The Tupolev ANT-40, also known by its service name Tupolev SB (Russian: Скоростной бомбардировщик - Skorostnoi Bombardirovschik - "high speed bomber"), and development co-name TsAGI-40, was a high speed twin-engined three-seat monoplane bomber, first flown in 1934. The design was very advanced, but lacked refinement, much to the dismay of crews and maintenance personnel - and of Stalin, who pointed out that "there are no trivialities in aviation".