Broadly similar to predecessors, incorporated new rotor proposed by I.P.Bratukhin with three large blades with articulated roots which provided lift, and three smaller blades with rigid attachment which provided control. Some accounts incorrectly state large and small rotors superimposed; all blades were in same plane, large and small alternating. This rotor worked, yet 5-EA appears not to have reached any considerable height or endurance (Western figures 13 miles and 1200 feet not confirmed in Soviet accounts). 5-EA flew from 1933 until late 1935 and was instrumental in providing research basis for machine with more powerful and more modern engine.
Bill Gunston "The Osprey's Encyclopedia of Russian Aircraft", 2000
Construction of this helicopter was similar to 1-EA and 3-EA, but the main rotor was radically redesigned (by I.P.Bratukhin). It became a combination of two 3-blade rotors of different diameters: the bigger one had fixed blades, the smaller one was used for aircraft control. Large rotor blades could change pitch all together to provide vertical evaluations. Smaller rotor was the fully instrumented one.
Was flown many times during 1933-1935, mostly to study behavior of the bigger 'lift' rotor. One built.
Technical data for 5-EA
Crew: 1, engine: 2 x M-2 pistone engine, rated at 120hp, rotor diameter: 12.0m and 7.8m, take-off weight: 1210kg, empty weight: 1047kg, max speed: 20km/h, ceiling: 40m, endurance: 0.7h