcasting Corp., Technical Research Laboratories, Tokyo, Japan), S. Furu- kawa, M. Okuda, I. Ono, N. Hayashi (Rion Co., Ltd., Kokubunji, Tokyo, Japan), and G. Nishinomiya. In: Inter-noise 80: Noise control for the 80's; Proceedings of the Ninth International Conference on Noise Control Engineering, Miami, FL, December 8-10, 1980. Volume 2. Poughkeepsie, NY, Noise Control Foundation, 1980, p. 1121-1124. An aircraft noise identification system is presented, in which two microphones are used to receive the sound emitted by aircraft. The angle of elevation recorded by the microphones is calculated from the change in the correlation coefficient pattern. Measurements are made by positioning the microphone installations on each side of the aircraft wake. The method, though inferior to radar in precision, can be used to make measurements under a variety of weather conditions and is therefore well suited for flight position (projected altitude and position on the earth) observations. The construction of the in-flight position detector and an example of the graphic recording display are given. J.F. A81 -46377 The impact and future direction of aircraft noise certification. M. J. T. Smith (Rolls-Royce, Ltd., Derby, England). In: Inter-noise 80: Noise control for the 80's; Proceedings of the Ninth International Conference on Noise Control Engineering, Miami, FL, December 8-10, 1980. Volume 2. Poughkeepsie, NY, Noise Control Foundation, 1980, p. 1187-1190. Positive aircraft noise control at the airport vs noise certification is considered, and the need for an adaptation of the latter to the needs of the future is stressed. The difference between airport control and certification control is discussed, methodology being the prime factor. Certification relies on limiting noise levels in fixed locations around an ideal aircraft flight profile, whereas airport control is based on a definition of the constant noise level contour, or the 'footprint'. The 'footprint' concept and the current certifica- tion methodology are compared. K.S. A81-46448 Determination of coking rate in jet fuel. A. Vranos, P. J. Marteney, and B. A. Knight (United Technologies Research Center, East Hartford, CT). Combustion Science and Technology, vol. 26, Aug. 1981, p. 171-175. Measurement of coking rate under isothermal conditions has been conducted for a variety of test conditions. Variables included time, fuel flow rate, tube diameter, and surface roughness. Coking rate increases with temperature and Reynolds number, but is not dependent on surface roughness. Examination of deposits by infrared spectroscopy and the electron microprobe indicates that oxygen is present in' large concentrations, both singly- and doubly-bonded to carbon; in addition, nitrogen may be present in an imide structure. Transmission electron microscopy indicates the presence of agglom- erates of particles about 15 A in diameter. This suggests that insoluble particles originate within the liquid, although the low overall activation energy and the dependence of coking rate on Reynolds number suggest that oxidation of the fuel is mass-transfer- dependent and surface-catalyzed. Gas chromatographic and infrared analysis of polar fractions of stressed and unstressed fuel are virtually identical, indicating that deposit precursors exist at very low levels. (Author) A81-46478 Avionics thermal integration for the Boeing 767 airplane. R. L. Slack and A. J. P. Lloyd (Boeing Commercial Airplane Co., Renton, WA). In: Life cycle problems and environ- mental technology; Proceedings of the Twenty-sixth Annual Tech- nical Meeting, Philadelphia, PA, May 12-14, 1980. Mt. Prospect, IL, Institute of Environmental Sciences, 1980, p. 11-18. With reference to Boeing aircraft B-747 and B-767, methods used to improve avionic reliability and reduce maintenance costs by lowering component operating temperatures are discussed. Attention is given to the following cooling concepts: (1) avionic cooling air exhausted overboard after cooling avionics; (2) avionic cooling air recooled using ram air; (3) avionic cooling air recooled using air conditioning system; and (4) avionic cooling air recooled using skin heat exchanger. A prototype avionic cooling system for the B-767 which employs a skin heat exchanger is presented. V.L. A81 -46480 /! Aircraft/avionics environmental integration program. P. Hermes and J. Wafford (USAF, Aeronautical Systems Div., Wright-Patterson AFB, OH). In: Life cycle problems and environmental technology; Proceedings of the Twenty-sixth Annual Technical Meeting, Philadelphia, PA, May 12-14, 1980. Mt. Prospect, IL, Institute of Environmental Sciences, 1980, p. 23-27. Activities of USAF/Aeronautical Systems Division related to aircraft/avionics environmental integration are reviewed with em- phasis on specifications and standards being developed to assist in acquiring equipments and systems in a cost effective manner. The primary purposes of these documents are: (1) to introduce new analyses and tradeoff studies in the early development phases; (2) to provide a contractual basis for informal activities previously accom- plished by the contractors; and (3) to replace or supplement universal requirements with engineering approaches tailored to specific applications. v.L. A81 -46483 Developing test profiles for multiple mission situations. A. Dantowitz (Grumman Aerospace Corp., Bethpage, NY). In: Life cycle problems and environmental technology; Proceedings of the Twenty-sixth Annual Technical Meeting, Phila- delphia, PA, May 12-14, 1980. Mt. Prospect, IL, Institute of Environmental Sciences, 1980, p. 49-51. Contract No. N00014-77-C-0662. 570 A81 46606 A methodology is presented for establishing environmental test profiles for multimission situations. Various approaches are consid- ered, and a composite test profile approach is recommended. It is suggested that the method outlined in MIL-STD-781C for selecting vibration levels can adequately serve as a basis for determining all environmental levels. F.G.M. A81-46491 The Hornet's operational mission environ- ment. R. D. Dighton and T. P. Thomas (McDonnell Aircraft Co., St. Louis, MO). In: Life cycle problems and environmental technology; Proceedings of the Twenty-sixth Annual Technical Meeting, Phila- delphia, PA, May 12-14, 1980. Mt. Prospect, IL, Institute of Environmental Sciences, 1980, p. 113-116. Environmental testing requirements for the avionic equipment of the F/A-18 Hornet naval strike fighter in the areas of temperature, vibration, and moisture are compared with the traditional MIL-STD- 7818 requirements. The methods used to establish the Hornet's operationaT~mission environment (OME) are reviewed. The missions and flight regime of the multimission Navy and Marine strike fighter are described, and differences between the OME approach and the conventional MIL-STD-781B specifications are examined. Accelera- ted testing techniques are discussed, along with thermal testing and combined testing environments with respect to vibration and nonoperational ground environment. The expected life-cycle cost savings of OME design and testing or M major pieces ot Hornet avionic equipment is estimated to be S108 million. F.G.M. A81 -46537 Parameter estimation of an SSR amplitude comparison monopulse extractor. G. Jacovitti (Roma, Universita, Rome, Italy). Electronics Letters, vol. 17, Sept. 3, 1981, p. 632, 633. The results of an investigation concerning the monopulse receiver used by the ADSEL (selectively addressed secondary radar system) are summarized. The results characterize the bias and the variance of the error as a function of boresight angle and the mismatching of channels. It is concluded that the relative phase shift does not have a significant effect on the accuracy of measurement in practical cases,-and that estimation bias is negligible. O.C. A81 -46575 Airport catchment areas and air passenger demand. 0. E. Moore (British West Indian Airways, Ltd., Port of Spain, Trinidad and Tobago) and A. H. Soliman. ASCE, Transpor- tation Engineering Journal, vol. 107, Sept. 1981, p. 569-579. 14 refs. Research supported by the Natural Sciences and Engineering Research Council of Canada and University of Manitoba. It is sought to construct suitable econometric models to explain variations in air travel demand among several area pairs in a given year, in terms of known factors characteristic of each pair. Special attention is given to the development of suitable demand functions enabling past and present passenger trip profiles to be expressed quantitatively in terms of such variables as populations, indicators of socioeconomic activity, and measures of air service. Where applicable, use is also made of combined cross-sectional and time series information in an attempt to improve the quality of the conclusions drawn. The independent variables used in the demand function developed for air travel in the market area are population, incomes, air fares, and empirically derived community-of-interest or attractivity measures. C.R. A81-46603 American Helicopter Society, Annual Forum, 37th, New Orleans, LA, May 17-20, 1981, Proceedings. Washington, DC, American Helicopter Society, 1981. 558 p. Members, S55.; nonmembers, S80. The topics considered are related to aerodynamics, aircraft design, avionics and systems, dynamics handling qualities, manufac- turing and product assurance, propulsion, structures and materials, test and evaluation, and acoustics. Attention is given to the prediction of dynamic stall and unsteady airloads for rotor blades, the active elimination of stall conditions, an optimization theory applied to higher harmonic control of circulation controlled rotors, helicopter airflow and wake characteristics for low speed and hovering flight from rocket interference investigations, an evaluation of advanced rotorcraft configurations for emerging military applica- tions, computer aided helicopter design, fiber optic technology for data transmission in the helicopter environment, an electronic master monitor and advisory display system, the determination of in-flight helicopter loads, a unified approach to the optimal design of adaptive and gain scheduled controllers to achieve minimum helicopter rotor vibration, the nonlinear dynamic characteristics of the rotor bifilar absorber, the impact on helicopter cockpits of integrated advanced flight controls and avionics, factors influencing the selection of tooling and fabrication methods in building a composite fuselage, future challenges in helicopter flight/propulsion control integration, advanced transmission component development, and the variable stress ratio fatigue strength curve. G.R. A81-46604 # Prediction of dynamic stall and unsteady airloads for rotor blades. S. T. Gangwani (United Technologies Research Center, East Hartford, CT). In: American Helicopter Society, Annual Forum, 37th, New Orleans, LA, May 17-20, 1981, Proceedings. Washington, DC, American Helicop- ter Society, 1981, p. 1-17. 12 refs. Research sponsored by the United Technologies Corp. A detailed study of the wind tunnel test data of oscillating airfoils has led to a relatively simple formulation, involving a compact set of dynamic parameters, which accurately predicts the unsteady aerodynamic coefficients of airfoils during dynamic stall. One of the main features of the formulation is that it adequately accounts for the effects of the formation and streamwise movement of the vortex shed from the airfoil leading edge during dynamic stall. Based upon this formulation, a new method has been developed that determines the unsteady aerodynamic loading acting on rotor blades operating in stall. The effects of the azimuthal variation in aerodynamic sweep angle and Mach number are appropriately incorporated in the method. The synthesized unsteady lift and pitching moment hysteresis loops match very well with the two- dimensional test data. The results of a limited correlation study involving the application of the present method to full scale helicopter rotor blades indicate improved correlation between analytical predictions and the test data. (Author) A81-46605 = Active elimination of stall conditions. M. Kretz (Giravions Dorand Industries, Suresnes, Hauts-de-Seine, France). In: American Helicopter Society, Annual Forum, 37th, New Orleans, LA, May 17-20, 1981, Proceedings. Washington, DC, American Helicopter Society, 1981, p. 18-25. 15 refs. Procedures for an active control of stall conditions are consid- ered. It appears that an approach based on direct blade pitch variations constitutes the simplest solution with respect to the current state of the art. A description is presented of tests in which this approach was used to control pitch by feedback based on the observation of the pressure coefficient. Attention is given to 2-D tests and F-rotor tests. The feasibility of active elimination of stall conditions could be experimentally demonstrated on a 6-foot rotor. A stall barrier feedback method involving the use of two distinct analog loops was employed in the experiment. The presence of unsteady forces acting on the airfoil was detected with the aid of local pressure sensors. G.R. A81-46606 ,?' Optimization theory applied to higher har- monic control of circulation controlled rotors. J. Abramson and E. O. Rogers (U.S. Naval Material Command, David W. Taylor Ship Research and Development Center, Bethesda, MD). In: American Helicopter Society, Annual Forum, 37th, New Orleans, LA, May 17-20, 1981, Proceedings. Washington, DC, American Helicopter Society, 1981, p. 26-36. The feasibility of using numerical optimization techniques to determine control inputs to a high speed rotor system employing circulation control aerodynamics was investigated. The objective was to determine the azimuthal loading distribution (cyclic pressure waveform) which would be optimum with respect to performance parameters such as compressor power, mass flow, or peak cyclic pressure. An optimization code, COPES/CONMIN, is coupled with an empirically derived model of the rotor based on cyclic control perturbation derivatives. For specific flight conditions, solutions were obtained for optimum cyclic waveforms. These control inputs were experimentally verified, producing up to a 20 percent reduction in compressor power as compared to the standard one-per-revolution cyclic control. Influences on blade loading are presented along with investigations of blade response to higher harmonic control inputs. 571 A81-46607 The mathematical concepts and procedures used should be applicable to conventional (unblown) rotors. (Author) A81 -46607 H The aerodynamic influences of rotor blade airfoils, twist, taper and solidity on hover and forward flight performance. G. J. Bingham (U.S. Army, Research and Technology Laboratories, Hampton, VA). In: American Helicopter Society, Annual Forum, 37th, New Orleans, LA, May 17-20, 1981, Proceed- ings. Washington, DC, American Helicopter Society, 1981, p. 37-50. 12 refs. The influences of rotor blade planform, twist, and airfoils on hover and forward flight performance are reviewed. Although the design philosophy described can be considered to be general in nature, the analysis presented is related to a UH-1 type helicopter. The results show that the radial position of the initiation of taper and taper ratio can have a significant influence on the efficiency of a rotor in both hover and forward flight. The influence of these two parameters decreases as blade solidity is increased. The influence of linear twist varies with location of taper initiation and taper ratio. It is observed that the blade planform, twist, and airfoils should be considered simultaneously on the basis of the lift coefficient-Mach number requirements for a given configuration. Design considera- tions such as autorotation characteristics and aircraft maneuvers must be considered also but are not addressed herein. However, the latter can be considered within the same context as the forward flight lift coefficient-Mach number operating conditions. (Author) A81-46608 ft Helicopter airflow and wake characteristics for low speed and hovering flight from rocket interference investigations. A. J. Landgrebe, R. B. Taylor, T. A. Egolf. and J. C. Bennett (United Technologies Research Center, East Hartford, CT). In: American Helicopter Society, Annual Forum, 37th, New Orleans, LA, May 17-20, 1981, Proceedings. Washington, DC, American Helicopter Society, 1981, p. 51-65. 