Schleicher K 7
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| Type designation | K 7 |
| Competition class | N/A |
| Number built | 370 |
| Crew | 2 |
| Length | 8.1 |
| Height | 1.6 |
| Wingspan | 16.00 m |
| Wing area | 17.50 m² |
| Aspect ratio | 14.6 |
| Wing profile: | Göttingen 535/549 |
| Empty mass | ca. 280 kg |
| Water ballast | N/A |
| Maximum mass | 480 kg |
| Maximum wing loading | kg/m² |
| Maximum speed | 200 km/h (108 knots) |
| Rough air speed | 130 km/h (70 knots) |
| Stall speed | 59 km/h (32 knots) |
| Minimum sink rate | ca. 0.85 m/s (170 fpm) |
| Best glide ratio | 27 at 80 km/h (43 knots) |
The K 7 "Rhönadler" ("Rhön Eagle") is a two-seater basic trainer glider that was built by Alexander Schleicher. (The Rhön is a German mountain range and also part of the name of Schleicher's workshop, Rhön-Rossiten Gesellschaft.)
[edit] History and Characteristics
Rudolf Kaiser, designer of the K 7, realised a boyhood dream when, as a young man, he built his first glider, the 10-metre Ka 1, and later flew it to gain his Silver 'C' badge. In 1952 he joined Alexander Schleicher GmbH & Co in Poppenhausen, Germany, and designed the wooden two-seat Ka 2 and its development, the Ka 2B, which became a very popular trainer in Germany.
This tandem two-seater training and club sailplane was designed to succeed the wooden two-seater Ka 2 and Ka 2B. The aim of the K 7 design was to produce a two-seat sailplane which would not only provide basic training but would enable pilots to continue without a break their training for flying the high performance sailplanes of that time.
The K 7 first flew in prototype form in 1959 and was intended to provide not only basic training but continuation training without a break for pilots graduating to the more advanced high performance sailplanes. In this it was successful and a total of 370 had been built by the spring of 1964. K 7s twice set new German distance records and the type also set a new German goal flight record for two-seaters over a decade after it first appeared.
Of conventional wood and fabric construction, with a steel tube fuselage which had fabric covering over wooden formers, the K 7 is characterised by high cantilever wings with a forward sweep of 6° 36' at the quarter-chord line and 4° dihedral. The single-spar wings are of pine and plywood with fabric covering and a plywood-covered leading edge torsion box; there are Schempp-Hirth air brakes above and below the wings and the wooden ailerons are fabric-covered.
The cantilever tail unit is of similar construction to the wings, and there is a trim tab in the starboard elevator. Landing gear consists of a non-retractable and unsprung Dunlop monowheel and a nose skid forward of it carried on rubber blocks for shock absorption; there is also a tailskid. The two pilots sit under a Plexiglas canopy the front portion of which hinges to starboard and the rear portion hinges rearwards.
The K 7 was a popular club glider and is still flying in several clubs today. The aircraft was succeeded by the ASK 13.
[edit] Sources
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