Experiments on propeller influence on a wing with active high lift

Abstract Boundary layer control (BLC) by tangential streamwise blowing of air from thin slots is a means of keeping flow attached to curved convex surfaces and against adverse pressure gradients by adding momentum to the boundary layer, making use of the Coandă effect. This effect is used in Active High Lift systems, which can be integrated into airplane wings to create large lift coeffcients with mechanically simple systems. In this work, the effect of a propeller engine mounted in front of the wing in a tractor configuration onto an active high lift wing is assessed in a wind tunnel experiment. A 1/9 scale semi-span model wing was built and equipped with a wing mounted electrically powered tractor propeller. The influence of the blowing momentum and the propeller thrust on the wing flow and the lift produced is examined. A simple correlation for the necessary blowing strength as function of propeller thrust is found. Results from the wind tunnel are compared to 2D and 3D CFD data, validating the numerical simulations as well as the assumptions made for calculation of total lift from pressure sections in the experiment.