RE: [PSUBS-MAILIST] Hydrogen Peroxide: on to the topic of flywheels

["Wade Carson" <wacarson@interchange.ubc.ca>]

Ahh ok.  I would have understood better if you'd said xxxx joules.  I was
sitting here wondering what the heck the person would have launched off of
to get that high in the air.  The only time I've heard that particular
terminology before is in fluid mechanics and it was fluid head in feet.  I
didn't make the relation.
I would agree that FW's don't sound particularly useful for submarines, but
on the other hand could you not use it in a much smaller form to even out
the rotation of your propellers?  Or perhaps you could use a much smaller
motor that simply needed to keep a small FW spinning and would kind of
separate the energy required for the propeller from the energy required to
rotate it.  You would probably have to start the flywheel spinning with a
handcrank or the like but it might allow you to run the subs motors much
more efficiently and use less energy because you could always keep it at the
optimum rate. Of course then you'd need some sort of transmission on the
other side or perhaps a controlled pitch prop which probably makes it too
complicated for a Psub.  So in the end you are still quite right that simple
and proven is better for P-subbers.

Wade


>     The 19,000 foot figure was simply used for reference to demonstrate
>how much energy a flywheel powered car can store.  If Popular Science had
>given the energy in Joules, most readers would have said, "Oh, xxxx
>Joules...  What's a joule?"  By saying that the energy was enough to lift
>the whole car to so many thousand feet the reader got a better
>picture.  The energy is directly proportional to the mass of the wheel, but
>proportional to the angular velocity squared.  If you double the rotational
>speed you raise the energy by a factor of 4.  If you double the mass the
>energy goes up by 2.  The trick is to get the highest speeds for rotation
>even if you have to sacrifice some mass.  This can be done by generating a
>flywheel that is not cylindrical.  It is thicker in the center than on the
>edges.  If you don't do this, less energy is stored before the FW material
>"flies" apart.  At these very high rotational speeds the mechanical linkage
>is difficult.  Sometimes, flywheels have been used to generate electricity
>which in-turn drives a motor.  The problem is the angular momentum.  The
>flywheel acts like a giant gyroscope when the vehicle tilts or relocates
>the axis of the FW.  Therefore, if their are two identical flywheels
>turning in opposite directions this effect is totally eliminated.
>     Once again, this is a very exotic form of energy.  The only reason
>that I ever considered it for subs was the fact that weight is not always a
>problem in a sub as it is in an automobile.  Right now, for most Psubbers
>conventional batteries offer the best source of energy.  It's interesting
>to think about exotic power sources, but the standard ones should be where
>most people focus.

>Gary Boucher