Experimental aerodynamics of a wing model with distributed propulsion in pusher configuration

Abstract

The goal of this project is to analyze the flow around a wing with distributed propulsion in pusher configuration in various positions, so that to find the aerodynamically-optimal configuration by assessing the pressure, 𝐶𝑃, lift, 𝐶𝐿, and drag, 𝐶𝐷, coefficients. The model was designed in SolidWorks software, manufactured using a 3D printer and tested in an open section subsonic wind tunnel from the External Aerodynamic Research Center (CPAERO) located in the Federal University of Uberlandia (UFU). Three main model configurations were tested: with one, two as well as no propeller, in order to assess the effect of attaching a second propeller on the aerodynamic coefficients of the wing. For this matter, the second propeller was affixed onto two different spanwise locations so that its optimal position could be assessed, while the first propeller was kept near the wing root. Additional tests using only a rake probe were made in order to get the velocity profile of the undisturbed flow. For this project, a half wing model, two propellers and two drone engines were used. The experiments suggest that the lift is increased when two propellers are affixed to the wing; this gain is strongest when the second propeller is placed closest to the wing tip, ameliorating the wing tip vortices. The effects of the propeller in the pusher configuration also include the delay in flow separation on the section near the propeller – which could be noticed during some of the experiments by an increase (in module) in the distribution values of the pressure coefficient towards the trailing edge of the wing. Finally, the drag coefficient of the wing seems to be reduced by the influence of the propellers, which is expected due to the decrease in the induced drag as well as the delay in the flow separation.