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Geared-elevator flutter studyAn experimental and analytical study was made of the transonic flutter characteristics of a supersonic transport tail assembly model having an all-movable, horizontal tail with a geared elevator. Two model configurations, namely, one with a gear-elevator (2.8 to 1.0 gear ratio) and one with locked-elevator (1.0 to 1.0 gear ratio), were flutter tested in the Langley transonic dynamics tunnel with an empennage cantilever-mounted on a sting. The geared-elevator configuration fluttered experimentally at about 20% higher dynamic pressures than the locked-elevator configuration. The experimental flutter dynamic pressure boundaries for both configurations were nearly flat over a Mach number range from 0.9 to 1.1. Flutter calculations (mathematical models) were made for the geared-elevator configuration using three subsonic lifting-surface methods. In one method, the elevator was treated as a discrete surface, and in the other two methods, the stabilizer and elevator were treated as a single warped-surface with the primary difference between these two methods being in the mathematical implementation used. A comparison of the experimental and analytical results shows that the discrete-elevator method predicted best the experimental flutter dynamic pressure level. However, the single warped-surface methods predicts more closely the experimental flutter frequencies and Mach number trends.
Document ID
Document Type
Conference Paper
Ruhlin, C. L.
(NASA Langley Research Center Hampton, VA, United States)
Doggett, R. V., Jr.
(NASA Langley Research Center Hampton, VA, United States)
Gregory, R. A.
(Boeing Commercial Airplane Co. Seattle, United States)
Date Acquired
September 3, 2013
Publication Date
May 1, 1976
Subject Category
Report/Patent Number
Meeting Information
Meeting: AIAA/ASME/SAE 17th Struct., Structural Dyn., and Mater. Conf.
Location: Valley Forge, PA
Country: United States
Start Date: May 5, 1976
End Date: May 7, 1976
Accession Number
Funding Number(s)
PROJECT: RTOP 743-01-12-01
Distribution Limits
Work of the US Gov. Public Use Permitted.
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