linclogs

I'm starting a new thread on this because I had asked some questions regarding this subject at the end of another gyro thread and didn't get much response. I think that thread was probably a little too old by the time I had joined in.

I want to try using a gyro ONLY on the rudder of a squirrelly tail dragger (airplane), and ONLY for take off. The radio I want to use is an older 7-channel non-computer FM radio (built by Futaba) and uses Futaba "J" plugs. I'd like to be able to turn the gyro on and off from the transmitter (or at least control the rate "from zero up" from the transmitter). I'm thinking I could use one of the proportional channel levers on the front of the transmitter, like one used for flaps (channel 6?), to control the rate.

From what I've read, the Futaba GYA 350 seems to fill the bill for what I want to do. If I understand what I've been reading, by adjusting the rate to zero (from the transmitter), then I'd have normal rudder control. Also, this transmitter has a built-in mixer, so I'd like to be able to use the gyro for takeoff, then switch it off (by adjusting the rate to "zero" from the transmitter) and switch on "mixing" for coordinated rudder and ailerons (I know, I know - I'm lazy!!!). Do you see any problems with this?

Does anyone have experience with Futaba's GYA 350 gyro that could tell me if it would work the way I've described above?

Thanks for your help guys. I'm always impressed with the knowledge and camaraderie here on RCUniverse.

Phil Cole

I don't know too much about "old 7-channel Futabas", but I would want to put the gain control on a switch.

To get zero gain, you have to set the gain control channel to the mid point. One direction from there gives you normal gyro operation at increasing gain. The other direction gives you AVCS mode, which you probably don't want except for playing around with hovering.

You also need to set the gain fairly precisely. Too little and the gyro action won't be enough. Too much and the tail will wag.

www.heli-world.com have simpler gain switched gyros. There are two pots on the gyro for the two gain settings. Adjust one pot to zero gain, and the other to the gain you want for takeoffs. The gain channel just selects which gain setting is in use.

linclogs

Thanks for responding, Phil.

I think I may not be understanding about adjusting the gain from the transmitter (or maybe I'm making this more complicated than it really is!).

I thought you needed to use a proportional control such as a rotary knob or lever type (like you would use for proportional flaps). I was thinking you contolled the gain with this knob or lever from "zero" (for no gyro effect on the rudder), and then adjusted the gain by rotating the rotary knob (or moving the lever) on the transmitter to increase the gain proportionally.

But if I understand what you're saying, the gyro does not work this way. I would use just an on/off switch (like the non-proportional "channel 5" retract switch) which only turns the gain on or off, but does not adjust the gain. Am I understanding correctly? Also, do I understand you're saying that by controlling the gyro from the transmitter with an on/off switch that I'd be either turning the gyro "on" with the switch set at one position, but by setting the switch to the opposite position, it would turn on "AVCS" and not just turn the gyro off? Maybe that's not what I want. Or is there an AVSC gain control on the gyro (I see 2 separate "trimmers") that would be set to "zero" so it would not have any function even though AVCS was switched on? But then, if I understand, I still would not be adjusting the gain for the rudder from the transmitter, but only turning it on or off? If this is the case, then I'd have to set the gain only on the ground and experiment with it in flight?

I'm not sure what "AVCS Mode" is - I downloaded Futaba's manual for the GYA 350 and they refer to "AVCS" many times, but I don't see anyplace they say what that actually stands for.

I'm not interested in hovering - only controlling the rudder on take-off. So I don't need (or want) any setting other than controlling the rudder. And I'd just like to be able to turn that function on and off, while being able to control the amount of gain (just for the rudder) from the transmitter.

It sounds like what I'm asking for may be something a lot less complicated than what a gyro can actually do. Maybe what I want is too simple a function? Or is there another gyro that will perform the way I described that will work with Futaba "J" equipment? I looked at some of the other gyros on link you provided but since I'm not clear on exactly how the different functions of a gyro work, it didn't help much. I was hoping someone could read my description about what I wanted to do and point me to the exact gyro I need. I know a lot of the different ones appear to be for helicopter use only.

Again, thank you for responding. I appreciate any light anyone can shed on this for me.

jfangohr

"I thought you needed to use a proportional control such as a rotary knob or lever type (like you would use for proportional flaps). I was thinking you contolled the gain with this knob or lever from "zero" (for no gyro effect on the rudder), and then adjusted the gain by rotating the rotary knob (or moving the lever) on the transmitter to increase the gain proportionally."

Linclogs,

This is exactly the way it works. When the rotaty knob is centered, the gyro is off. As you rotate it one way (40% travel or more) the gyro turns on.........either normal or avcs depending on which way you turn the knob. The further you turn the knob the more gain you get (up to the max that the gyro is set to). If your radio has adjustable ATV you can keep it out of one of the modes.

Normal mode just dampens rudder movement, in other words, if a strong cross wind hits the tail during takeoff the gyro will fight it but it may require a little help from you. In AVCS mode, it will return the aircraft to its original heading if deviated. In AVCS mode if the tail moves during takeoff, the rudder will move and STAY there until it returns to its original heading. In normal mode it will move the rudder momentarily then return it to center.

If you use AVCS (otherwise known as Heading hold or tail lock) be sure to turn it off as soon as the wheels break ground or it won't let you turn.

linclogs

Thanks for the reply.

The radio I want to use this with does not have a rotary knob. I was wondering if instead I could use one of the proportional levers on the front of the transmitter (like one you'd use for flaps)?

From the description you gave (if I understand correctly) I think what I'm looking for is a gyro that does not have an "AVCS"mode. What I'd like is a gyro that only operates in the "normal" mode but that can be turned on and off from the transmitter. Keep in mind the radio I want to use this with is an older, FM, non-computer radio (built by Futaba).

I had considered the Hobbico gyros but apparantly you can't switch them on and off in flight. The reason I want to be able to switch the gyro on and off is because (as I understand) when a gyro is on, it continually works the servo it's hooked to. It's recommeded that a larger flight pack be used because of all the extra servo movement. But if the gyro was only used for a few seconds for take-off, then switched off, that wouldn't be a concern.

Another issue is that the radio I want to use this with also has built in servo mixing - I can mix rudder with ailerons and turn "mixing" on and off from the transmitter. Obviously, I wouldn't want the gyro to control the rudder during mixing (I believe that wouldn't work at all). So what I need is to be able to take off with the mixing disabled, but have the rudder controlled by the gyro for take off, then switch the gyro off and flip on the mixer, if wanted. By the way, I could use the channel 5 switch (usually referred to as the "retract switch") for simple "on/off" function, if I can determine which gyro (if it exists) will work the way I want.

Do you know of a gyro that works in this manner ("normal" mode ONLY but can be switched on and off from the transmitter)?

Thanks again for your response. I appreciate all the help anyone can give.

Jon (linclogs)