경항공기의 공력특성에 미치는 지면효과에 관한 풍동실험 연구

In attempt to obtain quantitative effect of the ground, and to investigate aerodynamic characteristics of the single engined propeller light aircraft, experimental work has been conducted on 1/14.5 scaled down model in wind tunnel, wherethe presence of the ground was simulated a fixed plate. As a experimental results, both powered and unpowered conditions, the closer(h/b) of model is near ground plate, the more slope of lift curves and lift coefficient are increased. These results are similar to the theoretical results considering the dihedral effects, and as the distance goes to narrow, the nose up pitching moment decreased and the propeller effects contributed to the negative pitching moment by the slip stream. It was believed that the results of the experiment of representing the ground, although not exact because of the presence of the boundary layer on the plate and in small Reynold's number and so on, were sufficiently tendency to give value of aerodynamic characteristics in ground effects.