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Experimental Aerodynamic Characteristics of the Pegasus Air-Launched Booster and Comparisons with Predicted and Flight ResultsExperimental longitudinal and lateral-directional aerodynamic characteristics were obtained for the Pegasus and Pegasus XL configurations over a Mach number range from 1.6 to 6 and angles of attack from -4 to +24 degrees. Angle of sideslip was varied from -6 to +6 degrees, and control surfaces were deflected to obtain elevon, aileron, and rudder effectiveness. Experimental data for the Pegasus configuration are compared with engineering code predictions performed by Nielsen Engineering & Research, Inc. (NEAR) in the aerodynamic design of the Pegasus vehicle, and with results from the Aerodynamic Preliminary Analysis System (APAS) code. Comparisons of experimental results are also made with longitudinal flight data from Flight #2 of the Pegasus vehicle. Results show that the longitudinal aerodynamic characteristics of the Pegasus and Pegasus XL configurations are similar, having the same lift-curve slope and drag levels across the Mach number range. Both configurations are longitudinally stable, with stability decreasing towards neutral levels as Mach number increases. Directional stability is negative at moderate to high angles of attack due to separated flow over the vertical tail. Dihedral effect is positive for both configurations, but is reduced 30-50 percent for the Pegasus XL configuration because of the horizontal tail anhedral. Predicted longitudinal characteristics and both longitudinal and lateral-directional control effectiveness are generally in good agreement with experiment. Due to the complex leeside flowfield, lateral-directional characteristics are not as well predicted by the engineering codes. Experiment and flight data are in good agreement across the Mach number range.
Document ID
19970013282
Acquisition Source
Langley Research Center
Document Type
Technical Memorandum (TM)
Authors
Rhode, M. N. (NASA Langley Research Center Hampton, VA United States)
Engelund, Walter C. (NASA Langley Research Center Hampton, VA United States)
Mendenhall, Michael R. (Nielsen Engineering and Research, Inc. Mountain View, CA United States)
Date Acquired
September 6, 2013
Publication Date
June 22, 1995
Publication Information
Publisher: American Inst. of Aeronautics and Astronautics
Subject Category
Aerodynamics
Report/Patent Number
NAS 1.15:112004
AIAA Paper 95-1830
NASA-TM-112004
Meeting Information
Meeting: Applied Aerodynamics
Location: San Diego, CA
Country: United States
Start Date: June 19, 1995
End Date: June 22, 1995
Sponsors: American Inst. of Aeronautics and Astronautics
Accession Number
97N17204
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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