DARPA is pumping money into developing a submersible aircraft: a vehicle that can fly in the air and dive straight into the water, becoming a submarine. Badass!
The DARPA Submersible Aircraft research project is focused on making a submersible aircraft, not, as they not, a flying submarine. There's a difference! This would be a plane first, designed to spend most of its time in the air, spending only short periods underwater.
The challenge is balancing the needs of an aeroplane (low weight) with a submarine (high weight). Here are the major requirements of the craft:
* Flight: The minimal required airborne tactical radius of the sub-plane is 1000 nautical miles (nm). The minimum surface tactical radius is 100 nautical miles. The minimum subsurface tactical range is 12 nautical miles. Note that the ranges quoted are one-way ranges. The platform would need to be able to fly to a location, insert and extract personnel without refueling and this would require the total operational range to be 1000 nm airborne, 200 nm surface, 24 nm under water.
* Loiter: The platform should be capable of loitering in a sea-state five, in theatre between inserting and extracting personnel for up to 3 days (72 hours). The craft does not need to be submerged during loitering operations; it can operate at the surface.
* Payload: The platform should be capable of transporting 8 operators, as well as all of their equipment, with a total cargo weight of 2000 pounds.
* Depth: The operating depth of the platform will be constrained by balancing the need to reduce depth in order to minimize structural loads and snorkel complexity with the need to increase depth in order to minimise any potential signatures that could be generated by perturbing the free surface. The effect that the submerged platform will have on the free surface is exponentially proportional to the depth, therefore the platform should be able to operate at a relatively shallow depth and only have the snorkel affect the free surface.
* Speed: The speed of the platform in each mode of operation must allow the system to complete a tactical transit (1000 nm airborne,100 nm surface ,12 nm sub-surface) trip in less than 8 hours. This 8 hour time must include any time required by the platform to reconfigure between modes of operation.
If successful, it'll certainly be a feat of engineering. We'll see what they manage to come up with. [NetworkWorld]