10 refs. The flow field induced by the rotor wake system of a helicopter can have a significant effect on the trajectory of a rocket fired from the helicopter. The shortage of information on helicopter airflow and its influence on free flight rockets is, in this connection, a current concern of the Army. The considered investigation has the objective to show that the combined use of laser velocimetry, flow visualiza- tion, and computerized wake and airflow analyses can be applied to acquire an improved understanding of the aerodynamics of low speed flight. Experimental and analytical techniques employed in a number of studies are discussed, taking into account test facilities and model, test configurations and conditions, flow visualization, laser velocime- try, wake and airflow analyses, and rotor wake characteristics. Airflow velocity characteristics are examined, and attention is given to the influence of fuselage, gross weight, ground, and flight direction on the rocket trajectory. G.R. A81-46609 ji Safety - A prime factor in the design of Aerospatiales Super-Puma AS 332. E. Lefort (Societe Nationale Industrielle Aerospatiale, Division Helicopteres, Marignane, Bouches- du-Rhone, France). In: American Helicopter Society, Annual Forum, 37.th, New Orleans, LA, May 17-20, 1981, Proceedings. Washington, DC, American Helicopter Society, 1981, p. 66-71. In designing the Super Puma it was attempted to utilize the in-flight experience made with Puma helicopters. Factors which confer a high safety level on the Super Puma are related to its engine power, the fail-safe characteristics of the composite material compo- nents of its main and tail rotors, the redundancy of almost all circuits and systems, the almost infinite life of the main transmission assemblies, and the properties of the aircraft structure, the landing gear, the floor, and the seats. The Super Puma is equipped with an engine failure detection system. The helicopter is an aircraft with an all-weather capability. Anti-icing protection characteristics include a capability to detect icing conditions by means of the weather radar located in the radome. The aircraft can continue its mission on one engine should the other engine become inoperative. G.R. A81-46610 * ff An ABC status report. A. W. Linden and A. J. Ruddell (United Technologies Corp., Sikorsky Aircraft Div., Strat- ford, CT). In: American Helicopter Society, Annual Forum, 37th, New Orleans, LA, May 17-20, 1981. Proceedings. Washington, DC, American Helicopter Society, 1981, p. 72-87. 19 refs. Army-Navy-NASA-supported research. The Advancing Blade Concept (ABC) uses two rigid counter- rotating rotors in a coaxial arrangement to provide advancing blades on both sides of the aircraft. This makes use of the high dynamic pressure on the advancing side of the rotors at high forward speed, virtually ignoring the low dynamic pressure on the retreating side, while still keeping the rotor system in roll trim. Theoretically such a rotor system will maintain its lift potential as speed increases. The XH-59A was designed to investigate this theory. A description is provided of the flight test program from May, 1980 to January, 1981. A summary is presented of the knowledge gained throughout the entire program, and current pitfalls are reviewed. It is concluded that the ABC has been verified, with the XH-59A envelope of blade lift coefficient as a function of advance ratio greatly exceeding that of conventional helicopter rotor systems. G.R. A81-46611 U An evaluation of advanced rotorcraft configu- rations for emerging military applications. R. K. Wernicke and J. N. Fischer (Bell Helicopter Textron, Fort Worth, TX). In: American Helicopter Society, Annual Forum, 37th, New Orleans, LA, May 17-20, 1981, Proceedings. Washington, DC, American Helicopter Society, 1981, p. 88-96. In the considered studies, three advanced rotorcraft designs were developed to meet the Marine assault transport mission requirements, including a pure helicopter configuration and two configurations providing cruise speeds greater than that possible with a pure helicopter. In the evaluation, the helicopter is found to be the least complex aircraft with the lowest design gross weight. It is competi- tive for short range missions. However, it has the slowest speed and is not practical for self-deployment. The compound helicopter is more complex and has the highest design gross weight. The design is compact and it can reach high dash speeds. Long range cruise speed is only slightly better than that of the helicopter. The tiltrotor aircraft productivity is the highest from relatively short ranges out to very long ranges. Its cruise fuel efficiency, altitude performance, and self-deployability are characteristics that are becoming increasingly important in today's changing international situations. G.R. A81-46612 f- Late 80's advanced rotary wing aircraft poten- tial based on ATDE, ACAP, and ITR. J. W. White (U.S. Army, Applied Technology Laboratory, Fort Eustis, VA). In: American 1 Helicopter Society, Annual Forum, 37th, New Orleans, LA, May 17-20, 1981, Proceedings. Washington, DC, American Helicopter Society, 1981, p. 97-111. 16 refs. Attention is given to the 800 Horsepower Advanced Technology Demonstrator Engine (ATDE), the Advanced Composite Airframe Program (ACAP), and the Integrated Technology Rotor (ITR) Program. The integration of these technologies into an advanced helicopter design during the late 80's offers significant improvements in military and commercial operational envelopes, productivity, and fuel economy. Two additional Army advanced development pro- grams are related to the Advanced Digital Optical Control System (ADOCS) and the Helicopter Adverse Weather Fire Control/Acquisi- tion Radar (HAWFCAR). It is found that technology currently underway or planned provides options for future 7-10,000 pound gross weight aircraft with 50 percent improvement in productivity based on fuel usage while providing significant improvements in damage tolerance and crashworthiness. Two parametric aircraft designs are presented, including a medium utility helicopter and an attack helicopter. G.R. A81-46613 ff Computer aided helicopter design. H. J. Rosenstein and K. A. Stanzione (Boeing Vertol Co., Philadelphia, PA). In: American Helicopter Society, Annual Forum, 37th, New Orleans, LA, May 17-20, 1981, Proceedings. Washington, DC, American Helicopter Society, 1981, p. 112-127. This paper describes the formulation of the HEIicopter Sizing and Performance COMputer Program (HESCOMP) which is used as an analytical tool in the preliminary design process. The program integrates aircraft configuration sizing, performance aerodynamics and weights into a multidisciplinary rotary wing design tool which is ideally suited to rapidly perform comparative configuration design studies. To illustrate the HESCOMP capabilities, the program was used in the conceptual design study of an advanced military transport for introduction in the late 1980's. The purpose of this 572 A81 -46621 study was to compare on an equal basis the size and performance of a single and tandem rotor helicopter designed for a typical long range military transport mission. When designed for equal spotting factor (minimum folded size) and compared on the basis of gross weight the tandem rotor helicopter is approximately 4% lighter. (Author) A81-46614 H Fiber optic technology for data transmission in the helicopter environment. J. C. Wyatt, F. B. Snyder, and R. R. Giri (Harris Corp., Melbourne. FL). In: American Helicopter Society, Annual Forum, 37th, New Orleans, LA, May 17-20, 1981, Proceed- ings. Washington, DC, American Helicopter Society, 1981, p. 128-142. 7 refs. An optical fiber medium offers broad bandwidth capabilities and is inherently immune to electromagnetic interference/radio frequency interference and electromagnetic pulse effect generated by both lightning and, for military applications, nuclear events. The considered investigation is concerned with the implementations of dedicated point-to-point and multiplexed data buses using both wire and optical fiber interconnects. A system architecture for a helicop- ter fly-by-light multiplex system is presented, and the reliability of various fiber-optic system configurations is discussed. It is pointed out that improvements in technology will have positive impact on fiber-optic flight control systems within future avionic platforms. Operational and evolutionary improvements in fiber-optic compo- nents are expected along with the development of optical servovalves and transducers, and a relative cost reduction in fiber-optic compo- nents. G.R. A81-46615 if Electronic Master Monitor and Advisory Dis- play System. R. V. Kurowsky (U.S. Army, Avionics Research and Development Activity, Fort Monmouth, NJI and R. C. McLane (General Electric Co., Pittsfield, MA). In: American Helicopter Society, Annual Forum, 37th, New Orleans, LA, May 17-20, 1981, Proceedings. Washington, DC, American Helicop- ter Society, 1981, p. 143-152. 12 refs. Grant No. DAAK80-79-C- 0270. An Electronic Master Monitor and Advisory Display System (EMMADS) is designed around the requirements of the CH-47 helicopter with the intent of automating the crew's monitoring of the basic aircraft subsystems. The objective of the reported investiga- tion is the feasibility demonstration of a direct view flat panel technology (electroluminescent) display controlled by digital logic with integrated, programmable operator controls. The system design goal is to relieve the crew of routine 'housekeeping' tasks. The Human Engineering Program which supported the EMMADS design is considered, taking into account an information requirements analysis, a pilot evaluation, testing, control/display design criteria, and display formats. Beginning in mid-1981, the flight test phase of EMMADS will commence with further Human Engineering activity. G.R. A81-46617 H CH-53 Helicopter Night Vision System simula- tion experiments. G. W. Mowery, R. J. Milelli (Martin Marietta Aerospace, Orlando, FL), L. B. McDonald (McDonald and Associ- ates, Inc., Orlando, FL), C. Pontelandolfo (U.S. Naval Material Command, Naval Air Development Center, Warminster, PA), and P. Noggle (U.S. Navy, Naval Air Systems Command, Washington, DC). In: American Helicopter Society, Annual Forum, 37th, New Orleans, LA, May 17-20, 1981, Proceedings. Washington, DC, American Helicopter Society, 1981, p. 163-178. A Helicopter Night Vision Program has been undertaken to improve the low altitude night operational and reduced visibility capability of the Marine assault transport helicopter force. The Helicopter Night Vision Program is challenged with defining a Helicopter Night Vision System (HNVS) capable of being retrofitted into the transport helicopter force at the lowest possible cost, and with the highest possible performance characteristics. After a comparative examination it was concluded that forward looking infrared (FLIR) devices will perform better than other electro-optical systems. Consequently a FLIR system was selected for the assault transport helicopter. The HNVS simulation experiment is discussed. It was found that pilots can maneuver under 100 feet above ground level and between 60 to 80 knots in the night assault transport mission with a panel mounted display, gimballed sensor, and Doppler navigation. G.R. A81-46618 /'' Determination of in-flight helicopter loads. N. Giansante, R. Jones (Kaman Aerospace Corp., Bloomfield, CTl.and N. J. Calapodas (U.S. Army, Applied Technology Laboratory, Fort Eustis, VA). In: American Helicopter Society, Annual Forum, 37th, New Orleans, LA, May 17-20, 1981, Proceedings. Washington, DC, American Helicopter Society. 1981, p. 179-187. Results of tests on an AH-1G helicopter show that external vibratory forces, such as those of the main and tail rotors, acting on a helicopter in flight can be determined accurately from accelerometer measurements on the fuselage only. The methodology which is called Force Determination requires accelerations measured on the airframe in flight and a calibration matrix measured during ground vibration tests. The elements of the calibration matrix are partial derivatives relating acceleration at coordinate i to force at coordinate j on the airframe. The magnitudes and phases of the external forces acting on the aircraft in flight are obtained from the flight accelerations and the calibration matrix. (Author) A81-46619 ;: A unified approach to the optimal design of adaptive and gain scheduled controllers to achieve minimum helicop- ter rotor vibration. J. A. Molusis (Connecticut, University, Storrs, .CT), C. E. Hammond (U.S. Army, Applied Technology Laboratory, Fort Eustis, VA), and J. H. Cline (U.S. Army, Structures Laboratory, Hampton, VA). In: American Helicopter Society, Annual Forum, 37th, New Orleans, LA, May 17-20, 1981, Proceedings. Washington, DC, American Helicopter Society, 1981, p. 188-203. 15 refs. Attention is given to stochastic control theory, aspects of cautious control algorithm development, the advantages of adaptive controllers, the linear quadratic Gaussian controller, the perturbation controller, a proportional-integral controller, a combination adap- tive/gain scheduled controller, aspects of controller testing, the application of adaptive control algorithms, the application of gain scheduled controllers, and vibration reduction results. Six different control laws are developed. Four of them are implemented and evaluated in the Langley Transonic Dynamics wind tunnel. The obtained results provide the means for using control design to achieve theoretically minimum rotor vibration throughout the flight envelope. G.R. A81-46620 * tt Full-scale wind-tunnel test of the aeroelastic stability of a bearingless main rotor. W. Warmbrodt, J. McCloud, III (NASA, Ames Research Center, Moffett Field, CA), M. Sheffler, and J. Staley (Boeing Vertol Co., Philadelphia, PA). In: American Helicopter Society, Annual Forum, 37th, New Orleans, LA, May 17-20, 1981, Proceedings. Washington, DC, American Helicopter Society, 1981, p. 204-216. 12 refs. The rotor studied in the wind tunnel had previously been flight tested on a BO-105 helicopter. The investigation was conducted to determine the rotor's aeroelastic stability characteristics in hover and at airspeeds up to 143 knots. These characteristics are compared with those obtained from whirl-tower and flight tests and predictions from a digital computer simulation. It was found that the rotor was stable for all conditions tested. At constant tip speed, shaft angle, and airspeed, stability increases with blade collective pitch setting. No significant change in system damping occurred that was attribut- able to frequency coalescence between the rotor inplane regressing mode and the support modes. Stability levels determined in the wind tunnel were of the same magnitude and yielded the same trends as data obtained from whirl-tower and flight tests. G.R. A81-46621 ," Helicopter trim by periodic shooting with Newton-Raphson iteration. D. A. Peters (Washington University, St. Louis, MO) and A. P. Izadpanah. In: American Helicopter Society, Annual Forum, 37th, New Orleans, LA, May 17-20, 1981, Proceed- ings. Washington, DC, American Helicopter Society, 1981, p. 217-226. 9 refs. Grants No. DAAG29-77-G-0103; No. DAAG29-80-C-0092. The problem of finding a rotor trim solution involves both a search for the correct control settings that will give a desired flight condition as well as the calculation of the periodic solution to the nonlinear rotor equations, given those controls. In the present study, a method is developed whereby the correct controls and periodic solution (i.e., the correct blade initial conditions to yield periodicity) are found simultaneously. The use of initial conditions as unknown variables to obtain periodicity is not new and has been called 573 A81-46622 'periodic shooting'. The simultaneous solution of the controls and initial conditions, however, is an innovation developed here. Analysis shows that the new method is computationally superior to other methods in many practical applications. Numerical implementation on nonlinear flap-lag equations verifies the usefulness of the method even under extreme conditions such as instability, resonance, and high advance ratio. A detailed study of the convergence shows that the method may diverge for certain combinations of initial guesses, but that the divergence can be circumvented by simple procedures. (Author) A81-46622 ,7 Nonlinear dynamic characteristics of the rotor bifilar absorber. W.