The lift of a wing of finite span at a certain angle of attack is less than the lift of a two dimensional airfoil (which corresponds to a wing of infinite span). In general, the lift loss due to the wing tips is more pronounced, as the wing span is reduced.
This effect also means that the angle of attack required to reach the same lift must be higher as the wing span is getting smaller. The relation mainly depends on the aspect ratio of the wing and can be approximated as follows.
Procedure (abbreviations and symbols are listed at the end of this page):
(In general this value will be in the order of 5-6)
|Case AR <= 4|
|Case AR > 4|
either calculate the lift coefficient CL for a given angle of attack for the finite wing:
|e||span efficiency factor, typically between 0.85 and 0.95|
|a0||lift slope dCL/dalfa of the infinite wing (2D airfoil)|
|a||lift slope dCL/dalfa of the finite wing (3D wing)|
|a0||2D zero lift angle of the infinite wing (2D airfoil)|
|a2D||2D angle of attack of the infinite wing (2D airfoil)|
|a3D||3D angle of attack of the finite wing (3D wing)|
|lift coefficient of the infinite wing (2D wing)|
|CL||lift coefficient of the finite wing (3D wing)|
Last modification of this page: 08.09.03
[Back to Home Page] Suggestions? Corrections? Remarks? e-mail: Martin Hepperle.
Due to the increasing amount of SPAM mail, I have to change this e-Mail address regularly. You will always find the latest version in the footer of all my pages.
It might take some time until you receive an
answer and in some cases you may even receive no answer at all. I apologize for
this, but my spare time is limited. If you have not lost patience, you might
want to send me a copy of your e-mail after a month or so.
This is a privately owned, non-profit page of purely educational purpose. Any statements may be incorrect and unsuitable for practical usage. I cannot take any responsibility for actions you perform based on data, assumptions, calculations etc. taken from this web page.
© 1996-2006 Martin Hepperle
You may use the data given in this document for your personal use. If you use this document for a publication, you have to cite the source. A publication of a recompilation of the given material is not allowed, if the resulting product is sold for more than the production costs.
This document may accidentally refer to trade names and trademarks, which are owned by national or international companies, but which are unknown by me. Their rights are fully recognized and these companies are kindly asked to inform me if they do not wish their names to be used at all or to be used in a different way.
This document is part of a frame set and can be found by navigating from the entry point at the Web site http://www.MH-AeroTools.de/.
Impressum und weitere rechtliche Hinweise für Deutschland