Antenna design for surface wave suppression Patent

Development of method for suppressing excitation of electromagnetic surface waves on dielectric converter antenn

Means for measuring the electron density gradients of the plasma sheath formed around a space vehicle Patent

Development of method for measuring electron density gradients of plasma sheath around space vehicle during atmospheric entr

Simulator study of minimum acceptable level of longitudinal stability for a representative STOL configuration during landing approach

A fixed-base simulator study was conducted to determine the minimum acceptable level of longitudinal stability for a representative turbofan STOL (short take-off and landing) transport airplane during the landing approach. Real-time digital simulation techniques were used. The computer was programed with equations of motion for six degrees of freedom, and the aerodynamic inputs were based on measured wind-tunnel data. The primary piloting task was an instrument approach to a breakout at a 60-m (200-ft) ceiling

Simulation of decelerating landing approaches on an externally blown flap STOL transport airplane

A fixed-base simulator program was conducted to define the problems and methods for solution associated with performing decelerating landing approaches on a representative STOL transport having a high wing and equipped with an external-flow jet flap in combination with four high-bypass-ratio fan-jet engines. Real-time digital simulation techniques were used. The computer was programed with equations of motion for six degrees of freedom and the aerodynamic inputs were based on measured wind-tunnel data. The pilot's task was to capture the localizer and the glide slope and to maintain them as closely as possible while decelerating from an initial airspeed of 140 knots to a final airspeed of 75 knots, while under IFR conditions

A simulator study for the development and evaluation of operating procedures on a supersonic cruise research transport to minimize airport-community noise

Piloted-simulator studies were conducted to determine takeoff and landing operating procedures for a supersonic cruise research transport concept that result in predicted noise levels which meet current Federal Aviation Administration (FAA) certification standards. With the use of standard FAA noise certification test procedures, the subject simulated aircraft did not meet the FAA traded-noise-level standards during takeoff and landing. However, with the use of advanced procedures, this aircraft meets the traded-noise-level standards for flight crews with average skills. The advanced takeoff procedures developed involved violating some of the current Federal Aviation Regulations (FAR), but it was not necessary to violate any FAR noise-test conditions during landing approach. Noise contours were also determined for some of the simulated takeoffs and landings in order to indicate the noise-reduction advantages of using operational procedures other than standard

Active and passive microwave measurements in Hurricane Allen

The NASA Langley Research Center analysis of the airborne microwave remote sensing measurements of Hurricane Allen obtained on August 5 and 8, 1980 is summarized. The instruments were the C-band stepped frequency microwave radiometer and the Ku-band airborne microwave scatterometer. They were carried aboard a NOAA aircraft making storm penetrations at an altitude of 3000 m and are sensitive to rain rate, surface wind speed, and surface wind vector. The wind speed is calculated from the increase in antenna brightness temperature above the estimated calm sea value. The rain rate is obtained from the difference between antenna temperature increases measured at two frequencies, and wind vector is determined from the sea surface normalized radar cross section measured at several azimuths. Comparison wind data were provided from the inertial navigation systems aboard both the C-130 aircraft at 3000 m and a second NOAA aircraft (a P-3) operating between 500 and 1500 m. Comparison rain rate data were obtained with a rain radar aboard the P-3. Evaluation of the surface winds obtained with the two microwave instruments was limited to comparisons with each other and with the flight level winds. Two important conclusions are drawn from these comparisons: (1) the radiometer is accurate when predicting flight level wind speeds and rain; and (2) the scatterometer produces well behaved and consistent wind vectors for the rain free periods

An operational satellite scatterometer for wind vector measurements over the ocean

Performance requirements and design characteristics of a microwave scatterometer wind sensor for measuring surface winds over the oceans on a global basis are described. Scatterometer specifications are developed from user requirements of wind vector measurement range and accuracy, swath width, resolution cell size and measurement grid spacing. A detailed analysis is performed for a baseline fan-beam scatterometer design, and its performance capabilities for meeting the SeaSat-A user requirements. Various modes of operation are discussed which will allow the resolution of questions concerning the effects of sea state on the scatterometer wind sensing ability and to verify design boundaries of the instrument

Simulator study of flight characteristics of a large twin-fuselage cargo transport airplane during approach and landing

A six degree-of-freedom, ground-based simulator study was conducted to evaluate the low speed flight characteristics of a twin fuselage cargo transport airplane and to compare these characteristics with those of a large, single fuselage (reference) transport configuration which was similar to the Lockheed C-5C airplane. The primary piloting task was the approach and landing. The results indicated that in order to achieve "acceptable' low speed handling qualities on the twin fuselage concept, considerable stability and control augmentation was required, and although the augmented airplane could be landed safely under adverse conditions, the roll performance of the aircraft had to be improved appreciably before the handling qualities were rated as being "satisfactory.' These ground-based simulation results indicated that a value of t sub phi = 30 (time required to bank 30 deg) less than 6 sec should result in "acceptable' roll response characteristics, and when t sub phi = 30 is less than 3.8 sec, "satisfactory' roll response should be attainable on such large and unusually configured aircraft as the subject twin fuselage cargo transport concept

Beaufort/Bering 1979 microwave remote sensing data catalog report, 14-24 March 1979

The airborne microwave remote sending measurements obtained by the Langley Research Center in support of the 1979 Sea-Ice Radar Experiment (SIRE) in the Beaufort and Bering Seas are discussed. The remote sensing objective of SIRE was to define correlations between both active and passive microwave signatures and ice phenomena assocated with practical applications in the Arctic. The instruments used by Langley during SIRE include the stepped frequency microwave radiometer (SFMR), the airborne microwave scatterometer (AMSCAT), the precision radiation thermometer (PRT-5), and metric aerial photography. Remote sensing data are inventoried and cataloged in a user-friendly format. The data catalog is presented as time-history plots when and where data were obtained as well as the sensor configuration

Simulator study of the low-speed handling qualities of a supersonic cruise arrow-wing transport configuration during approach and landing

A fixed-based simulator study was conducted to determine the low-speed flight characteristics of an advanced supersonic cruise transport having an arrow wing, a horizontal tail, and four dry turbojets with variable geometry turbines. The primary piloting task was the approach and landing. The statically unstable (longitudinally) subject configuration has unacceptable low-speed handling qualities with no augmentation. Therefore, a hardened stability augmentation system is required to achieve acceptable handling qualities, should the normal operational stability and control augmentation system fail. In order to achieve satisfactory handling qualities, considerable augmentation was required