High Quality Content by WIKIPEDIA articles! The ASW-15, designed in 1968 by Gerhard Waibel and built in series by Schleicher, is a glass composite sailplane, with shoulder-mounted wings and all-flying tailplane. The placement of its single tow-release is a compromise between the ideal placement for winching and aerotowing. The later ASW-15B had several improvements, including a tow-release placed on the plane of symmetry, an 11cm taller rudder, a slightly larger main wheel, and the provision of a 90 litre water ballast system.