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From: robert werner <cryocycle_at_hotmail.com>
subject: [Paddlewise] gyroscopes for kayaks
Date: Thu, 31 Jan 2002 22:13:27 +0000
My daughter and I are thinking of doing a science fair project on gyroscopic 
stabalization of kayaks.  We are building small models for this and testing 
them in a wave tank.  Has anyone ever done this before or have any ideas if 
it would work?

Robert and Margo Werner
cryocycle_at_hotmail.com

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From: Michael Daly <michaeldaly_at_rogers.com>
subject: Re: [Paddlewise] gyroscopes for kayaks
Date: Fri, 1 Feb 2002 00:57:49 -0500
From: "robert werner" <cryocycle_at_hotmail.com>

> My daughter and I are thinking of doing a science fair project on gyroscopic 
> stabalization of kayaks.  We are building small models for this and testing 
> them in a wave tank.  Has anyone ever done this before or have any ideas if 
> it would work?

Sounds interesting!

Ever notice that a top, if it isn't spinning perfectly vertically, starts
to rotate in a circle about its point?  This motion, called precession,
is due to conservation of momentum.  The same thing will happen to a 
gyro-stabilized kayak.

Imagine this scenario.  You are sitting in the kayak, gyro spun up and
in perfectly calm water.  A boat crosses your bow at a distance, creating
a wake.  The first wave strikes your bow and the kayak pitches up.  You
have created the same situation as a spinning top.  The kayak will 
precess.  The result will be that the kayak will heel over.  If the gyro
is spinning clockwise as seen from above, the kayak will roll to port
(I think that's correct, having done the vector analysis with my hands
here - the physics equivalent of counting on one's fingers :-)  (Wait,
I have a gyroscope here... hmmm can't get enough force to feel it,
ok - it remains an execise for you).

This assumes a single gyro wheel.  If you want to counteract this, you
can add another wheel that will stabilize it against this rolling,
say by mounting a wheel on an axis that runs athwartships.  With two
gyros, you'll still get precessional effects (yaw).  Add a third, 
mutually perpendicular wheel and you get the equivalent of an 
inertial guidance system in which the precession of each wheel is 
countered by another wheel.  The trick is to create three wheels 
that will fit into the kayak with sufficient angular inertia to 
have an effect and not make the kayak too heavy.

I would say that if you could show the precession problem with one
wheel (pitch causes roll) and explain it, this would be a reasonable
project.  Showing that three wheels solves this (and demonstrating
it is or is not feasible) would be a super project.   Just figuring 
out how big a gyroscope is needed for a kayak is pretty fancy stuff
for high school!

Mike
(Who spent a year teaching high school physics while in grad school)

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From: Nick Schade <schade_at_guillemot-kayaks.com>
subject: Re: [Paddlewise] gyroscopes for kayaks
Date: Fri, 1 Feb 2002 10:12:50 -0500
At 12:57 AM -0500 2/1/02, Michael Daly wrote:
>From: "robert werner" <cryocycle_at_hotmail.com>
>
>>  My daughter and I are thinking of doing a science fair project on gyroscopic
>>  stabalization of kayaks.  We are building small models for this and testing
>>  them in a wave tank.  Has anyone ever done this before or have any ideas if
>>  it would work?
>
>Sounds interesting!
>
>Ever notice that a top, if it isn't spinning perfectly vertically, starts
>to rotate in a circle about its point?  This motion, called precession,
>is due to conservation of momentum.  The same thing will happen to a
>gyro-stabilized kayak.
>
>Imagine this scenario.  You are sitting in the kayak, gyro spun up and
>in perfectly calm water.  A boat crosses your bow at a distance, creating
>a wake.  The first wave strikes your bow and the kayak pitches up.  You
>have created the same situation as a spinning top.  The kayak will
>precess.  The result will be that the kayak will heel over.  If the gyro
>is spinning clockwise as seen from above, the kayak will roll to port
>(I think that's correct, having done the vector analysis with my hands
>here - the physics equivalent of counting on one's fingers :-)  (Wait,
>I have a gyroscope here... hmmm can't get enough force to feel it,
>ok - it remains an execise for you).
>

