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Old Apr 27, 2009, 08:12 PM
Team Wack-a-Mole
Melnic's Avatar
Maryland
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Quote:
Originally Posted by Big Johnny
Rate gyros are also very good at dampning the rudder on a taildragger, expecialy WW II Fighters. Makes Take Off alot more predictible
I have plenty of tail draggers but don't have issues with take offs. But lots of people at my field do I wish I could give gyros out to them like band aids

I fly off grass but recall tail draggers were harder to stear on pavement. I have not flown off pavement in I think 19 years where I first learned to fly. Small runway that was paved. Pilots were 2'from the runway and no barriers to protect them like now adays. Only thing protecting them was someone yelling at the pilots "hey, a little right rudder on takeoff why don't ya". come to think of it, I still hear that once and a while where I fly
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Old Apr 28, 2009, 03:25 PM
Sussex, UK
RobinBennett's Avatar
Crawley, West Sussex, UK
Joined Jun 2004
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Quote:
the aileron would drift on the ground to full difflection
This is standard behaviour in HH mode.

As I understand it, it works like this: the gyro detects some tiny movement away from level (maybe even just a little noise in the sensor) and moves the aileron a tiny amount to compensate. At this point a rate gyro would then re-centre the aileron but a HH gyro knows that the plane hasn't rotated in response to it's control input, so it increases the control throw. This still does nothing, so it adds more control throw, and more until it reaches full throw.

This goes away in the air, because the model responds to the initial small movement.

Having said all that; you said you saw this behaviour in rate mode not HH mode? That's odd; I'd usually test which mode I was in by looking for this behaviour. For example I'd move the model a couple of inches in one direction and would expect to see the servo creeping in one direction, then I'd move the model a few inches in the other direction and expect to see it creeping back. If the servo re-centred as soon as the model stopped moving, I'd call it rate mode. FWIW, your video does look like rate mode.

Anyway, I've got to give this a try now - it's great to hear some detailed results.
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Old Apr 30, 2009, 11:07 AM
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Maryland
Joined Oct 2008
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Robin,
That was in HH mode

Here is my full quote (at least the one I found)
Quote:
where in heading hold mode, the aileron would drift on the ground to full difflection
If I said that it would drift in Rate mode, let me know, I'll correct it because it will not drift in Rate mode.

What you wrote about how HH mode compensates is correct. Even with a Heli, I have to correct the drift in HH mode or the tail will rotate on takeoff. I typically on a heli switch from Rate to HH mode as I spin up.

yea, the video w/ the camera looking at the left wing is in Rate mode and at 50% gain which is where I flew this particular Gyro that day. 3 more flights yesterday and it was really smooth, like no wind. 15mph with some gusts.

I'm working on a web page to hopefully put a step by step guide to setting up a gyro w/ some pictures or diagrams on it. As a Heli pilot it's easier for me but for those not familiar, it's going to be like talking in a foriegn language. Gyros are one of the harder things that newbie heli pilots have trouble with understanding and troubleshooting.
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Old May 14, 2009, 03:00 AM
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latin105fm's Avatar
London, UK
Joined Jan 2009
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Quote:
Originally Posted by Melnic
Robin,
That was in HH mode

Here is my full quote (at least the one I found)


If I said that it would drift in Rate mode, let me know, I'll correct it because it will not drift in Rate mode.

What you wrote about how HH mode compensates is correct. Even with a Heli, I have to correct the drift in HH mode or the tail will rotate on takeoff. I typically on a heli switch from Rate to HH mode as I spin up.

yea, the video w/ the camera looking at the left wing is in Rate mode and at 50% gain which is where I flew this particular Gyro that day. 3 more flights yesterday and it was really smooth, like no wind. 15mph with some gusts.

