Flying submarine
The flying submarine is a combination of a seaplane and a submarine , which can alternatively be called a diving plane . This aircraft is designed to fly like an airplane, land on the water, submerge and move underwater like a submarine. A new start from the surface of the water is also planned.
Since the requirements for the design of a submarine differ almost diametrically from the requirements for an effective aircraft construction, mostly only moderate technical requirements are placed on the performance as an aircraft or as a submarine.
Soviet Union
| parameter | value |
|---|---|
| Crew members | 3 |
| Take-off mass | 15,000 kg |
| Airspeed | 100 kt (about 185 km / h) |
| Range | 800 km |
| Service ceiling | 2,500 m |
| Engines | 3 × AM-34 |
| Flight operations performance | 3 × 1,200 hp |
| Maximum wind speed at takeoff |
4–5 Bft |
| Underwater speed | 2-3 kt |
| Maximum diving depth | 45 m |
| Range in diving trip | 5-6 NM |
| Maximum diving time | 48 hours |
| Submersible screw performance | 10 hp |
| Duration of immersion | 1.5 min. |
| Duration of surfacing | 1.8 min. |
| Armament | 2 18-inch torpedoes; 2 machine guns |
In the mid-1930s, the Soviet Union began building a strong fleet. There were battleships built aircraft carriers and ships of other ship classes. This also stimulated considerations for new technical and tactical solutions, and people became more open to suggestions.
In the Soviet Union there was a design for a flying submarine from the time of the Second World War , but its construction never got beyond the design stage. The project to build a flying submarine, which began in the Soviet Union in the 1930s, was never realized. The secret project for the flying submarine (Russian Летающая Подводная Лодка, abbreviation: ЛПЛ; transcription: Letajuschtschaja Podwodnaja Lodka; LPL), a three-engine propeller plane with two floats and a periscope, was made by Boris P. 1934-1938 by Boris P. . Борис П. Ушаков) headed.
While still studying at the Dzerzhinsky Naval Engineering College in Leningrad (Russian Высшее военно-морское инженерное училище), which he graduated in 1937, the student Boris Ushakov presented the design for a project in 1934, in which the characteristics of a -Boot should be united - his flying submarine. In fact, this design was a seaplane that could dive.
The project was revised in the following years and presented in several variants, in order to then test the resilience and durability of the individual construction elements. In April 1936, the appraiser determined that Ushakov's idea was interesting and should be implemented. In July 1936, the “Flying U-Boat” draft project was examined and positively assessed by the Army's Scientific Research Committee (Russian: Научно-исследовательский военный комитет; abbreviation: НИВК). The committee recommended continuing the project in order to check its feasibility by means of appropriate calculations and laboratory tests.
The project was included in the committee's plan "W" (Russian "В") in 1937. However, the project was then abandoned after a re-examination. Ushakov, at that time a "1st rank military technician" in the "W" department of the committee, continued the project in his spare time.
In January 1938, the draft and the basic tactical and technical elements of Ushakov's flying submarine were re-examined by the 2nd division of the committee.
This flying submarine was to be built in all-metal construction, have a projected airspeed of 100 kt and move under water at 3 kt. The engines should be closed with metal plates when underwater.
The flying submarine should have six hermetically sealed chambers in the hull and in the wings: three chambers, in each of which one of the three engines ( АМ-34 ; 1000 HP; with turbo compressor at the start 1200 HP) was hermetically sealed during diving, as well as the hermetically sealed cockpit, a chamber for the accumulator and a chamber for the electric motor. All other cavities in the aircraft should fill with water when diving. The preparation time and the actual immersion should only take a minute and a half. A riveted cylinder made of duraluminium with a diameter of 1.4 m and a wall thickness of 6 mm was to serve as the fuselage . The cockpit should be flooded when diving after the flight instruments have been lowered into a watertight shaft. The crew should switch to the steering position in the hull for underwater travel and control the submarine from there.
The outer skin of the wings and the tail unit should be made of steel, the floats of duralumin. These components should fill with water when submerged so that they do not have to be designed for the increased water pressure in the diving depth. After opening the corresponding valves, the water should flow into these components by itself.
The containers for fuel and lubricating oil should be placed in rubber reservoirs in the hull of the flying submarine.
To protect against corrosion, the flying submarine should be treated with appropriate paints and varnishes.
The two 18-inch torpedoes were to be attached to special brackets under the aircraft fuselage; the planned payload was to be 44.5% of the take-off mass. That was a typical value for heavy aircraft at the time.
To ascend the water ballast should be pumped out of the cavities. For this, the electric motor should be used for the underwater drive.
The flying submarine was intended to be used in the open sea for torpedo attacks on enemy ships. It was supposed to locate the enemy ship from the air and clarify its course. Then it should land out of sight of the enemy and ambush him in a submerged state and then sink him with torpedoes.
