It's the MAI (Moskovskiy Aviatsionniy Institut) Sokol, designed
by a student named F. Kurochkin.The 860 hp Hispano Suiza
engine drove two 4m props. A 2 m prop was in the tail, to
balance the aircraft in a hover. Lenght would have been 7,53m,
span 5,8m, without the props. There was no horizontal tail surface.
(Informations via VSTOL.org)