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Low Speed Airfoil Design
Joan Puig
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
Tools
● Panel Method to generate Cp distribution● Shape adjusting function● Optimizer● Drag estimation tools (future work...)
Shape Adjusting Function
● It generates any reasonable airfoil starting from a guess and a set of linerly independent bump functions.
Bad bump function choice
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
Guess
20 Iterations
40 Iterations
60 Iterations
Final Result
Convergence rate
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