Development of a Simulation and Optimization Framework for Improved Aerodynamic Performance of R/C Helicopter Rotor Blades

To improve the performance of small unmanned rotorcraft systems based on commercially available radio controlled helicopter components the simulation and optimization framework Qoptr was developed. Two simulation modules model main rotor performance in hover using blade element momentum theory and in forward flight conditions employing a blade element theory approach. The forward flight module incorporates empirical induced inflow models and rigid blade motion. Two software packages based on viscous-inviscid interaction methods were evaluated on their ability to generate the low Re aerodynamic airfoil performance coefficients required by the simulation modules at conditions applicable to large r/c helicopters. The Qoptr hover module was integrated into an optimization scheme using an algorithm from the MATLAB Optimization Toolbox. Starting from a rotor using typical r/c rotor blades the optimization raised the rotor figure of merit from 0.56 to 0.70 by adjusting rotor speed, solidity and spanwise distributions of blade pitch and chord length.