Experimental investigations on the ground effect characteristics of the U-shaped and V-shaped wing designs for the Aero-Train

This paper describes the investigations on the aerodynamic characteristics of a U-shaped and V-shaped wing in ground effect. The lift, drag, side force, and rolling moment were measured in a low turbulance wind tunnel, using a 6-component balance. The flow over the upper surface was visualized by the tuft method. The results obtained were as follows: The U-shaped and V-shaped wing had an almost equivalent lift-to-drag ratio compared to a planar wing. This was due to the dihedral angle of U-shaped and V-shaped wing, resulting in a decrease of the induced drag. While separation only occurred on the V-shaped wing at an attack angle of 6 degree, a higher lift-to-drag ratio of the U-shaped wing was obtaind at attack angle of 4 and 6 degree. With both wings, an almost equal restoring force and an even higher restoring moment were obtained than with a conventional boxshaped wing. Thus, the U-shaped and V-shaped wing offer a more suitable wing configuration for the Aero-Train than a conventional wing does.