Capt Jim

My Feedback: (168)

I have been wanting to try a gyro in a plane for an awful long time now...not in a heli...and I find it impossible to get any detailed information on the subject. When I say detailed information...I'm looking for paragraphs, and chapters, etc...not one-liner comments! Pretty much everything I've seen about gyros refers to a helicopter. Futaba has discontinued so many gyros in the last year or two...it makes me feel as though they just can't quite get it right...ever.
Is there a better one out there?
A few users here on RCU have made vague references to gyro model numbers that remain obscure, and made comments like..."works good!". That simply isn't very helpful to me, and Towers catalog, and even Futabas website really does not address the subject in any meaningful way. I'm not in a hurry...i've thought about it for a couple of years now, but there just isn't any educational info to learn on....and I'd rather learn first, before making an unwise investment. I guess we could profit greatly from an article written by a knowlegable person who has used them over the years, in planes, and can write at length about his experiences and their features, benefits, and upsides as well as downsides.
So, the quest continues to find a rudder gyro for large or giant scale planes, that will actually yield the promised "straight-as-an-arrow" tracking...on ground, or in the air. Any new suggestions?
Thanks for all your help.

BarracudaHockey

My Feedback: (11)

http://www.futaba-rc.com/faq/faq-gyros.html#q340

Have you read that?

The 352 is the dual axis airplane gyro.

Capt Jim

My Feedback: (168)

Hi..and thanks for the lead, but yes, I have seen that FAQ on Futabas web site. They open that infomercial with a situation wherin someone asks about using a two axis gyro to torque roll....but that is not my objective. The other items in that same thread address particular set-up problems with a particular Futaba gyro under some unique circumstances. It was OK reading, but it doesn't address in depth the use in an airplane rudder application... solely to achieve perfectly straight lines..., and since it is Futaba...it doesn't mention any other manufacturers.
I get the feeling that the vast majority of gyro users are heli applications. Plane flyers either have had bad or disappointing experiences with them, or just dont care....and then with Futaba discontinuing so many of their formerly finest offerings.....well..it just doesn't give me a very good feeling about Futaba gyros.
Thanks much anyway...
Jim

carrellh

I have a Futaba GYA350 in my Astro Hog. With the gear switch in one position it is in heading lock (ACVS) mode and in the other position it is ‘normal.’ I think I have the ATV set at around 80 percent for heading lock and 30 or 40 percent for normal. The two little dials on the gyro itself are set at whatever was on the instruction sheet.

In normal mode I cannot tell the gyro is there. An Astro Hog may not be the best test subject for this because it is a very stable plane to begin with. And I’m not a great pilot so it may be doing more than I realize. Since I don’t fully understand what it ‘should’ be doing in normal mode I have no idea if it is doing it.

In heading lock mode it will drive straight down the runway. Even if the throttle is slammed from idle to full it goes in the intended direction. I hesitate to say it goes “straight as an arrow� but it does go pretty darn straight. Our runway is grass and it has a few dips and undulations. Running from one end to the other it does seem to follow the slant of the runway and may work toward the left or right side of the strip a little but it’s always headed South.

I bought the gyro specifically to keep the plane straight on the takeoff run. I have a neurological condition that left me with extremely limited feeling and mobility in my hands, one much worse than the other. I cannot manually use the rudder to maintain a straight path down the runway.

Prior to this, my gyro experience was zero. I’m no gyro expert and can only relate what I have personally seen or done.

JohnBuckner

My Feedback: (1)

I and several others who are gyro users on certain airplanes for rudder stabilization answered your last thread with no reply here:

http://www.rcuniverse.com/forum/m_40...tm.htm#4027825

I have been using them for three years now very successfully on these airplanes. I do not use the Futaba product as the inexpensive Hobbico Piezo Gyro works just fine and airplane size is not an issue. Would be glad to answer any of your questions but its pointless to type when you are unresponsive.

