Wind shear and turbulence simulation

The aviation community is increasing its reliance on flight simulators. This is true both in pilot training and in research and development. In moving research concepts through the development pipeline, there is a sequence of events which take place: analysis, ground based simulation, inflight simulation, and flight testing. Increasing fidelity as progress toward the flight testing arena is accompanied by increasing cost. The question that seems to be posed in relation to the meteorological aspects of flight simulation is, How much fidelity is enough and can it be quantified. As a part of the Langley Simulation Technology Program, there are three principal areas of focus, one being improved simulation of weather hazards. A close liaison with the JAWS project was established because of the Langley Simulation Technology interests regarding reliable simulation of severe convective weather phenomena and their impact on aviation systems. Simulation offers the only feasible approach for examining the utility of new technology and new procedures for coping with severe convective weather phenomena such as wind shear. These simulation concepts are discussed in detail

Aeronautical Engineering. A continuing bibliography with indexes, supplement 156

This bibliography lists 288 reports, articles and other documents introduced into the NASA scientific and technical information system in December 1982

Aeronautical Engineering: A continuing bibliography, supplement 120

This bibliography contains abstracts for 297 reports, articles, and other documents introduced into the NASA scientific and technical information system in February 1980

Aeronautical Engineering: A special bibliography with indexes, supplement 62

This bibliography lists 306 reports, articles, and other documents introduced into the NASA scientific and technical information system in September 1975

Aeronautical engineering, a continuing bibliography with indexes

This bibliography lists 567 reports, articles and other documents introduced into the NASA scientific and technical information system in January 1984

Controlling Sideslip Angle to Reduce the Radar Exposure of a Tactical, Rotary Winged UAV

This work investigates another way of contributing to the radar minimization solution for air vehicles in a threat environment. While much research has been conducted on structural solutions to radar exposure minimization, not much work has been done in the area of using control to continuously assess and present the smallest radar cross section of an air vehicle to oncoming threat radar systems by changing the aircraft\u27s orientation. This work looks at the application of sideslip/beta angle feedback control of an unmanned helicopter to minimize radar cross section exposure in a hostile radar environment. A new way of controlling aircraft trajectory is introduced that incorporates both path and orientation optimization feedback; the aircraft\u27s heading is controlled to orient the vehicle in a way that reduces its radar cross section, while sideslip angle is used to control the aircraft\u27s path. A representative hostile environment is created and results show that a substantial reduction in radar cross section exposure can be achieved with beta feedback control. A linear state space model is derived for the OH-6A helicopter with the JANRAD software program. Eigenstructure assignment is used to shape the response of the helicopter into desired response modes. A Matlab based flight control system is developed around the derived helicopter model with altitude, heading, and beta angle command signals that drive four conventional helicopter control inputs

Aerospace Medicine and Biology: A continuing bibliography with indexes, supplement 192

This bibliography lists 247 reports, articles, and other documents introduced into the NASA scientific and technical information system in March 1979

Flight investigation of the effect of tail boom strakes on helicopter directional control

A joint U.S. Army/NASA flight investigation was conducted utilizing a single-rotor helicopter to determine the effectiveness of horizontally mounted tail boom strakes on directional controllability and tail rotor power during low-speed, crosswind operating conditions. Three configurations were investigated: (1) baseline (strakes off), (2) single strake (strake at upper shoulder on port side of boom), and (3) double strake (upper strake plus a lower strake on same side of boom). The strakes were employed as a means to separate airflow over the tail boom and change fuselage yawing moments in a direction to improve the yaw control margin and reduce tail rotor power. Crosswind data were obtained in 5-knot increments of airspeed from 0 to 35 knots and in 30 deg increments of wind azimuth from 0 deg to 330 deg. At the most critical wind azimuth and airspeed in terms of tail rotor power, the strakes improved the pedal margin by 6 percent of total travel and reduced tail rotor power required by 17 percent. The increase in yaw control and reduction in tail rotor power offered by the strakes can expand the helicopter operating envelope in terms of gross weight and altitude capability. The strakes did not affect the flying qualities of the vehicle at airspeeds between 35 and 100 knots

Research and Technology Objectives and Plans Summary (RTOPS)

A compilation of the summary portion of each of the Research and Technology Operating Plans (RTOP) used for management review and control of research currently in progress throughout NASA is presented along with citations and abstracts of the RTOPs. Four indexes are included: (1) subject; (2) technical monitor; (3) responsible NASA organization; and (4) RTOP number

Aeronautics and space report of the President, 1982 activities

Achievements of the space program are summerized in the area of communication, Earth resources, environment, space sciences, transportation, aeronautics, and space energy. Space program activities of the various deprtments and agencies of the Federal Government are discussed in relation to the agencies' goals and policies. Records of U.S. and world spacecraft launchings, successful U.S. launches for 1982, U.S. launched applications and scientific satellites and space probes since 1975, U.S. and Soviet manned spaceflights since 1961, data on U.S. space launch vehicles, and budget summaries are provided. The national space policy and the aeronautical research and technology policy statements are included