The history of the MK-1, or ANT-22, began in July 1931, when TsAGI received a request from the Air Force Directorate to develop an aircraft that in many ways had no analogues in the world. A large machine was required for long-range flights, capable of destroying entire groups of enemy ships with bomb and torpedo strikes. Also, the aircraft's functionality included escorting and covering its own ships from the air and working as a long-range naval reconnaissance officer. The classic single-boat scheme for the future seaplane was not fully suitable. Firstly, the boat turned out to be very high and wide, and also required large underwing floats for lateral stability. Secondly, the military demanded from MK-1 the ability to transport large torpedoes and even small submarines. All this would excessively increase the size of the boat, and the engineers had to look for another solution. As a result, the lead designer of the project, Ivan Pogossky, settled on the scheme of a two-boat seaplane-catamaran equipped with six engines at once. This was not TsAGI's know-how - by this time several small Italian S.55 winged catamarans were already in operation in the Soviet Union.
The domestic project, in comparison with the Italian one, of course, was striking in scale. "Sea cruiser" was supposed to take on board at least 6 tons of bombs and torpedoes, the wingspan was planned to be 50 meters, and the total power of six M-34R engines designed by Mikulin was 4950 hp. with. TsAGI rightly decided that for the construction of such a giant, it was possible to use the developments on the TB-3 ground bomber. The four-spar wing (with modifications) and the engine nacelle were borrowed. The engines were located in three tandem pairs one after another on special pylons. The front motors rotated two-bladed wooden pulling screws, and the ones at the back drove the pushing screws, respectively. The choice of such a design was primarily due to a decrease in drag in flight. However, this was one of the main mistakes of the designers - the pushing propellers were in the wake of the pulling propellers during the flight and they sharply lost in efficiency. In the future, it was planned to replace the low-rise M-34R engines with more powerful ones with a mechanical supercharger M-34RN or M-34FRN, but after testing the aircraft, this idea was abandoned. To ensure the declared thousand-kilometer flight radius, 9, 5 thousand liters of aviation kerosene were stored in four fuel tanks.
The stability of the MK-1 on the water was ensured by two huge double-run boats, the complex shape of the bottom of which was designed taking into account full-scale tests in the TsAGI hydro channel. To simplify and reduce the cost of assembly, the fuselages of the boats were made absolutely identical. Each boat with its own profile covered the extreme pairs of engines located above them from water spray, and the crew cabin protected the central engine nacelle from water. In the gigantic 15-meter space between the boats, it was possible to place a fairly large cargo - a small submarine or a semi-submersible torpedo boat.
People and weapons
Such a huge aircraft (length - 24.1 m, wingspan - 51 m, height - 8.95 m) required a large crew. The flight was directly controlled by two pilots, the commander of the ship and the navigator. They, together with the flight mechanic, were located in the central gondola or, as it was also called, "limousine". The boats housed six shooters (three in each), who controlled two Oerlikons, DA-2 sparks and a pair of ShKAS machine guns. When meeting with an enemy, the MK-1 could successfully snap back - from almost all angles the plane was covered with machine gun and cannon fire. It was supposed to equip the cannons with 600 rounds of ammunition, and the machine guns with 14 thousand rounds. MK-1 lifted 6 tons of aerial bombs or four TAN-27 torpedoes with a total weight of 4.8 tons into the air. At the same time, the bombs were located in different ways: 32 ammunition of 100 kg each could be loaded into eight bomb compartments in the wing center section, which reached almost one and a half meters in height. The second option was external beam holders, on which it was possible to mount six 1000 kg bombs, or 12 500 kg each, or 20 250 kg each, or four 1200 kg torpedoes.
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In addition to the flight crew and gunners, the right boat housed a radio operator from the PSK-1, which made it possible to conduct telephone conversations at a distance of up to 350 km. In addition, the 13-PS radio station, which provided aircraft driving through beacons, as well as AFA-13 and AFA-15 cameras, belonged to the on-board equipment.
The construction of the "Sea Cruiser" was carried out in the Moscow workshops of the TsAGI experimental design plant, which were erected on Radio Street in 1932. The assembly was carried out from 1933 to mid-1934. Since there was nowhere to test the sea giant in the Moscow region, the car was disassembled and transported to the TsAGI hydro base in Sevastopol. On August 8, 1934, the factory commission began testing the flying catamaran. Timofey Vitalievich Ryabenko was appointed test pilot. It was he who in August lifted MK-1 into the air from the water area of the Omega Bay. But the very first flights showed that the giant is too slow-moving: the maximum speed is only 233 km / h, and the cruising speed is 180 km / h. At the same time, the plane climbed to an altitude of 3000 meters for almost endless 34 minutes, which categorically did not suit the customer in the face of the Navy. And the ceiling of 3500 meters "Sea Cruiser" was gaining almost an hour! And this is in a lightweight version of the naval reconnaissance. When the car was loaded with five tons of bombs, the maximum speed, as expected, dropped to 205 km / h, and the flight range was reduced to 1330 km. The pilots noted the good controllability and maneuverability of the "Sea Cruiser" in flight, it obeyed the rudders well, and the giant made a full turn in 85 seconds. Perhaps the only significant advantage of the MK-1 was its excellent seaworthiness. The plane could land on one and a half meter waves with a wind speed of 8-12 m / s and kept perfectly on the water surface. But the low speed, gluttony and complexity of production put an end to the serial prospects of such an aircraft. In addition, the difficult operation of the MK-1 was of great importance. With a total mass of more than 33 tons, the seaplane-catamaran required specific hydraulic launches in the sea, as well as winches to pull the whopper out of the water. It was also not easy to equip the plane with heavy bombs and torpedoes: technicians secured ammunition, swinging on inflatable pontoon boats under the center section. Therefore, there was no need to talk about some kind of operational readiness of the vehicle in the event of hostilities - the MK-1 took too long to go on the road.
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The only manufactured copy of the "Sea Cruiser" managed to distinguish itself with a couple of seaplane records. The first was registered as a world one: in 1936, a load of 10,400 kg was lifted to a height of 1942 meters, and a little later, already 13 tons. True, the latest achievement was not officially registered. After record-breaking flights, all work on the MK-1 was closed, and it occasionally took off until 1937.
The construction of such a large aircraft became one of the milestones of the hobby for aviation gigantomania, gave TsAGI specialists invaluable experience in the design of amphibians and showed the futility of further increasing the size and number of engines.