John

Capt Jim

My Feedback: (168)

Thanks for the comments Carrellh...you make an interesting case for the Futaba GYA350. It sounds like your experiences are quite close to my objectives.
Thanks.
Jim

Capt Jim

My Feedback: (168)

JohnB...Your positive comments on the piezo gyros come as a surprise to me. The Futaba advertisments would have us believe that the piezo gyro is substantially less effective than their current high tech offerings. Price is not necessarily the big issue here. I would pay the price of a quality device, but I seem to run into difficulties such as....the seemingly good gyro/servo combination doesn't like 6 volts on the digital servo.....and...the super fast servo that comes with the Futaba gyro is a wimpy thing, not at all up to the task of holding a giant scale rudder. It is this sort of dead end street that makes me think that the gyros are for light heli's only, and they aren't there yet with the muscle required for larger aircraft. I'm hoping to learn that such is not the case. I'm not a big fan of Hobbico gear...they appear to make things as cheaply as they can...and not necessarily as good as could otherwise be done.
But I do appreciate your comments....its all becoming a part of my learning curve.
Thanks.
Jim

bentgear

Capt Jim, I would think that any gyro that is capable of holding a plane in a torque roll would have easy going keeping it pointed straight on takeoff.

What if you use the gyro to drive something like a match box with separate battery attached? That way the gyro is only providing the signal and the match box is providing for the load. Just throwing some thoughts out, not a gyro expert on this end, and no.......I didn't stay at Holiday Inn Express last night.

Ed M.

carrellh

Jim, I'm not using a special servo at all, my Hog has Futaba 3004s all around. My GYA350 didn't come with a servo. The recommended coreless unit is expensive (to me) and doesn't have great speed or torque specs. As far as I can tell you can use just about any servo with the gyro. The only restriction would seem to be voltage; it appears that all Futaba units are designed for 4.8 volt systems. The gyro is just sending a signal, like a receiver does, so it doesn't care what kind of servo is on the end of the wire.

Capt Jim

My Feedback: (168)

Well here we go again...heh heh....I liked the idea of employing a matchbox if I need the power, so I went to Towers website to order a GYA350 just like carrellh is using....well dont you know, Futaba has discontinued that one too. Is this an omen, or what?
thanks guys.
Jim

BarracudaHockey

My Feedback: (11)

http://www.duralitebatteries.com/accessories.html

Scroll down under assecories and you will find a tail servo step down, that will solve your voltage problem.

You really dont need a digital tail servo to get a gyro to do its thing on an airplane. I had a Gy401 on a Funtana and you could goose the throttle as hard as you wanted on the ground and it will take off like a rocket and straight as an arrow. The problem I had was to run the gain high enough to make it effective it would start wagging the rudder at high speeds. I needed it for a helicopter so I took it out after a few flights, it really didn't make that big a difference for a torque roll but it surely helped on take off. Any of the gyros, fancy or other will run on a standard servo they just wont be as effective, something that on a plane you probably wouldn't notice as much as you would on the tail of a helicopter.

JR makes some good gyros as well but again for what you get out of it a cheap piezo gyro would probably be just as effective http://www.horizonhobby.com for the JR stuff. Also CSM makes a line of rate and heading hold gyros, click on the CSM link on http://www.rchelisplus.com

Capt Jim

My Feedback: (168)

Tnx for the tips 'cuda....I looked at that stepdown...it isn't a reg'r...so what is it really? It also says it wants a "Regulated" 6 volt source. I try to keep the component count down, so I run 6 volt NiMh batteries without any reg'r. They do top off at a higher voltage though. My Rx and servos are all quite happy with it that way. Also, that thing says not for use with NiCd or NiMh batteries.....gee...lots of restrictions and warnings, without any explanation. I'd sure like to know the "WHY" of these things, rather than just blindly follow their suggestions without a reason....that's just me thinkng again I guess. ...trying to learn something.
As for the digital servo...yeah...I can do without that...I was hoping to be able to use the digital speed, but it is so sensitive to voltage source....I'll continue to avoid them.
thanx.
Jim

BarracudaHockey

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Jim if I were you I would surf the classifieds here or at RunRyder.com and get a cheapo gyro and give it a shot and see if it works for you.

