Submarine Design

[zeroname]

links not working

[Submarine Tom]

Sorry about that, this should fly:

http://www.psubs.org/projects/123768...00submersible/

Tom

[karabacak]

the link do not work tom unfortunately

[Submarine Tom]

I just tried it and it worked...

[bntii]

Wow- Remarkable effort and result in that sub.

[Submarine Tom]

Yes, no expense spared. He is semi-retired but busy as hell.

He still has only two or three sea-trials under his belt.

I look forward to further test results.

Tom

[bntii]

Tom- do you know if this is being put together as a prototype for a production boat or a one off?
The page on psubs is great on photos but a little lite on back story. I would like to know a bit more about the build.

[Submarine Tom]

bntii,

Both. Cliff is a pretty private guy and he doesn't/didn't want a lot of

publicity with his build. He is a "retired" fluid dynamics engineer with his

own company. He built it as a one-off but to spec for production and

commercial sale should he decide to go that way. It's fly-by-wire, 10kw,

touch screen. I recall about 3-tonnes submerged. We corresponded

for some time by email but I haven't heard from him for months now...

He's got 20 degree all-round articulation on the jet nozzle and I assume

the "ailerons" function as pitch and roll control surfaces via the fly-by-wire

computer. Pretty well my dream machine if I had the $$$.

There are a few things I would do differently, but not much.

Tom

[bntii]

Thanks

[tspeer]

Originally Posted by karabacak

...We are thinking about design a submersible for a competition that organised The Chamber of Turkish Naval Architects & Marine Engineers. We need proffesional help about our project especially for submerged devices stabilty. Can you help us about this way?

To the best of my knowledge, there has only been one successful flying submarine - the Reid RFS-1.

This was basically a submersible airplane. The air propeller had to be removed and the engine sealed before it could submerge. The cockpit was completely flooded, so this was a wet sub. But it did both submerge and fly.

What are the requirements for your craft? I suggest stability when submerged is the least of your problems. If you have a configuration that is stable in the air, making it stable underwater should be straightforward. I think you should focus on more fundamental issues, such as performance, both airborne and submerged.

If you think through the issue of a flying sub, I believe you will realize that any air space when submerged is a huge problem if the craft has to fly, because the weight needed to overcome the buoyancy of the air space has to be lifted when the craft flies. Fuel becomes a problem both submerged and flying, because fuel is lighter than water and any buoyancy is detriment to being able to submerge.

Treat this as an airplane that can submerge rather than as a submarine that can fly. That was Reid's approach, and I think it's the only practical one. I suggest you don't try to submerge using negative buoyancy, but fly the craft down using negative lift and positive buoyancy. I also suggest you do not try to make a dry sub, but flood every void within it - including the fuel tanks (use bladders to separate the fuel from the water).

[Submarine Tom]

tspeer,

I don't believe anyone said anything about flying in the air, rather flying in

the water, unlike a conventional submarine.

Interesting photo you posted though.

[oralpiskin]

hi,
is it reasonable to use ITTC 1957 method to calculate the resistance of a submerged vehicle?

[DarthCluin]

I think what KARABACAK is designing is a heavier than water craft. He doesn't expect it to fly in air, he wants it to fly in water.
I think I read about them in a novel, possibly by Martin Caidin, or Lee Corey (G. Harry Stine's pen name).
Submarines as we currently know them are the aquatic equivalent of ballons, blimps, and dirigibles. A heavier than water craft would use hydrofoils to generate lift while in motion and water jets to hover.
The main advantage is that if you don't have to float, you can build heavy, to go deeper, put bigger motors in to go faster, or just build smaller.
The main disadvantage is if you lose power, you sink.
I don't know if anyone has tried to build one before, and if they did, I hope they tested it someplace shallow.

[Gannet]

Originally Posted by DarthCluin

...A heavier than water craft would use hydrofoils to generate lift while in motion and water jets to hover.
The main advantage is that if you don't have to float, you can build heavy, to go deeper, put bigger motors in to go faster, or just build smaller.
The main disadvantage is if you lose power, you sink.
I don't know if anyone has tried to build one before, and if they did, I hope they tested it someplace shallow.

Graham Hawkes' Sumersibles always have positive buoyancy and uses negative hydrodynamic lift to keep the submersible down so that if it losses power or propulsion it would always rise to the surface. See attachments

Enjoy
Gannet

[DarthCluin]

As a firm believer in Murphy's Law, I would feel a lot safer in the Hawkes boat, however, it is still a dirigible.
Mind you I like dirigibles. I think the best one in the water was the U.S.S. Albacore AGSS569 (though in the air I have other preferences ).