This also assumes the gyro spins around a vertical axis. This is not 
necessary for stabilization. You could also mount the gyro on a 
transverse (side to side) axis. In this case if a wave comes along 
from the front it would not cause any procession problem. A tipping 
force from the side would try to force the boat to turn. And any 
turning force would tend to make it tip.
-- 
Nick Schade
Guillemot Kayaks
824 Thompson St
Glastonbury, CT 06033
(860) 659-8847
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From: David Anderson <squtch_at_quiet-like-a-panther.org>
subject: Re: [Paddlewise] gyroscopes for kayaks
Date: Fri, 01 Feb 2002 16:35:44 GMT
Michael Daly writes: 

> From: "robert werner" <cryocycle_at_hotmail.com> 
> 
>> My daughter and I are thinking of doing a science fair project on gyroscopic 
>> stabalization of kayaks.  We are building small models for this and testing 
>> them in a wave tank.  Has anyone ever done this before or have any ideas if 
>> it would work?
> This assumes a single gyro wheel.  If you want to counteract this, you
> can add another wheel that will stabilize it against this rolling,
> say by mounting a wheel on an axis that runs athwartships.  With two
> gyros, you'll still get precessional effects (yaw).  Add a third, 
> mutually perpendicular wheel and you get the equivalent of an 
> inertial guidance system in which the precession of each wheel is 
> countered by another wheel.  The trick is to create three wheels 
> that will fit into the kayak with sufficient angular inertia to 
> have an effect and not make the kayak too heavy. 
> 
> I would say that if you could show the precession problem with one
> wheel (pitch causes roll) and explain it, this would be a reasonable
> project.  Showing that three wheels solves this (and demonstrating
> it is or is not feasible) would be a super project.   Just figuring 
> out how big a gyroscope is needed for a kayak is pretty fancy stuff
> for high school! 
> 
> Mike
> (Who spent a year teaching high school physics while in grad school)

My biggest concern would be that if the boat ever does move from perfectly 
vertical it would then try and stay in it's new angle. If you capsize it 
would be a real pain to flip back up. 

I wonder whether it would be better to solidly mount the gyros or if it 
would be better to do some sort of soft mount with rubber or possibly even 
small shock absorbers to allow the boat some movement while still affecting 
the stability. 

Dave
(Who has the greatest respect for physics teacher who make it fun) 

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From: PeterO <rebyl_kayak_at_iprimus.com.au>
subject: RE: [Paddlewise] gyroscopes for kayaks
Date: Sat, 2 Feb 2002 06:54:45 +1100
Dave wrote:
>My biggest concern would be that if the boat ever does move from perfectly
>vertical it would then try and stay in it's new angle. If you capsize it
>would be a real pain to flip back up.

G'Day,

If the gyroscpe is rotated with an electric motor then it could be switched
off before rolling - but its still going to be too heavy to roll - use water
as the mass to fill the rotator and pump it out for the roll - or switch the
gyros in appropriate sequence for an automatic roll!

Is there a design lesson from bicycles which are gyroscopically balanced and
easy to steer?

Thanks Michael for the lucid explanation!! and Robert and Margo for the
fascinating thread!

All the best PeterO

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From: <FoldingBoats_at_aol.com>
subject: Re: [Paddlewise] gyroscopes for kayaks
Date: Fri, 1 Feb 2002 10:38:11 EST
In a message dated 2/1/2002 10:14:41 AM Eastern Standard Time, 
schade_at_guillemot-kayaks.com writes:

> This also assumes the gyro spins around a vertical axis. This is not 
> necessary for stabilization. You could also mount the gyro on a transverse 
> (side to side) axis. In this case if a wave comes along from the front it 
> would not cause any procession problem. A tipping force from the side would 
> try to force the boat to turn. And any turning force would tend to make it 
> tip.

