Effects of Propeller Position and Rotation Direction on the Ishii Wing at a Low Reynolds Number

The aerodynamic characteristics of a wing in a propeller slipstream were investigated at a low Reynolds number. The effects of propeller position and rotation direction on the wing were clarified by aerodynamic measurements and particle image velocimetry. The propeller positions were the center and tip of the wing model, whereas the rotation directions were clockwise and counterclockwise. The center propeller configuration with a clockwise rotation showed a constant pitching moment and increased the lift-to-drag ratio. This was caused by the high-speed propeller slipstream (i.e. 12 and 10 m/s on the upwash and downwash sides, respectively) and the wingtip vortex effect on the slipstream separation. The separation point at an angle-of-attack of 18° was delayed from x/c ≈ 0.1 to 0.3 by the wingtip vortex. Hence, the following two factors must be considered to enhance the aerodynamic characteristics of a Mars airplane: (i) the ratio of the area of the upwash and downwash sides of a wing in a propeller slipstream, and (ii) the effect of the wingtip vortex on the propeller slipstream.