Grokhovskii G-37, ULK
Purpose: ‘Universal flying wing’.
Design Bureau: WS-RKKA Leningrad, Chief Designer Vladimir Rentel.
The numbering of’Grokhovskii’ aircraft is difficult to interpret, and this aircraft preceded the G-31. The concept was that of a versatile aircraft for airborne assault, but it was soon evident that a Universalnoye Letayushchyeye Krylo, universal flying wing, would have wide commercial appeal. Construction was assigned to Vladimir Rentel, who had the aircraft built in Grebno (rowing) port, Leningrad. It was taken to the airfield where from November 1935 it was tested by VPChkalov, who was impressed. He later flew it to Moscow in 2hrs SOmin (average 250km/h, 155mph, which Shavrov says was ‘almost a record’). The G-37 was used for a long series of tests, including dropping of heavy loads.
The G-37 was a remarkably capable early example of an aeroplane designed to lift a detachable payload container (later types in
cluded the Fi333, Miles M.68 and Fairchild XC-120). To save time the wing was that of an ANT-9 (PS-9), made of Kolchug duralumin with mainly corrugated dural skin, though the ailerons did not project beyond the wing tips. It is possible this wing came from a crashed PS-9 along with the 680hp BMW VI water – cooled V-12 engines, though these were in a different installation. The engine cowls were extended down into large trousers over the main landing gears, which contained the engine-cooling radiators. At the rear they extended into tail booms, all these structures being of light alloy. Each boom had a tailwheel, and the twin-finned tail was duralumin with fabric covering. On the centreline the wing was expanded into a small nacelle for the pilot and engineer. The underside of the centre wing was provided with attachments for a standard pre-loaded payload container, though no photographs have been found with this in place. The completed G-37 was painted with gay stripes and stylized red stars and slogans.
There seems little doubt that this was an excellent and potentially versatile aircraft, and it is not known why it was never ordered for military or civil use.
Dimensions |
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Span |
22.5m |
73ft93/4in |
(possibly for a develops:d version, |
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Shavrov cites) |
23.7m |
77 ft 9/4 ill |
Length |
13.85m |
45 ft 5% in |
(Shavrov) |
16.0m |
52 ft 6 in |
Wing area |
84.0m2 |
904 ft2 |
Weights |
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Empty |
3,100kg |
6,834 Ib |
Loaded |
5,700kg |
12,566 Ib |
Performance |
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Max speed at sea level |
235km/h |
146 mph |
at 2,500m (8,200ft) |
285 km/h |
177 mph |
Cruising speed at |
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2,500m (8,200 ft) |
250 km/h |
155 mph |
Time to climb to 6 km |
16min |
(19,685ft) |
Service ceiling |
6,500 m |
21,325ft |
Landing speed |
90 km/h |
56 mph |
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