# Calculation of lift and thrust

• pratikk

#### pratikk

I need some information and guidance on how to calculate net lift and thrust produced by wings of an MAV(micro air vehicle) which are flapping and active pitching.

I know only about one method which is the Blade Element Analysis, but it is just an approximation and doesn't accounts for pitching. Other methods are experimental testing but I don't want to go for it. I want to create a formulation of the design first and then make a prototype and for that I need to know about the lift and thrust generated by wings of 15cm span and inverse zimmerman planform.

I'd check out a text by Azuma, "The Biokinetics of Flying and Swimming". It includes an inviscid model for a flat plate undergoing pitching and heaving motion, typical in flapping flight. You can extend the model however you like for your application, as the mathematics are not too complex.

I would not expect to get great results from an inviscid model however, as it will fail to predict the leading edge vortex dynamics, spanwise flows and stalling behaviour present in flows over aerofoils at low Reynold's numbers, which are critical to wing performance.

This area is being researched heavily lately, so I would do a literature search of recent papers on pitching and heaving aerofoils. If I recall you should be able to find some good data (both computationally and experimentally) given that your wing is actively pitching. I'm working presently on predicting the deformation characteristics of a passively pitching flapping wing.

which are critical to wing performance
Extremely. Especially in something like a flapping wing, in which the vortices are a major component of both lift and thrust.

Unsteady airfoil theory is not terribly difficult to use and it can be applied to a body in arbitrary motion. It is probably what DylanB is mentioning in the book. You may be able to extend this to create an unsteady lifting line code.