I'm working on a web page to hopefully put a step by step guide to setting up a gyro w/ some pictures or diagrams on it. As a Heli pilot it's easier for me but for those not familiar, it's going to be like talking in a foriegn language. Gyros are one of the harder things that newbie heli pilots have trouble with understanding and troubleshooting.
Hey there. An information web page would be amazing. I'm looking to build a plane that I can use for AP and FPV later on down the line and I'd really like to put some gyro's on to make the video footage smooth.

I'd like to know what are the correct gyros to get because I believe there are different types and then, how to set them up would be great too..

Cheers

Dan
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Old May 14, 2009, 07:12 AM
Sussex, UK
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Crawley, West Sussex, UK
Joined Jun 2004
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Quote:
An information web page would be amazing
May I suggest you add a page to www.eflightwiki.com - then we can all help.
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Old May 14, 2009, 08:48 AM
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Maryland
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I"ve started on something to my existing website. I will check out the eflightwiki.

I've had about 10 flights on the Esky 704A with the Sapac 330L. So far, it's been great.
I'll next test out the newer version the 704B.
http://www.xheli.com/esky-gyro-ek2-0704b.html

After that I'm going to switch to the colco GY400.
http://www.r2hobbies.com/proddetail.php?prod=rcps61801
I have been flying both on helicopters now for 6-12 months and they have been working well with helicopters.
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Last edited by Melnic; May 14, 2009 at 01:14 PM.
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Old May 14, 2009, 01:14 PM
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Here is my first stab at a step by step web page.
If anyone hooks up a gyro, let me know how it goes so I can add it to my list.
http://www.mycoolheli.com/gyro/

I will try to add more pictures and video links soon.
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Old May 15, 2009, 01:55 PM
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I tested the Colco GY400 from today. Just one flight but it flew about as good as the Esky 704A HH gyro did.
Nice thing about this gyro is that it has a reverse switch.
Gyro is mounted with label facing the nose or tail.
Set reverse switch so that lifting the wing causes that aileron to raise. (like in my gyro test)
This gyro also has the connector for the Servo on an extention wire unlike the Esky 704A where you have to plug it directly into the gyro. This makes a more secure connection and you can tape the cables if you like.
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Last edited by Melnic; May 15, 2009 at 02:51 PM.
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Old May 15, 2009, 06:20 PM
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Joined Jun 2008
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Quote:
Originally Posted by Melnic
If you have run a gyro before PLEASE PLEASE post any info you have for others to learn from your experiance!
Yes... I ran rate gyros on my last MPX Twinstar... (that plane was stolen from my car, building another one right now) My experience of them is pretty much the same as yours.

I used the really cheap e-sky rate ones. You can pick them up for about $6.00 USD each in the US and about 5.00 GBP each from Hong Kong vendors (ebay).

The advantages I found to Gyros is 1) they're very cheap! I do remember when they used to cost a fortune, back in the 1980's 2) that unlike the CPD4 (co-pilot system) it doesn't feel like somebody is flying the plane for you. In the sense that whatever you do with the CPD4 system the plane will just right itself to straight and level, which is more like a heading hold gyro whereas the cheap Rate Gyros will just help hold it, in whatever attitude you give it.

I did have them set up so that I could switch them out from the TX when I wanted to. To do this requires a radio operated "Double Pole Double Throw" DPDT switch... I forget who makes those... But you stick it on the AUX channel and you can then bypass the gyro with it. I think they were designed for switching landing lights on and off..... As long as you leave the gyro powered up when it's in bypass it's not a problem. If however you were to set it up so that the gyro actually powered down when you bypassed it, then you'd have trouble getting it to initialise when you switched back again.

I could probably whiz up a quick wiring diagram for that if you wanted...

I found them great for cross wind landings... you can just set the sink rate with the throttle and let the gyros take care of the rest. They're great for taking care of sudden changes in air pressure or sudden gusts of wind because they'll just counter almost any sort of wind shear.

