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CONTRACT OR GRANT
REPORT NUMBERS
PRICE CODE

Stanley Fay, Stephen Gates, Timothy Henderson, Lester Sackett,
Kim Kirchwey, Isaac Stoddard, and Joel Storch

205 p

(Contract NAS9-17560)

Sep. 1988

PUBLICATION DATE

(NASA-CR-172095; R-2088; NAS 1.26:172095) Avail: NTIS HC
A10/MF A01 CSCL 22B

The second Control Of Flexible Structures Flight Experiment
(COFS-2) includes a long mast as in the first flight experiment,
but with the Langley 15-m hoop column antenna attached via a
gimbal system to the top of the mast. The mast is to be mounted
in the Space Shuttle cargo bay. The servo-driven gimbal system
could be used to point the antenna relative to the mast. The
dynamic interaction of the Shuttle Orbiter/COFS-2 system with
the Orbiter on-orbit Flight Control System (FCS) and the gimbal
pointing control system has been studied using analysis and
simulation. The Orbiter pointing requirements have been assessed
for their impact on allowable free drift time for COFS experiments.
Three fixed antenna configurations were investigated. Also
simulated was Orbiter attitude control behavior with active vernier
jets during antenna slewing. The effect of experiment mast dampers
was included. Control system stability and performance and loads
on various portions of the COFS-2 structure were investigated.
The study indicates possible undesirable interaction between the
Orbiter FCS and the flexible, articulated COFS-2 mast/antenna
system, even when restricted to vernier reaction jets. Author

AVAILABILITY SOURCE
COSATI CODE

xii

TE SOURCE

ON DATE

TY SOURC

E

NATIONAL

USA

ADMINISTRATION

VOLUME 27 NUMBER 21 / NOVEMBER 8, 1989

Scientific and Technical Aerospace Reports

A Semimonthly Publication of the National Aeronautics and Space Administration

01 AERONAUTICS (GENERAL)

N89-26807# Air Force Systems Command, Wright-Patterson AFB, OH. Foreign Technology Div.

ACTA AERONAUTICA ET ASTRONAUTICA SINICA, VOLUME 8, NUMBER 12, DECEMBER 1987 (SELECTED ARTICLES) 15 Feb. 1989 71 P Transl. into ENGLISH from Hangkong Xuebao (Peoples Republic of China), v. 8, no. 12, Dec. 1987 p 8557-8562, 8585-8593, and 8601-8610

(AD-A206782; FTD-ID(RS)T-0942-88) Avail: NTIS HC A04/MF A01 CSCL 01/2

Aircraft take off and landing gear are studied in order to understand nose wheel shimmy and provide measures to prevent it. It also deals with an analysis of runway dynamics and other such similar areas as nose wheel operation. Semi-Prepared Airfield and Design of Double-Action Shock Absorber: Airfields, in wars of the future, most necessarily suffer damage. To satisfy the peculiar demands of using this type of airfield, the design concepts of double action or double gas chamber shock shock absorbers. Moreover, as concerns their static and dynamic characteristics as well as the main parameters in the principles for their selection, it makes a relatively detailed comparative analysis. The settlement on standards for the unevenness of airfield runways, is based on the concept of power spectra. It introduces basic methods for measuring random variables from the unevenness of airfield runways. It drafts curves for the power spectra of uneven runways and carries out a preliminary analysis of the dynamic effects in aircraft ground surface taxing. GRA

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RESEARCH CENTER
Y.-C. Cho

Aug. 1989

8 P

Presented at the International

Society for Optical Engineering's 1989 Technical Symposia on
Aerospace Sensing, Orlando, FL, 27-31 Mar. 1989
(NASA-TM-102217; A-89167; NAS 1.15:102217) Avail: NTIS
HC A02/MF A01 CSCL 01B

Two sensor development programs being conducted at the Fluid Mechanics Laboratory, NASA Ames Research Center are described, one in progress and the other being initiated. The ongoing program involves digital image velocimetry for velocity field measurements of time-dependent flows. The new program involves advanced acoustic sensors for wind tunnel applications.

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A wind tunnel test was conducted to evaluate the aerodynamic characteristics and wing pressure distributions of a variable wing sweep aircraft having wing panels that are modified to promote laminar flow. The modified wing section shapes were incorporated over most of the exposed outer wing panel span and were obtained by extending the leading edge and adding thickness to the existing wing upper surface forward of 60 percent chord. Two different wing configurations, one each for Mach numbers 0.7 and 0.8, were tested on the model simultaneously, with one wing configuration on the left side and the other on the right. The tests were conducted at Mach numbers 0.20 to 0.90 for wing sweep angles of 20, 25, 30, and 35 degrees. Longitudinal, lateral and directional aerodynamic characteristics of the modified and baseline configurations, and selected pressure distributions for the modified configurations, are presented in graphical form without analysis. A tabulation of the pressure data for the modified configuration is available as microfiche. Author

N89-26811*# National Aeronautics and Space Administration. Langley Research Center, Hampton, VA.

14 P

A PROCEDURE FOR COMPUTING SURFACE WAVE
TRAJECTORIES ON AN INHOMOGENEOUS SURFACE
Raymond L. Barger Washington Aug. 1989
(NASA-TP-2929; L-16558; NAS 1.60:2929) Avail: NTIS HC
A03/MF A01 CSCL 01A

Equations are derived for computing surface waves on smooth surfaces, including surfaces with a nonuniform wave speed. The prior literature dealt primarily with the theoretical development with little consideration given to computational methods, and examples were limited to waves on surfaces of simple analytic description, such as cones, spheres, and cylinders. The computational procedure presented is a relatively general method. Sample

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