Tupolev ANT-17

The Tupolev ANT-17, also known as the TSh-B or TSh-1, was a late 1920s design by the Tupolev Design Bureau for a ground-attack aircraft. It grew out of the worldwide trend toward mechanised armies, which created a need for a combat aircraft able to take on tanks and light armoured vehicles. In 1929 the bureau drew up an unconventional four-seat biplane with maximum offensive armament and armour: a recoilless gun designed by Leonid Kurchevskiy, eight machine guns, over 1,400 kg of bombs and more than 900 kg of armour. The weight of the armour made Tupolev doubt that the aircraft could deliver the required performance, and the project was cancelled.