Primary aerodynamic analyses of a new light aircraft in symmetrical flight configurations

Abstract

The paper is confined to the preliminary aerodynamic analyses of a new light aircraft with different combinations of flaps and elevator deflections, which correspond to the symmetrical flight conditions. Initial calculations have been performed using a 3D vortex lattice method. Since the applied computational model is based on inviscid flow concept, the non-linear calibration diagrams for the effectiveness of control surfaces and circulation influence have been derived from wind tunnel test data for an existing airplane. Then the calibration functions have been interpolated for a new light aircraft, and a wide scope of analyses for lift and moment coefficients with different flaps and elevator deflections has been performed Of special importance was the determination of lift-induced drag polars. Namely, deflected flaps and elevator generate local lift distributions which contribute to the induced drag, even at angles of attack when the total airplane 10 is zero, which has been successfully determined by the applied CFD model. Parasite drag components, omitted by CFD calculations, have been estimated using DVL, Datcom and Douglas methods and superimposed with the induced drag results, giving complete diagrams for the new aircraft in different symmetric flight configurations.