Experimental, Latest, Pioneers

The Quest to Build a Flying Submarine

In 1961 kids (and some adults) around the world were introduced to the concept of a vehicle that could both fly and travel underwater – a flying submarine. The television show Supercar emerged from the fertile imaginations of British television show maker Gerry Anderson and his team at AP Films.

Viewers were thrilled by the exploits of pilot Mike Mercury and his crew as they battled bad guys in the air, underwater and even at the edges of space. Anderson would go on to create other futuristic classic TV shows including Fireball XL-5, Thunderbirds and Captain Scarlet, but Supercar was his first foray into advanced technology.

Many of us who grew up in the 1960s fondly remember these shows for their bold creation of unlikely vehicles. However, what is perhaps more surprising is that there were attempts to create flying submarines intended to be crewed by humans rather than puppets. This is the unlikely story of the flying submarine.


The Ushakov LPL

Long before Supercar, in the late 1930s, a young engineer named Boris Ushakov was completing his studies at the Dzerzhinsky naval engineers academy in Saint Petersburg. By 1936, Ushakov had completed a design for a truly radical aircraft: a submersible seaplane capable of attacking underwater using torpedoes.

A drawing of Ushakov's flying submarine.
Ushakov’s flying submarine.

The utility of such an aircraft was obvious – it could conduct patrols while in flight and, if it spotted enemy ships, it could land on the sea, submerge and lie in wait to conduct a torpedo attack. It could also enter enemy harbours protected by anti-submarine nets and mines at night, conduct a submerged attack and then surface and take off to return to base.

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Ushakov seems to have presented the first outline proposal for the LPL as early as 1934, but it wasn’t until 1936 that his ideas were formally adopted by the Military Commission for Scientific Research (NIVK) and he moved to detailed design work.

His proposal was truly unique. The craft was to be a low-wing monoplane with an odd manta ray-shaped wing and supported on water by two large floats. Power was provided by three 1,000hp AM-34 radial engines, one mounted in each wing and one in the nose, which was predicted to give a cruising speed of around 100 knots in flight.

The AM-34 was going to power the flying submarine.
Over 10,000 AM engines of different variations were built from 1934-43.

The main fuselage was a 1.4m diameter cylinder constructed from 6mm thick duralumin. The floats were also to be constructed of duralumin while the wings and oddly shaped tail were to be steel.

The concept envisaged six watertight compartments within this structure: one for each engine (closed off using metal plates before diving), one for a conning tower mounted above the fuselage, one for the main electrical components and one for an electric motor that would drive a small propellor in the tail. Fuel and lubricants would be stored in rubber bladders within the fuselage.

Box art for a model of the LPL flying submarine.
Box art for a model of the LPL.

The notion was that the aircraft could be landed on water at which point the crew would move to the watertight compartment in the conning tower. The flying instruments would then be retracted into a watertight tube and all parts of the aircraft that weren’t designed to be watertight (including the cockpit and floats) would then be flooded and the aircraft would submerge. This, Ushakov claimed, could be achieved in under two minutes.

The three-man crew would then operate the LPL as a conventional submarine, using a periscope to set up an attack using the two 457 mm (18”) torpedoes carried beneath the wings.

It was claimed that the craft would have an underwater speed of 2-3 knots using its electric motor and would be able to safely dive to a depth of 40m if required. When the attack was complete, the crew would pump water from the flooded compartments, causing the LPL to surface. Once water drained from the cockpit and other areas, the engines would be re-restarted the LPL would take off as a conventional seaplane.

LPL flying over some Russian ships.
If successful the LPL would have been an extremely useful asset.

This wasn’t just an unusual design, it was something completely unlike any previous military aircraft and, unsurprisingly, the Russian authorities seemed uncertain about what to do with it.

Records are sketchy, but it seems that in 1936, the NIVK permitted detailed design work to be carried out. However, in 1937, this project seems to have been cancelled. Ushakov appears to have continued to tinker with the design in his spare time, but without official backing. According to some sources, the project was resurrected in 1943 on the direct instructions of the head of the NKVD, Lavrenti Beria.

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There have also been suggestions that in 1947, as the Cold War was building, some “testing” of the LPL was undertaken. However, as far as is known, no prototype was ever built so precisely what this testing might have involved is not clear. It is believed that this project was finally cancelled in the mid-1950s after Nikita Khrushchev became the new leader of the Soviet Union following the death of Stalin.

The Reid RFS-1 “Flub

Although the Ushakov LPL was a bold concept, as far as we know it never flew or submerged. It would take an eccentric American inventor to create and successfully test the very first flying submarine, the RFS-1 “Flub”.

Reid's attempt at a flying submarine could be considered successful.
The ‘Flub’. Photo credit – Donald E Reid.

Engineer Donald V. Reid had a day job with the Naval Turbine Test Station in West Trenton but in his spare time, he created oddball inventions at his home in Ocean Township, New Jersey. Reid built several radio-controlled aircraft until in the late 1950s, he began work on the creation of a flying submarine!

