Chipman Glider Field, the Edmonton Soaring Club, Dr. Dave Marsden's home club, 1982
(courtesy Bruce Friesen)
Designed by David Marsden, the side-by-side two-place Gemini, which flew in 1973, has a genuine variable geometry planform. Marsden, who successfully modified the British Operation Sigma Type C variable geometry glider, used a number of the Sigma features in his design. It has full span 35 % chord Fowler flaps which are extended when climbing and retracted when cruising. When extended, a high maximum coefficient of lift of 2.2 is achieved, giving a good climb performance. The flaps also deflects to 80 degree for approach control. It has slotted ailerons for improved roll control. During the 1970’s the Gemini set seven Canadian multi-place records, including the 500 km speed triangle.
The Gemini is all metal except for GFRP forward fuselage; stainless steel ribs, fittings and control system.
Wing span: 18.5m / 60.75ft
Wing area: 11.52sq.m / 124sq.ft
Empty Weight: 356kg / 785lb
Payload: 220kg / 455lb
Gross Weight: 576kg / 1240lb
Wing Load: 50kg/sq.m / 10lb/sq.ft
Water Ballast: 0
L/D Max: 40 119 kph / 64 kt / 74 mph
Min Sink: 0.63 m/s / 2.08 fps / 1.23 kt
Aspect ratio: 29.8
Airfoil: Wortmann FX-61-163/35SF mod.
No. Built: 1