Capt Jim

My Feedback: (168)

I'm looking at the Futaba 401....at $140 from Tower, it is not a terribly expensive gyro, and if nothing else, it'll give me a basis for forming opinions and making judgements. I'll just run my standard rudder servo (Hitec HS-645MG) on it and see what happens. I am thinking that this gyro is switchable from the Tx, so I can turn it on or off as I see fit. That should give me the straight lines for take off and landing...which is my main focus, and then turn it off at high speeds to avoid tail wagging.
Myself and a few friends play around with formation flying with giant scale warbird planes, and the T/O and landings in particular is where you really want to maintain your designated line on the runway.
( It gets real noisy if you mess up! )
Thanks for all the advice....I guess now it's time to take the plunge....if I can just get it before Futaba discontinues this one too!
jim

BarracudaHockey

My Feedback: (11)

That gyro isn't going any where and Ricks http://www.ronlund.com has it for less (you have to email them for a quote but it will be 120 plus about 3 bucks priority mail shipping)

You really can't turn it "off" from the transmitter, you can switch it back and forth between AVCS (heading hold mode) and Rate mode by setting the end points on the gear channel (or any channel w/ a toggle switch) the end point being the gain percentage for that mode, in a plane I would be careful using heading hold mode as the results won't be quite what you expect. If you have a fancy radio with a gyro menu like the 9c you can set both sides of the switch to rate mode and a very low gain on one end which will in effect turn it off.

Also no worries mail ordering from Ricks they are the class of the business as far as heli's are concerned.

JohnBuckner

My Feedback: (1)

You will discover there is no need to turn off in flight. Tail waggle under 'G' at higher speeds is an indication that the gain is a little high, it is not a big issue, its simply a matter of adjusting a little before the next flight. If the gain were adjustable in flight I suspect this would be very counter productive as it would be most difficult to do.

For stabilization of runway excursions I beleve all these units: cheap units with pizzo sensor, expensive units with pizzo sensor or antiquated ones with mechanical motor driven flywheel sensor will do the job.

I,ve also used the israli built BTA-1 gyro built for RC fixed wing use I think about twelve or thirteen years ago Even it could handle the job its problem was it was large and very heavy requiring its own heavy power source.

My P-38s use 4.8v but there is only one reason for their existance and that is is warbird pylon racing, I suspect they see speeds and loading your giant scale will never see.
That cheapy gyro does a great job in buying a few extra seconds to identify and react on an engine out. Of course that is not your problem however it does a fantastic job of stabilizing the typical runway waltz, I think thats what you,ve been talking about all the time.

Other folks are also starting to use the simple gyros in the warbird racing venue as some of these deliberately overpowered airplanes with lousy scale landing gear geometry are frequently lost in T/o excursions before the racing even starts. You know what? it works.

It would seem to me as many others you are over engineering the simple device to death and going nowhere as another poster suggested just get a cheapy of any brand and try it. Its certainly not going to crash your airplane. Otherwise you will never know or benefit.

One last thought is yes it will enormously help in stabile T/o runs but it will not help in your formation flying efforts that you hinted at. The problem there is not in yaw stabilization but pilot induced excursions in pitch and roll aggrivated by poor pilot visual perception. As always formation flight and I mean the real thing is almost the holy grail of RC flight. I assure you formation flight in full scale aircraft is relatively easy when compared to RC.


Just go for it and enjoy

John

Capt Jim

My Feedback: (168)

Hey 'cuda'...I got it in my hands already...from my LHS at $132. plus tax, and I do have a Futaba 9C, so I guess I'm ready to rock & roll with this thing. As a test bed, I'll put it in my big old 1/4 scale Cub. That plane wants to have a lot of rudder input to make her fly correctly....coordinated turns, etc...so I figure it'll be a good place to start learning about the gyro. Also, being a taildragger, I will see immediately the effect it has on throttle up and take off.
Thanx again for the guidance and tips.
jim

Capt Jim

My Feedback: (168)

JohnB...you may be correct...I do tend to over-engineer things in my zeal for perfection. Now that I have the 401, I'll just give it a good try and see what happens.
As for our formation flying...it is largely a good luck and by golly affair. We put up anywhere from 6 to as many as 13 planes at once, in a gaggle, and after that it is just a little skill and a lot of luck that we dont meet in the air. Our r/c perceptions of pitch and roll are pretty good, but yaw is almost undetectable. I think thats why pattern and IMAC flyers will use rudder to sneak back onto their line without signaling to the judges that they went off. It is hard to detect from our grounded vantage point. We do however attempt a pair, or trio of planes taking off, and/or landing, together, and thats where I'm hoping to see some benefit from the gyro. My thought being that once my line on the runway is established, it will tend to hold the line better with the gyro...again...because yaw is more difficult to detect, and correct quickly enough, while pitch and roll are fairly obvious.
We shall see.
Thanks for all.
jim

BarracudaHockey

My Feedback: (11)

Jim when you set it up I would do this.

