Tupolev ANT-22

The Tupolev ANT-22, also known as the MK-1, was a very large flying boat built in the Soviet Union in 1934 for Soviet Naval Aviation. It was an unusual design with two hulls joined by a wing and six engines grouped in three nacelles, each pairing a tractor and a pusher engine. It was derived from the ANT-11 project, a design that was never built. The aircraft was heavily armed for its type, with cannon and machine guns in dorsal, nose and tail turrets and a bomb load carried under the wing centre section, and it carried a crew of eight. Its great weight, about 33 tonnes when loaded against roughly 21.7 tonnes empty, badly limited its performance, with a top speed of 233 kilometres per hour and a service ceiling of 3,500 metres. The type never progressed beyond the experimental stage.