RRG Prüfling
| Prüfling | |
|---|---|
| |
| Role | Secondary training glider |
| National origin | Germany |
| Manufacturer | Rhön-Rossitten Gesellschaft (RRG) |
| Designer | Alexander Lippisch and Fritz Stamer |
| First flight | 1926 |
The RRG Prüfling (Template:Lang-en) of 1926 was a Secondary training glider designed by Alexander Lippisch It was sold as plans for club production and was built in Germany and across the world.
Design and development
Secondary gliders were meant to be used by student pilots after an introduction to flight in very simple primary gliders. Both types needed to be cheap to build, given the difficult financial position of many Germans after World War I and also simple enough that skilled amateur builders, but within and without gliding clubs, could successfully construct them from plans. The Martens gliding school on the Wassserkuppe was absorbed into Rhön-Rossitten Gesellschaft (RRG) at the end of 1925 and their chief instructor Fritz Stamer and Lippisch were brought together to produce two gliders, intended to work as primary and secondary pair. Within a few days the Zögling (Template:Lang-en) and the Prufling designs were complete. In the these circumstances, it's not surprising that there some parts, for example the wings and to a lesser extent the horizontal tails of the two aircraft had some similarity.[1]
Both had almost rectangular, two spar, wooden structured, two piece wings with fabric covering] every except the leading edges, which were plywood covered. The Prüfling's wing tips were more rounded and its span 500 mm (19.7 in) greater. They both had simple ailerons reaching to the tips, where they were cropped, though the Prüfling's were a little longer. Both had triangular tailplanes, carrying elevators that were rectangular apart for a cut-out for rudder movement, though the Prüfling's tailplane was more strongly swept and was broader in chord.[1]
The major difference between the two were in the fuselages. The Zögling had a very simple open frame girder, the Prüfling a more conventional hexagonal cross section, wood framed structure, ply covered forward from under the wing and fabric covered aft. The wing was supported over the fuselage with a pair of parallel lift struts on each side, bracing it at almost mid-span at the spars to the lower fuselage longerons. The open cockpit was below the wing on two pairs of cabane struts to the upper fuselage longerons, single and vertical ones just in front with an inverted V-pair just behind. At the centre there was a noticeable gap between the wing, bridged by a short span wooden link. The horizontal tail was positioned on the upper longerons. with a triangular fin carrying an upright, straight edged balanced rudder which was slightly angle below the heel and extended down to the keel. The Prüfling landed on a rubber sprung skid below the whole forward, ply skinned fuselage, assisted by a very small tailskid.[1]
It first flew in 1926 and was soon in use with the RRG related Rhön and Rossitten gliding clubs. Plans were sold and many were built inside and outside Germany.[1] One was flying with the Lancashire Gliding Club in 1931.[2] Despite such success, the Prüfling was something of a disappointment as a secondary training aircraft, for its performance was not much better than typical primaries. [1]
Specifications
Data from Sailplanes 1920-1945 (2006)[1]
General characteristics
- Capacity: One
- Length: 5.484 m (18 ft 0 in)
- Wingspan: 10.50 m (34 ft 5 in)
- Wing area: 15.24 m2 (164.0 sq ft)
- Aspect ratio: 7.23
- Empty weight: 105 kg (231 lb)
- Gross weight: 195 kg (430 lb)
Performance
- Wing loading: 12.8 kg/m2 (2.6 lb/sq ft)
References
- ^ a b c d e f Simons, Martin (2006). Sailplanes 1920-1945 (2nd revised ed.). Königswinter: EQIP Werbung & Verlag GmbH. pp. 38, 40–44. ISBN 3 9806773 4 6.
- ^ "Westland Woodpigeon". Flight. XXIII (11): p.226. 1931.
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