-L. Miao and T. Mouzakis (United Technologies Corp., Sikorsky Aircraft Div., Stratford, CT). In: American Heli- copter Society, Annual Forum, 37th, New Orleans, LA, May 17-20, 1981, Proceedings. Washington, DC, American Helicopter Society, 1981, p. 227-236. Army-supported research. A coupled rotor/bifilar/airframe analysis has been developed under contract to the U.S. Army Structures Lab (AVRADCOM). This analysis has been used to study the dynamic characteristics of the centrifugally tuned, rotor-hub-mounted, bifilar vibration absorb- er. The performance of the bifilar absorber is shown to be a function of its basic design parameters: dynamic mass, damping and tuning. Since the absorber acts to reduce the motion of its attachment point to the main rotor hub, hub impedance is of equal importance. For the case of a bifilar absorber which reacts cyclic response (e.g., 3/rev rotating response on a four-bladed rotor), the degree of symmetry of hub impedance in the two orthogonal directions also influences absorber eftectivity. Because of manufacturing tolerances, every individual bifilar mass can be slightly different from the others in terms of its basic parameters. Results are presented which show the cause of dissimilar bifilar mass motions and the resulting non-N/rev excitation of the airframe. Flight test results for the Black Hawk helicopter which demonstrate the key results from the analysis and their correlation are also presented. (Author) A81-46623 * 8 A flight investigation of static stability, con- trol augmentation, and flight director influences on helicopter IFR handling qualities. J. V. Lebacqz, J. M. Weber (NASA, Ames Research Center, Moffett Field, CA), and L. D. Corliss (U.S. Army, Aeromechanics Laboratory. Moffett Field, CA). In: American Helicopter Society, Annual Forum, 37th, New Orleans, LA, May 17-20, 1981, Proceedings. Washington, DC, American Helicopter Society, 1981, p. 237-251. 15refs. A flight experiment was conducted using the NASA-Army V/STOLAND UH-1H variable-stability helicopter to investigate the influence of several longitudinal-static-stability, control- augmentation, and flight-director parameters on helicopter flying qualities during terminal area operations in instrument conditions. This experiment, which was part of a joint NASA/FAA program pertaining to helicopter IFR airworthiness, was designed to corrobo- rate and extend previous ground simulation results obtained in this program. Variations examined included stable and neutral longitudi- nal control position gradients, rate-damping and attitude-command augmentation, and raw data versus flight-director displays. Pilot rating results agreed excellently with the ground simulation data, indicating an adequate instrument capability with rate-damping augmentation and neutral statics and the need for pitch-roll attitude augmentation to achieve a satisfactory system. (Author) A81-46624 H The impact on helicopter cockpits of integrat- ed advanced flight controls, avionics and optics. E. D. Diamond and J. R. Maciolek (United Technologies Corp., Sikorsky Aircraft Div., Stratford, CT). In: American Helicopter Society, Annual Forum, 37th, New Orleans, LA, May 17-20, 1981, Proceedings. Washington, DC, American Helicopter Society, 1981, p. 252-262. It appears that existing cockpits will be inadequate for perfor- mance of anticipated future helicopter missions. Further prolifera- tion of discrete mission related equipment in the cockpit will not solve the problem. A new approach is, therefore, required. Pilot productivity has to be increased by controlling workload and reducing fatigue for a given mission. Pilot productivity, in this connection, means that the pilot can perform the anticipated ing and .inspection principles witn an examination of the main advantages obtained. The development methodology for composite material components is discussed, with attention given to the theoretical forecast, dimensioning criteria, fabrication methods, quality control, and certification. C.R. A81-46725 Survivors on the RPV front. D. Chopping. Interavia, vol. 36, Sept. 1981, p. 898, 899. A review is made of current remotely piloted vehicle (RPV) system development programs. Among.the aircraft discussed are: (1) the CL-289, which is intended to replace the existing CL-89 battlefield surveillance system while meeting the needs of an army corps, rather than only a division; (2) the CL-227 short-range RPV, for brigade use; (3) the Mirach 100, which may be launched either from ground vehicles or helicopters; (4) the IAI Scout, which has already been proven in combat in the middle east; (5) the Argus, a tethered rotary-wing surveillance platform; (6) the MTC II, a mini-helicopter employing two contra-rotating, three-bladed rotors; and (7) the Aquila, which incorporates such advanced 'stealth' technology features as a shrouded rotor, Kevlar/plastic composite construction and blended wing/body planform. O.C. A81 -46626 * A preliminary flight investigation of cross- coupling and lateral damping for nap-of-the-earth helicopter opera- tions. L. D. Corliss and G. D. Carico (U.S. Army, Aeromechanics Laboratory, Moffett Field, CA). In: American Helicopter Society, Annual Forum, 37th, New Orleans, LA, May 17-20, 1981, Proceed- ings. Washington, DC, American Helicopter Society, 1981, p. 276-287. 9 refs. A helicopter in-flight simulation was conducted to look at the effects of variations in roll damping, roll sensitivity, and pitch and roll rate cross-coupling on helicopter flying qualities for NOE operations. The experiment utilized the Ames UH-1H helicopter in-flight simulator, which is equipped with the V/STOLAND avionics system. The response envelope of this vehicle allowed for the simulation of configurations in the low-to-moderate damping and sensitivity range. A visual, low-level slalom course was set up, using the 1000-ft markers of an 8000-ft runway to evaluate the various configurations. Test results are shown in terms of Cooper-Harper pilot ratings. These results show good consistency with previous ground simulator results and with some elements of flying qualities criteria, such as those of MIL-F-83300 and MIL-H-8501A. (Author) A81-46627 •? Handling qualities of the SH-60B Seahawk. I. Alansky, R. Faull, and J. Skonieczny (United Technologies Corp., Sikorsky Aircraft Div., Stratford, CT). In: American Helicopter Society, Annual Forum, 37th, New Orleans, LA, May 17-20, 1981, Proceedings. Washington, DC, American Helicop- ter Society, 1981, p. 288-306. A review is provided of the flying qualities, the automatic flight control system, and the developmental testing of the U.S. Navy's most advanced helicopter. Primary mission of the SH-60B Seahawk are related to anti-submarine warfare and anti-ship surveillance and targeting. Its secondary missions include search and rescue, commu- nications relay, medical evaluation, and vertical replenishment. The operational considerations for the SH-60B helicopter require that these missions be performed from nonaviation type ships in conditions reaching upper sea-state 5. An examination is conducted of the primary differences between the Seahawk and the UH-60A Black Hawk. The differences result primarily from the Light Airborne Multi-Purpose Systems (LAMPS) MK III mission require- ments. Handling qualities design considerations are discussed, taking into account the aerodynamic effects of mission equipment, a SH-60B simulation math model, control requirements, static stability characteristics, shipboard landings, and hydrodynamic stability con- siderations. G.R. A81-46628 ri Factors influencing the selection of tooling and fabrication methods in building a composite fuselage. J. J. Barto, Jr. (United Technologies Corp., Sikorsky Aircraft Div., Stratford, CT). In: American Helicopter Society, Annual Forum, 37th, New Orleans, LA, May 17-20, 1981, Proceedings. Washington, DC, American Helicopter Society, 1981., p. 307-315. Grant No. DAAK51-80-C-0001. A description is presented of the development and fabrication methods selected in the construction of large advanced composite laminating molds for helicopter fuselage structures, taking into 574 A81-46639 account investigations related to the conversion of the rear fuselage of the UH-60A Black Hawk helicopter to composite construction. Fabrication of the rear fuselage is highly labor intensive and amenable to cost reduction by conversion to molded composite construction. The composite structure is anticipated to be 10% lighter and 35% lower in unit cost than current metal counterparts. Design to cost producibility studies, and risk reduction trials have been conducted. These investigations have provided tooling and manufacturing concepts for cost effective processes and economical tooling. G.R. weight advantages, is high contact ratio gearing. Since the means taken to obtain a high contact ratio tend to produce an inherently weaker tooth, it is noted that reliance must be placed on the multiple load-sharing feature of this design to achieve an advantage over low contact ratio gears. The considerations which must be addressed in the design stage to achieve optimum results are discussed. Two UH-60A helicopter main transmission housings fabricated from a stainless steel alloy (to replace the conventional magnesium alloy casing) are described. Design details and fabrication methods are discussed. C.R. A81-46629 I: Manufacturing methods for a composite main rotor blade for the YAH-64 helicopter. R. L. Kiraly (Hughes Helicopters, Inc., Culver City, CA) and J. Tutka (U.S. Army Aviation Research and Development Command, St. Louis. MO). In: American Helicopter Society, Annual Forum, 37th, New Orleans, LA, May 17-20, 1981, Proceedings. Washington, DC, American Helicopter Society, 1981, p. 316-321. This paper describes the manufacturing methods utilized in the fabrication technique associated with the wet filament winding (WFW) cocure process for the Advanced Attack Helicopter YAH-64 composite main rotor-blade. This new technology method is a result of the experience gained with the development of multitubular spar main rotor blades for the AH-1G aircraft and NASA wind tunnel test blades. The WFW cocure process eliminates a major portion of the hand labor encountered with conventional wet lay-up composite structures by substituting machine assembly techniques, thereby making its assembly simpler without sacrificing structural integrity. (Author) A81-46632 # Waterjet trimming of cured composites. S. E. Kosturak (United Technologies Corp., Sikorsky Aircraft Div., Strat- ford, CT). In: American Helicopter Society, Annual Forum, 37th, New Orleans, LA, May 17-20, 1981, Proceedings. Washington, DC, American Helicopter Society, 1981, p. 332-343. In the case of Kevlar/epoxy, a composite material widely used in aircraft structures, experience has shown that conventional machin- ing methods do not produce acceptable results. The edges of the Kevlar are left in a fuzzy condition and require hand sanding. The sanding is labor consuming, costly, and produces critical dust problems. To eliminate cutting associated problems, an investigation was conducted concerning the employment of a high pressure waterjet cutting system for trimming cured Kevlar composites. The process does not create dust hazards and it minimizes the need for expensive exhaust systems. In addition, waterjet cutting offers the potential of significantly -increased cutting rates, enhanced edge quality, and low noise levels. The introduction of waterjet cutting made it possible to reduce the trimming man-hours per piece by 75%. G.R. A81-46633 i: Future challenges in helicopter flight/propul- sion control integration. L. D. Emerson, Jr. (United Technologies Corp., Pratt and Whitney Aircraft Div., West Palm Beach, FL). In: American Helicopter Society, Annual Forum, 37th, New Orleans, LA, May 17-20, 1981, Proceedings. Washington, DC, American Helicopter Society, 1981, p. 344-348. It is noted that digital electronic systems have reached adequate maturity to allow their use for critical flight control functions, including propulsion control. It is thought that helicopter operation- al suitability and mission reliability can be improved through proper integration of electronic systems. The challenge posed by an advanced helicopter flight and propulsion control system is dis- cussed, as is an approach to developing the technology needed to assure maximum flight safety and operational effectiveness with a reasonable ownership cost. C.R. A81-46634 H Advanced transmission component develop- ment. K. M. Rosen and H. K. Print (United Technologies Corp., Sikorsky Aircraft Div., Stratford, CT). In: American Helicopter Society, Annual Forum, 37th, New Orleans, LA, May 17-20, 1981, Proceedings. Washington, DC, American Helicop- ter Society, 1981, p. 349-364. 8 refs. Gearbox design concepts are discussed that permit high tempera- ture operation at increased speeds without degrading strength or weight goals. One approach, which shows promising strength and A81-46636 ~ HH-65A Dolphin engine condition monitoring system. K. K. Ehlers (Aerospatiale Helicopter Corp., Grand Prairie^ TX). In: American Helicopter Society, Annual Forum, 37th, New Orleans, LA, May 17-20, 1981, Proceedings. Washington, DC, American Helicopter Society, 1981, p. 386-394. The approach to engine condition monitoring incorporated into the Coast Guard's HH-65A Dolphin Short Range Recovery helicopter is discussed. It is noted that this approach requires no dedicated hardware for the Engine Condition Monitoring System (ECMS) but uses hardware which is required for other functions. The five major aircraft subsystems that contribute to the ECMS are described. These are the Sensors, the Mission Computer Unit (MCU), the Control Display Unit (CDU), a caution advisory CDU annunciator, and the Flight Data Storage Unit (FDSU). It is noted that engine data are already available in digital form from the vertical scale electrical optical engine instruments. By means of the ECMS software, the MCU performs the data processing. The flight crew controls the systems using the CDUs, on which the data are displayed. C.R. A81-46637 /;' Projected power and specific fuel consumption development of the Rolls Royce Gem engine. A. R. Sanderson (Rolls-Royce, Ltd., Aero Engine Div., Watford, Herts., England). In: American Helicopter Society, Annual Forum, 37th, New Orleans, LA, May 17-20, 1981, Proceedings. Washington, DC, American Helicopter Society, 1981, p. 395-402. The basic Gem-2 engine rated at 830 SHP for take-off has been in production since 1975. The first stage of uprating, the Gem-41 in service since 1979, gives a 20 percent power increase to 1000 SHP. The paper describes the route proposed for two further steps in the power growth program to circa 1500 SHP and an efficiency improvement program aimed at a 6 percent reduction in SFC at cruise power. (Author) A81-46638 ft Designing safety into helicopter transmissions. C. Albrecht (Boeing Vertol Co., Philadelphia, PA). In: American Helicopter Society, Annual Forum, 37th, New Orleans, LA, May 17-20, 1981, Proceedings. Washington, DC, American Helicopter Society, 1981, p. 403-409. The Boeing Model 234 helicopter is a commercial derivative of the U.S. Army CH-47C helicopter. Although the Chinook has an excellent safety record, features have been incorporated in the 234 that further enhance the design and provide additional safety. Specific items discussed are the use of double-vacuum-melt steels; shotpeening of all critical components; nital etching of all machined and ground surfaces; ultrasonic inspection of the gear steel at the mill; fatigue testing and qualification procedures; overload testing of all the main drive gears and shafting; and auxiliary oil capability. (Author) A81 -46639 H Some results from a crash energy absorption test for evaluating composite fuselage construction. R. L. Foye (U.S. Army, Applied Technology Laboratory. Fort Eustis, VA) and W. T. Hodges (U.S. Army, Structures Laboratory, Hampton, VA). In: American Helicopter Society, Annual Forum, 37th, New Orleans, LA, May 17-20, 1981, Proceedings. Washington, DC. American Helicopter Society. 