On Wed, 7 Nov 2007 16:41:36 -0500, "Eisboch"
wrote:


"Short Wave Sportfishing" wrote in message
.. .

Interesting video.

I wonder how it affects bow-to-stern movement? It is a gyro - seems
to me that if it has that much of an effect on side-to-side roll, it
would have the same effect on bow-to-stern movement..

The gyro vacuum enclosure appears to be mechanically restricted to fore and
aft gimble movement, so I suspect it stabilizes on one axis only.

How the fore and aft movement translates to stabilizing beam to beam I think
has something to do with the principles of gyroscopic progression, similar
to helecopter controls of blade pitch.

But, I might be wrong.

I didn't think of that.

Good point.

"Short Wave Sportfishing" wrote in message
...
On Wed, 7 Nov 2007 16:41:36 -0500, "Eisboch"
wrote:


"Short Wave Sportfishing" wrote in message
. ..

Interesting video.

I wonder how it affects bow-to-stern movement? It is a gyro - seems
to me that if it has that much of an effect on side-to-side roll, it
would have the same effect on bow-to-stern movement..

The gyro vacuum enclosure appears to be mechanically restricted to fore
and
aft gimble movement, so I suspect it stabilizes on one axis only.

How the fore and aft movement translates to stabilizing beam to beam I
think
has something to do with the principles of gyroscopic progression, similar
to helecopter controls of blade pitch.

But, I might be wrong.

I didn't think of that.

Good point.

Further on my boring analysis of this system ....

The manufacturer acknowledges that the system is similar to another similar
system, but claims it is superior due to the gryo being located within a
vacuum enclosure, thereby reducing the friction due to air. The gyro can
spin at a higher speed, therefore can be made smaller and uses less power.

Fine.

But, having mucho years trying to make mechanical objects spin, move, etc.
in a vacuum environment, there is one potential issue that comes immediately
to mind.

In a vacuum there is no convective heat transfer to speak of, and very, very
little conductive heat transfer due to virtual point contact. Bearings
generate heat, particularly in high speed applications and if that heat
cannot be transfered away from the balls and races, the bearings tend to
self destruct. We used to use specially prepared aerospace bearings
designed for space flight in the systems we built ... and even then often
had problems with high speed applications.

It seems to me the big "breakthrough" in this product is the vacuum
enclosure of the high speed gyro. I'd be interested in how they handled the
issue I've described.

Eisboch

On Wed, 7 Nov 2007 17:08:34 -0500, "Eisboch"
wrote:


"Short Wave Sportfishing" wrote in message
.. .
On Wed, 7 Nov 2007 16:41:36 -0500, "Eisboch"
wrote:


"Short Wave Sportfishing" wrote in message
...

Interesting video.

I wonder how it affects bow-to-stern movement? It is a gyro - seems
to me that if it has that much of an effect on side-to-side roll, it
would have the same effect on bow-to-stern movement..

The gyro vacuum enclosure appears to be mechanically restricted to fore
and
aft gimble movement, so I suspect it stabilizes on one axis only.

How the fore and aft movement translates to stabilizing beam to beam I
think
has something to do with the principles of gyroscopic progression, similar
to helecopter controls of blade pitch.

But, I might be wrong.

I didn't think of that.

Good point.

Further on my boring analysis of this system ....

The manufacturer acknowledges that the system is similar to another similar
system, but claims it is superior due to the gryo being located within a
vacuum enclosure, thereby reducing the friction due to air. The gyro can
spin at a higher speed, therefore can be made smaller and uses less power.

Fine.

But, having mucho years trying to make mechanical objects spin, move, etc.
in a vacuum environment, there is one potential issue that comes immediately
to mind.

In a vacuum there is no convective heat transfer to speak of, and very, very
little conductive heat transfer due to virtual point contact. Bearings
generate heat, particularly in high speed applications and if that heat
cannot be transfered away from the balls and races, the bearings tend to
self destruct. We used to use specially prepared aerospace bearings
designed for space flight in the systems we built ... and even then often
had problems with high speed applications.

It seems to me the big "breakthrough" in this product is the vacuum
enclosure of the high speed gyro. I'd be interested in how they handled the
issue I've described.

It might be that their "vacuum" is really a low pressure inert gas
system which might allow for heat transfer. Looking at the video, the
exterior of that ball looks like it might have heat sinks on it.

Yes/no?

It also depends on how fast the flywheel is rotating. They don't
mention the RPM figure that I can find.

On Wed, 7 Nov 2007 17:08:34 -0500, "Eisboch"
wrote:

It seems to me the big "breakthrough" in this product is the vacuum
enclosure of the high speed gyro. I'd be interested in how they handled the
issue I've described.

Good questions. They were talking about using signicant power to spin
it, something like 1.5 KW even though it's in a vacuum. That would
imply that it has a fair amount of friction and quite a bit of heat to
dissipate. It will generate a lot of side loading on the bearings as
it resists the boats rolling motion. Imagine the chaos on board if it
ever jumped loose from its cage!

This has all been tried before if my memory is correct. As I recall,
the problem with the older systems was that the gyro had to be quite
large, probably because they were running it at a lower speed.

