Trex 700 Tail problems with Gp780

[MaSt0RaS]

Hello guys i just build an LE and i have problems with the tail...

It goes left and right like having a lot of gain..

When i go the gain to 65 it is moving slowly left and right and whne i go to 75-80 its going faster.... and on the mid at 70 its moving again....
I have ds650 and GP780 any ideas?
i have put the stock tape for the gyro...

i have changed tail blades but nohting changed...
79aBCOXJdF0

[Katanadude]

I had a similar problem on my Trex 450Pro with the GP750 when using the stock align gyro foam pad. The Align pad is thin and not very spongy. When I replaced the Align stock gyro pad with a Spartan gyro pad my drift problems went away. Granted there is a big difference between a 450 electric and 700 nitro but if the GP780 is susceptible to vibrations the same way the GP750 is you may want to try the Spartan gyro foam pad setup. If you have not already tried the Spartan pad setup for the 700 it consists of two foam pads with a steel plate sandwiched between.

[MaSt0RaS]

Yeap its hard and thin i will change it with the Spartan tape..!

[ualdrivr]

Hello guys i just build an LE and i have problems with the tail...

It goes left and right like having a lot of gain..

When i go the gain to 65 it is moving slowly left and right and whne i go to 75-80 its going faster.... and on the mid at 70 its moving again....
I have ds650 and GP780 any ideas?
i have put the stock tape for the gyro...

i have changed tail blades but nohting changed...
79aBCOXJdF0

Mastora, kalispera,

I think vibration is the problem. Go with thicker gyro foam pads. Spartan or Futaba with the metal plate in between. How is your mechanical setup? Are you holding strait in Rate Mode?;)

[MaSt0RaS]

i didnt try ratemode....! i will try the pad and i will post again...!

thx!!

[ualdrivr]

This is how I have my Spartan mounted. Spartan recommends in high vibration environments to use two thick foam pads with the metal plate in the middle.

http://www.helifreak.com/showthread.php?t=181234&page=7

Cheers,

Panos

[MaSt0RaS]

Yeap i know for the spartan i have 3 spartans.. :):)

[Katanadude]

OK Mastoras, What's the verdict? Did the Spartan pads solve your tail ptoblem?

[lukeduff]

We just built three new 700 le helis at my club and everyone has this tail issue with the 780. I agree that it could be from vibration so I am going to try and limit that out. I like the 780 gyro somewhat but am not as impressed with it as my 611 on my other 700. I have trimmed mine out in rate mode mechanicaly and have two foam pads. I will try the metal plate in between next. The gyro doesnt bother me as much as my 610 servos. I have had two diffrent ones go out in fast forward flight and resulted in exteme crashes. I have always supported the 610 and have flown them for a year on my other choppers with no problem. Why the issue now? Man it gets costlt though. Its like the motor in them just quits

[DenisFerrari]

Hello guys i just build an LE and i have problems with the tail...

It goes left and right like having a lot of gain..

When i go the gain to 65 it is moving slowly left and right and whne i go to 75-80 its going faster.... and on the mid at 70 its moving again....
I have ds650 and GP780 any ideas?
i have put the stock tape for the gyro...

i have changed tail blades but nohting changed...
79aBCOXJdF0

Hi, that's EXACTLY what it happens to my 700! Only difference is that I've a GP750 gyro.
Actually I've 1 align pad + 1 metal pad + 1 align pad and cbles tied with a plastic strip after around 1 inch from the gyro.
Maybe it's better changing to thicker pads ? Or even 2 pads + metal plate + 1 pad ?
Cheers
Denis

[Katanadude]

Hi, that's EXACTLY what it happens to my 700! Only difference is that I've a GP750 gyro.
Actually I've 1 align pad + 1 metal pad + 1 align pad and cbles tied with a plastic strip after around 1 inch from the gyro.
Maybe it's better changing to thicker pads ? Or even 2 pads + metal plate + 1 pad ?
Cheers
Denis

Yes, use the Spartan 2-pad + plate setup. I bet it will make a difference. The Align pads are just too thin and rigid.

[fatnfunky]

Have just sent my 780 back after tail problems with a brand new 250 SE. Have now fitte a new 750 and all ok.
Maybe there is an issue with the 780??
Rob

[helistef]

I've had the exact same problems with my GP780. First tried the align bleu silicone gyro pads, but that made no difference at all.
Today I've tried the spartan set-up: foam/metal plate/foam and the tail is perfect now.

Grtz

[MaSt0RaS]

Guys the gyro has problem... i put a spartan and now its all ok...

The 780 is a piece of SHIT....>!

