Further low speed wind tunnel tests on slender cambered wings with apex blowing.
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Authors
Cole, Joseph D.
Subjects
Advisors
Spillman, J. J.
Date of Issue
1968-09
Date
1968-09
Publisher
Cranfield, England: College of Aeronautics
Language
en_US
Abstract
A family of five slender cambered wings with apex blowing has been compared by means of an experimental investigation carried out in the 8 ft. x 6 ft. low speed wind tunnel at the College of Aeronautics, Cranfield. The flow field was investigated with different blowing momentum coefficients, Cµ, at a Reynolds number, Rc = 2.8 x 10(6), by the use of: Kiel tube traverses, measuring the total head variation at various chordwise stations; photography with a water vapor screen technique; and surface flow pattern visualization. The lift, drag, and pitching moment were measured at Cµ=0, 0.04, 0.08, and 0.12 on the various models through an incidence range from -10° to +20°, at a Reynolds number, Rc= 3.2 x 10(6).
It was found that the apex blowing air formed discrete jets which followed curved paths across the leading edges, over the shoulders, and then along the central portion of the model to the trailing edge. With apex blowing the leading edge vortices did not start to develop until aft of the positions where the blowing jets crossed the leading edges. The development of the leading edge vortices was inhibited when the shoulders of the model were close to the leading edges.
Apex blowing increased the aerodynamic lift at incidences above 4°. The greatest increment in lift due to blowing was obtained on the MGW model. The lift-dependent drag was decreased on all wings by an increased blowing coefficient. At Cµ = 0.12 the maximum lift-drag ratio on all wings was higher than at Cµ = 0, although at lower values of Cµ the maximum was less than in the unblown case. Apex blowing generally had a stabilizing effect and the useable range of CL's was increased.
It was shown that apex blowing, applied to an all-wing airbus, can reduce the required landing distance by about 28%.
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Thesis
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This thesis document was issued under the authority of another institution, not NPS. At the time it was written, a copy was added to the NPS Library collection for reasons not now known. It has been included in the digital archive for its historical value to NPS. Not believed to be a CIVINS (Civilian Institutions) title.
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Aerodynamics
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Approved for public release; distribution is unlimited.
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This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.