Somewhere, somewhere I once saw a photograph of a gyro-stabilized early 
two-wheeled car. The picture showed the vehicle at rest (film exposure was 
too slow back then to catch one in motion, I suppose), with a well dressed 
couple sitting in their seats perfectly relaxed. The caption explained that 
the flywheel was spinning on a vertical axis and was housed under the floor 
boards. I guess that concept did not take off ... but it remains intriguing 
nonetheless.

Regarding Nick's comments: Isn't tipping the one thing we're trying to 
reduce? I suspect that the occurrence of precession in a horizontal plane 
when using a vertical axis flywheel would not be such a big problem with a 
long object (like a boat) sitting in a relatively viscous medium (like 
water), especially when the boat is underway. And if there is any perceptible 
precession while at rest, the operator (paddler, pedaller ...) could surely 
counteract this with ease.

Ralph

Ralph C. Hoehn
Ralph_at_PouchBoats.com
www.PouchBoats.com

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From: Michael Daly <michaeldaly_at_rogers.com>
subject: Re: [Paddlewise] gyroscopes for kayaks
Date: Fri, 1 Feb 2002 12:21:46 -0500
From: <sildriel_at_ciateq.net.mx>

> Hi Mike, 
> 
> I am afraid I disagree with your theory. 
> 
> I believe that precession is present, and assuming the gyroscope axis is 
> longitudinal to the kayak, and if a wake moves the bow upwards, then the 
> gyroscope will NOT FORCE A ROLL. I think it will force a left turn or right 
> turn only.

Yes, but that would only add a stabilization effect for logitudinal
motions, which is where a sea kayak is already the most stable.
I assumed that they want to stabilize for for rolling, for which a
kayak is least stable .

> As I said, if you want to be stable with respect to leaning by side waves, then 
> the gyro should be horizontal but perpendicular to the kayak axis. Again the 
> effect of it, when a wave lifts one side would be to resist the lifting and to 
> turn the bow and/or kayak right or left.

That is correct and Nick point out the same.  I chose the vertical axis version
initially because it is the easiest to fit into a kayak - perhaps under the
seat.  A horixontal axis will put a gyroscope wheel in a vertical plane and 
take up valuable room.

Mike

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From: <sildriel_at_ciateq.net.mx>
subject: Re: [Paddlewise] gyroscopes for kayaks
Date: Sat, 02 Feb 2002 12:09:35 -0600 (CST)
Keeping on with your thoughts, I think the vertical gyroscope has some 
interesting features as you pointed out.

I can think of two instances, that could change momentum and force the 
gyroscope to preceed.

1.- If the boat is going out against waves and the bow is lifted or falls down 
in a trough, the effect of the gyroscope precession will be to roll the boat. 
That is to rotate around the boat axis. The roll tendency would be depending on 
the gyro rotation direction. That would be a strange situation. If you are 
surfing back and the stern is violently risen by a back coming wave, the boat 
will roll, due to the gyroscope and some bracing or leaning will be needed. How 
much? depends on the gyro characteristics.

2.- If the boat is rocked sideways by waves then the effect would be to react 
to the rocking and to sink the bow or stern. This would require a lot of gyro 
force to compensate for the buoyancy of the long boat.

The vertical arrangements seems to be an interesting choice, if the rolling 
force due to bow to stern rocking can be controlled.

I think the transversal horizontal arrangement has an added advantage. 
(BROACHING REDUCER). If you have a side wave and give the gyro the rotation in 
the proper direction, it will help you to avoid broaching. That is, if the boat 
is lIfted from a wave coming on the left side, and the boat turns right, then  
it will turn the tip from the wave, and the same happens if the lifting is on 
the rigth side then the turn will be to the left.

If the gyro is turned in the opposite direction then it will be able to carve 
turns easier when leaning.

It would be interesting to try to control the boat by leaning using the gyro 
assistance.

