The Tupolev ANT-29 (military designation DIP – Dvukhmotorny istrebitel pushechny, "twin-engined cannon fighter") was a 1930s twin-engined, cannon-armed fighter designed by Alexander Arkhangelsky and built by Tupolev.
Design work started in 1932 on a twin-engined aircraft capable of carrying two APK-100 cannon.
[1]It was a monoplane with a tall and narrow fuselage, powered by two Hispano-Suiza 12Ybrs engines.
[1] The cannon were mounted at the bottom of the fuselage, and unusually they were accessible to the crew in flight for loading and maintenance.
[1] During tests the machine had reasonable performance but was longitudinally unstable.