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The Development of High Lift, Single-Component Airfoil Sections

Published online by Cambridge University Press:  07 June 2016

J.L. Kennedy  and
D.J. Marsden
J.L. Kennedy
Affiliation:
Department of Mechanical Engineering, University of Alberta
D.J. Marsden
Affiliation:
Department of Mechanical Engineering, University of Alberta
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Summary

This paper investigates the possibility of increasing the maximum lift of a single element wing section by the introduction of camber near the trailing edge. The optimum upper surface velocity distribution consists of a constant high velocity “rooftop” over the forward part of the wing section followed by transition and an optimised turbulent boundary layer recovery region to the trailing edge. The height of the rooftop, which essentially determines the maximum lift coefficient, is limited by the amount of recovery attainable without separation of the turbulent boundary layer. An increase in the upper surface velocity at the trailing edge would allow the whole top surface velocity distribution to be raised resulting in a considerable increase in maximum lift. The introduction of camber over the rear part of the wing section should produce the required increase in trailing edge velocity on the upper surface. The practical possibilities of using this technique for increased maximum lift were examined by designing a high lift wing section and testing it in the University of Alberta Low Turbulence Wind Tunnel. The results showed that the new wing section behaved qualitatively as expected. A difference of about 0.5U∞ between upper and lower surface velocities at the trailing edge was achieved, even though the thick boundary layers near the trailing edge tend to reduce the effect of camber. A maximum lift coefficient of 2.64 was measured at a Reynolds number of 1.0 × 106.

Type
Research Article
Information
Aeronautical Quarterly , Volume 30 , Issue 1 , February 1979 , pp. 343 - 359
Copyright
Copyright © Royal Aeronautical Society. 1979

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References

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