1981. p. 410-418. Composite cylindrical shell specimens have been crushed in compression as a means of observing and measuring their energy absorption characteristics. These tests have provided a practical basis for comparing various composite construction concepts to alumi- num. However, in full scale helicopter drop tests it can be seen that a part of the vehicle kinetic energy is absorbed in skin shear. Therefore, to compare the shear and compression behavior, a 575 A81-46641 duplicate set of cylindrical specimens were tested in torsion. These tests compared aluminum, fiberglass, Kevlar, and graphite in the form of sandwich and stiffened skin construction. The energy absorption characteristics differed between shear and compression and the results were more complex. However, some of the conclusions from the compression tests remained valid. Namely, sandwich construction absorbed more energy than stiffened skin construction. Aluminum and Kevlar/aluminum hybrid had the highest energy absorption capacity of the stiffened skin specimens. Also, Kevlar and aluminum stiffened skins had superior skin tearing resistance. (Author) A81-46641 // Development of composite material helicopter structures. M. Torres (Societe Nationale Industrielle Aerospatiale, Division Helicopteres, Marignane, Bouches-du-Rhone, France). In: American Helicopter Society, Annual Forum, 37th, New Orleans, LA, May 17-20, 1981, Proceedings. Washington, DC, American Helicopter Society, 1981, p. 427-436. 7 refs. The experience with composite materials parts in civil and military aviation is discussed in terms of manufacture, quality control, and operational use. The aircraft Dauphin 2 is discussed in analyzing such composite parts as the rotor assembly (with its Starflex hub and new generation blades), the primary structure components containing carbon, the suspension elements, and the secondary parts involving the use of Kevlar. The description of each component is followed by a presentation of the overall manufactur- ing and inspection principles with an examination of the main advantages obtained. The development methodology for composite material components is discussed, with attention given to the theoretical forecast, dimensioning criteria, fabrication methods, quality control, and certification. C.R. A81-46642 # Helicopter External Gondola System. J. D. Porterfield (Kaman Aerospace Corp., Bloomfield, CT) and S. G. Riggs, Jr. (U.S. Army, Applied Technology Laboratory, Fort Eustis, VA). In: American Helicopter Society, Annual Forum, 37th, New Orleans, LA, May 17-20, 1981, Proceedings. Washington, DC, American Helicopter Society, 1981, p. 437-447. 6 refs. The design, fabrication, static test, and flight test of the lightweight HEGS-20 module, the newest member of the Army's Helicopter External Gondola System (HEGS), is described. A structural efficiency (structural strength to weight ratio) of 40:1 was made possible through innovative structural concepts and by the use of flexible, high-strength, Kevlar diagonal cables. (Author) A81-46643 ft An economical approach to automated flight test data reduction. S. A. Walters (Aerospatiale Helicopter Corp., Grand Prairie, TX). In: American Helicopter Society, Annual Forum, 37th, New Orleans, LA, May 17-20, 1981, Proceedings. Washington, DC, American Helicopter Society, 1981, p. 448-455. In connection with the introduction of mini- and microcomput- ers, it is how economically feasible to acquire a complete computer system, tailored specifically to flight test requirements, to support a single flight test program. The described system offers a number of advantages over the traditional large system approach. First, the flight test department has exclusive use of the system. Second, the system is easily expanded in the event of increased data monitoring requirements by the simple addition of processors in parallel with the current Central Processing Unit. A third advantage of the present system configuration is the ease with which it can be converted for application requiring telemetry of data to the Ground Data Center while the aircraft is in flight. The fourth, and probably biggest advantage of the new approach, is the initial cost of the system. G.R. A81-46644 * = Influence of sideslip on the kinematics of the helicopter in steady coordinated turns. R. T. N. Chen and J. A. Jeske (NASA. Ames Research Center, Moffett Field, CA). In: American Helicopter Society, Annual Forum, 37th, New Orleans, LA, May 17-20. 1981, Proceedings. Washington, DC, American Helicopter Society, 1981, p. 463-477. 16 refs. A steep coordinated helical turn at extreme angles of attack with inherent sideslip is of primary interest in this study. Unlike fixed-wing aircraft, the helicopter in a steady coordinated turn will inherently sideslip. A set of exact kinematic equations describing this motion in steady helical turns has been developed, and a rational definition for the load factor that best characterizes a coordinated turn for a helicopter has been proposed. An analysis has also been completed on the effects of sideslip on the kinematic relationships in a coordinated turn which is based on new closed-form solutions which relate the aircraft angular rates and pitch and roll attitudes to the turn parameters, angle of attack, and sideslip. The results show that the bank angle of the aircraft can differ markedly from the tilt angle of the normal load factor and that the normal load factor can also differ substantially from the accelerometer reading along the vertical body axis of the aircraft. Generally, sideslip has a strong influence on the pitch attitude and roll rate of the helicopter. The study also indicates that pitch rate is independent of angle of attack in a coordinated turn and that in the absence of sideslip, angular rates about the stability axes are independent of the aerodynamic characteristics of the aircraft. (Author) A81 -46645 :: Reliability and maintainability evaluation of rotor systems. R. A. Hall (U.S. Army, Applied Technology Laborato- ry, Fort Eustis, VA) and U. S. Garganese, Jr. (Kaman Aerospace Co., Bloomfield, CT). In: American Helicopter Society, Annual Forum, 37th, New Orleans, LA, May 17-20, 1981, Proceedings. Washington, DC, American Helicopter Society, 1981, p. 478-483. The considered study is conducted in connection with an investigation of several advanced rotor systems for helicopters performed by the Army. The study has the objective to develop an evaluation procedure and use it to evaluate eight rotor systems, taking into account the research and development parameters of main rotor systems, which may have either a positive or negative effect on the other systems of the helicopter. The parameters considered include mean time between failure, mean time between removal, maintenance man-hours per flight hour and mean time to repair. The motor systems analyzed are the elastomeric rotor, the bearingless main rotor, the Starflex rotor, the higher harmonic rotor, the circulation control rotor, the reverse velocity rotor, the advanc- ing blade concept rotor, and the Bell-412 rotor. G.R. A81-46646* H A piloted simulation of the backup control system engagement for the YAH-64. C. L. Blanken, E. W. Aiken, R. K. Merrill (U.S. Army, Aeromechanics Laboratory, Moffett Field, CA), and V. L. Ross (NASA, Ames Research Center, Moffett Reid, CA). In: American Helicopter Society, Annual Forum, 37th, New Orleans, LA, May 17-20, 1981, Proceedings. Washington, DC, American Helicopter Society, 1981. p. 484-492. A piloted simulator experiment, designed to evaluate and optimize certain backup control system (BUCS) engagement parame- ters and to provide pilot familiarization with aircraft response prior to flight test of the BUCS in the YAH-64 Advanced Attack Helicopter, is described. Key elements of the simulation were the representation of a control system jam, the pilot's breaking of a shear pin in the jammed control, and the resultant BUCS engagement. To minimize the excursions in aircraft motion which could result from the pilot's control inputs after shear pin breakage, the BUCS control function is blended in gradually. The experiment's results indicate that optimum time to full control authority after shear pin breakage is three seconds in all axes for certain critical tasks. Special pilot training in the recovery from a control system jam may be necessary to minimize unacceptably large aircraft transients in the off-axis. (Author) A81-46647 -jr Helicopter manufacturers economic impact assessment of FAA proposed helicopter certification noise rules /NPRM 79-137. R. G. Schlegel (United Technologies Corp., Sikorsky Aircraft- Div., Stratford, CT). In: American Helicopter Society, Annual Forum, 37th, New Orleans, LA, May 17-20, 1981, Proceed- ings. Washington, DC, American Helicopter Society, 1981, p. 503-514. 17 refs. The NPRM 79-13 was published July 19, 1979 in The Federal Register (Reference 3). Its three provisions are basically concerned with assuring that helicopter noise levels will not exceed the so-called Stage 2 limits. As the result of analyses conducted by the helicopter industry since early 1980, it was concluded that if the rule proceeded as originally proposed by the FAA, that the world helicopter market, which is projected to increase from around 800 million dollars in 576 A81-46847 1980 to 2.2 billion dollars in the year 2000, in 1980 dollars, would be seriously impacted. It is pointed out that valid noise measure- ments on the twenty-five helicopters that will be affected by the regulation proposed in NPRM 79-13 are not available. The proposed regulation sets limits that are too low and are incompatible with the capabilities of available technology for predicting and controlling helicopter noise. A regulation at this time is thought to be premature because uncertainty in the actual noise of many affected helicopters prevents a complete analysis of the regulation's economic impact. It is proposed to conduct a joint FAA/NASA/lndustry helicopter noise reduction research program. G.R. A81-46649 # Prediction of helicopter rotor noise from measured blade surface pressure. G. P. Succi (Bolt Beranek and Newman, Inc., Cambridge, MA) and J. T. Brieger (Bell Helicopter Textron, Fort Worth, TX). In: American Helicopter Society, Annual Forum, 37th, New Orleans, LA, May 17-20, 1981, Proceedings. Washington, DC, American Helicopter Society, 1981, p. 522-531. 14 refs. The current techniques of helicopter rotor noise prediction attempt to describe the details of the noise field precisely and remove the empiricisms and restrictions inherent in previous meth- ods. These techniques require detailed inputs of the rotor geometry, operating conditions, and blade surface pressure distribution. The purpose of this paper is to review those techniques in general and the Farassat/Nystrom analysis in particular. The predictions of the Farassat/Nystrom noise computer program, using both measured and calculated blade surface pressure data, are compared to measured noise level data. This study is based on a contract from NASA to Bolt Beranek and Newman Inc. (BBN) with measured data from the AH-IG Helicopter Operational Loads Survey flight test program supplied by Bell Helicopter Textron. (Author) A81-46714 Soviet military air cushion vehicles - Mecha- nized amphibious assault. J. S. Dibbern (U.S. Army, Foreign Science and Technology Center, Batesville, VA). In: Canadian Symposium on Air Cushion Technology, 14th, Ottawa, Canada, September 22-24, 1980, Proceedings. Ottawa, Canadian Aeronau- tics and Space Institute, 1980, p. 173-185. An assessment is given of the technological sophistication, operational capabilities, performance characteristics and military significance of three air cushion vehicle (ACV) classes currently deployed by the Soviet Union in its amphibious warfare forces. The classes are: (1) the 27,000-kg GUS class, which can carry a platoon of troops at up to 90 km/hr and is equipped for all-weather operation; (2) the AIST class, which with its 270,000 kg maximum weight can carry two medium tanks and large numbers of motorized infantry; and (3) the most recently launched, LEBED class, of 120,000 kg, which strongly resembles the U.S. Navy's projected JEFF-B amphibious assault landing craft. It is concluded that the significance of these designs does not lie in their technological sophistication so much as in the fact that they are already operational and accumulating valuable experience. O.C. A81-46725 Survivors on the RPV front. D. Chopping. Interavia, vol. 36, Sept. 1981, p. 898, 899. A review is made of current remotely piloted vehicle (RPV) system development programs. Among the aircraft discussed are: (1) the CL-289, which is intended to replace the existing CL-89 battlefield surveillance system while meeting the needs of an army corps, rather than only a division; (2) the CL-227 short-range RPV, for brigade use; (3) the Mirach 100, which may be launched either from ground vehicles or helicopters; (4) the IAI Scout, which has already been proven in combat in the middle east; (5) the Argus, a tethered rotary-wing surveillance platform; (6) the MTC II, a mini-helicopter employing two contra-rotating, three-bladed rotors; and (7) the Aquila, which incorporates such advanced 'stealth' technology features as a shrouded rotor, Kevlar/plastic composite construction and blended wing/body planform. O.C. A81-46749 Inverse problems of guided-flight dynamics - Longitudinal motion. B. N. Petrov and P. D. Krut'ko (Moskovskoe Vysshee Tekhnicheskoe Uchilishche, Moscow, USSR). lAkademiia Nauk SSSR, Doklady, vol. 255, no. 1, 1980, p. 43-47.) Soviet Physics - Doklady, vol. 25, Nov. 1980, p. 895-897. Translation. The paper deals with the development of a new approach to the construction of aircraft control algorithms. The approach is based essentially on the concept of inverse problems of dynamics, introduced by Petrov, Krut'ko, and Popov (1979). The basic aspects of automatic aircraft control are analyzed on the basis of a nonlinear mathematical model whose equations are written in a system of velocity coordinates. V.P. A81 -46782 Local approximation of a vortex layer by a system of discrete vortices. D. N. Gorelov. IPMTF - Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, Sept.-Oct. 1980, p. 76-82.) Journal of Applied Mechanics and Technical Physics, vol. 21, no. 5, Mar. 1981, p. 638-643. 9 refs. Translation. It is shown that the system of discrete vortices can approximate the velocity induced by a continuous eddy layer including the points in the layer in the vicinity of its ends. Expressions are derived for determining the coordinates of these points which take into account the local velocity field near the eddy layer. A.T. A81 -46783 Automatic damping of vibrations of an air- plane wing by internal control forces. V. I. Merkulov. IPMTF - Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, Sept.-Oct. 1980, p. 91-99.) Journal of Applied Mechanics and Technical Physics, vol. 21, no. 5, Mar. 1981, p. 650-656. Translation. Various methods of damping elastic vibrations in aircraft wings include automatic control of amplitude, frequency, and phase of the acting forces. Weight shifting, internal tension, flexible shafts, and gyrometers were examined as controlling elements; these methods are effective in airport operations where aircraft is subjected to maximum dynamic loads. A.T. A81-46813 $ Use of carbon composites in aircraft structures (Primenenie ugleplastikov v konstruktsii letatel'nykh apparatov). lu. N. Rabotnov, A. A. Tupolev, V. F. Kut'inov, V. P. Kogaev, A. V. Berezin, and V. V. Sulimenkov. (Vsesoiuznaia Konferentsiia po Mekhanike Polimernykh i Kompozitnykh Materialov, 4th, Riga, Latvian SSR, Oct. 1980.1 Mekhanika Kompozitnykh Materialov, July-Aug. 1981, p. 657-667. 33 refs. In Russian. Methods for calculating deformation and strength characteristics of laminated composites are reviewed with reference to the results of static, dynamic, and fatigue testing of carbon composites with various ply patterns. A method for calculating additional safety factors is proposed along with a standardized finite-element proce- dure for calculating the stress-strain state of composite control surface structures. Examples illustrating application of the proposed method are presented. V.L. A81-46794 ji Electric installation work on aircraft (Elektro- montazhnye raboty na letatel'nykh apparatakh). A. V. Chernyshev, N. I. Tsibizov, and B. V. Boitsov. Moscow, Izdatel'stvo Mashinostroe- nie, 1980. 