2. Low Speed Airfoil Design Joan Puig

3. Project Goals ● Maximize L/D ● Easy to build ● Keep Cm at a value that is not going to make the airplane unstable ● Have space for a strong structure ● Design an optimal airfoil for my RC airplane

4. Tools ● Panel Method to generate Cp distribution ● Shape adjusting function ● Optimizer ● Drag estimation tools (future work...)

5. Shape Adjusting Function ● It generates any reasonable airfoil starting from a guess and a set of linerly independent bump functions.

6. Bad bump function choice

7. Optimization Process Review ● Don't assume anything about the input data ● Fit the input data using a spline to the desired X coordinate values ● Pass appropriate parameters to the optimization function ● Collect data periodically

8. Guess

9. 20 Iterations

10. 40 Iterations

11. 60 Iterations

12. Final Result

13. Convergence rate

14. Speed ● Solving a matrix is o(n^3) -> most of the time is spent here ● Try to be able to fit your matrix in the cache – 32*(n^2+8n)/(8*1024)<available cache ~128-512 ● Don't calculate x^2, x^3, sin(...) exp(...^n)... every time, compute them at the beginning and use them as global variables