On Wed, 07 Nov 2007 19:05:03 -0500, Wayne.B
wrote:

On Wed, 7 Nov 2007 17:08:34 -0500, "Eisboch"
wrote:

It seems to me the big "breakthrough" in this product is the vacuum
enclosure of the high speed gyro. I'd be interested in how they handled the
issue I've described.

Good questions. They were talking about using signicant power to spin
it, something like 1.5 KW even though it's in a vacuum. That would
imply that it has a fair amount of friction and quite a bit of heat to
dissipate. It will generate a lot of side loading on the bearings as
it resists the boats rolling motion. Imagine the chaos on board if it
ever jumped loose from its cage!

When I was on the fire department, we responded to an injury call
where a building collapsed. I went direct to the scene and when I got
there, the whole saw mill had collapsed. After we got the workers
out, the Fire Marshall began looking and found what happened.

The fly wheel came loose from the 30 hp two lung jug engine and just
ripped the place apart. Max rpm on that thing was only 40 rpm. Of
course it weighed 900 pounds, but still... :)

This has all been tried before if my memory is correct. As I recall,
the problem with the older systems was that the gyro had to be quite
large, probably because they were running it at a lower speed.

I'm still confused about how it actually stops the mass of the boat
from moving in only one direction.

Then again, I'm not the brightest guy on the face of the planet.

On Thu, 08 Nov 2007 00:39:04 GMT, Short Wave Sportfishing
wrote:

I'm still confused about how it actually stops the mass of the boat
from moving in only one direction.

Probably the best way to get an intuitive grasp is to go out and buy a
toy gyro. Get it spinning and hold on to it by each end while you try
to turn it 90 degrees to its spin axis. It will try to fight back,
same effect that you sometimes get with a high powered electric drill.

I couldn't even begin to describe it mathematically but the reason it
resists is because of angular momentum. It wants to continue spinning
in the same direction, and it takes force to change it. That is why a
gyro will balance on one end while spinning, or suspend itself
horizontally if held on one end by a string. On a boat all you have
to do is securely fasten each end of the spin axis, and the whole hull
structure becomes an extension of the gyro itself, which will
consequently resist any force perpendicular to the spin plane.

Wayne.B wrote:
On Thu, 08 Nov 2007 00:39:04 GMT, Short Wave Sportfishing
wrote:

I'm still confused about how it actually stops the mass of the boat
from moving in only one direction.

Probably the best way to get an intuitive grasp is to go out and buy a
toy gyro. Get it spinning and hold on to it by each end while you try
to turn it 90 degrees to its spin axis. It will try to fight back,
same effect that you sometimes get with a high powered electric drill.

I couldn't even begin to describe it mathematically but the reason it
resists is because of angular momentum. It wants to continue spinning
in the same direction, and it takes force to change it. That is why a
gyro will balance on one end while spinning, or suspend itself
horizontally if held on one end by a string. On a boat all you have
to do is securely fasten each end of the spin axis, and the whole hull
structure becomes an extension of the gyro itself, which will
consequently resist any force perpendicular to the spin plane.


Try "inertial space." The angular momentum of the spinning rotor causes
the gyro to maintain its attitude even when its gimbal is tilted.

On Wed, 07 Nov 2007 20:26:53 -0500, HK wrote:

Try "inertial space." The angular momentum of the spinning rotor causes
the gyro to maintain its attitude even when its gimbal is tilted.

Yes, but if you are trying to stabilize a boat I don't think you use a
gimballed mount.

On Wed, 07 Nov 2007 20:11:58 -0500, Wayne.B
wrote:

On Thu, 08 Nov 2007 00:39:04 GMT, Short Wave Sportfishing
wrote:

I'm still confused about how it actually stops the mass of the boat
from moving in only one direction.

Probably the best way to get an intuitive grasp is to go out and buy a
toy gyro. Get it spinning and hold on to it by each end while you try
to turn it 90 degrees to its spin axis. It will try to fight back,
same effect that you sometimes get with a high powered electric drill.

I couldn't even begin to describe it mathematically but the reason it
resists is because of angular momentum. It wants to continue spinning
in the same direction, and it takes force to change it. That is why a
gyro will balance on one end while spinning, or suspend itself
horizontally if held on one end by a string. On a boat all you have
to do is securely fasten each end of the spin axis, and the whole hull
structure becomes an extension of the gyro itself, which will
consequently resist any force perpendicular to the spin plane.

I finally figured it out - it was the fixed axis thing that was
bugging me. I was always under the impression that gyros do represent
a fixed axis.

"Short Wave Sportfishing" wrote in message
...


I'm still confused about how it actually stops the mass of the boat
from moving in only one direction.


Study the little graphic they have of the gyro enclosure and how it is
mounted.

When the boat rocks, the spinning gyro imparts a force on the enclosure.
The enclosure, which is attached via telescoping arms to a beam or stinger
in the boat, is gimbaled to only move on one axis (fore and aft which is 90
degrees retarded from the boat's rocking movement (gyroscopic progression).

I think.

Eisboch