240 p. 5 refs. In Russian. The book contains basic information on methods used in installing the electric equipment of aircraft with emphasis on wiring techniques. Consideration is given to the most common and time-consuming installation, control, and test procedures. The design and operation of recommended tools and devices are examined. Finally, safety techniques are discussed. V.L. A81-46847 jj Self-oscillations of a wheel on a self-aligning landing gear strut with a nonlinear damper (Avtokolebaniia kolesa na orientiruiushcheisia stoike shassi s nelineinym dempferom). L. G. Lobas. Prikladnaia Matematika i Mekhanika, vol. 45, July-Aug. 1981, p. 756-759. In Russian. An asymptotic method is used to determine the amplitude and frequency of self-oscillations of a wheel on a self-aligning landing- gear strut subjected to flexural strain. The strut has a square-law damper developing turbulent resistance and connected in parallel with an elastic element. The obtained solution makes it possible to control the wheel shimmy amplitude by selecting an appropriate damping coefficient for the square-law damper. V.L. 577 A81-46848 A81-46848 ;j Erosion strength of aircraft engine and power plant parts (Erozionnaia prochnost' detalei dvigatelei i energoustano- vok letatel'nykh apparatov). R. G. Perel'man. Moscow, Izdatel'stvo Mashinostroenie, 1980. 247 p. 225 refs. In Russian. Erosion due to high-velocity interaction between liquid particles and a solid is discussed from the theoretical and engineering points of view. Computer algorithms for calculating erosion of the blades of gas turbine engines and space power plants as well as methods for designing parts of specified erosion strength are presented and illustrated by examples. Erosion strength characteristics are given for various aerospace materials. V.L. A81 -46850 ,-7 Analytical and computer-aided design of auto- mated systems for the testing of aircraft engines (Analiticheskoe i mashinnoe proektirovanie avtomatizirovannykh sistem ispytanii avia- tsionnykh dvigatelei). iu. V. Kozhevnikov, V. S. Moiseev, lu. V. Meluzov, and A. Kh. Khairullin. Moscow, Izdatel'stvo Mashinostroe- nie, 1980. 272 p. 58 refs. In Russian. Problems of the analytical and computer-aided design of automated systems for the testing of aircraft engines are considered from unified scientific and methodological points of view. The problems are examined in the light of systems analysis, the mathematical modeling of test objects and processes, and the theories of optimization, statistical decision making, and queueing. Attention is given to methods for the optimal evaluation and correction of engine characteristics, and to criteria for the computer- aided optimization of structures and the evaluation of the efficiency of automated test systems. B.J. A81-47125 # Precision DME for microwave landing system. F. Chiarini, M. Gori (Fabbrica Apparecchiature per Communicazioni Elettriche Standard S.p.A., Laboratorio Centrale Industrie, Pomezia, Italy), G. Corazza, and G. Falciasecca (Fondazione Ugo Bordoni, Centre Onde Millimetriche, Pontecchio Marconi, Italy). Electrics/ Communication, vol. 55, no. 4, 1980, p. 292-303. 8 refs. It is noted that the distance measuring equipment (DME) that will be used with the new microwave landing system must provide much better accuracy than the existing system. To ensure interopera- bility with the existing system, however, it is desirable to upgrade the present equipment rather than to design a completely new one. An L-band fully compatible precision DME with the required accuracy is proposed on the basis of a new technique known as double pulse shaping. An example is presented of the application of the technique based on a tentative error budget. C.R. 578 N81-30088 STAR ENTRIES N81-30080* # National Aeronautics and Space Administration. Ames Research Center. Moffett Field. Calif. INFLUENCE OF FRICTION FORCES ON THE MOTION OF VTOL AIRCRAFT DURING LANDING OPERATIONS ON SHIPS AT SEA James C. Howard and David 0. Chin Sep. 1981 40 p refs (NASA-TM-81305: A-8641) Avail: NTIS HC A03/MF A01 CSCL 01 B Equations describing the friction forces generated during landing operations on ships at sea were formulated These forces depend on the platform reaction and the coefficient of friction. The platform reaction depends on the relative sink rate and the shock absorbing capability of the landing gear. The friction coefficient varies with the surface condition of the landing platform and the angle of yaw of the aircraft relative to the landing platform. Landings by VTOL aircraft, equipped with conventional oleopneumatic landing gears are discussed. Simplifications are introduced to reduce the complexity of the mathematical description of the tire and shock strut characteristics. Approxima- ting the actual complicated force deflection characteristic of the tire by linear relationship is adequate The internal friction forces in the shock strut are included in the landing gear model A set of relatively simple equations was obtained by including only those tire and shock strut characteristics that contribute significantly to the generation of landing gear forces. A.R.H. N81-30083*# National Aeronautics and Space Administration. Ames Research Center. Moffett Field. Calif. EXPERIMENTAL AERODYNAMIC CHARACTERISTICS OF TWO V/STOL FIGHTER/ATTACK AIRCRAFT CONFIGURA- TIONS AT MACH NUMBERS FROM 1.6 TO 2.0 Walter P Nelms. Donald A. Durston. and J. R. Lummus (General Dynamic Corp.. Fort Worth. Tex.) May 1981 292 p refs Sponsored in part by the Navy (NASA-TM-81286: A-8559) Avail: NTIS HC A12/MF A01 CSCL 01A Tests were conducted in the Ames 9 by 7 ft supersonic wind tunnel to measure the aerodynamic characteristics of two horizontal attitude takeoff and landing V/STOL fighter/attack aircraft concepts. One concept featured a jet diffuse! ejector for its vertical lift system and the other employed a remote augmentation lift system (RALS). Test results for Mach numbers from 1.6 to 20 are reported. Effects of varying the angle of attack (-4 deg to +17 deg). angle of sideslip (-4 deg to +8 deg) Mach number, and configuration building were investigated. The effects of wing trailing edge flap deflections, canard incidence, and vertical tail deflections were also explored as well as the effects of varying the canard longitudinal location and shapes of the inboard nacelle body strakes. A.R.H. N81-30084*# Boeing Commercial Airplane Co.. Seattle. Wash. AN INVESTIGATION OF ENGINE INFLUENCE ON INLET PERFORMANCE Brent K. Hodder 1981 88 p refs (Contract NAS2-06017) (NASA-CR-166136: D6-49228) Avail: NTIS HC A05/MF A01 CSCL 01A The performance of a conventional engine/inlet installation, in which inlet and engine flow field interaction occurs, was compared to the performance of the same inlet remote coupled to the engine. The remote coupled inlet configuration decouples the influence of the engine on the inlet flow field and simulates current small scale inlet test techniques in which inlet airflow is provided by a vacuum source or coupled engine. The investigation was conducted in the NASA-Ames 40- by 80-foot wind tunnel using a General Electric TF-34 turbofan engine and a subsonic inlet havng an average inlet contraction ratio of 1.26. Test results indicated that engine interaction allows the inlet to operate with lower distortion levels at and beyond the separation angle-of-attack experienced without engine interaction. T.M. N81-30085* # Douglas Aircraft Co.. Inc.. Long Beach. Calif. ANALYSIS OF MACH NUMBER 0.8 TURBOPROP SLIP- STREAM WING/NACELLE INTERACTIONS Final Report H. Robert Welge. Dan H. Neuhart. and John A. Dahlin 6 Aug. 1981 84 p refs (Contract NAS2-10881) (NASA-CR-166214: ACEE-25-FR-1564) Avail: NTIS HC A05/MF A01 CSCL 01A Data from wind tunnel tests of a powered propeller and nacelle mounted on a supercritical wing are analyzed. Installation of the nacelle significantly affected the wing flow and the flow on the upper surface of the wing is separated near the leading edge under powered conditions. Comparisons of various theories with the data indicated that the Neumann surface panel solution and the Jameson transonic solution gave results adequate for design purposes. A modified wing design was developed (Mod 3) which reduces the wing upper surface pressure coefficients and section lift coefficients at powered conditions to levels below those of the original wing without nacelle or power. A contoured over the wing nacelle that can be installed on the original wing without any appreciable interference to the wing upper surface pressure is described. J.D.H. N81-30086*# National Aeronautics and Space Administration. Langley Research Center. Hampton. Va. EFFECT OF SIMULATED IN-FLIGHT THRUST REVERSING ON VERTICAL-TAIL LOADS OF F 18 AND F-15 AIRPLANE MODELS E. Ann Bare, Bobby L. Berner. and Francis J. Capone Aug. 1981 53 p refs (NASA-TP-1890: L-14531) Avail: NTIS HC A04/MF A01 CSCL01A Investigations were conducted in the Langley 16-Foot Transonic Tunnel to provide data on a 0.10-scale model of the prototype F-18 airplane and a 0.047-scale model of the F-15 three-surface configuration (canard, wing, and horizontal tails). Test data were obtained at static conditions and at Mach numbers from 0.6 to 1.2 over an angle-of-attack range from 2 deg to 15 deg. Nozzle pressure ratio was varied from jet off to about 8.0. T.M. N81-30087*# National Aeronautics and Space Administration. Langley Research Center. Hampton. Va. WING-ALONE AERODYNAMIC CHARACTERISTICS FOR HIGH ANGLES OF ATTACK OF SUPERSONIC SPEEDS Robert L. Stallings. Jr. and Milton Lamb Jul. 1981 190 p refs (NASA-TP-1889: L-14546) Avail: NTIS HC A09/MF A01 CSCL 01A An experiment was conducted to determine wing-alone supersonic aerodynamic characteristics at high angles of attack. The wings tested varied in aspect ratio from 0.5 to 4.0 and in taper ratio from 0 to 1.0. The wings were tested at angles of attack ranging rom -5 deg to 60 deg and at Mach number from 1.60 to 4.60. The aerodynamic characteristics were obtained by integrating local pressures measured over the wing surfaces. Presented and discussed are results showing the effects of aspect ratio, taper ratio. Mach number, and angle of attack on force and moment coefficients and center of pressure locations. Also included are tabulations of the pressure measurements. T.M. N81-30088*$ National Aeronautics and Space Administration. Langley Research Center. Hampton. Va. COMPUTER ANALYSIS OF FLOW PERTURBATIONS GENERATED BY PLACEMENT OF CHOKE BUMPS IN A WIND TUNNEL Richard L. Campbell Aug. 1981 44 p refs (NASA-TP-1892: L-14415) Avail: NTIS HC A03/MF A01 CSCL 01A An inviscid analytical study was conducted to determine the upstream flow perturbations caused by placing choke bumps in a wind tunnel. A computer program based on the stream-tube curvature method was used to calculate the resulting flow fields for a nominal free-stream Mach number range of 0.6 to 0.9. The choke bump geometry was also varied to investigate the effect of bump shape on the disturbance produced. Results from the study indicate that a region of significant variation from the free-stream conditions exists upstream of the throat of the tunnel. The extent of the disturbance region was. as a rule, dependent 579 N81-30091 on Mach number and the geometry of the choke bump. In general, the upstream disturbance distance decreased for increasing nominal free-stream Mach number and for decreasing length-to- height ratio of the bump. A polynomial-curve choke bump usually produced less of a disturbance than did a circular-arc bump and going to an axisymmetric configuration (modeling choke bumps on all the tunnel walls) generally resulted in a lower disturbance than with the corresponding two dimensional case. Author N81-30O91# Auburn Univ.. Ala. Engineering Experiment Station. AN AERODYNAMIC ANALYSIS OF DEFORMED WINGS IN SUBSONIC AND SUPERSONIC FLOW Final Report. Jan. 1980 - Apr. 1981 John E. Burkhalter. John M. Abernathy. and Milton E. Vaughn. Jr. Apr. 1981 201 p refs (Contract DAAG29-78-G-0036) (AD-A101675; ARO-15666.4-A-E) Avail: NTIS HC A10/MF A01 CSCL 20/4 The aerodynamic loading for deformed wings with elevons in both subsonic and supersonic flow is considered The solution procedure falls into the potential flow category with appropriate restrictions. For subsonic flow, a lifting surface Kernel function formulation is used in which the local pressure loading for both wing and eleven is determined simultaneously in a semi-closed summation manner. Cases under study included gaps between wing and elevon in addition to arbitrary wing-elevon deformations. Results for all cases compared very well with experimental data. Experimental data taken in a low speed wind tunnel is also presented for a cropped delta wing and rectangular elevon in which the wing-elevon gap was the primary test variable. For supersonic flow, 3-D supersonic theory forms the basis for the solution procedure. Deformations are accounted for with the use of the doublet paneling added to the basic 3-D solution. Results agree very well with existing experimental data. The gapped elevon and thick wing trailing edge problem is also addressed with satisfactory results. Author (GRA) N81-30098*# Control Data Corp., Hampton. Va. LEARNING GUIDE FOR THE TERMINAL CONFIGURED VEHICLE ADVANCED GUIDANCE AND CONTROL SYSTEM MODE SELECT PANEL Mark A. Anderson and Ron Callahan Jul. 1981 20 p refs (Contract NAS1-15673) (NASA-CR-165751) Avail: NTIS HC A02/MF A01 CSCL 01C This learning guide is designed to assist pilots in taking the PLATO presimulator training course on the advanced guidance and control system mode select panel. The learning guide is divided into five sections. The first section, the introduction, presents the course goals, prerequisites, definition of PLATO activities, and a suggested approach to completing the course The remaining four sections present the purpose, learning activities and summary of each lesson of the AGCS PLATO course, which consists of (1) AGCS introduction: (2) lower order modes: (3) higher order modes: and (4) an arrival route exercise. Author N81-30101*# National Aeronautics and Space Administration. Ames Research Center, Moffett Field. Calif. GUIDELINES FOR LINE-ORIENTED FLIGHT TRAINING. VOLUME 1 John K Lauber and H. Clayton Foushee Aug. 1981 46 p refs Proceedings of NASA/Industry Workshop. Moffett Field. Calif.. 13-15 Jan. 1981 (NASA-CP-2184: A-8585-Vol-1) Avail: NTIS HC A03/MF A01 CSCL 01C Line-Oriented Flight Training (LOFT) is a developing training technology which synthesizes high-fidelity aircraft simulation and high-fidelity line-operations simulation to provide realistic, dynamic pilot training in a simulated line environment. LOFT is an augmentation of existing pilot training which concentrates upon command, leadership, and resource management skills. This report, based on an NASA/Industry workshop held in January, 1981. is designed to serve as a handbook for LOFT users. In addition to providing background information, guidelines are presented for designing LOFT scenarios, conducting real-time LOFT operations, pilot debriefing, and instructor qualification and training. The final chapter addressed other uses of LOFT and line-operations (or full-mission) simulation. Author N81 30102# BDM Corp. McLean. Va DEFINITION OF INVESTIGATIVE AREAS FOR HUMAN- FACTOR ASPECTS OF AIRCRAFT ACCIDENTS Final Report. 13 Mar. - 23 Dec. 1979 Michael Fineberg, John Woelfel. Robin Ely. and Marcia Smith Dec. 1980 130 p refs (Contract F33615-79-C-0608: AF Pro). 2787) ( A D - A 101601: BDM/W-79-733-TR: SAM-TR-80-48) Avail: NTIS HC A07/MF A01 CSCL 01/3 This paper is the final report of a 9-month survey effort designed to identify the major pilot factors involved in aircraft mishaps, rank order the major pilot factors in relation to a return-on-investment metric, identify aviation technologies with a high potential for diagnosing and/or reducing these pilot factors, and suggest potentially high-payoff programs for researching the pilot factor aspects of aircraft for the purpose of reducing their incidence. Author (GRA) N81-30103# Federal Aviation Administration. Atlantic City. N.J. AIRCRAFT RESEARCH AND TECHNOLOGY FOR ANTIMIST- ING KEROSENE CONFERENCE Jun 1981 260 p Proceedings held at Atlantic City. N.J. 18-19 Feb.. 1981 (AD-A101347. FAA-CT-81-181) Avail: NTIS HC A12/MF A01 CSCL 01/2 Contents: Antimisting Fuel Engineering and Development Program, Wing Spillage Test, Flammability Comparison Test Apparatus, Large-Scale Aircraft Crash Test of Antimisting Fuel. The Use of Antimisting Kerosene in Turbofan Jet Engines, The Development of ICI'S FM-9 Antimisting Aviation Fuel. Cryo- genic Blending Polymer Additives in Fuel. Economic Aspects of Conversion to Antimisting Fuels. UK Programme on Safety Fuels. Fundamental Studies of Antimisting Fuels, Degradation and Characterization of Antimisting Kerosene. Antimisting Fuel Test Correlation Analysis, and KS/DC-10 Fuel System Simulator GRA N81-30104# Federal Aviation Administration. Atlantic City. N.J. Technical Center. A COMPENDIUM OF A IRCRAFT COCKPIT VISION SURVEYS. 