Central Aerohydrodynamic Institute (also written TsAGI), Moscow, founded December 1918 by N.Ye. Zhukovsky. Provided aerodynamic basis of knowledge for all significant Soviet aircraft, and managed early rotary-wing programmes: 1-EA by Prof. B.N. Yur’yev (August 1930), 5-EA and 11-EA by Bratukhin, 2-EA autogyro by Izakson (1931) and outstanding A-4 – A-15 used in Arctic and in Second World War.