DESIGN AND WINDTUNNEL TESTS OF AN AIRFOIL FOR THE HORIZONTAL TAILPLANE OF A STANDARD CLASS SAILPLANE

Abstract

Requirements, design and windtunnel tests results of a new airfoil for application in the horizontal tailplane of the Standard Class high performance sailplane ASW-24 have been presented. The airfoil was designed for application of artificial transition. Tests showed that the functions of a flexible flap gap sealing and a zig-zag turbulator can be integrated by cutting zig-zags in the front of the sealings stuck to the surface. With zig-zags of 0.5 mm nominai thickness and frontal peaks at 59% chord on upper and lower surface, the minimum drag of the new airfoil is about 10% lower and C lmax only 5% lower than the well-known tailplane airfoil FX71-L-150/25. Both test flights and actual practice with the ASW-24 have shown that the airfoil behaves very well, with ample reserve in difficult situations.