Researchers To Build Underwater Airplane

coondoggie writes to tell us that DARPA seems to still be having fun with their funding and continues to aim for the "far out." The latest program, a submersible airplane, seems to have been pulled directly from science fiction. Hopefully this voyage to the bottom of the sea is of the non-permanent variety. "According to DARPA: 'The difficulty with developing such a craft come from the diametrically opposed requirements that exist for an airplane and a submarine. While the primary goal for airplane designers is to try and minimize weight, a submarine must be extremely heavy in order to submerge underwater. In addition, the flow conditions and the systems designed to control a submarine and an airplane are radically different, due to the order of magnitude difference in the densities of air and water.'"

Comments

Water is 830 times more dense than air

[XSpud]

Before they go too far with the designs, DARPA might want to check their figures for the densities of water and air. Last time I checked they differed by a lot more than "an order of magnitude" and I'd think this might be important.

Re:Crazy DARPA

[Anonymous Coward]

Can I buy some pot from you?

Requisite Futurama Quote

[egyptiankarim]

"We're taking over 150 atmospheres of pressure!"

"How many atmospheres can this ship take?"

"Well, it's a spaceship, so I'd say anywhere between 0 and 1."

What is up with the tags recently?

[Rayeth]

since when is "fuckofftags" a useful tag?

diametrically opposed is good!

[Chris Burke]

They're saying how the requirements for submersibles and aircraft are diametrically opposed. That's good! If they were only kinda in opposite directions, that'd be a challenge. But calling on my vast electrical engineering knowledge (and what is mechanical engineering but electrical engineering with molecules instead of electrons?), I can tell you this is easy. What do you do if you discover that your current is diametrically opposed to what you want? That's right, you flip the terminals around, and bam your current is spot on!

So, using the same principle. In air you want the plane light and lift high because gravity means the natural tendency of the plane is to go downward and you want to go up. Underwater, gravity turns into buoyancy and your plane would naturally want to go up when you want it to go down. This sounds like our current problem -- we have a plane that flies perfectly in air, but in water goes the opposite direction of what we want. So what do we do? Yeah, we just flip it. Now the "lift" of the wings is pointed down. All you need then is an engine that works in air and water, and either a crew compartment that rotates to stay vertical, or sturdy straps and training for pilots to maneuver while upside-down. Done!

I just but the reversed-wing thing is actually used in some high speed submersible. Exercise on how to make it work in either direction above/below water left as an exercise for the DARPA grantee.