Born in 1906, Grushin worked on various aircraft at MAI. In 1935 he began scheming a tandem-wing aircraft, thinking this could form the basis of an attack aircraft with a rear gun turret. The single example of the Sh-Tandem (Shturmovik-Tandem) was constructed in the Institute's production training school. It was exhaustively tested by P M Stefanovskii from 5th December 1937. The key feature of this aircraft was that it had a main wing and a rear wing with 45 per cent as much area.