FoilSim was built to help students learn how wings work. It produces the correct trends (for example, doubling velocity will quadruple the lift and drag) but it does not give the exact value of lift or drag. FoilSim uses a very simplified analysis to calculate lift, and it interpolates experimentally measured drag data to determine the drag. The drag data was obtained by students using inexpensive models and an inexpensive wind tunnel. Please do not attempt to design, build, or fly a full scale aircraft using data from FoilSim. It is fine for models, but be careful .
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