RRG Professor
| Professor | |
|---|---|
| Role | Soaring glider |
| National origin | Germany |
| Manufacturer | Rhön-Rossitten Gesellschaft (RRG) |
| Designer | Alexander Lippisch |
| First flight | May 1928 |
The RRG Professor was a very early soaring glider and the first to use a variometer for finding thermals. It was designed by Alexander Lippisch in Germany, first flying in 1928. The Professor was widely built by both flying clubs and factories.
In early 1928 Professor Walter Georgii, an academic meteorologist and head of the Rhön-Rossitten Gesellschaft (RRG), began studies of thermals, previously assumed to be too weak to assist gliders. He directed flights of a light, powered aircraft which, with its engine idling, discovered uplifts of several metres per second. At about the same time Alexander Lippisch, who had earlier worked at Dornier on Zeppelins was considering the application of the variometer to gliding. These rapid response rate of climb instruments were known in lighter-than-air craft but had not been used on gliders. The two came together to produce a glider, designed by Lippisch and built at the RRG that had the performance to utilize thermal lift detected by the variometer. The result was the RRG Professor, first flown in May 1928 and intended by RRG to be built in numbers by clubs under licence, from their plans. The prototype was christened the Rhöngeist (English: Ghost of the Rhön Mountains) after Lippisch, who had earned this nickname during earlier visits to the Wasserkuppe gliding centre.
This was an all wood-framed aircraft, covered in a mixture of plywood and fabric, with a braced, three piece wing supported over the fuselage on a tall ply skinned, streamlined pedestal and built around a single spar. From the spar forward around the leading edge the wing was ply skinned, forming a torsion box; behind the spar the wing was fabric covered. Its rectangular centre section occupied about one third of the overall span and was braced to the lower fuselage on each side with a faired V-form lift strut. The outer panels were strongly straight tapered, with a taper ratio of 1:3. The whole trailing edge of each outer section was filled with a straight edged, slightly tapered aileron.
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