capt17

Mainly I care for Airplane applications. I know it somehow controls stability but how? What does a gyro hook to in the elctronic system? How does it work?

twostroke

My Feedback: (6)

A meat filled pita at the fair....the other one is a electronic orientation-stabilizing device

BarracudaHockey

My Feedback: (11)

It senses rotation about an axis (or multi axis in some cases) and applies a correction. It hooks up between the receiver and the servo it's controlling.

They are mainly used in helicopters though they have limited applications in planes.

capt17

Ok. So when would someone want to use this in an airplane?

MinnFlyer

My Feedback: (4)

they are mostly used for helicopter tail rotors, but you could put one on the rudder to help with yaw

CGRetired

My Feedback: (1)

I don't know how far you are into the hobby, but most of us have learned to fly without the gizmo's to "aid" the aircraft in going where we want it to go. The application of a gyro in a fixed wing is probably a real serious waste of both time and money.

Futaba sells a combination gyro and servo for $149. Heck, you can buy a new engine, or a new model, or a new radio for that cost, and the money is much better spent on that than on a gyro for a fixed wing.

http://www3.towerhobbies.com/cgi-bin...&I=LXVND7&P=ML

Take a look at this link.. so you can get an idea of what the cost of this is. The setup is probably way beyond most beginners, too.

My suggestion is to stick with the basics on the Rudder and keep it simple.

CGr.

capt17

I agree CG and use my rudder regularly, I've just never really heard of these in airplanes but just lately.  I just wanted a little bit of info so I was in the know.  Thanks all

Campgems

When I was still on the buddy box, I picked up a cheap Gyro at a going out of business sale at one of our late LHS. I was just starting on a tail dragger after killing my trainer. Take offs were not very nice. I hadn't aquired the rudder and tiail wheel control yet and I mowed a lot of weeds off the left side of the runway. I was sure the Gyro would fix this. And it did. Icould hammer the throttle and as long as the plane was pointed stright down the runway, that is where it went. About three or four flights in though it became obvious that while I could take off cleanly, turns were not so clean. It took me three days of flying before I pulled it and leaned to ease on the throttle and keep the tail wheel nailed untill the rudder could control the direction.

I've though about using one for the ailerons for landing, but you would really need one that you could set the gain from the TX and shut down for normal flight, and and and. The price for what I wanted keept going up and the need kept going down. Dial in some expo and low rates and fly.

Don

otrcman

Sounds like I may be in the minority here. I sort of like using gyros in airplanes. I'll tell you why, but first maybe I can expand on what a gyro does.

First off, there are lots of gyro devices in the world, but the ones we use in our models are more accurately known as "rate gyros". The rate gyro senses "rate of rotation" of the airplane in the axis for which it is installed. If you orient the gyro so it senses roll rate, then the gyro sends a signal to the aileron servo each time it senses motion in the roll axis.

Note: this means that the gyro sends no signal as long as the model is in steady level flight nor does it send a signal in a steady bank. It only acts for the time the airplane is rotating in roll. And the faster the airplane rolls, the greater the gyro input and the further the servo will move to oppose the roll motion. The upshot of this is the airplane will feel larger and more steady to the pilot. It also means that the airplane will not be as sensitive to gusts. The wings will stay much more level and will resist any quick little uncommanded motions as you are coming in to land.

If you orient the gyro to sense yaw and connect the plugs to the rudder servo, it will help to prevent your plane from veering off the runway on takeoff or landing. As Campgems said, this really works well on a tailwheel model where the yawing action is very quick. Campgems pointed out also that the yaw gyro can be a nuisance in flight if it is set to such a high gain that it causes the rudder to resist your intended turns.

When people talk about gyro gain, they are referring to how big a signal the gyro sends for any given airplane motion. With low gain, the gyro sends a small signal to the servo. With higher gain, the gyro sends a larger signal to the servo for the same amount of airplane motion. With low gain you may not even notice that the gyro is working. With higher gain the airplane becomes very steady, but may give you some of the problems that Campgems mentioned. If your gain is set very high, you may find that your model will waggle its tail (for a yaw gyro) when flying at high speed. That waggling is feedback, just like the annoying hum you used to hear in your high school PA system during assemblies.