Goto the advanced menu and then GYRO SENS
Set it to ON
Then Rate UP Nor 50
Rate DN Nor 25

That will give you normal mode 50 percent and 25 percent gain. Make sure CH is set to whatever you have the single wire plugged into, usually 5 and SW is set to a toggle, I use F but thats on the H version, whatever works best for you.

Take off with the gain at 25 and see what happens. When you get in the air try the switch and see again. If nothing wags land and try a takeoff at 50, you can keep bumping the gain and seeing what the most you can run is. Where you will see it start to wag is at higher speeds so carefully feel these out. When you get it to do what you want go back into the gyro menu and set the other side of the switch to the same number but AVC. You will see what I'm talking about. I'd always make sure you would takeoff in Normal mode then you can experement with heading lock mode in flight at a safe altitude but I think you will find you are using normal mode most of the time.

Let me know if you have any questions.
Have fun with it!
Andy

JohnBuckner

My Feedback: (1)

Great Jim good to see you 'bit the bullet' and are going ahead to experiment. I,ve no doubt at all you will enjoy the results especially with that big Cub. One other note, some folks like to make the assertion that gyro use is in some way cheating. Well not at all, what it really does is make it possible to fly in ways that were before just not possible.

That part about visual perception was intended to point out the differance in flying formation betweem full scale and RC formation. RC formation is vastly more difficult with the constantly changing visual relationship of the RC pilot and his aircraft, whole different ball park.

Enjoy the Technology

John

Capt Jim

My Feedback: (168)

Hey Andy...problem number 1. I am flying an airplane..not a heli, so I dont have an advanced menu in the 9C for planes. Somewhere in the 9C manual I think it trys to say that sensitivity gain equates to ATV. If I set the ATV (gain?) on ch#5...normally a gear channel...maybe that will yield the same results??? I am of course having difficulty with the sensitivity. In what I think may be AVCS mode, the gyro is telling the rudder to hold the last stick control input......not good....the rudder does not return to center when the stick is released. In what I think is normal mode, the rudder makes a quick corrective but small movement and then returns to center. I say "I think"...because the LED is not blinking exactly like the instructions say it should. And the instructions....they are written in some sort of a strange Japanese impression of English...which seems to make little sense...or at least at this point leaves me wondering what they are trying to tell me to do. heh heh...I was hoping to avoid all this grief and just buy a device and drop it in...with real english instructions to help set it up for an airplane. I dont know what to think about all this now....other than it is certainly not flyable as it sits, and I guess it's going to take a lot more experimentation to sort it all out.
I'm going to go try ch5 ATV and see what it does....of course I cant fly it in the garage, but hopefully tomorrow morning I can take it to the field and see what it does.
Thanks for your continued help.
jim

Capt Jim

My Feedback: (168)

OK guys...were making real progress now......
things are getting worse, but at a slower rate...heh heh...
just kidding. I've got it working...finally....I'll fly it tomorrow to see what it does.
A couple of interesting things though. In AVCS mode, the rudder holds the last rudder stick command. Not a real good idea. And, I had some rudder mixed in with ailerons, so I'll have to inhibit that mix. No problem there, I'll just do all the rudder by hand in the coordinated turns. I guess I can use the AVCS mode for take off, just to lock the heading, but kick it out quickly once the wheels leave the ground. Normal mode makes quick little corrections as the plane is shifted on the bench...I have absolutely no idea what the performance will be like in the air. I'll just fly it and see. Another interesting thing is that my dual rates on the rudder are no longer dual rates. Just one rate no matter which position the switch is in. Weird?
Well thats the latest...I'm pretty excited to see how it works tomorrow....
it'll be a great test too...lots of cross wind forecasted.
Thanks for all the help.
Jim

bentgear

Capt Jim, I assume you have checked to make sure the rudder still follows the stick correctly from your descriptions above, but have you moved the tail sharply to one side to make sure the gyro forces the rudder to correct in the right direction? If it goes the wrong way that could cause a rather interesting battle for directional control.

Ed M.

