Re: [PSUBS-MAILIST] Topic change

["Karl Fuller" <fullerk@voyager.co.nz>]

Hi Craig, have some comments to make :-)
----- Original Message -----
From: <CWall@swri.edu>
To: <personal_submersibles@psubs.org>
Sent: Wednesday, November 08, 2000 4:20 AM
Subject: [PSUBS-MAILIST] Topic change


> Ed said:
> I think a lot of discussion is going on concerning something that is WAY
> OUT of our league. I thought this was a Personal Sub list to enhance our
> potential and offer advice to built our own PSUB. I honestly don't
> envision any of us building a flying sub.

It is only as far out of "our" league as subs were to boatbuilders when they
were first concievied, not impossible but awaiting suitible technological
breakthroughs, like the welding of steel at that time.
>
> I agree with Stan - "To me the flying sub is SiFi, like in Voyage to the
> Bottom of the Sea. 2 different technologies that don t fit together."
>
>
****************************************************************************
***
> *******
>
> Yeah, I'd have to agree.  After 35 years of experimental aviation, if
someone
> put a gun to my head and said "build a flying submarine", I'd just take a
> two-seat Goodyear Inflatoplane and use the passenger weight for a skeleton
> chassis and electric propulsion system and be done with it. But it would
be a
> lousy submarine from a mediocre airplane....and who wants to waste their
time?

Probably what the sceptics said about the first ideas about flight itself !

> He's a new topic:  my dry sub design, as far as I've gotten (after a
couple
> hundred hours of design tradeoff studies) is a steel one-man cruising sub,
> optimized for long range on the surface and shallow dives- mostly 30ft and
> less.
>
> Here's the innovation (or at least I think it is, simply because I haven't
> heard of anyone else suggesting it):   Propane is used for both fuel and
> ballast blow.

To use propane you have to use oxygen in the pure form or atmosphereic. The
chances of explosion for whatever reason for me would be too high, these
gases combined in a closed space combined with electricity, not for me, even
if external to the hull ! May as well be depthcharged.......
>
> All propane plumbing is external to the pressure hull.  The only thing
> penetrating the P-hull are rotating valve actuators, steering linkages,
and the
>  prop shaft.
>
> The drive is parallel hybrid, like a normal sub, but the carburetor for
the
> Honda 5hp long life horizontal shaft engine is at the top of the snorkel,
again
>  so that no pressurized propane enters the P-hull.   Propane used to blow
the
> ballast tanks is not lost but can be delivered to the engine for use as
fuel
> when on the surface.

You have to use all that gas with engine before you dive again ? You would
risk the carburetor back firing and sending flame into the propane filled
ballast tanks? I 'm sure you would try to limit these possibilities, but now
amount of trying would be enough for me !
>
> Additional refinements may include pneumatic  compounding (a reciprocating
> motor used to extract the energy from the pressurized propane before
delivery
> to the engine and connected shaft-to-shaft, allowing the Honda to be run
> extremely lean for increased range) and exhaust turbo-compounding for
> additional battery charging.

I think you find the volume of gas expanding in order to run and engine
would be very minimal in the assistance of creating power, the pressure
dropping off as the propane is used. Propane being stored under relatively
low pressure and the volume of gas, once expanded and consumed by such a
small motor, very small. You get usable energy by either high pressure/low
volume or low pressure/high volume but you have low volume and low pressure
in this situation.
The benift of turbo charging an engine is that you increase the capacity of
the engine by 'forcing' the engine into increase it's swept volume of gas.
All the energy is used by the exhaust gases to compress air for the intake,
nothing left over to generate power, I think or if you are not using the
turbo to compress intake gas, why not just increase the generator size ?
More simple, less cost and more reliable. No free lunch here !
>
> The design goals are: 200 miles of surface range, 2 miles submerged range,
and
> room to lay down and sleep.  I think I can get this accomplished in a boat
> roughly 18 ft long, and it must be trailerable behind my little Isuzu
pickup.
>  (This really depends of what steel I can get my hands on.)   I don't
> contemplate wanting to go below 100 ft, so a 250 ft redline depth seems
> appropriate.  I would anticipate most dives to be shallower than 30 ft.
>
> The hull would be most likely fabricated from a section of steel tube 28
to 30
> inches in diameter, perhaps more, with the pressure section absolutely
round
> but the ends darted and drawn to get a good "guppy" shape.   (Sort of like
a
> moderated sea kayak- I want to make way on the surface even if there are
some
> swells...)   Fore and aft free-flooding ballast tanks would enclose the
propane
>  tanks and trim tanks, so that propane leaks would be captured, and side
> flooding ballast tanks would add bouyancy- syntactic foam would be used to
get
> nearly neutral trim with ALL ballast flooded.   A substantial droppable
keel
> and fore and aft shot hoppers would then get you to the surface if you ran
out
> of propane or went below the depth where the 90psi blow was inadequate.
>
> I've been doing cardboard models to get the geometry from straight tubing
with
> cuts and welds, and I've been very pleased with the shapes I've been able
to
> generate.  I have some other projects ahead of this one, but I have a
feeling
> this one has life to it.

If you value your life, I advise not to do it this way but to rethink some
more safety in your design. The motivation for me writing this is concern
that you may start a project which not only could disappoint but be life
threatening.

Regards,
Karl.
>