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Old 01-13-2010, 08:16 PM   #1
BillK
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Default Flying without a gyro ?

Just a curiosity type question for you guys that have been at this for a looong time. Did the very first RC Helis have gyros ? How difficult would it really be to fly one without the gyro to help ? I suppose I could bypass the gyro on my Blade 400 and find out

Also, am I correct in the understanding that in HH mode, the gyro should try to keep the heading exactly where you point it and in the rate mode, it simply limits the rate of turn when you hit the rudder stick ? I am still at the early stages of learning and it almost seems like it would be better to learn to keep the tail where you want it by yourself rather than the gyro doing it for you ?
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Old 01-13-2010, 08:40 PM   #2
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I have read that it is imposible for anyone to fly an RC heli with no gyro. Yes heading hold moves the rudder to keep in one direction, fighting wind. Rate compinsation your heli may slowly spin in circles in either direction.
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Old 01-13-2010, 08:42 PM   #3
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Quote:
Originally Posted by BillK View Post
it almost seems like it would be better to learn to keep the tail where you want it by yourself rather than the gyro doing it for you ?
No it wouldn't, I promise.

The way around not having a gyro in the old days was mechanical linkage that applied more pith to the tail rotor when throttle/collective was applied. It was still a handful though, any sudden changes in torque caused the tail to move in either direction. They did manage to fly, as some of those who actually experienced it can tell you.
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Old 01-13-2010, 08:48 PM   #4
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Heading hold keeps the helicopter pointed in one direction regardless of main rotor torque and external influence (side wind) until input is given.

Rate mode keeps the helicopter pointed in one direction regardless of torque changes from the main rotor, but external influence (side wind, forward flight) will change the direction.
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Old 01-13-2010, 09:00 PM   #5
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It would probably be too much to handle. I'm sure it can be done by someone, but that is a lot of yaw control for one pilot to try to manage. Not to mention just flying. The gyro is there to help fight heavy winds and changes in headspeed which on an RC heli, can be very fast, not to mention that heli's have little yaw damping. Old gyros, before solid state, where mechanical. They had a spinning mass which would adhere to conversation of momentum laws. Can't say before that. Everything now is solid state and controlled with a microcontroller and uses a simple feedback control loop. Good gyros use a control algorithm called PID. That is for another discussion.

I think you got the basics, but let me try to clear some things up.

In general, when you provide command input to the transmitter stick, the gyro essentially passes the command to the tail servo to move the heli in yaw. As soon as you center the stick and are no longer providing command inputs, the gyro basically is caged in a feedback closed control loop. The control loop command at this point is the current direction you are heading. Lets call it position or degree 0. Once the tail moves, the gyro measures the speed and integrates to get position that the tail moved and since there is now some position error, say 2 degrees, it will increase the tail rotor pitch(by servo) to provide counter thrust to not only to stop the motion, but to bring it back to the original position of 0 degrees. The gyro really doent's know which radial direction(N,E,S,W and inbetween) the heli is pointing, but it does know how far it has moved since you centered the stick!

Rate mode is similar, but will only arrest the moition of the tail and will not bring it back to the original position in which you centered the stick. So you could find that your tail motion has stopped, but your heading ends up being that two degrees. Rate mode is just that. It trys to null the rate(speed) of the tail, vs the heading(position) hold. This mode is like how an aircraft flys...Like a weathervane. Good for when you are just flying around and what to keep pointed into the wind!
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Old 01-13-2010, 09:35 PM   #6
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YES, I've been flying for nearly 26 years and back when I started with the GMP Compeitor there were NO gyros, nor heli radios. You can imagine how difficult it would be; upon increasing the collective/throttle which were connected to the same channel via "Y" connector, the heli would spin left so you had to constantly apply right rud, upon lift off and of course, it would swing around when you throttled back. No HH, throttle/pitch curves, wooden blades, ..... No 3D either.
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Old 01-13-2010, 10:08 PM   #7
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Many years back, a friend of mine had a GMP Cricket, fixed pitch, no gyro, simple four channel radio. We had a lot of "Run for your life!" incidents while 'attempting' to fly.
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Old 01-13-2010, 10:14 PM   #8
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I wouldnt go as far as to say that it is impossible. I know their are many people that has flown (hovered) helis without any help from gyros. The helis that was designed in the late 70's and early 80's didnt have the tail athority that heli's do today. There was no way my Shuttle could piro 720 deg a sec. I dont think it would even do 360 a sec. I couldnt do back in the day, I dont think i would even try it on purpose today. However I helped a friend with a Eflite Blade 400. He said it would keep yawing to the left no matter what he did. So I flew the heli, The only thing i did to preflight the aircraft was make sure the controls were moving in the right direction. So I lifted off. Yep turns to the left. Did a couple of pitch pumps, The tail was all over the place. Did a couple of piro test in both directions. It seemed to work. When I landed. I tested the gyro to see if was working properly. You know what? That gyro gain was not set. So there was no gyro action going on there. I set the gain for him and got it locked in. I realized later that day, that i actually hovered a heli without any gyro help.
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Old 01-13-2010, 10:14 PM   #9
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i saw a video about a guy that flew rc heli's without gyro's or tail blades, it just had a big weather vane type tail, i think they might have been the first rc heli's out there but i could be wrong....you could only hover if there was a steady wind, and was pretty much restricted to forward flight...
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Old 01-13-2010, 10:37 PM   #10
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Quote:
Originally Posted by sethf8403 View Post
i saw a video about a guy that flew rc heli's without gyro's or tail blades, it just had a big weather vane type tail, i think they might have been the first rc heli's out there but i could be wrong....you could only hover if there was a steady wind, and was pretty much restricted to forward flight...
Wouldnt that be more of a gyrocopter/plane? It doesnt have a gyro? Or it is a gyro? Im confused.
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Old 01-13-2010, 11:25 PM   #11
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Back in those days, some with FP, had tail shaft directly connected to main gearbox so if you increase throttle, tail rotor speed would increase too and somewhat compensate!