No great demands were placed on the flying submarine either in the air or under water, as it was only supposed to locate enemy ships in the air and should already lurk under water on the expected ship route. If the enemy ship did not pass close enough to the flying submarine, another attempt should be possible. The flying submarine should therefore reappear after the enemy ship was out of sight again, scout the enemy again and go back out of sight at the correct position in wait position.
Another planned application was the penetration into sea areas and naval bases that were cordoned off by mine belts. The flying submarine should overcome these mine belts by air and then land, submerge and act as a submarine under cover of darkness within an enemy restricted area, a harbor bay or a naval base. In daylight it could then spy on the enemy, scout out secret waters and attack when the opportunity arises.
The use of several flying submarines as a group was expected to have an effective effect. So three flying submarines could theoretically form a 15 km long barrier belt to block the likely path of enemy ships.
The project was rejected in 1938 by the Scientific Research Committee of the Army (Russian: Научно-исследовательский военный комитет; abbr .: НИВК) and declared over.
It was hoped that the project would offset a negative characteristic of the submarines, their poor mobility. The possibility of repeating the attack attempt by taking another short flight to a new lurking position was particularly valued if the enemy ship does not pass the position of the lurking submarine. This was seen as one of the main advantages of the planned flying submarine.
United States
During the Cold War , American planners expected extreme difficulties in penetrating the Baltic Sea , the Black Sea or the Sea of Azov with a conventional vessel . They wanted to achieve this goal with a flying submarine. It might even be possible to reach the Caspian Sea. Since the Soviets did not expect any hostile submarines in these areas, it was assumed that there were no special Soviet provisions for submarine hunting here either . The ultimate goal was to bring mini-submarines to the Soviet ships and successfully repatriate the submarine crew after the attack. Experience from the Second World War had shown that Japanese and Italian mini-submarines were successfully used, but that the crew could no longer be evacuated from the combat area afterwards.
The American inventor Houston Harrington filed a patent for a combination of airplane and submarine in 1945 .
In 1956, the American patent No. 2720367 for a flying mini-submarine was published. The underwater ride should be done by an electric motor. Take-off and landing should be done on a type of retractable water ski. The propulsion for the flight should be done by two jet engines, which were hermetically sealed during the underwater journey. A torpedo should be carried as armament.
In the United States, the US Navy is currently developing a similar project, the Cormorant combat drone - a drone that can be launched from a submarine .
Reid Flying Submarine (RFS-1)
In the early 1960s, Donald V. Reid built a fully functional radio-controlled demonstration model of a flying submarine that was one meter long. In 1964 the story of his submarine flight model appeared in a popular American magazine. There the name "Triphibian vehicle" was coined - based on amphibious vehicle. This immediately aroused the interest of the military who wanted to use such a vehicle to intercept enemy submarines. A design study for a flying submarine was awarded to Consolidated Vultee Aircraft Corporation and Electric Boat by General Dynamics in the United States in 1964 . As a result, the feasibility of the project was confirmed.
The military's requirements for the flying submarine were:
- Weight (without pilot and payload): 500 kg,
- Payload: 250–500 kg,
- Underwater speed: 10–20 knots,
- Flight speed: 500-800 km / h,
- Range
- under water: 80 km,
- in the air: 500–800 km,
- maximum diving depth: 25
- Flight altitude: 750 m,
- Take-off and landing up to a wave height of 1 m.
Reid built the prototype of the "Commander-1" in Asbury Park, New Jersey in 1964 as part of an armaments contract ("Defense contractor") for the US Navy . The "Commander-2" then actually flew and was fully operational. The "Commander" was the first American flying submarine. The prototype is now in the Mid-Atlantic Air Museum in Reading, Berks County, Pennsylvania .
He dived and drove at a depth of 2 m at a speed of 4 knots. The projected airspeed was 300 km / h, the airspeed reached 100 km / h. The first flight took place on July 9, 1964. After a dive at 2 m depth, there was a short flight at 10 m altitude. To dive, the engine inlets were sealed with rubber, the propeller removed, and the pilot put on a breathing apparatus . When underwater, the “pilot” sits in an open cabin with a breathing apparatus on.
In the stern there was an electric motor with one horsepower (736 W). The aircraft had the registration number N1740. It was powered by a 65 hp Lycoming engine (4 cylinder). The "Commander" was 7 m long, had delta wings and offered space for a pilot. The fuel tanks also fulfilled the function of the ballast tanks of a submarine. After landing in water, the fuel was simply pumped into the water and the heavier seawater was pumped into the fuel tanks. Refueling with fuel was not planned.
