in 1929, the tupolev okb undertook design of an unconventional aircraft with maximum offensive armament and armor protection. the ant-17 was a four-seat biplane armed with a recoilless gun designed by leonid kurchevskiy, 8 machine guns, and over 3000 pounds of bombs. the ant-17 would have featured over 2,000 pounds of armor. unfortunately, the weight of the armor meant that tupolev doubted the ability of the ant-17 to deliver the required performance, so the ant-17 project was cancelled.