The effect of the blade chord length on the aerodynamics of the MAV scale cycloidal propeller under hovering status

The effects of blade chord length play important role on the performance of the cycloidal propellers. However, only experiments with different blade chord length were performed. The effects of blade chord length has not been carefully studied and hence fully understood. The numerical simulations for cycloidal propellers based on different blade chord length are presented in this paper. The CFD simulation is based on sliding mesh and URANS. The result of CFD simulation indicates that the level of the aerodynamic force increases with blade chord length. With blade chord length increasing, the blade may generate thrust in some time interval if observed in moving reference frame. This results in positive torque and hence can significantly reduce the power consumption. However if the blade chord length is too long, very large negative vertical force is generated, which reduces the thrust of the rotor. Hence the rotor with moderate chord length, such that there is positive torque in some time intervals but without large negative vertical force, has the best efficiency.