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Old Nov 25, 2012, 12:40 PM
Mariner BC Canada
BluenosePacific's Avatar
Joined Feb 2012
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Would a Gyro be a Good Choice?

I'm asking for your input on a good way to control roll on my 20' (6m), pedal powered hydrofoil.

Attempts to do it manually have failed. It seems human reaction time is insufficient to accomplish the task.

The stumbling block is the buoyant bulb which produces 1/3 of the lift required to achieve "flight". While allowing for smaller hydrofoils (less drag), it produces incredible roll instability.

One way to manage this is by flooding the bulb at low velocities eliminating buoyancy. CO2 purging once making way restores buoyancy and can be more effectively managed by control surfaces.

Independant foil control (port and starboard) would be the preferred method but a centre canard (as shown) may be necessary.

The servo would be slide mounted to allow ride height control as velocity increases. This would be controlled by a mechanical surface sensing wand geared to move the servo and control rods up and down accordingly (a mechanical mixer).

The use of a canard would eliminate this complexity but add more wetted surface area.

There's only 100 watts available from the prop at steady state, sustained flight, which is the objective.

No radio is used here but the electronics from your hobby may be helpful.

I would ask for your proposed solution and then perhaps some dialogue to brainstorm a best case scenario.

The only caveat I would put out there is it needs to be relatively simple, plug and play. On my wish list would also be light weight and low power consumption.

This is a personal project only for my use, no commercial gain or profit.

Thanking you abundantly in advance.

This video may help:

 
HYDROFOIL -- High flying torpedo or low flying aircraft? Ray Vellinga edited video (5 min 59 sec)
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Last edited by BluenosePacific; Nov 28, 2012 at 08:47 PM. Reason: Addition, clarity.
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Old Nov 25, 2012, 02:33 PM
Sky's not the limit, ground is
skydanz's Avatar
USA, CA, San Jose
Joined Dec 2007
855 Posts
Sir, while this looks quite interesting, this forum deals with autogyros or "gyrocopters" and not gyroscopic stabilizers. You may have more succes in the boating forum or, perhaps, the helicopter forum, since they use gyros for stabilization. Good luck!
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Old Nov 25, 2012, 03:53 PM
Mariner BC Canada
BluenosePacific's Avatar
Joined Feb 2012
195 Posts
Sorry, my mistake.

Thank you for the reply.
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Old Nov 27, 2012, 10:46 AM
Mariner BC Canada
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Joined Feb 2012
195 Posts
Funny thing is, it was the boat guys that sent me here :-)
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Old Nov 27, 2012, 11:36 AM
Sky's not the limit, ground is
skydanz's Avatar
USA, CA, San Jose
Joined Dec 2007
855 Posts
Quote:
Originally Posted by BluenosePacific View Post
Funny thing is, it was the boat guys that sent me here :-)
That IS funny! While I can't help you much other than how to connect a store bought gyro to a receiver, I am interested in your project. Since we are group with "exotic and special interests", I'm sure many of us would follow along on your progress. If you start your own thread, make sure you at least post a link to it here.

Don
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Old Nov 27, 2012, 11:36 AM
AND FOR MY NEXT TRICK....!
jodini's Avatar
Omaha Millard, Nebraska, United States
Joined Sep 2004
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Too funny! Well I was talking to skydanz and we would love to see what you come up with! Fascinating video and very cool project!
Joe
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Old Nov 27, 2012, 11:37 AM
AND FOR MY NEXT TRICK....!
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Omaha Millard, Nebraska, United States
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You beat me to it Don!
Joe
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Old Nov 27, 2012, 11:50 AM
Mariner BC Canada
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Joined Feb 2012
195 Posts
Well thanks.

I am a complete newbie to "new" (in the last 25 years) electronics.

How would a gyro compare to a leveller in this situation.

Remember, I only want roll control out of it.
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Old Nov 27, 2012, 02:33 PM
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Elizabeth South Australia 5113
Joined Nov 2005
1,694 Posts
Just out of curiosity.....did you ever happen to use props on you boat that were made by Bolly in OZ ??as there were a couple of sizes that were made aspecially for the pedal powered guys...and if I remember correctly ..at one time held the world speed record..........
Chris...
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Old Nov 27, 2012, 03:10 PM
Mariner BC Canada
BluenosePacific's Avatar
Joined Feb 2012
195 Posts
Not me, but I know Rick Willowby(SP?) tried them at one point before he started making his own out of plate steel.

Airplane props are pretty well suited for this but custom made are better.

Variable pitch is the best scenerio.

The issue is very limited power.

For what I am aiming for, 100watts net coming out of the prop is sustainable.

For how long depends on your level of fitness but an hour is not that difficult for the average individual.

The word speed record is held by DECAVITATOR which utilizes an air prop!

Crazy but true. More efficient if you can believe it.

Who should I be talking to to create a self stabilizing roll controller, any idea?

I wouldn't think it that difficult for those in the know.

Cheers!
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Old Nov 27, 2012, 03:43 PM
AND FOR MY NEXT TRICK....!
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Omaha Millard, Nebraska, United States
Joined Sep 2004
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Facinating stuff.

I looked around here on a "gyro" place and other than "electronics", there really isn't one. When I think gyros however, the guys that seem to know the most about them are rc helicopter guys. You might want to post the comment here also:
http://rc.runryder.com/helicopter/f30p1/

www.runryder.com has the most helicopter guys and it would be a fair question to ask. I don't think anyone out here will complain to hear your questions (I know I won't) but I'm just not sure if you'll find the answer.

If anything, one thing that autogyros guys and you have in common is we like to tinker and figure out weird things!
Joe
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Old Nov 28, 2012, 01:09 AM
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norup's Avatar
Denmark, Capital Region of Denmark, KBH
Joined Jul 2009
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How about adding a few degrees of dihedral to the hydrofoils. That ought to reduce the roll instability.
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Old Nov 28, 2012, 12:13 PM
Mariner BC Canada
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Joined Feb 2012
195 Posts
It would norup, you're right, but not nearly enough and at a cost in drag.

There is a huge lack of propulsive power, it's the nature of the beast.

What I need here is electronics assistance...
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Old Nov 28, 2012, 03:42 PM
Sky's not the limit, ground is
skydanz's Avatar
USA, CA, San Jose
Joined Dec 2007
855 Posts
Will you have a small battery to run the electronics or are you generating electricy? Is the 100 watts the propulsive energy or electrical energy generated? A small Lipo battery of say less than 200g could be carried to run electronics. Do you have an idea how much energy the stabilizing planes will need to operate? I assume they will be servo operated?

I have a stabilization gyro that I have never used. It is a single axis rate gyro.
http://manuals.hobbico.com/fut/g133-...3bb-manual.pdf
Would this be useful to you?

I guess we'd have to know how much mechanical ability you have before we go engineering this.

Don
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Old Nov 28, 2012, 05:39 PM
Mariner BC Canada
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Joined Feb 2012
195 Posts
Skydanz,

Thanks for that.

What I need is a heading hold helicopter gyro.

I will have a small battery to power the electronics.

100 watts propeller output is mechanical energy produced via the pedals from a recumbent cycling position after line losses and inefficiencies, like the propeller.

Peaks of 400+ watts are attainable but not for long.

A 1/2" shaft drive with U-joints has been developed by a bloke in the UK.

The foils are balanced so the servo loading should be minimal requiring less power.

With sensitive, fast response roll control there should be less power consumed.

A small Lipo should do it.

Don, I'm not sure what you mean in your last sentence.

Is your gyro a heading hold unit?
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