He built several flying models before he began work on a full-size prototype. Like the LPL, this was to be a floatplane capable of submerging. Reid built this aircraft using whatever he could scavenge.

The main engine was a four-cylinder, 65hp Lycoming unit from a light aircraft. Underwater propulsion was provided by a tiny 1hp electric motor powering a small propellor. The fuselage and wings were constructed using whatever materials Reid had to hand, apparently including parts of an old bed frame and a pair of garbage can lids! The plywood pontoons were purchased for $100.

The first attempt at a dive of the 'Flub'.
The Flub could float and be submerged. Photo credit – Donald E Reid.

The RFS (Reid Flying Submarine) didn’t have watertight compartments. To submerge, the pilot (who had to wear scuba gear), first removed the main propellor, then stretched a rubber cover made from the lining of a fuel tank from a WW2 bomber over the engine to protect it from water ingress. The aircraft was flooded and would then submerge. Probably…

The most surprising thing about the shoestring RFS-1 was that it actually worked. Sort of. In 1962, it made its brief first flight from the Shrewsbury River in New Jersey with Reid’s son, Bruce, at the controls. It quickly became clear that the puny engine had great difficulty in allowing the aerodynamically clumsy aircraft to maintain level flight. It never managed to exceed an altitude of 70 feet or a speed of 60 mph. In truth, the flights that it made were short hops covering no more than 100 feet.

In June 1964, this bizarre aircraft was finally ready for a major full-cycle test: a flight followed by a short trip underwater. To the surprise of many, it succeeded! Its performance underwater was just as limited as its ability to fly: it achieved a maximum depth of 12 feet and a speed of under 2 knots, but it was able to turn and navigate underwater.

The Flub submerged. Photo credit - Donald E Reid.
The Flub submerged. Photo credit – Donald E Reid.

This test was sufficient to enable Reid to apply for a patent for his aircraft but, to his great disappointment, neither the US Navy nor Air Force was interested in his flying submarine. No further development on the RFS-1 was undertaken and the only prototype was donated to the Mid Atlantic Air Museum in Reading, Pennsylvania after Reid’s death in 1991.

Other Projects

Even before the RFS-1 completed its record-breaking flight and dive, the US Office of Naval Armaments issued a call for proposals for the design of a submersible aircraft for anti-submarine duties. Lockheed responded in 1964 with the CL-865, a radical design that would have used either a conventional propellor or a pair of propellor blowers on the fuselage sides.

Projected flight performance suggested a cruising speed of 250mph and a range of around 500 miles, Underwater, the CL-865 was intended to be able to achieve an immersion depth of 75 feet and a speed of 18 knots with an endurance of up to 10 hours. However, the cost of development was considered excessive and this project did not go beyond the stage of early design proposals.

Even that wasn’t the end of the quest for a flying submarine. In 2008 DARPA (the US Defense Advanced Research Projects Agency) issued a Broad Area Announcement (BAA) calling for designs for a “transmedium” vehicle, essentially a submersible aircraft for use in “future coastal insertion missions.

The Caderock flying submarine.
Carderock design plans for an underwater vehicle that could fly.

Rather than looking for a submarine that could fly, DARPA was interested in proposals for an aircraft with limited capacity to travel underwater at shallow depths. Such an aircraft would fly to the target area, land on the ocean, submerge, approach the coast, drop Special Operations operatives, loiter offshore, collect the returning troops and then take off to fly back to base.

One response to this BAA came from the US Naval Surface Warfare Center (NSWC) Carderock Division in Maryland. The Carderock design was for a triangular flying wing with a span of 100 feet powered by twin turbofan engines for flight and a single retractable electric thruster for underwater propulsion.

The design featured a crew of two and space for up to six passengers and their equipment. Carderock published their designs in 2010 and noted that small-scale models had been constructed and displayed satisfactory flight characteristics. Crucially, the report concluded that the creation of a workable submersible aircraft was “feasible within the current state of the art.


Supercar lives! We just don’t know what happened to the Carderock design after the completion of the initial study. It’s certainly possible that manned submersible aircraft are being used for clandestine operations right now. We do know that several transmedium UAVs/UUVs (Unmanned Aerial Vehicles/Unmanned Underwater Vehicles) have been successfully designed and tested.

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The Lockheed Martin Cormorant drone was tested and found to be capable of launching and recovery from submarines at depths up to 150 feet. A DARPA-sponsored design study undertaken at North Carolina State University in 2018 resulted in the creation of a UAV/UUV that successfully demonstrated “egress from water, flight in the air, ingress into the water in each flight, and water locomotion.”

Using modern materials and technologies, Gerry Anderson’s vision of a flying submarine now looks feasible. Perhaps one or more have even already been built. Watch the skies! And keep an eye on the ocean, just in case…

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