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Old Apr 19, 2009, 08:13 PM
Old age is not for sissies
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Old Apr 20, 2009, 07:54 AM
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Yea, I've seen RC power's video on that. I had not seen how he has shown people how to hook it up though.

I saw one video where he showed the gyro and mentioned it needed to be in the center line of the plane.It does not HAVE to be that way by the way. Almost no one in helicopters places the gyro right under the main shaft.
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Old Apr 20, 2009, 11:04 AM
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A very good question. I asked this question years ago and got a hostile response. Seems like it polarized people with "if you need a gyro you shouldn't be flying."

So I never asked again. Since the Heli bunch has to use them I don't think its as controversial.

My g4.5 simulator has a plane with and without gyros. The one with Gyros I find harder to fly. Feels like the sticks are connected by molasses. Go figure on that one.

I drew up a very weird plane years ago similar to a Flanker a bit before it came out. Never built it because I thought no one could fly it. I even bought a very expensive set of Futaba Gyros to use but returned them to Tower, cold feet.

So since you have figured out how to use gyros on airplane a little advice needed please. If you have ailerons using separate servos how do you sync the gyros? Heading hold on the rudder would seem ideal for take off and landing. I assume there is some way to switch the gyro on/off with a computer xmitter.

Drift on Gyros is bad. Who makes drift free gyros at a good price? Do you need high speed gyros or will standard ones work for airplanes?

I might put these on an Ugly Stik to see what happens before building a nightmare airplane.
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Old Apr 20, 2009, 11:19 AM
Old age is not for sissies
Azarr's Avatar
Dayton Intl, Ohio, United States
Joined Jan 2000
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Quote:
Originally Posted by Melnic
Yea, I've seen RC power's video on that. I had not seen how he has shown people how to hook it up though.

I saw one video where he showed the gyro and mentioned it needed to be in the center line of the plane.It does not HAVE to be that way by the way. Almost no one in helicopters places the gyro right under the main shaft.
I know I saw his hookup instructions somewhere, let me search.

Azarr

Edit: http://www.rcgroups.com/forums/attac...mentid=2167198
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Old Apr 20, 2009, 11:22 AM
ARF Hater Club
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Toronto, Ontario
Joined May 2004
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Good read so far..
I do not agree with the "if you need a gyro you shouldn't be flying" crowd. That means basically every fly by wire military aircraft should not be flying such as the F-117 or the F-22. Using stabilization/dampening systems is just another cool step forward in our hobby. Getting very complex designs to fly how you want them to with a realistic amount of pilot input...
Imagine if people were againts BL/lipo and new materials such as carbon etc.. where would we be?
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Old Apr 20, 2009, 01:33 PM
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Quote:
So since you have figured out how to use gyros on airplane a little advice needed please. If you have ailerons using separate servos how do you sync the gyros? Heading hold on the rudder would seem ideal for take off and landing. I assume there is some way to switch the gyro on/off with a computer xmitter
Most of my work (ok, all of it) has been with just doing the Ailerons.
I have a small Grayson EPP foam plane w/ 2 aileron servos. I plan to try it out where I put 1 gyro on just 1 of the ailerons. Since the gyro is on the aileron to dampen unwanted movement, I'm expecting I will be able to run a little higher gain on that one gyro since it is running just one aileron. I already fly it in the wind since it's pretty rugged and if I just drop the throttle, it does not get damaged on impact in the weeds I fly over. If you have 2 gyros, I am thinking it may cause oscillation but so does a single gyro if you crank up the gain too high. I've never put 2 gyros on before but my experiance with flybarless helis (Heading hold gyros on each of the 3 axis), they say to NOT match the gain on any 2 channels or it may cause oscillations. So I'm wondering if you had 2 gyros if you'd match gain or mismatch them. Dunno.

To the "if you need a gyro crowd", I ask what about "if you need a bigger plane"? Tell them that!. If I fly my .40 Nitro trainer in 20mph wind, am I a bigger man than them not flying their .60 Nitro? Once again, this hobby to many is about enjoying themselves. A gyro on the ailerons can help w/ high winds and allow you to worry less about controlling in a gust. I however don't plan to put a rudder gyro on any of my planes unless it were something that was REALLY uncontrollable on takeoff like a jet or something on pavement. I can handle a tail dragger rudder on take off just fine and encourage people to get better at it as well. But if yours gives you alot of grief, no reason not to do something that allows you to be more safe and enjoy yourself. Since I don't fly over pavement and don't have a jet. I don't think I'll be doing that any time soon. I don't think I'd put it on the rudder to do a better torque roll but I don't plan to insult anyone who tries it either.

BTW, a Rate Gyro on any control surface will dampen not just the unwanted movements but the wanted movements. So on the aileron, it will reduce the roll rate and make it feel "mushy" but only to the extent if you turn your gains up to high. (I though I had mentioned this at the top). Heading Hold Gyros don't do that but I think are not good to use to start out with.

