Konstantin Alekseyevich Kalinin directed aircraft repair factory 1923 and set up his own KB (GROSS) 1925, producing series of high-wing monoplane transports with elliptical wing, K-1 onwards. Most successful was K-5 (1929), 260 being built. K-7 was giant 7-engined bomber (1933), K-9 and -10 light sporting monoplanes and K-12 tailless twin-engined bomber (December 1936). In 1938 Kalinin caught up in Stalin’s terror, accused of 'conspiracy' and executed.