The dark side of a gyro? Don't ever hook it up backwards. You'll be into the ground so fast you'll wonder what happened. Very early in the flight test program of the full scale F-117 a gyro was installed backwards and the pilot barely got off the ground before crashing. I don't know all the details there, but it was a stunning reminder of what one little error can do.

One last thing: You will hear mention of "heading hold gyros". They're designed strictly for helicopters, although some folks have experimented with them in airplanes. They are complex and difficult to use. Best leave them alone until you become a very sophisticated flyer.

Dick Fischer

JohnBuckner

My Feedback: (1)

Indeed in the beginners forum the use of a gyro is inappropriate and counter productive to your climb up the airmanship ladder flying fixed wing aircraft, however there are a few limited applications where they are most useful and should not be considered a skills crutch.

One of these I have experiance with is when flying multi engine aircraft especially with more than two engines such as these, nice takeoffs can become very tough due to the uneven spoolups of all the engines. A single axis gyro set up on the rudder becomes a major asset.

Another multi engine application (gyro on the rudder) especially on two engine multi's (The configuration with the most trust disymetry when on one engine) A gyro will buy the pilot a few critical seconds to identify and react the proper rudder imput. It of course will not save the airplane but will indeed buy the pilot precious seconds.

John

DeferredDefect

I don't know anything about gyros, but JohnBuckner -  Those are incredible models! [X(] 

Campgems

John, thank you for this post. That little gyro that I put in the spare parts box now has a new life. I'm building up an ASM P-61 and never thought to use the gyro for a quick assist in the event of a dead engine. Glad I didn't give it away now.

Don

BarracudaHockey

My Feedback: (11)

JB, those are cool!

JohnBuckner

My Feedback: (1)

Thank you GE and BH its appriciated. Camp if you have that gyro do not let it lay in a drawer, Like the old drill sarge said "If ya got'em, Smoke'em" definately put it in your P-61.

The problem you had with it before is likely you ran it at an exessive gain. For airplane use its wise to always startout at no more than 50%. Set up right and you never know its there and you don,t need to switch it on and off in flight.

And guys don,t be embarassed about using them on rudder of some problamatical single engine tail draggers. For example a very scale P-51 with a scale forward tailwheel can be quite a handful on takeoff compared with most arfs with the tailwheel under the rudder. This is made worse with the typical big fourstrokes and long props.

I think I have now eight multi's all flying but only have two gyro's one on a Wing P-38 and the other on the Quad Kaydet. So its a matter of choice.

Here are my two latest Multi's and in a big push for late summer test flight on both. Both have those marvelous new 25AX's, those and the 35 AX are rapidly becoming my favorite, Hope we are on the right server now so the pics don,t get gigantisized:

Campgems

John, your tri-motors reminded me of this video a friend sent me a couple months back. I think you'll get a kick out of it. Argggggg. I should have checked the link before I posted it. It's defunct now. I'll see if I can find the clip in the way back machine and post it. It was a 30's movie of a Ford Tri Motor doing some aerobatics.

By the way, I think you are right about to much gain. I remember that if I would hold the plane level and then pop the tail one side or the other, it would just about peg the rudder. I haven't played with it in close to four years now. I'll dig it out and make sure I install it when I get to that point.

Don

Campgems

OK, this link should work

http://www.youtube.com/watch?v=I6f0tvqtAxQ&NR=1

And it does.

Those early pilots were more stunt men than what we think of a pilot being today.

Don

JohnBuckner

My Feedback: (1)

Yes thank you Don wonderful footage.

John

otrcman

John, Don, I'm looking for some input on the amount of gain your gyros have and what brands they are.

