Contra-rotating propellers (CRPs) have promising applications in stratospheric airships. However, the aerodynamic interference caused by the airship envelope could lead to thrust loss, efficiency decrease, and even structure fatigue. This paper constructed parameterized computational fluid dynamic (CFD) models to simulate the aerodynamic performance of CRPs at different positions relative to the airship envelope. The total thrust, torque, efficiency, and thrust generated by a single propeller blade all show different degrees of interference. It is advised that such interference be considered in the layout design of stratospheric airships to improve propeller efficiency and ensure a longer structure fatigue life.
Tao et al. (Wed,) studied this question.