Capt Jim

My Feedback: (168)

good morning Bentgear. Yes...the rudder follows the stick correctly, and the rudder moves in the right direction to counter a yaw, so I guess it is set to go. I don't yet understand the "delay" setting though, and I'm not sure about the sensitivity either. I set the sensitivity to the values as described in the example on the instruction sheet....which as I recall were something like "72" in AVCS and "54" in normal.
Flying in AVCS mode seems like it would be a disaster, because the gyro holds the last rudder stick input. Fortunately the rudder will re-center as soon as the tx switches the gyro back to normal. My guess is that it may be useful on a takeoff, where you want to maintain a straight line, (and of course keep my fingers off the rudder stick during the roll out) but I would switch it to normal as soon as the plane lifts off. In normal mode, my plan is to fly it and see what it does....tail-wag...etc, and adjust the sensitivity from there....and maybe the delay too??? This has been a steep learning curve for me...sort of a 8 hour crash course..ooops...did I say crash? Oh well, we shall see soon enough. Perhaps I will obtain the performance I am seeking in normal mode and not ever use AVCS mode. That would be good. I want to try and discover why it has taken over my dual rate on the rudder, and left me with just a single rate. I typically use high rudder rate for taxiing, and a lower rate for most flying. Bearing in mind, this is a Cub...not a 3D machine. More Futaba mysteries I guess.
Jim

BarracudaHockey

My Feedback: (11)

Ok let me explain a few things.

When you enter programming mode for the 9c you have basic menu and if you press the mode/page button again that gives you the advanced menu. If you have the super, the ACRO function gives you a gyro option. If you have the original 9c you set the gain with the atv's that the single wire is plugged into, usually channel 5.

The easiest way to explain how the gain works (in english) is to visualize it on a rotary knob. Any time the knob is turned to the left of center we are in avcs (heading hold or HH) mode. Any time its turned to the right of center its in normal mode. 1/2 way is the cut off point to change modes. When the knob is fully left you are in HH mode with 100 percent of the available gain, as we turn the knob slowly to the right we are still in HH and the gain value is decreasing until we get to the half way point where its at 0, as we cross 1/2 way we switch to normal mode and start increasing the gain till the knob is at full right when we are in normal mode and 100 percent gain. So with ATV's and a toggle we are simply setting the stop point of the knob either way. From 50 to 100 left is 0 to 100 gain in HH mode, a value of 75 yields half the available gain so 75/75 for the end points would give toggle up 50 percent gain in HH and toggle down would give 50 percent gain in normal. Thats about where you want to start your experements.

As for the rudder and hh mode you have to understand what's happening. The gyro is giving a command to turn (which it got from the stick) at a given rate. On the ground the airplane just sits there and it isn't obeying the command to turn so the gyro patiently waits for it to do so. If you yaw the nose in the direction the plane should be turning you will see it go back to neutral. Also if you move the airplane w/o a rudder command you will notice the rudder stays put till the plane returns to its original heading (desireable in a heli)

In normal or rate mode as we call it the gyro simply gives a correction to stop the rotation and return to neutral to await something else to do, if you were to spin the airplane in the yaw axis it would continue to give correction till it stops.

Now some other things you need to know. Make sure there is no rudder trim or subtrim in the model, mechanically center everything. Dont use the transmitter to change the trim after the gyro is initialized or your're going to have problems because the gyro memorizes center when it boots, any trim is taken as a command to turn. Also make sure you have the transmitter on first and the toggle in avcs mode, the gyro should flash for a few seconds then come on steady, make sure you don't move the rudder stick or the model till the lights on, you will hear the tail servo lock in but like I said, its a 3 second process. Then you can flip to normal mode (light off), any time there is a stick input it will double flash, thats correct too. If it just flashes 1 flash slowly its not gettting an init signal from the channel its hooked up to or the single wire isnt hooked up.

As for end points, set the end points on the rudder channel to 100 and adjust the throw with the limit pot on the gyro while the gyro is initialized correctly and in normal mode (light off). If you want to de sensitize the rudder reduce the atvs and it will reduce how fast the gyro tells the plane to turn, trust me it looks strange but it works.

As for delay since you are presumably using a standard servo, set DS MODE OFF or you'll burn up your servo and the dlay to about 1/4 turn from 0. If your rudder wags coming out of turns turn up the delay a bit at a time, if it wags in flight reduce the atv values to reduce the gain.

Do the following test, give right rudder and note correct movement.

Set AVCS mode on the transmitter and move the nose LEFT, (as viewed from above counter clockwise yaw) and note the rudder correcting to the RIGHT, if thats backwards flip the NOR-REV switch on the gyro.

I pm'd you my number call me if you have any questions.