Best Regards,

Rafael.
www.mayanseas.com  

Mensaje citado por: Michael Daly <michaeldaly_at_rogers.com>:

> From: <sildriel_at_ciateq.net.mx>
> 
> > Hi Mike, 
> > 
> > I am afraid I disagree with your theory. 
> > 
> > I believe that precession is present, and assuming the gyroscope axis
> is 
> > longitudinal to the kayak, and if a wake moves the bow upwards, then
> the 
> > gyroscope will NOT FORCE A ROLL. I think it will force a left turn or
> right 
> > turn only.
> 
> Yes, but that would only add a stabilization effect for logitudinal
> motions, which is where a sea kayak is already the most stable.
> I assumed that they want to stabilize for for rolling, for which a
> kayak is least stable .
> 
> > As I said, if you want to be stable with respect to leaning by side
> waves, then 
> > the gyro should be horizontal but perpendicular to the kayak axis.
> Again the 
> > effect of it, when a wave lifts one side would be to resist the
> lifting and to 
> > turn the bow and/or kayak right or left.
> 
> That is correct and Nick point out the same.  I chose the vertical axis
> version
> initially because it is the easiest to fit into a kayak - perhaps under
> the
> seat.  A horixontal axis will put a gyroscope wheel in a vertical plane
> and 
> take up valuable room.
> 
> Mike
> 
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From: Michael Daly <michaeldaly_at_rogers.com>
subject: Re: [Paddlewise] gyroscopes for kayaks
Date: Fri, 1 Feb 2002 12:49:39 -0500
From: "Nick Schade" <schade_at_guillemot-kayaks.com>

> This also assumes the gyro spins around a vertical axis. This is not 
> necessary for stabilization. You could also mount the gyro on a 
> transverse (side to side) axis. In this case if a wave comes along 
> from the front it would not cause any procession problem. A tipping 
> force from the side would try to force the boat to turn. And any 
> turning force would tend to make it tip.

It would also make the kayak more difficult to turn.  Sea kayaks are
are already difficult to turn, so that might not be the best choice.

Gyros stabilize in two dimensions, so you can choose:
 roll+yaw   (transverse axis), 
 roll+pitch (vertical axis) or 
 pitch+yaw  (longitudinal axis). 
 
But it also couples the two axes.

Choosing two axes will over-stabilize one (and over-
couple):

transverse + longitudinal = roll+pitch + pitch+yaw 
= roll + yaw + 2pitch, which overstabilizes pitch.  Induced 
pitching moments will affect both roll and yaw.

All three axes balances the stabilization completely, but that
makes the kayak difficult to rotate about any axis (hence the
reason such arrangements are used in inertial guidance systems).
This would make a good photography platform but a poor playboat.

This is an interesting exercise for a high school student.  


Mike

PS - In my previous post, my estimation of the pitch causing 
roll to port is wrong.  It would roll to starboard.  Oh, well - 
never trust your fingers at 1 am.  I used my right hand to 
model the gyro and then determined the roll using my _left_ 
hand, doh!

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From: Michael Daly <michaeldaly_at_rogers.com>
subject: Re: [Paddlewise] gyroscopes for kayaks
Date: Fri, 1 Feb 2002 14:32:07 -0500
From: "David Anderson" <squtch_at_quiet-like-a-panther.org>

> My biggest concern would be that if the boat ever does move from perfectly 
> vertical it would then try and stay in it's new angle. If you capsize it 
> would be a real pain to flip back up. 

Absolutely true.  It seems that whatever anyone tries WRT stabilization
(even sponsons) you get the same kinds of problems.  It's better until
something goes wrong, then it's worse.

> I wonder whether it would be better to solidly mount the gyros or if it 
> would be better to do some sort of soft mount with rubber or possibly even 
> small shock absorbers to allow the boat some movement while still affecting 
> the stability. 

Dampened stabilization.  Interesting idea.  

Just between you and me, I don't think anyone could get a gyro-stabilized 
kayak to work.  Without doing the numbers, I suspect that the weight of
the gyro would be prohibitive compared to the benefit (if not the weight,
then the spin velocity required).  

However, the experiment for a student is a valid one.  One thing that 
bugs me about this from my science fair days is a bias, conscious or 
otherwise, on the part of examiners to downplay the value of a negative 
result.  That is, they seem to put more value on a result that shows 
something works than one that shows something doesn't work, even though 
scientifically these outcomes are equally valid.  

