Can it be done?

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Can it be done?

Postby Blocka2 » Thu Feb 16, 2012 4:35 am

I have a number of scale rc yachts and would like the assistance of those in the know.
I have been thinking of putting a heading lock into one of my vessels but first I need to differentiate between terminology.
Hobby King have Gyros, Head Locks and all manner of gizmos, designed to keep helicopters on the straight and narrow.
I am assuming that the Head Lock product is exactly that. Designed to maintain (to a certain degree of accuracy) the heading of a craft it has been turned onto.
My other concern is that the action of a sedate sailing vessel is far removed from that of a helicopter. Do these devices require a rapid change in heading to active? or will they respond to a gradual change as well.
It would be nice to have some sort of course holding auto pilot.
Hope someone is able to respond.
cheers
Blocka
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Re: Can it be done?

Postby Keith » Thu Feb 16, 2012 9:10 am

I do not know that much about them but from using my 'real' boat i would imagine it would have to be some sort of GPS operated system....?
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Re: Can it be done?

Postby cynr100 » Thu Feb 16, 2012 12:01 pm

Have had one disasterous experience with an RC boat years ago (2m stiletto with 32cc racer, loss of control at full tilt, proceeded to wave skip through a marina, beached in a drydock, rudder mount the only salvage!!) Sorry I digress.
Am currently trying to fly my new 450 clone heli with no previous experience, it sustained severe damage in its first outing and I am now in a steep learning curve.
I like your theory and it would be fairly cheap to experiment, gyros can be had for $8 to $250. Two types available the PIEZO (cheap and somewhat unreliable) and MEMS ( supposedly the ducks, cheap to expensive). I have a Mini Mems (USD9.99) and a HK 12g digital servo (USD6.08) on order from Hobbyking to try and remove a slow left creep from my heli having exhuasted all mechanical avenues, if this doesn't work I"ll just keep increasing my spend value until it's fixed.
I have noticed that all heli pilots have varying degrees of success with varying types and values of gyros, this seemed unusual until I came across an article which delved into the issue of sympathetic and high freq vibrations and there effects on modern day gyros, what works for some does not necessarily work for others.
From reading lots I have learned that "head hold" and "head lock" are the same, I prefer to call it HH that way I'm not confused about what the gyro is suppose to do. All gyros have two levels HH or "rate" (this is for really experienced pilots who have 3 arms). HH is achieved through programming on your transmitter ( some gyros have a separate programming card) my present gyro is in HH when I set the gyro gain at greater than 50%, at 80%plus the tail rotor starts to flutter and control is lost.
Gyros work best with digital servos.
Back to your original idea, the gyro is there to provide assistance in negating uninitiated heading change either by torque turn from the main rotor and/or sudden wind shifts. Unless you are prepared to spend big the heli gyros do not provide say "course hold". Lots of heli videos on youtube make it look easy but in reality the pilot is constantly making stick movements to maintain flight course or even a hover. There are "auto pilot" systems available and generally these are to return your heli to stable flight hover.
A gymbal gyro would probably be a better option but I have yet to find one.

These are the parts I'm currently waiting on from HK:

GA-250 1 HobbyKing GA-250 MINI-MEMS Gyro $9.99ea $9.99
DS-929MG 1 Hobby King Digital Servo 2.2kg / 12.5g / .11sec $6.08ea $6.08

All up with freight just less than AUD20, might be worth an experiment?

Take this all with a grain of salt, remember I am only new to the RC game and I just didn't want to see your topic sitting there without any suggestions.

Cheers Dennis
Not enough time in the day for all my crazy ideas, I'm not slow, I'm just pacing myself
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Re: Can it be done?

Postby Blocka2 » Thu Feb 16, 2012 2:29 pm

Thanks for taking pity on me Dennis, I appreciate any input. RC's aint what they use to be and I guess I should be thankful for progress.
I did play around with a gyro from Hobbykink on one yacht, but even at the most extreme sensitivity it took a fairly rapid movement of the stern to operate the rudder.
But that was just an ordinary gyro. Might just do some experimenting.
Cheers
Paul
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Re: Can it be done?

Postby Blocka2 » Thu Feb 16, 2012 2:37 pm

hey Keith, you might be onto something there, where's my side cutters, I'll whip out to my boat!!! In all seriousness I think it all comes down to the dollars and sense (no not a typo). I haven't gone down the Hobbyking road of GPS's but i would imagine they are on the expensive side of commonsense.
Cheers
Paul
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Re: Can it be done?

Postby Shotglass » Thu Feb 16, 2012 10:12 pm

Blocka2 wrote:I am assuming that the Head Lock product is exactly that. Designed to maintain (to a certain degree of accuracy) the heading of a craft it has been turned onto.


yup any gyro in headinghold headinglock avcs (whichever the manufacturer likes to call it) will do just that
preferably with a mems sensor which wont lgive you any problems with the heading its holding drifting away from you all the time

My other concern is that the action of a sedate sailing vessel is far removed from that of a helicopter. Do these devices require a rapid change in heading to active? or will they respond to a gradual change as well.


nah they cann deal with slower movements just fine
weve used them to great success on pan cars (which otherwise are impossible to keep going straight) hovercrafts (just as horrible when it comes to going straight) and of course helis
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Re: Can it be done?

Postby Blocka2 » Fri Feb 17, 2012 5:32 am

Hi Shotglass,
Just the info I was looking for. Will try an experiment and see what happens.
Thanks to all
Paul
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