Issues with my 770 gyro...

[fiveoboy01]

Well I did some work on it today, I wanted to get rid of the drift.

I adjusted the linkage in rate mode for no drift, I couldn't get it perfect. At one point the heli would drift one way in rate, and if I flipped the switch for HH, it drifted the OTHER way

I seemed to get it worked out ok, there is a very small drift in HH but it's livable. I figure I'm making pretty much constant corrections to the tail anyhow, so no biggie.

But something else I'm having an issue with, is that the tail is twitching.

This isn't a wag, it's a twitch... Sort of random, almost like a glitch.

I know it's not the gain because I turned it up until I got a wag, then kept turning it down... The wag went away but I still had the twitching and no further reduction in gain made any difference. I settled on 21% gain(gear channel endpoint method).

A couple ideas I have - maybe it's vibration causing it, I thought about trying zeal tape(using 3M heavy duty double sided tape now), and trying a different set of tailblades other than the stock Align ones.

I am also wondering if my Arizona regulator might be acting up, since the gyro plugs into it.. It is a used gyro and I think I recall my Raptor doing this too.

Any ideas anyone has, I'm all ears. This is getting annoying.

[WayneBrown]

too rich, too lean, something binding, missing tooth on gear, or tooth on belt can all contribute to the twitch.

[fiveoboy01]

Well I know that there are no missing teeth

Nothing is binding as well.

I switched to zeal and am going to try it tonight. If that doesn't work, perhaps I need someone to tune my engine who knows what they're doing.

What am I wanting for backplate temp after a good long hover? I can put my finger on it for about 5-8 seconds before it becomes too hot to touch. I'm a tad less than 1-1/2 turns out from closed.

[Dré]

Fiveoboy01,


I not what is wrong with it, but I give you mine settings.

Travel is set at 150%L 150%R
Gyro is set at pos0 66% pos1 64%
Servo horn: center of servo to link is 11.50 mm


Hope this helps.


Greets


Dré

[TRAMTRAN]

I had the same problem when I mounted my in the front with the plastic gyro tray. then I putted in the tail box. It's work perfect. Here is my setting.

Rudd L150% R150% ATV
Gain +23% - 23% (using Gear switch)
Servo horn 11mm (Stock round)
D/R 75% (using this to control your tail rotation instead of Rudd)
EXP 30%
Head speed 2100

[LJS]

Hi Five,

I noticed that I had a bit of a twitch in my 611 this weekend. I've never had a twitch before. But the engine wasn't running perfectly because of the cold weather. That's what I'm attributing it to. And you're in Wisconsin...

Keep 'em flying.
LJS

[fiveoboy01]

Well mine is mounted on the tailbox.

These flights are being done in 60-70 degree ambient temperatures.

I found out my needle was amost 2 turns out... Oops.

I ended up at 2 clicks out from 1.5 turns and re-mounted the gyro with zeal tape.

STILL twitching but not as bad now, it seems. I think my next step is going to be either shortening the servo horn or trying some different tailblades like K&Bs.

[WayneBrown]

Your still on the rich side of things, as you break in the engine further the twitch will diminish.
quit spending money to find a cure, except on fuel

[Lota Fun R]

Spray the belt?

[fiveoboy01]

It's a torque tube

I'm going to defer to Wayne's experience and just not mess with it for a while. It doesn't make the heli un-flyable and as long as the tail holds I'll just fly it and see if the problem goes away after a couple more gallons.

[TRAMTRAN]

is your torque tube bent? I had the same problem before, then I changed the torque tube and moved my gyro to the tail box at the same time and the problem gone away. I did two at the same time, so I don't know which one causing it. I did checked my torque tube on the glass and it's fine.

[mccrind]

Are you using FM? Tail servo is the fastest so it shows glitches while regular speed servo's won't even bump.

[WayneBrown]

Originally Posted by mccrind

Are you using FM? Tail servo is the fastest so it shows glitches while regular speed servo's won't even bump.

where do you get your information??
That is a ludicrous statement.

[G MAN]

It the tape your using to mount the gyro,it needs to be softer because the 770 is sensitve to vibration.I use the Jr tape that comes with it and it doesn't twitch.It as to have some cushion.

[fiveoboy01]

Originally Posted by mccrind

Are you using FM? Tail servo is the fastest so it shows glitches while regular speed servo's won't even bump.

That makes no sense.

My cyclic servos are .03 slower than the tail servo, it'd show there too, plus my governor would act up....

Anyways I'm running Spektrum.

Taking it to the field tomorrow to fly around. We'll see how it does

[simmer]

I have and just setup my 770 with 8900 servo. My radio is the x9303. I used the gyro function and set it up, the expo and dual rate settings just like the manual states. There is also a function in the gyro screen for flight mode-0 flight mode-1 and flight mode-2 (all in the same gyro screen) I set these all up to auto except for the thold this I set inhibited. I don't know if these setting relate to the DX7 or not but thought I should let you know.

I used Zeal tape (worked really well I highly recommend it!

Your drift, I had this first tank and fixed it second tank. For the first tank I had to hold the rudder to the right to keep it from drifting to the left. when I finished that tank I set it on the bench and lengthened the rod to add some right to the tail (correcting for the right trim I had to give it for the first tank. the it is important to move the trim back to center and initialize in HH mode to test. Unlike the 401 do not try to set it up in normal, I personally think this is pointless (I never fly in HH anyway) I know that's a blanket statement and while even I would disagree a week ago my gyro is working mint now so stick with me a minute more

trim has to be in center or it will drift. I set the trim steps from 4 to 2 so it is more precise. This will enable you to get it right with out having it go one side tweak the trim then it goes to the other. I happened to go three full turns longer on the tail rod. at this point mine holds with no drift. If your still drifts to the same side, land, adjust the rod and re initialize in HH mode try again. The point of this exercise it to get the mechanical right so the hh does not drift without using trim, You can use trim but only to figure out which way to adjust the control rod, longer or shorter.

so three things.
Zeal tape its the best, it IS better than the tape that comes with it(yes this is a very sensitive gyro)
Set rudder trim step to smaller steps (from 4 to 2)
init in HH mode - test, figure out which way it drifts,- adjust the rod to correct it
RE-init the receiver in HH (might want to turn off the engine)
repeat until the drift is gone.

I started with the gain at 62 like the manual recommended slight wag, turned it down to 45 and ended up at 56 (non hh is about 48)

The auto setting in the gyro menu made a huge difference. I think this is auto trim mode on the x9303
to use this you have to enable the gyro function (if the DX7 has that)

Good luck!