First helicopter designated for Bratukhin himself. Scaled-up derivative of G-4, with slightly more powerful model of same engines. Transmission and other dynamic parts identical. Same configuration but new airframe with lifting aerofoil wing instead of space-frame outriggers and large passenger fuselage. Latter designed as duralumin semi-monocoque (not steel tube as has been reported) with level floor and door on right side. Total of eight seats, intended as two crew and three double passenger seats with aisle along right wall. Wings also of light-alloy stressed-skin construction with lifting profile to bear about 25% of weight in cruise. Fixed tricycle gear with bumber tail-wheel. Single example only, completed 1947, only limited testing because of inadequate wing stiffness.
Bill Gunston "The Osprey's Encyclopedia of Russian Aircraft", 2000
* * *
Instead of tube frame supporting the engine-rotor blocks, a straight wing was installed. In flight it provided 25% of a lift force, unloading main rotors.
Helicopter was flown, but tests were not completed. The reason was that there were no serious plans to use experimental aircraft (as helicopters were at the time) for passenger traffic.
Technical data for B-5
Crew: 2, passengers: 5, engine: 2 x AI-26GRF pistone engine, rated at 550hp, rotor diameter: 10.0m, take-off weight: 4032kg, empty weight: 2932kg, max speed: 236km/h, service ceiling: 6400m, hovering ceiling: 2280m, range: 595km