Some had effective tail fins, and I think you can fly figure 8s with them without ever touching the rudder!!
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Old 01-14-2010, 02:12 AM   #12
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In 1983 I had a revolution 40 which had no collective and no gyro. It was painful to learn to hover with that baby but I did get it hovering and even some forward flight. I moved on to a full collective GMP Cobra after that and it was so much nicer to fly. It had a Kraft rate gyro that actually had a spinning chunk of steel in it. Ring gyro's were a distant future possibility found only in popular mechanics.
There are always those who believe that its impossible to do things without the newest whiz-bang dinguses (dingi?) but it is possible and even probable. My dad learned to drive in a car that had no clutch, had an advance lever, throttle on the column and no brakes. I learned in a car that had a stick shift with no synchromesh, my sisters kids learned in cars with auto transmissions and gps. I even learned to fly in an airplane with an armstrong starter and a tailwheel in back where it belongs.....

If you don't believe its possible to fly with no gyro than unplug and give it a go. The tail will be twitchy but I'm sure its possible to do. In forward flight the tail rotor and fin keep the tail where it belongs so no biggie there.

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Old 01-14-2010, 03:31 AM   #13
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I may be mistaken here, but real heli's don't have gyro's....right? My understanding is that you have to control it with rudder inputs to counter act torque, wind etc...
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Old 01-14-2010, 05:17 AM   #14
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I learnt in the 80's without a gyro and it was a royal pain! We used one method which involved a length of string tied to the tail. You put a bit of forward trim in and get a mad helper to hold the other end. This would keep the tail straight as you learnt the effects of throttle and lateral cyclic. You would improve by letting the string go slack whilst trying to keep the tail straight. Heli radios introduced rev mixing which we still have and acceleration mixing which would 'kick' some tail input depending how quick you moved the throttle. Those were the days, and thankfully they are long gone!! I love my Spartan!!
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Old 01-14-2010, 05:43 AM   #15
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Quote:
Originally Posted by sethf8403 View Post
i saw a video about a guy that flew rc heli's without gyro's or tail blades, it just had a big weather vane type tail, i think they might have been the first rc heli's out there but i could be wrong....you could only hover if there was a steady wind, and was pretty much restricted to forward flight...
Here you go.
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Old 01-14-2010, 06:29 AM   #16
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Quote:
Originally Posted by Flying Fingers View Post
I may be mistaken here, but real heli's don't have gyro's....right? My understanding is that you have to control it with rudder inputs to counter act torque, wind etc...

not sure about more advanced machine but i've flown an R22 which deffinitely did not have a gyro or any kind of computer stabilising. I think they can get away with it because their performance envelope is so limited, if you applied heavy collective it would start to drift round slowly and require a slight touch on the pedals to hold it straight again.
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Old 01-14-2010, 07:00 AM   #17
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i have flown my raptor 30 without gyro straight from reciever to tail pitch servo and no mixing on the tail it swings around a lot and you have to be very gentle on the collective.

i wouldnt call myself an experinced pilot but i can fly without a gyro i tried it because i thought my csm sl 560 was rubbish and i wonderd how much it was actually doing. i wouldnt recomend trying to fly without a gyro to anyone who is not an expert you could lose your heli in the process. even if you think your gyro is rubbish it wont be as bad as flying without one. i now have a futaba gy520 and i think it is excellent.
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Old 01-14-2010, 09:40 AM   #18
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thats like doing your taxes without a calculator...
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Old 01-14-2010, 10:25 AM   #19
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For the first 4 or 5 days flying my heli I did not know that I never set the radio up correctly and it was never in heading hold. Of course I was only hovering, but I was still able to do it. But now that HH is active it makes things a little easier.
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Old 01-14-2010, 12:25 PM   #20
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I saw a video on youtube from Nightflyerr where he was flying ccpm heli and his gyro failed. He made some adjustments in his radio on the rudder channel an flew without the gyro . I found it very impressive.

He said: "who needs a stinkin' Tailrotor in fast forward flight " watch the video from 5min50 for gyro failure



So you see it is possible!!!
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