TsAGI A-8

First flown 29 June 1934, this was virtually an A-6 with two major alterations: wings had 5 degree dihedral instead of upturned tips, and as well as ailerons direct rotor control of roll was provided, even during autorotation (and found to be vastly superior to ailerons except at max speed). Other changes included auxiliary fins on tailplane and first air/oil shock struts in Soviet Union.

A-8
Engine: 1 x M-11
Rotor diameter: 11.0m
Wing area: 5.8sq.m
Length: 6.3m
Height: 3.2m
Weight empty: 595kg
Fuel/oil: 67kg
Weight loaded: 837kg
Max speed: 142km/h
Min speed: 48km/h
Ceiling: 2560m
Endurance: 2.5h
Take-off run: 50m
Landing run: 0m