I also had one on the elevator which stops the bobbing up and down that you suffer from. It's worth trying it. I didn't have any problems with it affecting the stall characteristics. If the plane stalled, the elevators would try and pick the nose up again, but if the plane doesn't have the airspeed to lift its nose then the up elevator has very little effect anyway and it soon settles to a stable nose down attitude, which is then recoverable. I would hate to think what would happen with a "Heading Hold" gyro in that situation though. That could cause a major problem. Which is why I'd stick to it being a rate gyro on elevator.

I also wouldn't bother with one on the rudder, but I see that Dave Powers did on the Wildhawk.

The only downside I found to them, is that because the Gyro is constantly tweaking the position of the control surface, the system does use up more current... and consequently shortens flight times.

Hope that's useful....

Best Regards,
Julian (Fozzy The Bear)
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Old May 15, 2009, 07:00 PM
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beavercreek,ohio
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What kind of gyros do you guys reccomend purchasing. I've seen some rate gyros on hobbyking but don't know much. I'm trying to pick out some gyros for my VTOL?

oh, and peferably the cheapest ones
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Old May 15, 2009, 07:09 PM
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foamand tape, Go to the website link in my post #37

On the links page, I have a list of gyros I've tested.
I'm going to add the 704 esky (blue/silver) rate gyro to the list and put fozzie's name on it. I have one but have not tried it yet.

I've only had one day of flying it in a plane but the colco GY400 wins my bet for cheap and functional. I might try it out w/ the gain disconnected to see if I can do it w/o as much Tx setup. Those gyros are about $20 shipped from Hong Kong and if you get more than one, less than that for a new gyro. I have a link to the seller on that table.

Fozzy, where you getting them for $6? ebay? heli forum sites?
I do know that heli flyers who get these on their arfs get rid of them pretty quickly.

At this time, I like the HH gyros used in rate mode for sport planes and the 704's should do well for simple setup but low roll rates. The holding power to resist wind on the Colco and 704A are just as good as the GY240 and GWS PG-03 I tested.

BTW, fozzy, GWS makes a gyro bypass switch called the PC-03.
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Old May 15, 2009, 07:44 PM
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thanks, that was what I was looking for (i should have taken the time to read it)
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Old May 16, 2009, 06:57 AM
Wakka Wakka
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Joined Jun 2008
962 Posts
Quote:
Originally Posted by Melnic
Fozzy, where you getting them for $6? ebay? heli forum sites?
I do know that heli flyers who get these on their arfs get rid of them pretty quickly.
Better than that... $3.81 each.... Hong Kong vendor.. here's the link:
Ebay Gyros EK2-704

They're kind of a blue and gold colour rather than blue and silver.
Here's a pic of them:


They're the same ones that Dave Powers uses on all his stuff . They worked fine for me too. maybe not accurate enough for critical heli use though. OK on cheap Heli, and fine on planes. They are budget items.

Here's Dave's vid on fitting Gyros
Put a GYRO on a RC Plane?


Quote:
Originally Posted by Melnic
BTW, fozzy, GWS makes a gyro bypass switch called the PC-03.
Have you got a link to those somewhere please?? I haven't seen them.

Best Regards,
Julian (Fozzy The Bear)
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Old May 16, 2009, 11:23 AM
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Melnic's Avatar
Maryland
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That one video of his was not too bad. I just don't like the cruise control comment. That's what heading hold is more like, not Rate mode.
Here is the PC-03
http://www.robotmarketplace.com/products/0-GWPC03J.html
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Old May 16, 2009, 11:31 AM
Wakka Wakka
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Joined Jun 2008
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Quote:
Originally Posted by Melnic
That one video of his was not too bad. I just don't like the cruise control comment. That's what heading hold is more like, not Rate mode.
Here is the PC-03
http://www.robotmarketplace.com/products/0-GWPC03J.html
Yeah... I agree. Although I think the point he was trying to make, while possibly managing to cause a bit of confusion at the same time, was that it looks for changes in attitude and reacts when it sees them.

Thanks for the link... I'm on the hunt now to see if I can track them down any cheaper.

Best Regards,
Julian (Fozzy The Bear)
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