In the endless Internet, I found beautiful images created on the basis of a 3D model, a unique Soviet project of the Flying Submarine. The project was born back in 1934 by a cadet of the Naval Engineering School. Dzerzhinsky by Boris Ushakov.
As a course assignment, he presented a schematic design of an apparatus capable of flying and swimming under water. In April 1936, the project was reviewed by a competent commission, which found it worthy of consideration and further implementation. In July of the same year, the project was considered by the military research committee of the Red Army, where it was accepted for consideration and recommended for further developments. From 1937 to early 1938, the author worked on the project as an engineer, military technician of the 1st rank in the "B" department of the research committee. The project received the designation LPL, which stands for Flying Submarine. The project was based on a seaplane capable of submerging under water.
The LPL project has been repeatedly revised as a result of which it has undergone many changes. In the latest version, it was an all-metal aircraft with a flight speed of 100 knots and an underwater speed of about 3 knots. The LPL were planned to be used to attack enemy ships. A flying submarine, after detecting a ship from the air, had to calculate its course, leave the ship's visibility zone and, having switched to a submerged position, attack it with torpedoes.
Also, on a flying substrate, it was planned to overcome enemy minefields around the bases and navigation areas of enemy ships. Unfortunately or fortunately, such a revolutionary project was not implemented, in 1938 the military research committee of the Red Army decided to curtail work on the Flying Submarine project due to the lack of mobility of the LPL in a submerged position. The decree stated that after the discovery of the LPL by the ship, the latter would undoubtedly change course. That will reduce the combat value of the LPL and with a high degree of probability will lead to the failure of the mission. In reality, such a decision was influenced by the enormous technical complexity of the project and its unrealistic nature, which was confirmed by repeated calculations, as a result of which the LPL project was subjected to further changes.
How did all this come about? BP Ushakov proposed six autonomous compartments in the design of the LPL. In three compartments were placed AM-34 aircraft engines, 1000 hp each. The fourth compartment was residential and was intended to accommodate a team of three people and control the LPL under water. The fifth compartment was dedicated to the battery.
The sixth compartment was occupied by a rowing electric motor. The fuselage of an underwater seaplane or the body of a flying submarine was proposed as a cylindrical riveted structure with a diameter of 1.4 m made of duralumin 6 mm thick. The LPL for airborne control had a light cockpit, which was filled with water when immersed. For this, the pilot devices were proposed to be battened down in a special waterproof shaft.
For fuel and oil, rubber tanks were provided, located in the center section. The wing and tail skins were to be made of steel, and the floats were made of duralumin. When submerged, the wing, tail unit and floats had to be filled with water through special valves. The motors in the submerged position were closed with special metal shields, while the inlet and outlet lines of the water cooling system of the aircraft motors were blocked, which excluded their damage under the influence of the seawater pressure. To protect the LPL from corrosion, it had to be painted and covered with a special varnish.
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Two 18 torpedoes were placed under the wing consoles on holders. The armament included two coaxial machine guns to protect the LPL from enemy aircraft. According to the design data: takeoff weight was 15,000 kg; flight speed 185 km / h; flight range 800 km; practical ceiling 2500 m; underwater speed 2-3 knots; diving depth 45 m; cruising range under water 5-6 miles; underwater autonomy 48 hours.
The boat was supposed to submerge in 1.5 minutes and surface in 1.8 minutes, which made the LPL fantastically mobile. To dive, it was necessary to batten down the engine compartments, cut off the water in the radiators, transfer control to underwater, and move the crew from the pilot's cabin to the living compartment (central control post). For immersion, special tanks in the LPL hull were filled with water; for this, an electric motor was used, which ensured movement under water.