Bratukhin Omega

Bratukhin 2MG

Bratukhin Omega II

Bratukhin G-2

Also designated 2MG (twin-engined helicopter), the Omega project was authorised on 27 June 1940 with two engine rotor groups side-by-side and steel-tube construction with fabric covering. Lateral structures carrying engine rotor units and fixed main landing gears were triangular spaceframes with two lower booms and one at top, with no covering. Fully articulated hubs of steel and light-alloy, carrying three duralumin blades, rotors being handed to rotate in opposite directions. Each rotor was driven by separate MV-6 engine linked with synchronizing shaft with universal joint on aircraft centreline. This shaft provided also opportunity to fly helicopter with any one of engines running. Engines of Omega were equipped with specially designed gearboxes, clutch and other elements. Manual controls, driving swash-plates in fixed and rotating parts of head for collective and cyclic pitch control. Much research into optimum method with differential collective to apply initial bank and then T-tail rudder, worked by pedals, to make turns. Emergency control for immediately autorotative setting of both rotors. Final 0.231 gearbox to rotors (577 rpm). No centrifugal clutches. Three mechanical clutches, with overrunning capability, engaged by observer after both engines were running. First drive to associated rotor was clutched-in; then interlink left/right shaft. Fuel tanks behind engines. Observer behind pilot.

The helicopter was ready for testing in August 1941, thr final design having no wheel or rotor brakes but trimming tailplane with pilot handwheel. Tentative hovering tests, interrupted by engine rough running and overheating. Six-month delay followed the evacuation of the OKB-3 in October 1941. Pilot K.I.Ponomaryov gradually made progress in 1942, discovering structural and control problems but remained tethered until early 1943. The engines seriously overheated.

The Omega II, sometimes called G-2 (helicopter 2), was the original design with superior engines in streamlined pods with fan-assisted cooling. Gearboxes, clutches, cooling system etc were redesigned. Drive ratio 0.32. Important progress was made in optimization of gearbox ratio. It resulted in increase of the rotor lift force by 300kg and substantial increase of ceiling.

Rotor masts and outriggers stiffened, and dymamic parts (cliutches and gearboxes) redesigned for a longer life. Test flown by Ponomaryov in September 1944 with good results, but damaged in January 1945, repaired and improved (drive ratio 0.283) and used again from July 1945, by this time for research and pilot training. With chief engineer D.T.Matsitskii as observer, gained a height of 3km. Demonstrated in Tushino by M.K.Baikalov in August 1946.

Omega
Engine: 2 x MV-6 pistone engine, 220hp
Rotor diameter: 7.0m
Length: 8.2m
Width with rotors turning: 14.2m
Take-off weight: 2050kg
Empty weight: 1760kg
Max speed: 186km/h
Service ceiling: 700m
Hovering ceiling: 290m
Range: 250km
Crew: 1

Omega II