Yakovlev EG

Yakovlev EG / Sh / Yak-M11FR-1

Manufacturer: Yakovlev
First flight: 1947
Introduction: 1947
Retired: 1948
Status: Cancelled

The Yakovlev EG (Eksperimentalnyi Gelikopter), also commonly known as the Yak-M11FR-1 and Sh (Shootka), was an experimental aircraft with coaxial rotors. The prototype was first flown by V.V. Tezavrovsky in December 1947.

Design and development

The fuselage of the EG was a welded steel tube truss with duralumin skinning on the fwd fuselage back to the rear of the engine compartment. The rear fuselage was fabric covered and supported a tailplane style with twin end-plate fins, as well as a tailskid. The Pilot and Passenger sat side by side under a glazed canopy with a car style door on each side. The M-11FR engine was mounted behind the gearbox which it drove via a short shaft. The gear box supported the Rotor pylon which had two, contra-rotating, co-axial, two-bladed rotors. A fixed tri-cycle undercarriage mounted on steel tube trusses supported the helicopter on the ground. Flight testing revealed vibration at forward spees above 20-30 km/h. In an effort to reduce vibration the tailplane and fins were removed. In early 1948 the M-11FR engine was replaced by an M-12, which proved troublesome so an M-11FR was refitted to complete the flight trials by 8th July 1948.

Specifications

Engine: 140hp, M-11FR-1 5-cylinder air-cooled piston engine
Rotor diameter: 10.0m
Length: 6.53m *Take-off weight: 1020kg
Empty weight: 878kg
Payload: 142kg
Fuel: 50kg
Max speed at sea level: 150km/h
Max speed reached: 70km/h
Hovering ceiling: 250m
Service ceiling: 2700m
Service ceiling reached: 180m
Range: 235km

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Source: WikiPedia