Link to FoilSim: http://www.grc.nasa.gov/WWW/K-12/airplane/foil3.html
|Opening Screen with Default Values
To start with I used default values which provide a wing of 100 square feet flying at 100 mph then I selected the flat bottom airfoil and the flat plate airfoil. Next I started increasing the angle of attack from zero in one degree increments, output data from this included amount of lift, drag, and L/D. To me it was interesting to note that L/D increased until about 3 degrees and then started to diminish. Which means at this point the drag of the wing is increasing faster than the lift.
|Starting at 0 Degrees with Flat Bottom Airfoil
|Increasing to 3 Degrees
The same data was entered for a wing that might be typical for a small model airplane with a wing area of only 1 square foot flying at 15 mph. Output was somewhat different but followed the same basic pattern. Calculations were also done for the flat plate airfoil.
|Changing to Model Size Wing Section
For me this is interesting because I had read many books on model aircraft design theory and it was fun to see the theory simulated. For one degree value of the model size wing I changed the aspect ratio from 4 to almost 8 to see the change in L/D, it improved considerably as predicted. My data and some of the output were entered in an Excel spreadsheet manually. Take a look at this fun simulator.
|Entering Data into Excel
For an explanation of many aspects of simple aerodynamics with math problems check out my article Basic Aerodynamics With a Lesson