T-rex 450XL CCPM

[harrier]

Hi guys,
I have this problem with my heli. When i throttle up, the tail hunts from left to right or right to left non stop even though i tried fighting with it.
Also tried to swap direction on gyro, still useless. Then tried swap direction on transmitter (cannot remember 5 or 6), also cannot.
Been circling around, playing with both my gyro and transmitter to find out the reason BUT to no avail.
Try seeking help from alot of people but also cannot. Hopefully expertise from the forum can do wonders. Thanks

[swatson144]

Hunting from side to side is usually indicative of too much gain, and not a reversal problem.

You didn't mention which gyro and radio.

On Futaba the rudder is on 4 and remote gain is on 5. It can be different with other makes of TX.

Steve

[harrier]

i am currently using futaba 9c as TX. for RX i am using telebee. and align servo plus 1 fast servo for tail

about the gains, yup, i tried that too, i start from high reducing about 3-4 at a time till the servo cant move much.

thanks

[swatson144]

On the telebee, it takes seemingly forever to boot. I've seen many a person try to use them without waiting for the tail servo to twitch indicating it is booted. About 15-20 secs.

Are you using chan 5 for the gain? or the onboard pot? I've seen a couple cases where the remote wire was plugged in and the guy was trying to adjust gain with the pot. The sig on the wire over rides the pot!

A fast simple sort it out is to unplug the remote, and set the pot to about 70% and see if the wag is still there. If the wag is gone then you need to sort out <gyro gain> in the TX. If it is still there it's either a bad gyro or a bad setup. Not having about 5mm V on the tail rotors can cause it to surge which isn't so much of a wag Wag is from side to side past center each direction ---) while a surge is not really past the center___) though it may over shoot a little it'll be mostly on one side.

My regular mechanical center looks about like this, Though it'll need a bit more or less depending on the HS. The pic shows a little extra for clarity about 5mm is a good place to start on the slider position IMO.

Steve

[harrier]

hi, yes i did wait even up to 1 minutes. i used ch 5 for gains. Also try remove gyro, i means OFF gyro, coz for my raptor 50, i started w/out gyro and gradually adjust till my raptor's tail dont wag anymore.
For my trex, i try the same application, but with or w/out the gyro, it still hunts. Did try to adjust so many times on both the TX and gyro to get the correct +/- gains, but to no avail. Maybe you are right about the gyro, is DEFECTIVE. Thats the only conclusions, thanks

[cooperd]

I have a Trex with a Futaba 401 Gyro and the tail is rock solid. I don't want to rain on your parade, but from reading many posts on several forums over the past few months, there is not much favorable to post about telebee gyros, or any other gyros for that matter except the Futaba 401 and as second best the Align. The 401 actually will hold heading, as opposed to just providing a bit of stablization. And it works very well. It isn't cheap, but that goes with this hobby.

[swatson144]

The align and the telebee are the same, it is sold under several brands.

Most comercial gyros work pretty well. The Futabas are better than the others at twice the price. I've had pretty good results with the few gyros I've used Telebee, PG-03, PG-02, HLG-200, MS-44. Of the 7 flying helis I have 3 are with GY-401, 1 with a GY-240. The MS-44, and the 2 PGs are still in use on micros. So I guess you could say I find the GYs worth the money in the long run.

Steve

[Sleepstalker]

I am aware that the current Align and Horizon gyros are rebadged Telebee products however I believe that the product was improved over the original Telebee offerings . Are you using a FAST digital servo for your rudder? and you are sure that servo to tail rotor pitch is friction free? Are you using carbon rod or steel rod in a plastic casing? You may well be right but if you have a flying buddy with a telebee/rebrand gyro swap with him and see what happens...Buy him a brewsky or 2 later...Sleepster.

[harrier]

thanks sleepstalker for your idea about swapping, but too bad none of my fren is using telebee. I am using a fast servo for my rudder. i can confirm there is no friction coz i tried moving it with my hand, steel rod in plastic casing very smmoooth is the words i guess

Maybe will write to telebee and tell them their product is abit.............. hahahahaha
i guess better use GY240

[casper7]

I had the very same problem, but I looked on the x400 site and they say you should not mount the telebee with the label face up or face down (this is what it says in the instructions) they say mount it with the label facing the front, back, left or right. I did this and the problem went away

Heres the link http://www.x400tuning.com/aligngyro.htm

[eddiemoth]

Wow, this is a very interesting discovery!

[swatson144]

That never occured to me. It is a known issue with the instructions.

If you mounted label up it would only act on roll or pitch depending on which way it was oriented and wouldn't act on yaw at all so the tail wouldn't hunt it'd just spin as if there was no gyro, though it'd likely stay level on one plane :wink: .

Steve

[Sleepstalker]

I bought mine as an Align gyro and it is very clear in the instructions that it must be mounted ( face and adjustment OUT)

[harrier]

yup, i agree with you guys about the telebee gyro instructions, not facing up. any direction is ok. but still same, my tail still run on 1 side when i counter. wanted to change the gyro to try but no one is willing to remove their gyro for me. hhmm..., anyone here willing to lent me their gyro (just kidding)
i am giving up on the t-rex, anyone wanna buy, hehehehe