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In-flight lift and drag measurements on a first generation jet transport equipped with wingletsA KC-135A aircraft equipped with wing tip winglets was flight tested to demonstrate and validate the potential performance gain of the winglet concept as predicted from analytical and wind tunnel data. Flight data were obtained at cruise conditions for Mach numbers of 0.70, 0.75, and 0.80 at a nominal altitude of 36,000 ft. and winglet configurations of 15 deg cant/-4 deg incidence, 0 deg cant/-4 deg incidence, and baseline. For the Mach numbers tested the data show that the addition of winglets did not affect the lifting characteristics of the wing. However, both winglet configurations showed a drag reduction over the baseline configuration, with the best winglet configuration being the 15 deg cant/-4 deg incidence configuration. This drag reduction due to winglets also increased with increasing lift coefficient. It was also shown that a small difference exists between the 15 deg cant/-4 deg incidence flight and wind tunnel predicted data. This difference was attributed to the pillowing of the winglet skins in flight which would decrease the winglet performance.
Document ID
Document Type
Conference Paper
Lux, D. P.
(NASA Hugh L. Dryden Flight Research Center Edwards, CA, United States)
Date Acquired
August 12, 2013
Publication Date
January 1, 1982
Publication Information
Publication: KC-135 Winglet Program Rev.
Subject Category
Distribution Limits
Work of the US Gov. Public Use Permitted.

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IDRelationTitle19840019618Analytic PrimaryKC-135 Winglet Program Review
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