Given this, perhaps Robert and his daughter should focus on showing 
the _effects_ of a gyro on a floating object (kayak or other) rather 
than trying to show a benefit.  A subtle difference, but meaningful 
in presentation.

Mike


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From: David Anderson <squtch_at_quiet-like-a-panther.org>
subject: Re: [Paddlewise] gyroscopes for kayaks
Date: Fri, 01 Feb 2002 20:51:42 GMT
Michael Daly writes: 

> From: "David Anderson" <squtch_at_quiet-like-a-panther.org>
>> I wonder whether it would be better to solidly mount the gyros or if it 
>> would be better to do some sort of soft mount with rubber or possibly even 
>> small shock absorbers to allow the boat some movement while still affecting 
>> the stability. 
> 
> Dampened stabilization.  Interesting idea.  

Thanks. I came up with an even more warped idea to get rid of all the issues 
(other than weight, space, wrong side up, and center of rotation while 
turning;-) Mount your 3 gyros that in a box that is mounted to a vetical 
axle. If you dampen the axle you should have a fairly maneuverable boat 
(other than the 200 pound contraption behind your seat). You would have 
limited pitch and roll (say 10 degrees) but unlimited yaw. 

Ok, you can go ahead and shoot hole in my brilliant idea now. 

> Just between you and me, I don't think anyone could get a gyro-stabilized 
> kayak to work.  Without doing the numbers, I suspect that the weight of
> the gyro would be prohibitive compared to the benefit (if not the weight,
> then the spin velocity required).  

Not to mention the sympathetic vibrations thant might annoy the nearest 
devilfish into whacking you with his tail. 

> However, the experiment for a student is a valid one.  One thing that 
> bugs me about this from my science fair days is a bias, conscious or 
> otherwise, on the part of examiners to downplay the value of a negative 
> result.  That is, they seem to put more value on a result that shows 
> something works than one that shows something doesn't work, even though 
> scientifically these outcomes are equally valid.  

I would agree with you there. It's a great project with almost no commercial 
value. 

Unfortunately the mindset of the world tends that way. Because of this 
attitude great effort is put into trying to force failure into success, 
instead of using the failure to narrow the focus. I have tried to explain to 
some of my bosses that the reason they put a reverse gear in your car is so 
that if you turn into a blind alley you can back out instead of trying to 
bash your way through several brick walls. 

Of course the biggest physics science fair (nobel) only rewards the 
successes, so why shouldn't the local ones? 

> Given this, perhaps Robert and his daughter should focus on showing 
> the _effects_ of a gyro on a floating object (kayak or other) rather 
> than trying to show a benefit.  A subtle difference, but meaningful 
> in presentation.

An excellent idea! 

Dave
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From: John Blackburn <digipixs_at_erols.com>
subject: Re: [Paddlewise] gyroscopes for kayaks
Date: Fri, 01 Feb 2002 14:46:14 -0800
Michael Daly wrote:

> never trust your fingers at 1 am.  I used my right hand to
> model the gyro and then determined the roll using my _left_
> hand, doh!

I made the same mistake on a college physics final!  Writing with my right hand
and blissfully determining force with the old "left hand" rule.  The fact that
I was using the wrong hand never entered my mind.  I ended up with a C in the
course after going into the final with a solid A.   It was a hard lesson.

John Blackburn

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From: Shin, Harry K. <shin_at_SLAC.Stanford.EDU>
subject: RE: [Paddlewise] gyroscopes for kayaks
Date: Fri, 01 Feb 2002 13:29:14 -0800
How about a miniature gyro, hooked via a PID controller to servo actuated "stabilization wings" on the sides of the boat?  Forward mounted for paddle clearance.  This would only work as the boat was moving, but would eliminate/reduce the need for bracing.  Lunch stops/potty breaks will still require rafting or s******s.  The entire system would weigh about two pounds, including the solar cells for battery re-charging. 

Harry

PS: Yes, I'm currently building a radio control model airplane ;-)

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