The Grob G 103 Twin Astir was a two-seat sailplane developed in Germany in the 1970s by Grob Aircraft AG as a counterpart to the single-seat G 102 Astir then in production. Construction throughout was similar, although to preserve the balance of the design, the wings were given a slight forward sweep. While many two-seat derivatives of single-seat sailplanes have fixed undercarriage, due to the added space restrictions created by the second seat, Grob devised a novel retraction system for the Twin Astir. The single wheel was designed to rotate 90° sideways before retracting "flat" under the rear seat, resulting in a rather unusual seating position. (Source Wikipedia)