Hi,

I am not new to aerodynamics, and I have had my go at designing radio control aircraft, and have recently gotten a book called Mechanics of Flight by Warren F. Phillips. It is a great book, but it is a bit too hard to understand for me, who is 17 years old.

My question is, can you please write down for me a formula for calculating the induced angle of attack cause by downwash of the wing/vorticity of the wing. Also, I would much appreciate if you would state what all the variables in the formula stand for- as when we use different notations in complex formulae it gets very confusing.

Please, please, please explain me how to find the induced angle of attack as I am trying to figure how much twist to give to my airplane's wingtips so that the induced drag is not oh so significant!!!

Best Regards,
Sparrow99

Try to get this book: [link=http://www.amazon.de/Aerodynamik-reinen-Unterschallstr%C3%B6mung-Fritz-Dubs/dp/B0000BHJZF]Fritz Dubs: Aerodynamik der reinen Unterschallströmung.[/link] PP. 119-130. Great book, quite easy to understand, Swiss author.

Thanks for the recommendation, but after spending 120 dollars on buying Mechanics of Flight which is a dictionary of calculus equations I don't quite understand- I will stick with reading that and also the internet. If you have the book, can you please summarize how to fins the induced angle of attack and the formula for it please?

Thanks,

Lafayette.

Well, in short, induced AOA = lift coefficient / pi * aspect ratio [rad], that is for elliptical lift distribution. For other cases it's rather complex. Won't help you much either because you can't do that much about induced drag with washout. So I'd still recommend getting a good textbook

I would swap the books for a few good foam models and see W T H actually happens.

Lafayette, in general as model builders we choose to put washout into the wingtips for tip stall delay related handling reasons instead of drag reasons. Although I think most realize that some drag advantage comes with its use. With the way our models fly drag avoidance is just not something we need to worry about other than in a few VERY specific cases such as thermal sailplanes.

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