1950 THROUGH 1980, VOLUME 1 Final Report. 1950-1980 Anthony J. Barile May 1981 148 p refs (AD-A101473: FAA-CT-81-40-Vol-1) Avail: NTIS HC A07/MF A01 CSCL 01/3 This publication contains a history of cockpit of visibility surveys which were conducted to measure and record aircraft (General Aviation. Transport, Helicopter. Military) cockpit visibility. Many of the aircraft were involved in midair collisions, accident investigations, research and development, and the design up through production implementation. The Federal Aviation Administration (FAA) Binocular Camera is a standard means to accurately measure cockpit visibility, which in the certification process for civil aircraft is an invaluable tool for industry and the FAA. Therefore, the information contained in this document is intended to contribute to aviation safety. Author (GRA) N81-30105# Messerschmitt-Boelkow-Blohm G m b H , Otto- brunn (West Germany). Unternehmensbereich Drehfluegler. APPLICATION OF DAMAGE TOLERANCE CONCEPTS FOR MBB HELICOPTERS M. vonTapavicza and F. Och 12 Sep 1980 11 p refs Presented at 51st AGARD Struct, and Mater. Panel on Helicopter Fatigue Life Assessment, Aix-en-Provence. France. 14-19 Sep. 1980 (MBB-UD-309/80-OE) Avail: NTIS HC A02/MF A01 Components were tested in order to determine the location and modes of damage, and to establish how many redundant elements can fail without adversely affecting the capacity of the equipment to withstand limiting loads. Maximum safety and performance are sought for minimum weight and costs. The time elapsing between the onsat of damage and the moment when failure occurs is deteimined from inspection tests Probable lives are calculated from experimental S-N curves, the correspond ing strength reduction factor being an important parameter Damage tolerance is based on combined safe life and slow crack growth evaluations. The methodology adopted for two types of helicopter is presented. It is shown that safety criteria can be respected by applying stringent conditions to just a few vital components. These components are defined and some test results are given. Author (ESA) 580 N81-30116 N81-30106*# Battelle Columbus Labs.. Mountain View. Calif. OPERATIONAL PROBLEMS EXPERIENCED BY SINGLE PILOTS IN INSTRUMENT METEOROLOGICAL CONDITIONS Interim Report Stacy Weislogel 5 Aug. 1981 74 p refs (Contract NAS2-10060) (NASA-CR-166236) Avail: NTIS HC A04/MF A01 CSCL 17G The development and implementation of a search strategy to extract pertinent reports from the Aviation Safety Reporting System-2 (ASRS-2) database are described. For any particular occurence to be pertinent to the study, it must have satisfied the following conditions: the aircraft must be of the type usually flown by a single pilot: operation on an IFR flight plan in instrument meteorological conditions: pilot experienced an operational problem. The occurances consist of reports by the pilot about his own performance, by the pilot about the system performance, or by an air traffic controller about a pilot's performance. T.M. N81-30107# Mitre Corp.. McLean. Va. DISCRETE ADDRESS BEACON SYSTEM DATA LINK CAPACITY REQUIREMENTS Final Report Anand D. Mundra Dec. 1980 124 p refs (Contract DOT-FA80WAI-4370) (AD-A101731: MTR-80W302: FAA-RD-81-56) Avail: NTIS HC A06/MF A01 CSCL 17/7 The Federal Aviation Administration plans to deploy the Discrete Address Beacon System (DABS) as a key feature of its upgraded third generation Air Traffic Control System DABS provides an integral data link capable of conducting rapid transfer of data between the sensor and DABS equipped aircraft. This study establishes the performance requirements of the DABS data link to be able to provide the various services that may reasonably be expected to be delivered by DABS during its life time. GRA N81-30110*# National Aeronautics and Space Administration. Langley Research Center. Hampton. Va. THE USE OF INTERPRACTJVE GRAPHIC DISPLAYS FOR INTERPRETATION OF SURFACE DESIGN PARAMETERS Noel A. Talcott. Jr. May 1981 27 p refs (NASA-TM-81963: L-14112) Avail: NTIS HC A03/MF A01 CSCL 01C An interactive computer graphics technique known as the Graphic Display Data method has been developed to provide a convenient means for rapidly interpreting large amounts of surface design data. The display technique should prove valuable in such disciplines as aerodynamic analysis, structural analysis, and experimental data analysis. To demonstrate the system's features, an example is presented of the Graphic Data Display method used as an interpretive tool for radiation equilibrium temperature distributions over the surface of an aerodynamic vehicle. Color graphic displays were also examined as a logical extension of the technique to improve its clarity and to allow the presentation of greater detail in a single display. Author N81-30111*# National Aeronautics and Space Administration. Hugh L. Dryden Flight Research Center. Edwards. Calif. COMPARISON OF THREE THRUST CALCULATION METHODS USING IN-FLIGHT THRUST DATA Donald L. Hughes Jul. 1981 35 p refs (NASA-TM-81360: H-1141) Avail: NTIS HC A03/MF A01 CSCL QIC The gross thrust of an experimental airplane was determined by each method using the same flight maneuvers and generally the same data parameters. Coefficients determined from thrust stand calibrations for each of the three methods were then extrapolated to cruise flight conditions. The values of total aircraft gross thrust calculated by the three methods for cruise flight conditions agreed within -r or - 3 percent. The disagreement in the values of thrust calculated by the different techniques manifested itself as a bias in the data. There was little scatter (0.5 percent) for the thrust levels examined in flight. T.M. N81-30112*# National Aeronautics and Space Administration. Langley Research Center. Hampton. Va. BEHAVIOR OF AIRCRAFT ANTISKID BRAKING SYSTEMS ON DRY AND WET RUNWAY SURFACES: HYDROME- CHANICALLY CONTROLLED SYSTEM John A. Tanner. Sandy M. Stubbs. and Eunice G. Smith Aug. 1981 176 p refs (NASA-TP-1877; L-14549) Avail: NTIS HC A09/MF A01 CSCL 01C The investigation utilized one main gear wheel, brake, and tire assembly of a McDonnell Douglas DC-9 series 10 airplane. The landing-gear strut was replaced by a dynamometer. During maximum braking, average braking behavior indexes based upon brake pressure, brake torque, and drag-force friction coefficient developed by the antiskid system were generally higher on dry surfaces than on wet surfaces. The three braking behavior indexes gave similar results but should not be used interchangeably as a measure of the braking of this antiskid sytem. During the transition from a dry to a flooded surface under heavy braking, the wheel entered into a deep skid but the antiskid system reacted quickly by reducing brake pressure and performed normally during the remainder of the run on the flooded surface. The brake-pressure recovery following transition from a flooded to a dry surface was shown to be a function of the antiskid modulating orifice. T.M. N81-30113# Systems Technology. Inc.. Hawthorne. Calif. INVESTIGATION OF HIGH ANGLE-OF ATTACK MANEU- VER-LIMITING FACTORS. PART 1: ANALYSIS AND SIMULATION Final Report. 13 May 1976 - 30 Jul. 1980 Donald E. Johnston. David G. Mitchell, and Thomas T. Myers Dec. 1980 203 p refs (Contract F33515-76-C-3072: AF Proj. 2403) (AD-A101646: STI-TR-1081-1-PM: AFWAL-TR-80-3141-Pt-1) Avail: NTIS HC A10/MF A01 CSCL 01/3 The high angle of attack, low speed stall/departure character- istics of the F-4J and F-14A are analyzed, using a six degree of freedom mathematical model with nonlinear aerodynamics. Cause-effect relationships are investigated for maneuver limiting factors including wing rock, nose slice, and rolling departures. Cross derivatives of L alpha, N alpha, and M beta alter key transfer function parameters. A piloted simulation validates analytic predictions and demonstrate that departure warning, susceptibil- ity, and severity are strongly influenced by the static cross derivatives. A connection between roll numerator parameter values and pilot perception of departure susceptibility and severity is identified. Potential modifications for the high AOA sections of the MIL-F-8785B Flyin Qualities Specifications are proposed: a criterion for the real part of the roll numerator root, further recommendations for minimizing departure susceptibility and certain sideslip influences, and a flying quality rating form for assessing departure and recovery characteristics. GRA N81-30114# Systems Technology. Inc.. Hawthorne. Calif. INVESTIGATION OF HIGH ANGLE OF ATTACK MANEU- VER-LIMITING FACTORS. PART 2: PILOTED SIMULATION ASSESSMENT OF BIHRLE DEPARTURE CRITERIA Final Report. 13 May 1976 - 30 Jul. 1980 David G. Mitchell and Donald E. Johnston Dec. 1980 51 p refs (Contract F33615-76-C-3072: AF Proj. 2403) (AD-A101647: STI-TR-1081-1-PI-2: AFWAL-TR-80-3141-PI-2) Avail: NTIS HC A04/MF A01 CSCL 01/3 Analytical prediction and piloted simulation results for a specific set of programmed control deflections are compared for the F*-4J and F-14A aircraft. GRA N81-30115# Systems Technology, Inc.. Hawthorne. Calif. INVESTIGATION OF HIGH ANGLE OF ATTACK MANEU- VER-LIMITING FACTORS. PART 3: APPENDICES. AERODYNAMIC MODELS Final Report. 13 May 1976 - 30 Jul. 1980 David G. Mitchell. Thomas T. Myers. Gary L. Teper. and Donald E. Johnston Dec. 1980 124 p refs (Contract F33615-76-C-3072: AF Proj. 2403) (AD-A101648: STI-TR-1081-1-PI-3: AFWAL-TR-80-3141-PI-3) Avail: NTIS HC A06/MF A01 CSCL 01/3 Aerodynamic models employed in the F-4J and F-14A high angle of attack analysis and validation are presented as well as the equations of motion, aerodynamic models, and control system configurations, used in the piloted simulation. GRA N81-30116$ Naval Ship Research and Development Center. Bethesda. Md. Aviation and Surface Effects Dept. EXPERIMENTAL DEVELOPMENT OF AN A D V A N C E D CIRCULATION CONTROL WING SYSTEM FOR NAVY STOL AIRCRAFT Research and Development Report J. H. Nichols. Jr.. R. J. Englar. M. J. Harris, and G. G. Huson 581 IM81-30117 May 1981 19 p refs Presented at the AIAA Aerospace Sci. Meeting (19th). St. Louis. 12-15 Jan. 1981 (WF41421000) (AD-A101309: DTNSRDC/AERO-1272: DTNSRDC-81/045: AIAA-Paper-81-0151) Avail: NTIS HC A02/MF A01 CSCL 20/4 An advanced high lift system is being developed which combines a Circulation Control Wing (CCW) with Upper Surface Blowing (USB) to produce significant lift for STOL operations by Navy aircraft. The concept uses circulation control to pneumatically deflect USB engine thrust and thus augment aerodynamic wind lift produced by the outboard CCW. Two series of wind tunnel investigations have confirmed significant thrust turning to angles near 160 deg. suggesting the possibility for a simple, highly effective STOL and thrust reverser system Two dimensional investigations of reduced diameter CCW trailing edges suggest their application as a no-moving-parts high lift system with minima! cruise penalty. The paper presents these experimental results and summarizes the technology development progressing towards an advanced STOL aircraft. Author (GRA) N81-30117# Kaman Aerospace Corp. Bloomfield. Conn. VIM&T: LOW COST PRODUCTION/INSTALLATION OF URETHANE LEADING EDGE GUARDS ON ROTOR BLADES Final Report, 23 Aug. 1979 - 9 Dec. 1980 M. L. White and A I Belbruno Jun 1981 57 p (Contract DAAK51-79-C-0024) (AD-A101603: R-1627A: USAAVRADCOM-TR-81-D-10) Avail: NTIS HC A04/MF A01 CSCL 01/3 A process for a low cost production/installation of urethane leading edge guards for rotor blades was developed. A survey of manufacturers and literature was conducted for suitable erosion guard materials. Flow, bonding, and temperature characteristics of the selected material were determined. The feasibility of the process of molding a boot on a 4 foot section of blade was demonstrated. From the results obtained in the molding phase, the tool concept and design was refined and a tool was fabricated to mold an erosion boot on a full length blade. Four full scale leading edge erosion boots were formed, bonded, and inspected. The costs were compared to current production process. GRA N81-30119# Army Aviation Engineering Flight Activity. Edwards AFB. Calif. Directorate for Development and Qualification. AH 1 LIGHTWEIGHT AIRBORNE LAUNCHER JETTISON EVALUATION Final Report. Sep. - Nov. 1980 Larry B. Higgins and John D. Ottomeyer Apr 1981 22 p refs (AD-A101461: USAAEFA-79-03) Avail: NTIS HC A02/MF A01 CSCL 19/7 An A H - 1 S jettison evaluation was made of the M261 19-round M260 7-round pre-production. Lightweight Airborne Launcher (LWL). Forty-one flights totaling 11.5 flight hours were flown. The jettison characteristics of separation distance, time to clear or LWL motions did not appear to be significantly influenced by airspeed, sideslip angle or rate of descent. Satisfactory jettison envelopes for the pre-production M260 and M261 LWL were defined statically, at a hover, and in pilot perceived coordinated level flight to an airspeed of V(H) and partial power and autorotational descent to an airspeed of V(maxglide). The M260 and M261 LWL met the separation criteria of AMCP 706-203 GRA N81-30120# General Electric Co.. Burlington. Vt. Armament and Electrical Systems Dept. HIGH IMPULSE GUN AIRBORNE DEMONSTRATION. GAU-13/A WEAPON. FEED SYSTEM. GUN DRIVE AND ELECTRONIC CONTROLS Final Technical Report. 3 Aug. 1979 - 31 Oct. 1980 Edwin J. DePasqual May 1981 34 p refs (Contract DAAK10-79-C-0267) (AD-A101698: Rept-81APB521) Avail: NTIS HC A03/MF A01 CSCL 19/6 The HIGAD test bed described in this report consists of a four barrel. GAU-8/A class. 30-mm Catling type weapon with associated feeder and dual rate drive, and a microprocessor- controlled, hydraulically-operated recoil attenuation system. This recoil system is referred to as FORC (Force Optimized Recoil Control) and is used for the 360 shot-per-minute (spm) rate. A second recoil system is used for the higher rate of 720 spm. This system is a passive low force recoil system. Complete interface requirements were established through many joint meetings between General Electric, Honeywell, and ARRADCOM. The resulting test program has demonstrated flawless gun system performance in the HIGAD test bed. A total of 161 rounds were fired for set-up and checkout purposes at the General Electric Firing Range prior to delivery to ARRADCOM At Rock Island, 972 rounds were accumulated on the gun system during evaluation of the FORC recoil system. GRA N81-30121# Messerschmitt-Boelkow-Blohm G.m.b.H.. Otto- brunn (West Germany). Unternehmensbereich Drehfluegler BK 117: A NEW HELICOPTER THROUGH INTERNATIONAL COOPERATION E. Weiland and I. Kagitomi (Kawasaki Heavy Industries. Gifu. Japan) 4 Sep. 1979 28 p Presented at 5th European Rotorcraft and Powered Lift Aircraft Forum. Amsterdam. 4-7 Sep. 1979 (MBB-UD-274/79-OE) Avail: NTIS HC A03/MF A01 The design of the BK-117 helicopter and the selection of the main parameters are discussed. Results of ground and flight testing are included. The BK-117 is an engine multipurpose helicopter equiped with AVCO-Lycoming LTS101 turboshaft engines with a 11 m four-bladed rotor of the rigid type. The maximum takeoff weight is 2800 kg and cruise speed is 265 km/h. A high degree of commonality with the BO-105 (from which it was developed) was sought. Author (ESA) N81-30122# Messerschmitt-Boelkow-Blohm G.mbH. Otto- brunn (West Germany). Airplane Div. STRUCTURAL OPTIMIZATION OF ADVANCED AIRCRAFT STRUCTURES G. Schneider. H. Goedel. and 0. Sensburg 11 Aug. 1980 15 p refs Presented at 12th ICAS Congress. Munich. 12-17 Oct 1980 (MBB-S/PUB/32) Avail: NTIS HC A02/MF A01 The application of sof tware systems for the automatic design of minimum weight structures (several elements) is described. The structural layout of a carbon fiber composite forward swept wing is depicted. It is shown that a structural optimization system can be very useful in the preliminary design of an aircraft, especially one divided into several modules (static load calcula- tions: deformations and stress calculations by finite elements: static aeroelastics: weight calculations: unsteady aerodynamic forces: vibration calculations and flutter calculations) which can be used separately and independently. Cross checks can be performed, and postulated design goals can be achieved. The low divergence speed of forward swept wings can be increased sufficiently with zero or a small weight penalty. The system is suitable for future high performance aircraft. Author (ESA) N81-30123# Messerschmitt-Boelkow-Blohm G.mb.H.. Otto- brunn (West Germany). Unternehmensbereich Drehfluegler. DEVELOPEMENT OF ANTIRESONANCE FORCE ISOLATORS FOR HELICOPTER VIBRATION REDUCTION D. Braun 18 Aug. 1980 20 p refs Presented at 6th European Rotocraft and Powered Lift Aircraft Forum, Bristol. England. 