Warsztaty Szybowcowe SG-7
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| SG-7 | |
|---|---|
 | |
| General information | |
| Type | Single seat, high performance sailplane |
| National origin | Poland |
| Manufacturer | Warsztaty Szybowcowe |
| Designer | Szczepan Grzezezyk |
| Number built | 2 |
| History | |
| First flight | Spring 1937 |
| Developed from | Warsztaty Szybowcowe SG-3 |
The Warsztaty Szybowcowe SG-7 was a Polish high performance, single seat sailplane. Two prototypes flew in 1937 but, outperformed by their contemporaries, no more were built.[1]
The SG-7, a development of the Warsztaty Szybowcowe SG-3 with reduced dimensions, was designed during 1936-7 to meet a government call for a high performance sailplane. It first flew in the late spring of 1937, followed in July by a second and final airframe.[2][3]
The SG-7 was a wooden aircraft with a two-part, cantilever, high gull wing. Each part was built around a single spar which acted as the rear member of a torsion-resistant D-box formed with plywood surfacing around the leading edge. Behind the spar the wing was fabric-covered apart from a ply reinforced region at the join over the fuselage. The wing was trapezoidal in plan out to rounded tips, with differential ailerons over more than half the span.[2][3][4]
Its fuselage was an oval-section, semi-monocoque plywood structure with the wing mounted above it on a faired pylon. Its enclosed cockpit was ahead of the pylon. The fuselage tapered aft to a narrow, integral fin which carried a fabric-covered, roughly D-shaped unbalanced rudder. The fin also mounted, a little above the fuselage, a narrow, ply-covered tailplane carrying rounded, fabric-covered elevators with a gap for rudder movement. The landing gear consisted of an under-fuselage, pneumatically sprung skid, assisted by a tailskid.[2][4]
When competed, the SG-7s were 28 kg (62 lb) overweight, reducing their predicted performance.[3]