[Date Prev][Date Next]
[Chronological]
[Thread]
[Top]
RE: [PSUBS-MAILIST] Hydrogen Peroxide: on to the topic of flywheels
Wow,
I think we must be talking about a fairly different size of flywheel. 19000
feet? That's crazy. I'm guessing the fellow didn't survive. I think that
most of the flywheels proposed for HP subs were fairly small and were simply
intended to give a good burst of acceleration off the line and to keep the
propeller turning at a constant rate (same sort of application as the one in
any automobile).
As for the counter rotating props, I have heard various things. The last
fellow I talked to about them actually said almost the complete opposite
from you. He said that the flow field generated by the first prop would be
much better as it came through the second prop and that most of the thrust
would come from the second prop. I suppose this might depend how much of a
vortex was created by separation at the aft end. The first prop might just
get the water headed back in the right direction. Anyhoo, I don't know a
great deal about it either but I'm trying to learn so if anyone does know
please say so. We have already come up with a design to do it so if it is
not going to be an advantage then I'd like to shut it down real quick.
Thanks.
Wade
-----Original Message-----
From: owner-personal_submersibles@psubs.org
[mailto:owner-personal_submersibles@psubs.org]On Behalf Of Gary R.
Boucher
Sent: Wednesday, July 26, 2000 11:12 PM
To: personal_submersibles@psubs.org
Subject: RE: [PSUBS-MAILIST] Hydrogen Peroxide: on to the topic of
flywheels
Wade,
A sub powered by a flywheel would be of little use with the exception
of breaking some sort of speed record for underwater craft. Such a craft
would be far from the design of a human powered wet-sub. Back in the
1960's someone put a flywheel in a Corvair. I remember as a kid reading
that the amount of energy stored in that flywheel was enough to raise the
whole car some 19,000+ feet above sea level. That's quite a bit of kinetic
energy stored. This would be too exotic for most all
applications. However, if you wanted a sub that had the equivalent of a
6-liter V8 for about 2 minutes, it may be what you're looking for. Yes, it
would be one heck of a ride.
The problem with FW propulsion has always been the coupling of the
energy to the wheels of a car. As the energy is drained from the FW, the
RPM decreases. You can pull the same amount of power from a FW system from
start to finish but you must take the power with an ever decreasing RPM
(angular velocity). This means you will have to increase the torque
loading as the RPM slows down. This is very difficult in an
automobile. However, if you had variable pitch blades on your props you
could couple the right amount of torque to deliver a steady power transfer.
Yes, this would be dangerous. But there are some that would like to
set the land speed record and others that want to set the speed record for
boats (hydroplanes). I am not proposing to do this. It is just something
that I have pondered through the years. The actual speed record for
submarines is classified but way over 50 knots.
When I said, "Counter Rotating Props", I was talking about two
propellers turning in opposite directions. Some subs have the two props
co-located. This has to do with torque. I am not a prop expert so I am
unsure of the efficiencies. But, when two props are used together
turbulence from one will have a negative effect on the other. This can be
prevented by using two props and separating them. Will they let you have
two props?
GB
At 08:43 PM 7/26/00 , you wrote:
>Gary,
>Such things are often considered in the human powered submarine world but
>have been strictly banned because they go against the spirit of the
>competition or something like that. I imagine they would give you quite a
>jolt. Actually, having seen some of the submarines it might also be
>dangerous. That kind of power could probably rip some of the subs in half.
>But it would certainly be a fun thing to try. I wonder how fast you could
>go?
>BTW do you know what kind of efficiency you might gain from a counter
>rotating prop (aside from balancing the angular momentum)? We are
>considering the idea for next year.
>Also BTW, and speaking of the Guiness book and alternate drives, the Uni of
>California in San Diego broke the world record for alternate propulsion by
>over half a knot with their mammal-like tail drive. Congratulations to
>them. It is quite an amazing sub.
>
>Wade
>
>-----Original Message-----
>From: owner-personal_submersibles@psubs.org
>[mailto:owner-personal_submersibles@psubs.org]On Behalf Of Gary R.
>Boucher
>Sent: Wednesday, July 26, 2000 10:19 PM
>To: personal_submersibles@psubs.org
>Subject: [PSUBS-MAILIST] Hydrogen Peroxide
>
>
> One last note on exotic propulsion systems. Here's one I bet nobody
>thought of. If you want a great deal of propulsion for a relatively short
>period of time build a sub with the propulsion energy stored in
>flywheels. I did some calculations on the energy you could store and it's
>impressive. However, the forte for such propulsion is in the tremendous
>release of energy in a very short time frame. It would make a good drag
>sub. You would have to have two flywheels that counter rotated to cancel
>the angular momentum (if you planned to turn). You would have to have two
>counter-rotating props to couple that much power due to the
>torque. Perhaps this would open a whole new page in the Guiness Book.
>
>GB