This was a project I did with Kiko Weichberger in Worpswede, an artists' colony in West Germany. The glider was of a square Rogallo type, developed in California around that time, in the early '70s. The sail was a 5 m. square of polythene, fixed to a bamboo frame with double-sided tape. The frame was held together with glass-reinforced strapping tape, leather straps and bolt hinges at the nose. The pilot held on to two "hang bars" in the manner of Otto Lilienthal. It was quite stable because of its long keel, about the same length as the wingspan. We made a number of flights from Worpswede's Weyerberg (51m.)