Aeroship
The “Aeroship”, a two-seater subplane with jet engines, was built on the basis of Reid's “Commander”. Landing on the water took place on retractable runners, which are comparable to water skis. The turbojet engine is hermetically sealed during landing (air inlet and thrust nozzle). The fuel tanks are in the wings. The Aeroship has a range of 300 km, a flight speed of 130 km / h and an underwater speed of 8 knots.
The aeroship was presented to the public at the New York Industrial Exhibition in August 1968: it landed on the water, dived down and up again, and then flew away again.
Technical problems
The flying submarine must be able to move effectively both in the air and in the water. The density of water is 775 times greater than the density of air.
The biggest technical problem is the mass of the flying submarine. According to Archimedes' principle , a submarine must have a balance between its weight and its displacement (the weight of the displaced water) for travel in a constant water depth. In contrast, the technical requirement for an aircraft is to be as light as possible.
In order for the aircraft to travel under water, the weight under water must be increased many times the weight of the aircraft. Large water tanks (around 30% of the aircraft volume) must be installed in the fuselage or the wings to hold the ballast water required for diving. For this high weight, however, there is no sufficiently powerful electric motor and accumulator available in the flying submarine for underwater travel.
Another major technical problem is the very high resistance of the wings under water. This only allows a flying submarine to travel slowly underwater. Otherwise, either the wings would have to be folded away or an extremely powerful electric motor would have to be used.
The next technical problem is the high pressure under water. The water pressure increases by one bar for every 10 m diving depth , and there is also a pressure of 1 bar on the water surface. At a diving depth of 25 or 50 m there is a pressure of 3.5 bar or 6 bar. These are orders of magnitude that are unknown in aviation and that no conventional aircraft can withstand. In order for a vehicle to function in the air and in the water, it needs a gigantic weight.
(Note: the additional pressure that is added to the usual air pressure is decisive for the pressure on the outer hull. Since there is already about 1 bar counterpressure in the submarine, only about 1 bar acts on the hull at a depth of 10 m. )
If the flying submarine is not only supposed to take off from the surface of the water like an ordinary seaplane, but directly from the water, then the launch requires extremely powerful engines that literally tear it away from the water.
Because of the forces acting during movement in the air or in the water, the flying submarine had to meet both the requirements of aerodynamics and those of hydrodynamics . So to speak, “hydro-aerodynamics” (or “aero-hydrodynamics”) had to be taken into account.
Further development
The flying submarine was an attempt to further develop the flying boat , but ended up in a dead end. Other unconventional approaches such as the Ekranoplan or the flying car were also unsuccessful. In contrast, the development of amphibious vehicles was successful.
Another technical approach is the underwater aircraft (or underwater flight apparatus ; English subplane ). This is a radical redesign of the submarine. In a sense, it is a submarine that “flies” underwater like an airplane instead of carrying ballast tanks like a conventional submarine. It is lighter than the displaced water and has a tendency to rise when it is still. It has wings that generate negative lift (ie “downforce”) - but only as long as the underwater aircraft is moving. Such an underwater aircraft dives slowly and only reaches a shallow depth.
The picture shows an experimental submarine in Monterey Bay that works on the principle of an underwater airplane.
Flying submarines in the science fiction genre
In the science fiction genre there are flying submarines, for example in the computer game X-COM : Terror from the Deep, the Japanese "Seawing" in red alert 3, in the American television series The Seaview - On a Secret Mission , in the film Sky Captain and the World of Tomorrow (diving planes) or in the Japanese films “Atragon” and U 2000 - Tauchfahrt des Horens both from 1963. Also in the literature by Mark Brandis in the book “Testakte Kolibri”; the submarine is also suitable as a spaceship.
Submarine-based aircraft
An alternative solution to the flying submarine was the use of airplanes that were supposed to be launched from submarines. Another alternative approach is to drop or set down mini-submarines from airplanes.
Individual evidence
- ↑ Archive link ( Memento of the original from March 5, 2008 in the web archive archive.today ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice.
- ^ "Proposed Study of a Flying Submersible ASW Vehicle," General Dynamics / Convair report HP-62-016, from 1962.
swell
- Геннадий Петров (Genadij Petrov): Летающая подводная лодка. (The flying submarine) In: Вестник Воздушного Флота. (Zeitschrift der Luftflotte) No. 3 (Jan./Feb.), 1995, pp. 52-53, ISSN 0373-9821 .
literature
- Bruce Reid: The Flying Submarine: The Story of the Invention of the Reid Flying Submarine, RFS-1 . Heritage Books, Inc., 2004, ISBN 0-7884-3136-6
Web links
- The US Navy and Flying Submarines (English)
- Flying Submarines (English)
- Drawing of a flying submarine (Russian lettering; not from 1938, as a jet aircraft is shown)