Quasi-steady aerodynamic model of tilt rotor based on optimization algorithm

There are many hypotheses and limitations about the flight condition and blade shape in the quasi-steady aerodynamic model of conventional helicopter rotor, and many of them were eliminated considering the special blade shape, hub structure and flight condition of tilt rotor. Aerodynamic loads were calculated through numerical integration based on the blade element theory, and flap coefficients of tilt rotor were solved through sequential quadratic programming (SQP) algorithm. Induced velocity distribution was adopted as the steady form of Pitt-Peters dynamic inflow model. The aerodynamic performance and flap coefficients of the rotor of XV-15 tilt rotor aircraft were predicted by this method. The theoretical results and wind tunnel tests data make good agreement with error less than 8% and this method has high calculation efficiency that one case can be solved within 5 minutes, therefore, this method is applicable for aerodynamic performance prediction in preliminary design of tilt rotor aircraft and suitable to set up its flight dynamics model.