Years ago, the dual Rate mechanical gyros were RATE gyros and you could control the gain. Since NONE of the gyros I've tested so far work the way I want them to in rate mode, I have yet to see a way to say flip a switch and turn on the gyro. That's one of my goals is to find such a gyro that one could flip the switch on way and say the gyro is either off, or a really low gain, then flip the swith the other way and the gyro is on.

I am hoping to first find out what gyros people are using and get that info out there. Then I can start keeping a list of what people can/have used and how they used it.
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Last edited by Melnic; Apr 20, 2009 at 01:48 PM.
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Old Apr 20, 2009, 01:36 PM
Team Wack-a-Mole
Melnic's Avatar
Maryland
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Quote:
Originally Posted by Azarr
I know I saw his hookup instructions somewhere, let me search.

Azarr

Edit: http://www.rcgroups.com/forums/attac...mentid=2167198
Thx,

Although I understand what he's doing, this is FAR too complicated for the first time Gyro user which is what I'm working on in this thread. An aileron gyro is as simple as putting it inline w/ the Rx and the Aileron Servo.

-David
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Old Apr 20, 2009, 01:38 PM
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Here's the Futaba link I was looking for:
http://www.futaba-rc.com/faq/faq-gyros.html#q340

And a very good article that covers alot of info (I have not read all of it yet):
http://findarticles.com/p/articles/m...0/ai_n8903410/
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Old Apr 20, 2009, 02:13 PM
Old age is not for sissies
Azarr's Avatar
Dayton Intl, Ohio, United States
Joined Jan 2000
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I've used two of the no longer produced Century micro rate gyro on a foamy, but on the elevator and rudder for high wind conditions, didn't try it on the ailerons. It smoothed it out quite a bit in high wind conditions, perfect large loops, even with the high winds, but other than that I saw no real advantage and it just added weight and another thing to adjust. (is that the temperature drift you mention?)

Is drift a matter of price? I find it hard to believe a 3d heli pilot would put up with it.

I do think they have their place in planes though, particularly in the experimental area. TechDad made good use of them in his X-42 twin.

Azarr
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Old Apr 20, 2009, 03:03 PM
Team Wack-a-Mole
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The GWS gyro "setup" dial needed adjusting with temperature.
Yes, better gyros have temperature compensation.
The Futaba GY240 I tested last week was PERFECT. No drift and I had to do nothing to it other than mount it, turn off the AVCS. That's what is going into my Spitfire when I build it up. I don't really think I need the gyro in the spitfire to FLY it. I'm putting it in on the ailerons for stability in high winds. I'll be flying it at local events where I will fly no matter what the wind conditions are (to an extent). I chose the ailerons because I felt that the ailerons are the largest surface that wind can catch hold of and mess up the attitude of the plane. This is mostly a factor of landings in high winds where you need ALOT of aileron difflection at low speeds to compensate for a gust. With the gyro, the worse the wind does is bounce my plane up and down and I can handle that. I may put it on the elevator next to see how it deals with that. Rudder in a cross wind I'm fine with since I fly helicopters.
Yes, 3D heli pilots run gyros that are $100-$500.
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Old Apr 22, 2009, 12:47 PM
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Crawley, West Sussex, UK
Joined Jun 2004
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Quote:
one of my goals is to find such a gyro that one could flip the switch on way and say the gyro is either off, or a really low gain, then flip the swith the other way and the gyro is on.
Most of the high-end gyros have a gain control that you plug into channel 5 on the receiver - then you can either use a slider to control the gain directly or adjust the end points for the channel and use a 'gear' switch to toggle between 0% and 30% gain.

I know you said the high-end gyros didn't work the way you wanted, even in rate mode - could you explain the problem please?
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Old Apr 22, 2009, 01:05 PM
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Did a flight test yesterday w/ my Grayson Hobby Sukhoi.
This setup is not standard per their plans but has 2 aileron servos The aileron servos were on seperate channels. I had it set up for flapperons. One on each wing. I connected just one of the ailerons to the gyro and it worked to stabilize in the wind. Wind was only 8mph but I noticed the difference vs. not being installed. 2nd flight was w/o the gyro and I could feel the wind gusts more.
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Old Apr 22, 2009, 01:25 PM
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Quote:
Originally Posted by RobinBennett
Most of the high-end gyros have a gain control that you plug into channel 5 on the receiver - then you can either use a slider to control the gain directly or adjust the end points for the channel and use a 'gear' switch to toggle between 0% and 30% gain.

I know you said the high-end gyros didn't work the way you wanted, even in rate mode - could you explain the problem please?
Prepare yourself for my long winded response:.......

