Hostname: page-component-cd9895bd7-q99xh Total loading time: 0 Render date: 2024-12-26T23:01:49.712Z Has data issue: false hasContentIssue false
  • English
  • Français

On the Minimum Induced Drag of Ground-Effect Wings

Published online by Cambridge University Press:  07 June 2016

P. R. Ashill
P. R. Ashill*
Affiliation:
Cranfield Institute of Technology*
Get access

Summary

An approximate theory, which yields the minimum induced drag of a planar wing with end-plates in ground effect, is presented. As a check on the accuracy of the method, it is compared with the exact linearised theory in the case of end-plates of vanishing depth (planar configuration). This shows that, within the limitations of the linearised lifting-surface theory, the present method is accurate in the range of wing heights of interest. In Section 5 the theory is compared with experiment. In this comparison two interpretations of the theory are employed. The first assumes that the vortex trace is the projection of the trailing edge of the configuration onto a plane normal to the direction of motion when the wing incidence is zero. The second is different from this only in that no constraint is placed on the wing incidence. Of the two interpretations the first is found to be in better agreement with experiment than the second for the planar configuration. However, the opposite is found to be true when end-plates of sufficient depth are fitted. A reason for this is proposed in Section 5.

Type
Research Article
Information
Aeronautical Quarterly , Volume 21 , Issue 3 , August 1970 , pp. 211 - 232
Copyright
Copyright © Royal Aeronautical Society. 1970

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1. De Haller, P. La portance et la traîné induite minimum d’une aile au voisinage du sol. Mitteilungen aus den Institut für Aerodynamik, Zurich, Vol. 5, p. 99, 1936.Google Scholar
2. Wieselsberger, C. Über den Flugwiderstand in der Nähe des Boden. Zeitschrift für Flugtechnik und Motorluftschiffahrt, Vol. 10, p. 145, 1921.Google Scholar
3. Carter, A. W. Effect of ground proximity on the aerodynamic characteristics of aspect-ratio-1 airfoils with and without end-plates. NASA TN D-970, 1961.Google Scholar
4. Munk, M. M. The minimum induced drag of aerofoils. NACA Report 121, 1921.Google Scholar
5. Thwaites, B. (Editor) Incompressible aerodynamics. Clarendon Press, Oxford, 1960.Google Scholar
6. Byrd, P. F. and Friedman, M. D. Handbooks of elliptic integrals for engineers and physicists. Springer, Berlin, 1954.Google Scholar
7. Ashill, P. R. On some aspects of the aerodynamic performance of ground-effect wings. Ph.D. thesis, The University of Southampton, 1968.Google Scholar
8. Robinson, A. and Laurmann, J. A. Wing theory. Cambridge University Press, 1956.Google Scholar
9. Fink, M. P. and Lastinger, J. L. Aerodynamic characteristics of low-aspect-ratio wings in close proximity to the ground. NASA TN D-926, 1961.Google Scholar