Some time back I used an old Kraft mechanical gyro with good results, especially considering the state of the art in gyros & servos at the time. More recently I bought an "Ikarus Micro Gyro" from Hobby Lobby for my F3F. The gain of this gyro seems much lower. Even at max gain and swinging the tail of the plane from side to side quite rapidly I only get about 5° rudder deflection. On my old Cub with the Kraft gyro it seemed like the rudder would nearly hit the stops if I swung the tail so quickly.

None of the gyros that I've looked at advertise their gain range. You'd think at least some of the helicopter guys would be sophisticated enough to ask about that.

I haven't flown my F3F yet, but I'm thinking the gyro won't be adequate even at max gain. I did try an Ikarus in my GWS Tiger Moth 400 just to evaluate performance. The gyro had very little effect in the TM, but I chalked that up to the very docile behavior of the basic airplane and the fact that the servos aren't particularly fast. Now I'm beginning to think I'm just short on gain.

I do understand the problems of excessive gain, but from prior experience I don't think I'm even close to that end of the spectrum. How sensitive are your gyros when you swing the tail from side to side ?

Dick Fischer

Campgems

Dick, the little gyro I have is a real cheapie. I bought it from Fast Lap Hobbies when they went under for something like $12. I'm not sure what the street price was.The gain is set by a screwdrive. It will swing the rudder stop to stop if you set the gain up, Not knowing where to set it, I just chose the mid point. I've got an older Futaba mechanical gyro system, two pieces also.

A lot of the newere one will let you set the gain from the TX. Seems that might be desirable.

One other thing that I'm looking at for dead engine on a twin is the Twin Sync. Less than a good gyro, and I've read good things about it. It slows the fast engine to the speed of the slow one, but gives you the ability to gain full control of the running engine by going to idle and back to throttle up. My concern with it would be a dead stick on approach, One then the other engine going to stop and then idle might just be the end of your plane at low speed and altitude. The gyro may give enought help that you could save it. Got to think that over some.

Don

JohnBuckner

My Feedback: (1)

Hi Dick the two gyros I have and still use are the now discontinued hobbico piezo gyro. Actually I think all modern gyros are in reality piezo gyros, using a piezo generated current from a magnetic flux gate to sense a movement about the selected axis. I am however no expert. I also have some testing experiance back in the ninetys with a unit called BTA (I think) that was a real motor driven gyro and was designed in the middel east. It was hugh, very expensive and impratical but did do as intended.

These were inexpensive units marketed through hobbico for fixed wing use. even with full gain they are incapable of full control throws and I beleve that is undesirable anyway.


The whole point of any stability augmentation system is speed, not wild control movement in an effort to catch up after the aircraft is already departing wildly and to do this far faster than the human pilot can react and to never need large control throws. That is how perfect appearing takeoff runs are acheved.

I cannot quantify any specific setting or engineering benchmark only you can do that by test with your particular product and application.

Alway start with a low percentage of gain and work up until you feel you are fighting with your rudder imputs. If the gain is too high the result will be a hunting back and forth in yaw at high speeds. No big deal slow down, land and tone it down some.

I have never felt the need to be able to turn the things off in flight as I really don,t know they are there untill I get those four engines throttling up unevenly on takeoff and then you really know its there.

John

pilotpilatuspc12

to see a cool use of gyros, go tohttp://www.youtube.com/watch?v=6Npcr...eature=channel. Also try http://www.youtube.com/watch?v=1_Eh3pMC-1otosee some cool gyro action.

This guy is a crazy to be using gyros like this. He's got like3 gyros on that thing, not including after he uses more to control the movement of the motors when hovering. Unless you're as crazy as this guy, I do not see any reason to put that many gyros on your plane , but hey, different strokes for different folks.

Anyways, just thought I'd throw that in this discussion.

opjose

For yucks I put a pair of heading hold gyros on my Funtana S90.

One for the rudder and another for the elevator.

I hooked these up so I could disable or enable them with another transmitter channel.

With both in place I could fly the plane into a nose up entry into a hover, flip the switch, and the plane would torque roll all by itself until it ran out of fuel.

It impressed people who did not know what was going on, but I quickly lost interest.

Still it was sort of fun for a flight or two.