While it's untrue that Lieutenant John L. Worden, the commander of the Civil War submarine the U.S.S. Monitor was heard to curse under his breath that he wished his vessel could fly, some United States Naval officers have gone on record expressing that exact desire.
A flying sub
It's been a dream long in coming, only fulfilled by special effects teams working on such films as "Atragon" (Toho, 1963) a film about a submarine that could fly, or the late Irwin Allen's popular 1960s TV series, "Voyage to the Bottom of the Sea," that featured a "flying sub" able to detach itself from the mother ship Seaview and launch itself into the atmosphere. [Photo]
It's said that Allen, a stickler on details, turned thumbs down on model after model for the flying sub until one Hollywood special effects modeler came up with a realistic idea. Allen gave a big thumbs up for that one and the flying sub was born--at least on the airwaves if not the ocean waves.
Now the Pentagon's Department of Advanced Research Projects Agency (DARPA) has thrown its metaphorical hat into the flying submarine fray attempting to replace science fiction with science and fantasy with a usable technology.
As is often the case life imitates art--to a point. In the TV series the flying sub was docked inside a submarine, whereas the DARPA idea is to create a stealthy aircraft that can dive into the water, travel submerged, attack a target such as a ship or enemy coastal installation, and then emerge from the sea miles away to escape undetected.
Engineers working on the feasibility of the project admit that some pretty big hurdles lie ahead of them. Perhaps the biggest is the fact that few things could be farther apart than an aircraft and a submarine. Fighter aircraft are light and travel at high altitudes with low atmospheric pressure, whereas submarines are heavily reinforced against the immense pressures of the ocean depths to withstand a crushing implosion.
The undersea fighter
An underwater craft that actually flies through the water utilizing negative buoyancy, is likely what DARPA is seeking. Such a concept was the central idea behind author Martin Caidin's 1967 novel, "The Last Fathom."
In the story Caidin described a submersible that actually flew through the water like a fighter jet instead of propelling itself along like a standard submarine.
Caidin. an avid aviator, space enthusiast and author of 80 books, perhaps is most famous for the novel "Cyborg" that later became the basis for the popular TV series "The Six Million Dollar Man."
Design challenges
When a flying sub is in the air, it must have positive lift; when it's underwater it must have negative--or downwards--"lift." It sounds simple until actual engineering enters the picture. Yet, it's remarkable that many of the challenges the engineers face today are exactly the ones anticipated and addressed by Caidin in his book 43 years ago.
One of the primary keys to engineering a successful flying sub is the type of propulsion used. Most engineers agree that for airborne flight jets are a natural. A few carry that argument forward to submersible flight. They point out that a jet engine can be powered to provide underwater thrust if the fans within the jet are run with electricity.
The trick is protecting against seawater corrosion if utilizing the fans for both air and submersible propulsion.
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