World’s largest aircraft from 1930: Giant Russian K-7 flying fortress

The Soviet aircraft industry really like building big. We recently reported on the Hotelicopter , a converted Soviet Mil V-12 Heavy Lift Helicopter, which proved to be an April Fools prank. The Russians can still claim the title of world’s largest aircraft, though, with the Antonov AN-225 heavy lift transport, which has a larger wingspan than the Airbus A380. Both of these modern day wonders have still not eclipsed the Hughes H-4 Hercules or “Spruce Goose” for size and we have just unearthed pictures of something the Russians were working on in the 1930s that may have dwarfed even the Spruce Goose.
With a wingspan of 132.5 meters – for reference, a Boeing 747’s is 68.5 m – and 20 propeller engines, this design is based on a 1932 prototype called the Kalinin K-7, which was a Soviet heavy experimental aircraft. The 3D Computer generated model shown is 2.5 times the scale of the original K-7 but retains the same gigantic elliptical wing of extremely thick airfoil, with two triangle section tail booms. The K-7 was designed as a multipurpose civil and military aircraft. Passengers and payload were housed in the wing, with plans to carry up to 128 passengers. Other designs arranged 16 luxury cabins for 64 passengers, much like the Hotelicopter.

The military version of the aircraft was a real “flying fortress”, which emerged 10 years before the American Boeing B-17. It had as many as 12 gunner positions, which included an electric cart running along the tail booms to transport gunners to two tail machine guns. It could carry more than 16 tons of bombs, 112 fully equipped paratroopers or 8.5 tons of parachute drop-able equipment. While no specs are provided for the 2.5-times-larger version, the original K-7 prototype did fly with a take off weight of 38 tonnes, although the aircraft was destroyed when it crashed in 1933, and no further prototypes were built.