Yakovlev EG

Yakovlev EG

Company type	Experimental aircraft
Industry	Aerospace
Founded	December 1947
Key people	V.V. Tezavrovsky (test pilot)
Products	Helicopters

The Yakovlev EG (Eksperimentalnyi Gelikopter), alternatively identified as the Yak-M11FR-1 or Sh (Shootka), was a coaxial rotor experimental helicopter. Its initial flight was conducted by V.V. Tezavrovsky in December of 1947.

Design and development

The EG's airframe consisted of a welded steel tube framework, with duralumin panels covering the forward fuselage extending to the rear of the engine compartment. The aft section was fabric-covered and incorporated a tailplane assembly featuring twin endplate vertical stabilizers, accompanied by a tailskid. Both pilot and passenger were seated side by side beneath a transparent canopy, each having access through car-style doors on either side.

Positioned behind the gearbox was the M-11FR engine, connected via a short driveshaft. The gearbox supported the rotor mast, which carried two contra-rotating, coaxial rotors each with two blades. The helicopter rested on the ground supported by a fixed tricycle landing gear mounted on steel tube framework.

During flight evaluations, vibrations were detected at forward speeds exceeding 20–30 km/h (12–19 mph; 11–16 kn). To mitigate this issue, the tailplane and vertical fins were removed.

In early 1948, the original M-11FR engine was substituted with a 190 hp (140 kW) M-12 model; however, due to reliability problems, the M-11FR was reinstalled to finalize flight testing by 8 July 1948.