Airfoil-Flap Gap Distance and Shape Performance Analysis

Model aircraft, as well as full-scale aircraft, utilize flaps, ailerons, and other control surfaces to produce forces and moments necessary to control the flight of the aircraft, as well as to augment lift and drag. This computational fluid dynamics (CFD) study attempts to quantify some of the important parameters which determine the performance of these control surfaces. The effects of the airfoil-to-flap gap distance and flap size are investigated, for a standard Gottingen 523 airfoil shape, to determine their effects on lift and drag. The flap length is varied from 10% to 15% of the chord length, while the gap size is varied between 1% and 5% of the chord length. Analyses of both flat and curved airfoil trailing edges and flap leading edges are performed and examined. In all cases, the freestream velocity is 25mph, to simulate the application to a model aircraft. The lift, drag and pressure coefficients are determined and compared, and conclusions drawn.