I'm looking for some free or cheap software to help me design a standard wing for a small, motor powered, traditionally shaped airplane. I'm familar with solid wing design but not ribs and spars.

My project is to build a very tought plane with a span of 32 - 36 inches and a RTF weight of 310 grams. It will be electrically powered and radio controlled. It should look something like a block of wood impersonating a P51.

I need something pretty simple. I majored in business and can't deal with coefficient of friction and so forth.

Thanks for your help!

Mike