Kohler built the Alpha in 1965 as a development of the Schreder Airmate HP-11. He used the wings from the HP-11 and combined this with a newly designed fuselage and tail. Kohler expressed the opinion that a sailplane's performance is mostly determined by its wing, while the fuselage imparts character to the design. The fuselage that he designed must have contributed to the performance, though, as the Alpha has a glide ratio two points higher than the HP-11 with the same wing.[1][2]
The Alpha fuselage is made from wood, with some fiberglass components incorporated. The fuselage uses a circular cross-section from nose to tail, with the diameter varying from the 12 in (30 cm) diameter at the tail to a 24 in (61 cm) diameter at the cockpit. The HP-11 wing is of all-metal and features a 26:1 aspect ratio, a 52 ft (15.8 m) wingspan and a NACA 65 (3)-618 airfoil. The v-tail is removable by first removing the tailcone and then withdrawing two pins. The controls are adapted from a Piper PA-24 Comanche. The landing gear is a retractable monowheel and a tail skid. The tail skid was later replaced with a tail wheel.[2]