YES, almost all the heading hold gyros now adays have a seperate gain channel. If you think of a servo as having a neutral point and CCW and CW rotation then the way they work (I have yet to find one that does not work this way) is one direction is Heading Hold (HH) and the other is rate mode (dampening). So if CCW is HH mode, CW is rate mode. A gear switch would be by default 100% CCW in one direction and 100% CW in the other direction. Your Travel adjust (ATV) then controls the gain for each mode. Set switch to 30 for CCW and you'd get HH mode w/ 30% gain. Set CW to 50 and you get 50% rate mode. There are LOTS of places on helicopter sites that explain this. There is also a way to set up the switches in helicopter mode of Transmitters so that your switch switches between 2 differen HH modes.

Now for the problem with these HH gyros.
Normally, the servo travel follows the stick. Say you take a servo and your travel adjust is 100%. Lets say your aileron difflection is 1". Move your servo half way to the right and the aileron servo moves 50% rotation to the right. Your aileron difflection is now 1/2" (yes, I know its not going to be linear but humor me). Move your aileron stick 75% to the right and the aileron difflection is 3/4" right? simple.
Well, with the HH gyros that I tested in rate mode, they did not do that. Basically with say 30% gain in Rate mode, when I moved the aileron stick 50%, I got 1" difflection (100% servo travel). As I moved the stick from 50% right all the way up to 100%, the aileron just stayed at 100%. UGHHH!
This is not what I got when I used the GWS PG03, Esky 704 or the Futaba GY240. Those gyros when the airplane was still, responded just like when the gyro was not there.
I have yet to try a HH gyro in rate mode because of what I saw but I DO intend on trying it. I will have to get someone to help me out and to time a bunch of concecutive rolls and see if the roll rate with 50% right stick vs. 100% right stick are the same or not.
If the roll rates are different (more roll rate w/ full stick) then that tells me that I"m worried about nothing and that the gyro senses the stick movement as well as the rotation speed. IF this is the case then the downside of loosing roll rate is solved by these HH gyros.

The other problem I saw was that when my gain was less than 30%, the total travel of the servo was not the same, the travel was reduced to almost 0 at 0 gain. Even in HH Mode.

What I was hoping for was that if I set 0 gain in HH, that I could essentially turn the gyro off with a switch. In other words, my gear/gyro switch would be ON(30% rate gain) or OFF (No gyro compensation). I have yet to find that.
I have however found a seperate device that is reported to all me to do that. It's a GWS PC03. See the thread:
http://www.rcgroups.com/forums/showthread.php?t=274793

So if you experiment w/ a gyro, Look to see if the gyro inline w/ your servo plays havoc on your servo throw.
Check back next week and hopefully, I will have flown w/ a HH gyro in rate mode by then to report my findings. The plane I'm using is an EPP foam plane and is virtually indestructable so long as you drop your throttle and minimize impact speed. I'm flying over tall or clumpy grass anyway. I have lots of room for error to do these experiments.
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Old Apr 27, 2009, 03:48 PM
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I take back ALL that I just said about HH gyros being used in Rate mode.

I did a real world flight test with an Esky 704A gyro on my foamie.
It was the BEST solution yet!

I had an online conversation with someone and he explained that the heading hold gyros in rate mode use the travel adjust (ATV) as the piro (rotation) rate adjustment JUST like in Heading Hold mode. I knew this about HH mode but did not realize it would work the same in Rate mode. He said that just because you move the aileron stick half way and the ailerons move all the way, it will not do that when in motion in flight. He prodded me to give it a try and I did.

I did a flight test and the roll rate was linear to my stick movement. In other words, even though the ailerons moved 100% at half stick, the roll rate at at full stick was 2x fast as at 1/2 stick.

I'd definitly say that today's flight w/ the 704A gyro was the closest to wind free on the ailerons as any other gyro I've tested so far. Plus there was very little if any aileron wag today. I had about 50% gain in Rate mode and about 30-50% gain in Heading Hold mode. I felt that Heading Hold mode was a little too sensitive (wishy washy) and that if flew tighter in Rate mode. The good news was other than takeoff (I did not film this), there was nothing that during flight would make Heading Hold mode make the plane go crazy. During take off, there was a drift where in heading hold mode, the aileron would drift on the ground to full difflection. I could trim it out, but that meant that the aileron in Rate mode was not centered. Changing the gain in Rate mode meant I had to re-trim the aileron again. Note that this gyro wants the trim pretty close to center or it will not initialize.
The 704A turns red during initialization in which you DO NOT move the plane, then turns blue and you can see the aileron center.

Once again, to test the gyro reverse, The aileron LIFTS UP on the wing you lift up during the rotation.
I've attached a youtube video of the camera showing the ailerons lifting as I rotate that wing upwards.
Also a flight test in winds of 10mph gusting to 15.
Example of an Aileron Gyro on an RC plane (1 min 3 sec)


Gyro Test RC plane using Esky 704A on a Sapac 330L (2 min 54 sec)
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Old Apr 27, 2009, 05:51 PM
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Big Johnny's Avatar
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Rate gyros are also very good at dampning the rudder on a taildragger, expecialy WW II Fighters. Makes Take Off alot more predictible
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