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A Base Drag Reduction Experiment on the X-33 Linear Aerospike SR-71 Experiment (LASRE) Flight ProgramDrag reduction tests were conducted on the LASRE/X-33 flight experiment. The LASRE experiment is a flight test of a roughly 20% scale model of an X-33 forebody with a single aerospike engine at the rear. The experiment apparatus is mounted on top of an SR-71 aircraft. This paper suggests a method for reducing base drag by adding surface roughness along the forebody. Calculations show a potential for base drag reductions of 8-14%. Flight results corroborate the base drag reduction, with actual reductions of 15% in the high-subsonic flight regime. An unexpected result of this experiment is that drag benefits were shown to persist well into the supersonic flight regime. Flight results show no overall net drag reduction. Applied surface roughness causes forebody pressures to rise and offset base drag reductions. Apparently the grit displaced streamlines outward, causing forebody compression. Results of the LASRE drag experiments are inconclusive and more work is needed. Clearly, however, the forebody grit application works as a viable drag reduction tool.
Document ID
19990026605
Acquisition Source
Armstrong Flight Research Center
Document Type
Technical Memorandum (TM)
Authors
Whitmore, Stephen A. (NASA Dryden Flight Research Center Edwards,CA United States)
Moes, Timothy R. (NASA Dryden Flight Research Center Edwards,CA United States)
Date Acquired
September 6, 2013
Publication Date
March 1, 1999
Subject Category
Aircraft Design, Testing And Performance
Report/Patent Number
H-2333
AIAA Paper 99-0277
NASA/TM-1999-206575
NAS 1.15:206575
Meeting Information
Meeting: Aerospace Sciences
Location: Reno, NV
Country: United States
Start Date: January 11, 1999
End Date: January 14, 1999
Sponsors: American Inst. of Aeronautics and Astronautics
Funding Number(s)
PROJECT: RTOP 242-33-02
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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