16-19 Sep. 1980 Sponsored by Bundesministerium fuer Forschung und Technologie (MBB-UD-305/80-OE) Avail: NTIS HC A02/MF A01 A conventional isolator with elastomeric pivots was devel- oped and tested. This type of pivot was found to be the most suitable pendulum bearing. Another type of isolator of a simple wear resistant design provided with a passive hydraulic force generator was developed. It is completely symmetrical in structure and exhibits a very low degree of inherent damping. Accurate theoretical descriptions were established for both types of isolator, which are arranged at several points in different operating directions between the gearbox and fuselage. A uniaxial functional model was used to simulate the vertical motion of the helicopter. Good agreement is achieved between the theoretical and practical models. Quasi-static and dynamic life tests on the hydraulic version lead to the prediction of a service life of at least 2000 hours. Author (ESA) N81-30124# Royal Netherlands Aircraft Factories Fokker. Schiphol-Oost. VFW Technological Centre. OPERATIONAL EXPERIENCE WITH ADHESIVE BONDED STRUCTURES 582 N81-30134 Rob J. Schliekelmann 1979 31 p refs (FOK-BO-1235) Avail: NTIS HC A03/MF A01 Problem areas that require service, the principle causes of possible failures, and ways of achieving fully reliable bonded joints are discussed. Tables and diagrams detailing information received from airlines are given. With some exceptions, operational experience with honeycomb sandwich components is poor, but with metal-to-metal joints there is wide variation. The nature of the durability problems is such that causes of failure are identifiable and there is a good basis for improvement in bonded struc- tures. Author (ESA) N81-30125$ Messerschmitt-Boelkow-Blohm G m b H . Otto- brunn (West Germany). Helicopter and Transport Div. HELICOPTER TECHNOLOGIES OF THE FUTURE Kurt Pfleiderer 13 Oct. 1980 33 p Presented at Soc. of Automotive Engr. 1980 (MBB-UD-314/80-OE) Avail: NTIS HC A03/MF A01 An assessment of the future possibilities for the helicopter is presented, within the broad spectrum of all transport systems. Special attention is paid to weight reduction by extensive use of composites such as Kevlar fiber reinforced plastics. Crash resistance, ergonomic configuration optimization, aerodyna- mic improvements, vibration reduction, specific fuel consumption and noise reduction are discussed. Examples from the BO 105 and BK 117 helicopters are given. By the end of the century the helicopter is expected to reach the discussed development limits. Author (ESA) N81-30127# AiResearch Mfg. Co.. Torrance. Calif. CRASH SURVIVABLE FLIGHT DATA RECORDING SYSTEM STUDY Final Report 30 Jun. 1981 355 p (Contract F33615-80-C-0135) IAD-A101503: Rept-81-17693: ASD-TR-5011) Avail: NTIS HC A16/MF A01 CSCL 14/3 This study reviews the requirements and available technology for crash survivable flight data recording systems. Primary efforts relate to fighter/attack aircraft, with the A-10. F-15 and F-16 used as specific examples Results include design and perfor- mance characteristics of recommended systems and an analysis showing a high cost-effectiveness for implementation of such a CSFDRS. GRA N81-30128# Armc Research Corp.. Annapolis. Md DEVELOPMENT OF AVIONICS INSTALLATION INTERFACE STANDARDS Stewart Bailey. Neil Sullivan, and Also Savisaar Jun. 1d81 220 p (Contract F04606-79-G-0082: AF Proj. 2257) (AD-A101423: Rept-2258-03-2-2477) Avail: NTIS HC A10/MF A01 This document reports on the development of avionics installation standards for the avionics bay and cockpit areas of military aircraft. The standards were being developed through a co-operative industry/government open forum series of meetings. This report covers the preparation for the first meeting and the results of industry/government participation in the open forum. The draft avionics bay standard and a strawman control and display unit standard are attachments to the report. Author (GRA) N81-30130*# National Aeronautics and Space Administration. Lewis Research Center, Cleveland. Ohio. ROTOR WAKE CHARACTERISTICS RELEVANT TO ROTOR STATOR INTERACTION NOISE GENERATION Loretta M. Shaw and Joseph R. Balombin 1981 25 p refs Presented at 7th Acoustic Conf.. Palo Alto. Calif.. 5-7 Oct. 1981: Sponsored by AIAA (NASA-TM-82703: E-984) Avail: NTIS HC A02/MF A01 CSCL 21E Mean and turbulent wake properties at three axial locations behind the rotor of an aerodynamically loaded 1.2 pressure ratio fan were measured using a stationary cross film anemometer in an anechoic wind tunnel. Wake characteristics at four radial immersions across the duct at four different fan speeds were determined utilizing a signal enhancement technique. The shapes of the waveforms of the mean rotor relative and mean upwash velocities were shown to change significantly across the span of the blades. In addition, an increase in fan rotational speed caused an increase in the maximum wake turbulence intensity levels near the hub and tip. Spectral analysis was used to described the complex nature of the rotor wake. Author N81-30131# Garrett Turbine Engine Co.. Phoenix. Ariz. SMALL TURBINE ENGINE AUGMENTOR. PHASE 1: PRELIMINARY DESIGN STUDIES OF AFTERBURNER AND DUCT-BURNER CONFIGURATIONS Interim Technical Report, 1 Aug. - 29 Oct. 1980 T. E. Kuhn. T. W. Bruce, and H. C. Mongia Mar. 1981 47 p refs (Contract F33615-80-C-2001: AF Proj. 3066) (AD-A101595: Rept-21-3805(01): AFWAL-TR-81-2008) Avail: NTIS HC A03/MF A01 CSCL 21/5 Several candidate afterburner and duct-burner concepts were evaluated. The evaluation procedure included assessing engine and augmentor performance when integrated with airframes and mission data available from ATCM potential contractors. From the candidates analyzed, two configurations were chosen for further design evaluation. Of the several augmentor concepts screened, the conventional flameholder with mixer-nozzle and the partial-swirl augmentor were determined to produce the highest combustion efficiency with the least impact on the size or performance of the core engine. These two designs were therefore selected for detail analysis. Two engines were evaluated for use in augmented cruise missiles. The lower-bypass-ratio engine was selected because of its smaller diameter, similarity to the Boeing ALCM-L engine, and greater suitability for augmentation. The effect of using JP-10 and RJ-6 fuels was predicted to be small, but carbon-slurry fuel will require extensive modifications to the fuel manifold. Author (GRA) N81-30132# General Electric Co., Cincinnati, Ohio. Aircraft Engine Business Group. HIGH TEMPERATURE STRAIN GAGE SYSTEM FOR APPLICATION TO TURBINE ENGINE COMPONENTS Final Report. 15 Jun. 1976 - 15 Aug. 1980 R. A. Weise and J. H. Foster Jan. 1981 253 p refs (Contract F33615-76-C-2075: AF Proj. 3066) (AD-A101713: R80AEG388: A F W A L - T R - 8 0 - 2 1 26) Avail: NTIS HC A12/MF A01 CSCL 14/2 A three-phase program was completed to develop reliable, high temperature dynamic strain gage systems for application to turbine engine components operating to 1500 F. The strain gage element, intermediate leads and gage fabrication processes that evolved are used over the full temperature range: however, two different application techniques are required to achieve maximum fatigue strength to 1500 F. A composite-ceramic application design is recommended to 700 F. At higher temperatures, the all-FSA or Rokide design is preferred. Gage factor stabilization procedures were established. A strain gage reliability demonstration was conducted on an engine compressor and showed the composite-ceramic gage to have better reliability below 700 F. The report includes a detailed procedure of gage fabrication and application. Author (GRA) N81-30133# Rolls-Royce Ltd., Derby (England). PROGRAMMES FOR MILITARY ENGINES WITH COST OBJECTIVES Claude Foure 1980 47 p Transl. into ENGLISH from French Conf. paper presented at AGARD Conf. (PNR-90058: AGARD-LS-107: Trans-15261) Avail: NTIS HC A03/MF A01 Management techniques for military aircraft engine design, production and maintenance referred to cost objectives are discussed. Life cycle cost, engine reliability, direct operating cost, purchasing cost, and the relationship between technical and cost objectives are examined. The techniques for cost forecasting are reviewed. The type of organization suited to follow both technical and cost objectives is analyzed. A maintenance method called Individually Repaired Subassemblies is detailed. The maintenance studies done for the Larzac aircraft fleet are presented. The spectrometric analysis of oil. particle analysis, vibration analysis, gammagraphy and endoscopy as maintenance techniques are also discussed. Author (ESA) N81-30134*# Kansas Univ. Center for Research. Inc . Lawrence Flight Research Lab. A PROGRAM TO EVALUATE A CONTROL SYSTEM BASED ON FEEDBACK OF AERODYNAMIC PRESSURE DIF- FERENTIALS. PART 1 Interim Report Ronald R. Hrabak. David W. Levy. Paul Finn, and Jan Roskam 583 N81-30135 Aug. 1981 213 p refs (Grant NAG4-5) (NASA-CR-164684; KU-FRL-490-1-Pt-1) Avail: NTIS HC A10/MF A01 CSCL 01C The use of pressure differentials in a flight control system was evaluated The pressure profile around the test surface was determined using two techniques: (1) windtunnel data (actual): and (2) NASA/ Langley Single Element Airfoil Computer Program (theoretical). The system designed to evaluate the concept of using pressure differentials is composed of a sensor drive and power amplifiers, actuator, position potentiometer, and a control surface. The characteristics (both desired and actual) of the system and each individual component were analyzed. The desired characteristics of the system as a whole are given. The flight control system developed, the testing procedures and data reduction methods used, and theoretical frequency response analysis are described J.M S N81-30135*# Kansas Univ. Center for Research, Inc.. Lawrence. Flight Research Lab. A PROGRAM TO EVALUATE A CONTROL SYSTEM BASED ON FEEDBACK OF AERODYNAMIC PRESSURE DIF- FERENTIALS. PART 2: DATA REPORT FOR PHASE 1 WIND TUNNEL TEST Interim Report Ronald R. Hrabak. David W. Levy. Paal Finn, and Jan Roskam Aug. 1981 119 p refs (Grant NAG4-5) (NASA-CR-164685: KU-FRL-490-1-PI-2) Avail: NTIS HC A06/MF A01 CSCL 01C Wind tunnel test data are presented. The purpose of the test was to determine the sensor location for sensitivity to flap deflection and to determine the range required of the sensor The calculations followed to correct the raw pressure measure- ments, the corrected measurements, which represent the static pressures along the airfoil surface, and the static pressures tabulated and in coefficient form are described. However, the chordwise locations of the upper and lower surface taps do not coincide. An interpolation routine is performed to find the lower surface pressure coefficients at the upper surface tap locations. The difference. C sub P(lower) - C sub P(upper), is calculated and listed and the data are reorganized with respect to each tap location. A numerical regression performed to quantify the slopes of the graphs allows more accurate comparison of sensitivity and linearity J M.S. N81-30136*# National Aeronautics and Space Administration Ames Research Center. Moffett Field. Calif SIMULATION STUDY OF TWO VTOL CONTROL/DISPLAY SYSTEMS IN IMC APPROACH AND LANDING Vernon K. Merrick Aug. 1981 90 p refs (NASA-TM-81295: A-8592) Avail: NTIS HC AO5/MF A01 CSCL 01C Both systems had full attitude command; the more complex system (Type 11 also had translational velocity command. The systems were applied to existing models of a VTOL lift-fan transport and the AV-8A Harrier. Simulated landings were made on a model of a DD963 Spruance-class destroyer. It was concluded that acceptable transitions and vertical landings can be performed, using the Type 1 system, in free-air turbulence up to 2.5 m/sec and sea state 6 and. using the Type 2 system, in free-air turbulence up to 1.5 m/sec and sea state 4. T.M. N81-30137*# Vigyan Research Associates. Inc.. Hampton, Va SUBSONIC PITCH-UP ALLEVIATION ON A 74 DEC DELTA WING Dhanvada M. Rao and Thomas D. Johnson. Jr. (Kentron International. Inc.. Hampton. Va.) Jul. 1981 20 p refs (Contract NAS1-16259) (NASA-CR-165749) Avail: NTIS HC A02/MF A01 CSCL 01C Fixed leading-edge devices were investigated for alleviating the tow speed pitch-up and longitudinal instability of a 74 deg delta wing model. In wind-tunnel tests. Pylon Vortex Generators were shown to be highly effective, compared to leading-edge fences and slots, in raising the pitch-up angle of attack from 8 deg to 28 deg. The subsonic drag penalty was negligible. Author N81-30138*# Air Force Wright Aeronautical Labs., Wright- Patterson AFB. Ohio. Control Dynamics Branch. A CONTINUOUSLY RECONFIGURING MULTI- MICROPROCESSOR FLIGHT CONTROL SYSTEM Final Report. 1 Aug. 1979 - 30 Apr. 1981 Stanley J. Larimer and Scott L. Maher May 1981 150 p refs (AF Proj. 2403) (AD-A101412: AFWAL-TR-81-3070) Avail: NTIS HC A07/MF A01 CSCL 09/2 Recent research at the US Air Force Wright Aeronautical Laboratories (Flight Dynamics Lab) has resulted in the development of a promising microprocessor-based flight control system design. This system is characterized by a collection of cooperatively autonomous distributed microcomputers interconnected by an arbitrary number of common serial multiplex busses. Each processor in the system independently determines its assignments using a simple algorithm that dynamically redistributes system functions from processor to processor in a never-ending process of reconfiguration. This approach offers several benefits in terms of system reliability, and the architecture in general incorporates many state-of-the-art features which promise improved system throughput, expandability, and above all. ease of programming. GRA N81-30139# Messerschmitt-Boelkow-Blohm G m b H , Otto- brunn (West Germany). Unternehmensbereich Drehflueger FLIGHT INVESTIGATIONS OF A HELICOPTER LOW AIRSPEED ESTIMATION SYSTEM BASED ON MEASURE- MENT OF CONTROL PARAMETERS A. J. Faulkner and F. Buchner 11 Aug. 1980 23 p refs Presented at 6th European Rotocraft and Powered Lift Aircraft Forum. Bristol. England, 16-19 Sep. 1980 (MBB-UD-306/80-OE) Avail: NTIS HC A02/MF A01 An indirect method for estimating airspeed, particularly suitable for modern hmgless rotor helicopters, is described. Air-speed indication is useful since handling characteristics are primarily dependent on the rotor in-plane component. The theoretical analysis developed uses of an existing simplified analytical solution (not involving nonlinear effects) for rotor flapping and thrust equations. These equations are inverted and appropri- ate approximations made for second-order quantities. Equations are thus derived for the longitudinal and lateral aerodynamic velocity components Experimental results obtained for trimmed and transient flight states are presented. A 16 bit processor was employed. Particular attention is given to the rotor down-wash model together with instrumentation and accuracy improvements obtainable. Author (ESA) N81-30140# Messerschmitt-Boelkow-Blohm G m.b.H.. Otto- brunn (West Germany). Unternehmensbereich Drehfluegler. PARAMETER IDENTIFICATION OF A HINGELESS ROTOR HELICOPTER IN FLIGHT CONDITIONS WITH INCREASED INSTABILITY M Kloster. J. Kaletka (DFVLR. Brunswick), and H. Schaeufele 1 Sep. 1980 24 p refs Presented at 6th European Rotocraft and Powered Lift Aircraft Forum. Bristol. England. 