[lukeduff]

I would have to agree. But once you just get to flying u dont really notice it. On my 700le it holds in tailslides ,hurricanes, very fast backwards flight. Yeah the tail does as everyone describes when u hover. But in all reality it is a good 3d gyro. Its handlse any 3d manuever u throw at it. Im guess it is just realy sensitive to vibration. I replaced my clutch bell and clutch to see if I could get some vibration out but its still too mutch. I think when it comes down to it the gro will work fine for 3d style flying, If u r just hovering and practicing basic things the 611 and sparton sound better I guess. I also have this issue on my 700 3g heli.

[MaSt0RaS]

I would have to agree. But once you just get to flying u dont really notice it. On my 700le it holds in tailslides ,hurricanes, very fast backwards flight. Yeah the tail does as everyone describes when u hover. But in all reality it is a good 3d gyro. Its handlse any 3d manuever u throw at it. Im guess it is just realy sensitive to vibration. I replaced my clutch bell and clutch to see if I could get some vibration out but its still too mutch. I think when it comes down to it the gro will work fine for 3d style flying, If u r just hovering and practicing basic things the 611 and sparton sound better I guess. I also have this issue on my 700 3g heli.


Yeap but i cannot have it on... !!!

[DenisFerrari]

Hi all, just to share how I solved my Trex700 tail oscillations while hovering and flying :

After have tried many things, I could almost eliminate my oscillations, now my tail oscillations are
around 1/10th of the original, so almost not visible and probably GP750 - that's an incredible sensible
gyro - now only resents of the slightly rich engine setup I like to have, but I think this is no
problem.

Here's a brief list of what I've done to solve my case :

1) Rotated 180° my GP750 gyro installation ;
2) In the beginning I put a plastic strip after less than 1 inch of cables from the gyro to secure
them ; now I've tied the cables only after 2 to 3 inches from the gyro
3) In the beginning I already had 1 Align pad + 1 metal pad + 1 Align pad ; now, I have 2 Futaba gyro
pads + 1 metal pad + 1 Futaba pad and it's much more soft, but I think not too much.
4) Installed a Quick.Uk metal tail upgrade : that's fantastic! If you just take the tail slider with
your fingers you DO NOT feel any play, nothing! Align plastic tail (my one at least) really has a lot
of play in term of "command-play". I understand the axial play that is for thrust bearing and so on,
and of course Quick-Uk has some too.

As already told, now my slight tail oscillations are almost not visible anymore, or at least 10 times
less than before (that were around 10-15mm in amplitude).

Also, it's much better to look the hely hovering and flying slowly.

Hope this could help someone else...

Best regards
Denis

[ShankBones]

I had a similar issue and was driving me crazy. I changed from gy611 to gp750, also adding more foam tape and I still had the same wag.

Turned out to be a bad rear bearing on my 91h engine, so I replaced both bearings and problem went away.

[jondabear]

Anyone notice that the wag coincides with the way the engine sounded? Mine used to do that untill I got my engne purring like a kitten and into its correct power band.

Just an observation.:cheers

[ShankBones]

Anyone notice that the wag coincides with the way the engine sounded? Mine used to do that untill I got my engne purring like a kitten and into its correct power band.

Just an observation.:cheers

jondabear, yes that is a very good observation. I too pay close attention to the engine pitch sounds when I see the wag dance. I do hear it on the youtube video posted here, but was reluctant to comment on it.

I have found as in my prior post, that most of the tail wag issues I've experienced on nitro could be more than likely engine related due to break-in, fuel mixture, bad engine bearings, glow plug, sticky oneway bearings etc.. list goes on with many other things of course.

[rymps]

Mine did that on my 3G. I lowered th again and all that junk. Finally i went to the stock set up i started with and changed the tail blades to CYs. It is perfect now

[Kelvin80]

Hi. had the same problem. but i moved the link on the servo horn 1 hole closer to the midle and have 2pads 1 metal plade and 1 pad under my gyro. have 3cm slop on the wires and have no problems now

[Kelvin80]

Hi. had the same problem.
my solution:
2xpads + 1 metal plate + 1 pad under my gyro.
then have 5cm slop on the wires.
and i moved the link on the servo horn 1 hole closer to the midle and my tail is rock solid :-)
had almost same problem on my 250. and just moved the link closer to the center of the horn and never had any problems.

[justin keaton]

mastoras, gain at 65 on my 600 will do that bad, i run my gain at like 35 on gp780, go as low as you have to go to get it to stop, as long as it holds its ok, no matter if the gain ends up at 25 if it holds fly it, try it might work.

[MaSt0RaS]

After i sold it i tryied to install a 780 to a friends 500..

I had the same problems...

I found how to solve this problem..
First of all i change the pad with the spartan PAd...
And secondly i go the Ball as close as 7.5-8.8mm from the center of the servo..
THats the most important thing tha i havent done on the 700...!

Now its rock solid without any vibes or whatever..!