Kalinin K-7

Kalinin K-7 History

Konstantin Kalinin (1889-1938) made aviation history as a Red Army pilot during the Russian Civil War (1918-1920). After joining the Communist Party after the war (1912-1991), he established a design studio to continue his career.

Design work resulted in several post-war aircraft, all named after him, and the stables included the Kalinin "K-4" and "K-5". The K-5 was particularly notable because it became the most-built Soviet passenger aircraft at the time, with around 260 aircraft built starting in 1929.

From this work emerged one of the greatest Kalinin designs of the gigantic "K-7", intended for use as a military bomber and passenger aircraft. However, the design remained only an experimental prototype, and its future was greatly questioned after Kalinin himself was executed during Stalin's high purges before World War II (1939-1945).

The K-7 is a massive creation, even by modern standards, at 91 feet 10 inches long, with a wingspan of 173 feet 11 inches, and over 40 feet tall. The fuselage weighs 54,000 pounds when empty and 84,000 pounds fully loaded. This beast required no less than six engines, with a seventh (in a "slider" configuration at the rear of the fuselage) later added when the plane required it. The engine type is a Mikulin AM-34F 12-cylinder piston engine type, each producing 750 hp and driving a two-bladed propeller.

This arrangement allows for a top speed of 140 mph and a service cap of 13,125 feet.

Structurally, the aircraft featured a large, wide wing with distinctly rounded tips. The cockpit and main crew area are contained in a central cabin that uses a heavy-duty frame for good visibility. Three engine nacelles are buried in the leading edge of the wing, and three are mounted on either side of the flight deck. The double outriggers form the rear of the fuselage, which are connected to the rear of the fuselage by large horizontal planes mounted below and between the two vertical stabilizers.

The landing gear is mounted in large fairings under the front of the outriggers under the wings, which have huge landing wheels. A strut mesh connects the equipment and fairing to the actual aircraft structure. The frame of the K-7 is constructed of welded steel to the required tolerances.

A standard operator becomes 11 people, while the passenger version can carry around 120 passengers in addition to cargo. The military version has gun turrets in the nose, forward of each landing gear fairing, and in the middle of the tail boom.

Armament includes machine guns and automatic cannons with a capacity of over 20,000 pounds.

Construction of the K-7 began in Kharkiv, Ukraine in 1931, and its maiden flight took place on 11 August 1933. Two more prototypes were signed. The K-7 completed several test flights in short periods of time in the air before suffering damage during a test in November 1933.

Advanced technology can be found throughout the period (the K-7 definitely looks a bit dated). ) and political conflict within the Communist Party, the K-7 program was officially cancelled in 1935.

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