16-19 Sep 1980 (MBB-UD-307/80-OE) Avail: NTIS HC A02/MF A01 Hover and flight at maximum speed were studied. Both flight conditions were performed with maximum weight and a mid center of gravity position. An attitude feedback control system was necessary because of the instability. A strapdown system was used for measurements. Closed loop stabilization was obtained with an onboard computer. The input signals of the unstabilized helicopter were optimized. Time and frequency calculations show that special input signals are needed for the closed loop system. A special distribution of the power spectrum leads to a quasi-optimized input signal. These signals were filtered with second order linear filters to suppress rotor dynamics, derivatives identified from flight tests (six degree of freedom rigid body model) are compared with the results of nonlinear simulation and quasistatic theory. In general, agreement is good. Author (ESA) N81-30141f Naval Civil Engineering Lab.. Port Hueneme. Calif. RECYCLING OF PORTLAND CEMENT CONCRETE AIRPORT 584 N81 30190 PAVEMENTS: A STATE-OF-THE-ART STUDY Final Report. Oct. 1979 - Sep. 1980 M. C. Hironaka. R. B. Brownie, and G. Y. Wu Apr. 1981 36 p refs (Contract DOT-FA77WAI-704) (AO-A101482: FAA-RD-81-5) Avail: NTIS HC A03/MF A01 CSCL 11/2 An investigation was performed to assess the state-of-the-art of recycling Portland cement concrete (PCC) airport pavements. Previous laboratory studies have shown that recycling of PCC pavements is technically and economically feasible. This has been demonstrated in airport reconstruction projects at Jackson- ville International Airport (Florida). Love Field (Texas), and Coffeyville Municipal Airport (Kansas), where PCC was recycled into econocrete base and aggregate subbase. cement stabilized base, and part of the aggregate base course, respectively. Recycling of PCC for surface courses in airport pavement construction has not yet been performed, but this should also prove to be beneficial as has been experienced by the Iowa DOT and other state highway agencies who have recycled PCC for surface courses. Equipment for recycling PCC pavements is currently available in the construction industry: however, these, along with the technology of PCC recycling, could be improved substantially Recommendations for specific improvements are therefore made. Author (GRA) N81-30143# Messerschmitt-Boelkow-Blohm G.m.b.H.. Otto- brunn (West Germany). Unternehmensbereich Apparate. DIGITAL DATA BASES FOR VISUAL AND RADAR SIMULATION Barbara Diess 5 Sep. 1980 12 p refs (MBB-UA-549/80-OE) Avail: NTIS HC A02/MF A01 Criteiia for a relevant mathematical description of the a simplified real world are defined and a computerized interactive system is described for facilitating the generation of data bases for flight simulators with high performance characteristics. The automatic generation of digital visual and digital radar scenes requires continuous updating and upgrading. The implementation of a system using a Perkin/Elsser 8/32 with 1 M byte store, a floating point processor and array processor, and standard input and output units is described. ARM N81-30158# Institute de Pesquisas Espaciais. Sao Jose dos Campos (Brazil). ESTIMATION OF AERODYNAMIC FORCES ACTING ON EARTH SATELLITES. APPLICATION TO AN EXPERIMENTAL SATELLITE [ESTIMACAO DAS FORCAS AERODINAMICAS EM SATELITESTERRESTRES. APLICACAO A UM SATELITE EXPERIMENTAL] Valdemir Carrara Nov. 1980 43 p refs In PORTUGUESE; ENGLISH summary (INPE-1944-RPE/262) Avail: NTIS HC A03/MF A01 The forces acting on an artificial satellite are described. Computable expressions are written for them. A subroutine called DRAG, which estimates the forces due to aerodynamic drag acting on a satellite with a general shape, was written. The equations were derived from Boltzmann equation, with a Maxwellian distribution of velocity and using atmospheric parameters. S.F. N81-30159# Air Force Wright Aeronautical Labs.. Wright- Patterson AFB. Ohio. High-Speed Aero-Performance Branch. HIGH ANGLE OF ATTACK MISSILE AERODYNAMIC AT MACH NUMBERS 0.30 TO 1.5 Final Report. Mac. 1974 - Apr. 1979 Valentine Dahlem. Jack I. Flaherty, Donald E. Shereda. and Christian E. G. Przirembe (Rutgers Univ.. N.J.) Nov. 1980 330 p refs (AF Proj. 2404) (AD-A010210: AFWAL-TR-80-3070) Avail: NTIS HC A15/MF A01 CSCL 01/1 Wind tunnel tests of a smooth missile model with several interchangeable nose parts were conducted at subsonic through supersonic speeds at angles of attack from 0 to 180 degrees. Measurements of both surface pressures and total forces and moments were made at a variety of Mach numbers and Reynolds number combinations. Data were supplemented with wake flow field measurements of the impact pressure and flow direction at angles of attack where maximum induced side force was expected to occur. The important variables of the high angle of attack flow phenomena are numerated. The high angle of attack data are analyzed to deduce the vortex shedding location, the vortex strength, and the vortex paths in the wake. Discrete vortex theory is examined as a method which could be modified, based on experimental data, and used to predict the aerodynamic characteristics of missiles to greater accuracy. E.A.K. N81-301608 Air Force Inst. of Tech.. Wright-Patterson AFB. Ohio. Dept. of Engineering. MAXIMUM INFORMATION TRAJECTORY FOR AN AIR TO AIR MISSILE INTERCEPT M.S. Thesis - Texas Univ. at Austin Stephen Wendell Larson Dec. 1980 80 p refs (AD-A101497: AFIT-CI-80-68T) Avail: NTIS HC A05/MF A01 CSCL 16/2 This thesis presents a method for finding the trajectory to complete an air-to-air missile intercept which maximizes information. This is accomplished by formulating a parameter optimization problem and using a penalty function-Lagrange multiplier method to solve for the optimal path. The performance index is the trace of the information matrix. This information matrix is derived using an extended Kalman filter formulation, in cartesian coordinates, which makes state estimates based only on angle measurements. The trace operation on the information matrix is used because the trace and the integration operations commute allowing a scalar performance index. Further, reduction in the functional form of the performance index is achieved by weighing the information matrix by the inverse of the measurement power spectral density. This also avoids numerical difficulties near intercept. Author (GRA) N81 30188# Executive Office of the President. Washington. DC Office ol Science and Technology Policy. C A R B O N / G R A P H I T E COMPOSITE MATERIAL STUDY Annual Report 15 Jan 1981 122 p refs (AR-31 Avail: NTIS HC A06/MF A01 A coordinated federal government action plan was announced in January 1978 to study the potential problems arising from the projected increased use of carbon fiber composite materials in civilian applications. The primary concern was the electrical hazard associated with carbon fibers released from burning of carbon fiber composites and disposal of carbon composite waste or worn out parts. The federal government action plan assigned responsibility for various elements of the study to appropriate federal agencies. The third annual report of the Office of Technology Policy (OSTP) contains the final reports of the NASA. DOT. DOE. AND DOC and the progress reports of the EPA. DHHS (NIOSH). DDL (OSHA). and the FEMA. Also included in this report are the findings of the OSTP. the status agency responsibilities, and a list of applicable references. For individual titles, see N81-30189 through N81-30191. N81-30189*# National Aeronautics and Space Administration. Langley Research Center, Hampton. Va. CARBON/GRAPHITE COMPOSITE MATERIAL STUDY. 3: AGENCY PROGRAM ACTIVITIES. NATIONAL AERO- NAUTICS AND SPACE ADMINISTRATION (NASA) In Executive Office of the President Carbon/Graphite Composite Material Study 15 Jan. 1981 p 6-10 (For primary document see N81-30188 21-24) Avail: NTIS HC A06/MF A01 CSCL 11D The accidental release of carbon fibers from civil aircraft and the need for protection of civil aircraft systems from such fibers were studied. It was concluded that the electrical hazard from carbon fibers accidentally released in an aircraft crash fire pose no threat to human life. Overall costs associated with carbon fiber release are predicted to be extremely low. The risk of electrical or electronic failures due to carbon fibers is so minimal that future exploitation of carbon composites in aircraft should be continued. Additional protection of aircraft avionics to guard against carbon fibers is unnecessary. A program to develop alternate materials specifically to overcome the potential electrical hazard is not justified. E.K. N81-30190* # National Aeronautics and Space Administration. Langley Research Center. Hampton. Va. CARBON/GRAPHITE COMPOSITE MATERIAL STUDY, APPENDIX A AND APPENDIX B In Executive Office of the President Carbon/Graphite Composite Material Study 15 Jan. 1981 p 48-100 (For primary document 585 N81-30198 see N81-30188 21-24) Avail: NTIS HC A06/MF A01 CSCL 110 A comprehensive assessment of the possible damage to electrical and electronic equipment caused by accidental release of carbon fibers from burning civil aircraft with carbon composite parts was completed. The study concluded that the amount of fiber likely to be released is much lower than initially predicted. Carbon fiber released from an aircraft crash fire was found (from atmospheric dissemination models) to disperse over a much larger area than originally estimated, with correspondingly lower fiber concentrations. Long term redissemination of fiber was shown to be insigificant if reasonable care is exercised in accident cleanup The vulnerability of electrical equipment to structural fibers in current use was low. Consumer appliances, industrial electronics, and avionics were essentially invulnerable to carbon fibers. Shock hazards (and thus potential injury or death) were found to be extremely unlikely. E.K. N81-30198# Messerschmitt-Boelkow-Blohm G.m.b.H.. Otto- brunn (West Germany). Unternehmensbereich Drehfluegler. DEVELOPMENT AND DESIGN OF A LARGE WIND-TURBINE BLADE Michael Hahn May 1980 26 p refs (MBB-UD-301/80-OE) Avail: NTIS HC A03/MF A01 The implementation of the mold concept in the fabrication of large blade-structures which require special surface definition and design features is described. These blades are intended for large horizontal axis windmills. Fiber reinforced composite materials produce rotor blades of high aerodynamic quality with very different profiles. It is possible to vary the stiffness of a cross-section with a given contour. Lightning protection features incorporated are described together with the protection character- istics afforded by erosion resistant paint. In the attachment area, the laminate is thickened considerably. The loads are transferred by means of prestressed studs in combination with cylindrical nuts which fit into holes bored in the thickened laminate. Author (ESA) N81-30199# Messerschmitt-Boelkow-Blohm G.mb.H., Otto- brunn (West Germany). Unternehmensbereich Drehfluegler. DEVELOPMENT OF A BEARINGLESS HELICOPTER TAIL ROTOR H. Huber. H. Frommlet, and W. Buchs 11 Aug. 1980 24 p refs Presented at 6th European Rotocraft and Powered Lift Aircraft Forum. Bristol. England. 16-19 Sep. 1980 (MBB-UD-304/80-OE) Avail: NTIS HC A02/MF A01 A composite bearingless tail rotor is discussed which uses fiberglass bending-torsion-flexure to accommodate bending deflections and collective pitch control. The low chordwise stiffness (soft-inplane concept) contributes significantly to low blade stresses, attainment of low control loads, and low weight. The stability of the soft-inplane tailrotor coupled with the airfcame modes is emphasized. Two tailrotor configurations, one three- bladed and the other four-bladed. are considered. The technical design approach is discussed as well as the dynamic characteris- tics, aerolastic stability, loads, and stress concentration. Results of the structural fatigue and frequency survey testing of components and full-scale blade assemblies are included. Expected weight and cost benefits are examined. Author (ESA) N81-30282# Radian Corp.. Austin. Tex. CHROMATOGRAPHIC SEPARATION OF CONVENTIONAL AND EXPERIMENTAL FUELS Final Technical Report. Sep. 1979 - Jun. 1980 Karl J. Bombaugh. Donald H. Rodgers. and John C. Beltz Oct. 1980 57 p (Contract F33615-79-C-2083: AF Proj. 2303) (AD-A101673: RAD-219-030-03: AFWAL-TR-80-2098) Avail: NTIS HC A04/MF A01 CSCL 21/4 This research was performed in order to develop a chromato- graphic method for the separation and isolation of the various classes of hydrocarbons present in conventional and experimental aircraft fuels. The objective of such a technique is to provide a convenient means of estimating the relative proportions of the hydrocarbon classes, i.e.. normal and branched alkanes. alkylben- zenes. alkenes. etc.. and to render the initially complex fuels tractable to conventional methods of analysis and characterization. The procedure developed consists of a semi-preparative column chromatographic method, using spherical particulate silica gel column packing and isobutane as the mobile phase. The fuel samples are fractionated by passing them through the column and collecting the eluting fractions at regular intervals. The volatile isobutane carrier is evaporated from the fractions and the residues are analyzed by techniques such as gas chromatography. Because the isobutane vaporizes quantitatively at low temperatures, the fractions are obtained free of interfering solvent. In this respect, the technique is novel and unprecedented Results of the analyses show that the method provides good separation of aliphatic and aromatic hydrocarbons, and partial resolution of aliphatic and olefinic hydrocarbons. Resolution may be improved substantially by optimizing the column temperature and by using low-boiling mobile phases of varying polarity. GRA N81 -30313# Oak Ridge National Lab.. Tenn. A MATRIX APPROACH TO BIOLOGICAL INVESTIGATION OF SYNTHETIC FUELS David L. Coffin Mar. 1981 79 p refs Conf. held at Research Triangle Park. N.C.. 26 Apr. 1979: sponsored by EPA and DOE (PB81-183477: EPA-600/9-81-009) Avail: NTIS HC A05/MF A01 CSCL 06T Documentation is provided for a conference on toxicological assessment of health effects from the rapidly developing synthetic fuels industry. The discussions focus on the Paraho crude shale oil produced and refined into diesel and jet fuels. Summaries of both operations are presented. Also discussed is the collection, storage, and distribution to toxicologists of sample materials from these operations. GRA N81-30331$ Institute de Pesquisas Espaciais. Sao Jose dos Campos (Brazil). TRANSVERSE VOICE RADIO LINK FOR STRATOSPHERIC BALLOONS [RADIOENLACE DE VOZ ATRAVES OE BALAO ESTRATOSFERICOS] Etiene Monteiro Schneider Jan. 1981 14 p refs In PORTU- GUESE: ENGLISH summary Presented at the 23nd Ann. Meeting of SBPC (INPE-1992-RPE/285) Copyright. Avail: NTIS HC A02/MF A01 A three-way communication system between a scientific balloon, aircraft, and ground tracking station is described. The balloon payload. which flies at an altitude of 40 km. is used as an active repeater. The system uses links already existing in this kind of flight: telecommand, telemetry, and radio localization. The signal from the ground station comes to the balloon through the telecommand link, is sent to the aircraft through the radio localization link. The signal from the aircraft comes to the balloon through the telecommand link and is sent to the ground station through the telemetry link. Aircraft and ground station use a normal VHF communication link. J.D.H. N81-30338# AMAF Industries. Columbia. Md. IMPACT OF LOW ALTITUDE COVERAGE REQUIREMENTS ON AIR-GROUND COMMUNICATIONS Final Report. Aug 1980 - Mar. 1981 B. Magenheim Washington FAA 31 Mar. 1981 93 p (Contract DOT-FA78WAI-830) (AD-A101642: FAA-RD-81-9) Avail: NTIS HC A05/MF A01 CSCL 17/2 A representative area of Appalachia surrounding Charleston. West Virginia is analyzed in terms of existing helicopter traffic patterns and communications facilities. Traffic patterns were established from telephone interviews with pilots flying this area regularly. Communications coverage was established from computer generated coverage contours obtained from the Electromagnetic CompatiDility Analysis Center (ECAC) and verified by pilot interviews and one flight test (as reported by the FAA Technical Center). Techniques for improving coverage are discussed. These include two new remote communication outlets located in the mountains west and south of Beckley. W. Va.. a high gain antenna at Charleston pointed in a southerly direc- tion, the use of mobile radio telephone to permit pilots to access nearby telephone facilities when on the ground at a remote site, short range less than 150 miles, hf radio, and a discrete frequency for exclusive use by low-flying aircraft. FAA activities directed at improving communications to helicopter flying to and from offshore oil and gas platforms in the Gulf of Mexico is presented in an Appendix. Author (GRA) N81-30388*| Old Dominion Univ.. Norfolk. Va. Mechanical Engineering and Mechanics. Dept. of 586 N81-30525 HADY 1. A FORTRAN PROGRAM FOR THF COMPRESSIBLE STABILITY ANALYSIS OF THREE-DIMENSIONAL BOUND ARY LAYERS Nabil M. £l-Hady tt± Hppi. oi ^>idUihiv

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