Ivan Pavlovich Bratukhin ran OKB-3 at MAI 1940-51. Concentrated on helicopters with aeroplane tail and left/right girders or wings carrying an engine/rotor group. Omega, or 2MG, delayed by German invasion until 1943. Helicopters Omega II, G-3, G-4, B-5, B-9, B-10 and B-11 progressively better, last 5 designs having 550-hp or 575-hp AI-26GRF engines.