T-Rex 450 Clone Spinning in circles????

[USMC-4-LIFE]

So here is my problem i just built this helicopter from a 450 kit i got off of hobby king Long story short after i built it the thing flew awesome.... After 1 minor hard landing i notices my tail servo making a weird noise. So i replaced it and now when i try to take off the tail just spins in circles and no matter what i do with the left stick on the radio it does not stop or correct it.. but when the blades are not moving all functions are working properly... Someone please help!!!!!!

[cotturj]

Originally Posted by USMC-4-LIFE

So here is my problem i just built this helicopter from a 450 kit i got off of hobby king Long story short after i built it the thing flew awesome.... After 1 minor hard landing i notices my tail servo making a weird noise. So i replaced it and now when i try to take off the tail just spins in circles and no matter what i do with the left stick on the radio it does not stop or correct it.. but when the blades are not moving all functions are working properly... Someone please help!!!!!!

go in your radio and inhibit the gyro once that is done check if your tail servo is centered happened to me one time. give it ago and let us know.

[Skiddz]

If the TR mechs are correct and if the TR blades are moving the proper way with stick input (trailing edges of the blades following stick movement when viewed from behind the heli) *AND* the gyro is correcting in the proper direction (trailing edges of the blades moving away from the boom as you pull the boom toward you) you've possibly got something slipping in the TR drive.

Hold the TR and try to spin the mains. The mains should be very hard to turn. If they turn with less than a moderate force, something in the driveline or at the TR shaft is slipping. If it's a belt drive, check the pulleys aren't slipping on their respective shafts. If it's a torque tube, make sure the drive gears are secure. Check the set screw on the TR hub to make sure it's not slipping on the shaft.

Start with that and let usknow the results and we'll move on from there.

[dwoodworker]

if you had to remove boom and make repair make sure belt is not twisted wrong direction

[USMC-4-LIFE]

So when i put the gyro into inhibit mode on my radio the tail blades went from one side to the other if that makes sense. is seems like when i move my rudder stick left it goes far but when i go right it doesnt have much room to turn idk... I"m very knew at this hobby so i dont know what a lot of these parts are

[USMC-4-LIFE]

the only think i have taken apart is the tail reciever. I have done some research on google and the belt being stripped makes the most sense. but since i built this heli it has literally been in the air maybe 20 minutes

[fatalsync]

Are you sure that the tail blades are spinning counter-clockwise?

[nukesrus]

Set your tail servo and gyro up in rate mode to start off with and ajust the servo arm to be 90 out, then ajust the linkage so your blades are centered and make sure they are correcting in the right direction

Sent from my DROIDX using Tapatalk

[Starcruiser]

check the servo reversing for the rudder. It is possible that the new servo behaves opposite of the old one, I have seen this on the DS520 versus the JR 3500G as an example.

[USMC-4-LIFE]

The tail is spinning correctly... But before i even touch that... when i throttle up even as the heli is skimming the ground the whole bird just does 360 and any correction i make has no affect but when i stop the heli and check the functions they all seem to be working correctly

[SSQATCH]

I had an idiot moment last month and forgot to tighten the tail servo . Each time I would try and correct things nothing seemed to work. It took a couple attempts but once I recentered the tail and tightened the servo, everything was back to normal.

[Wolfpackin]

Have you confirmed the gyro compensation direction is correct as mentioned previously?

[jaimesc8]

well this happened last month to me because I bought my new Copter X 450 and the servo was broken so I replaced it and after a few flights it started spinning counter clockwise as if the servo was not moving the tail blades.
happened the same thing as you when throttle was off the servo worked perfectly.
what you need to do is change the servo arm where you connect the ball link.
That is occurred because its not its arm and it goes loose, when it has do to some force (tail blades spinning) the servo arm goes loose.

What clone is it?

Hope it helped

[surfgeorge1]

Originally Posted by USMC-4-LIFE

The tail is spinning correctly... But before i even touch that... when i throttle up even as the heli is skimming the ground the whole bird just does 360 and any correction i make has no affect but when i stop the heli and check the functions they all seem to be working correctly

Check it again, and again, and again.
Either your tail is spinning the wrong way, or the gyro is inverted. Simple as that.

[Starcruiser]

The issue is setup if there is no mechanical failure.

if there is no other failure then it is as mentioned;

1. gyro response reversed
2. servo response is reversed

for #1 change the gyro response switch
for # 2 change the rudder servo reversing.

If you did not change the gyro settings when you replaced the servo, try reversing the Tx servo response. There is not very much that affects this, the other option is the servo arm is loose and cannot move the tail pitch control.

It does sound like the servo is reversed in the Tx to me, the gyro is just making it worse.

to check the rudder response, power up place the Heli in Throttle hold move the left stick to the right, the tail blades trailing edge will move to the right, if it does not then reverse the Tx setting for the servo in the reversing menu.

Physically move the tail to the right, the trailing edge of the tail blade should move to the right as well. If not then change the gyro response direction switch or setting, check again by moving the tail to the right, if it does move correctly.Do a test spin up on the ground, it should work fine.

[WH7A]

Originally Posted by Skiddz

If the TR mechs are correct and if the TR blades are moving the proper way with stick input (trailing edges of the blades following stick movement when viewed from behind the heli) *AND* the gyro is correcting in the proper direction (trailing edges of the blades moving away from the boom as you pull the boom toward you) ......

My first spinup resulted in the same thing; a rotating heli. In my case it was the rudder servo that needed to be reversed. The above quote got me going in the "right direction" (excuse the pun).

[USMC-4-LIFE]

How do i know if the Gyro is reversed..> As i said i'm very new to this hobby i love it!!!!! Just need to learn a lot more and the Heli is a HK-450Gt i built one plastic and one metal for when i get better.

[Wolfpackin]

Look at the leading edge of the tail blades or the pitch slider when you give right rudder input.

Now yaw/turn the heli with your hand CCW/nose left.

The leading edge of the blades and the slider should move in the same direction as they did when you gave right rudder input.
This is showing that the gyro is compensating correctly, it is trying to counter the left turn/yaw by moving the blades in the same direction as right rudder.

Make sense?

[jfranklyn]

you guys are the best. I really appreciate the help. I had replaced my tail boom and when putting the tail and belt back together, I put the belt on backwards so my tail rotor was spinning clockwise.

[Felix the cat]

Originally Posted by nukesrus

Set your tail servo and gyro up in rate mode to start off with and ajust the servo arm to be 90 out, then ajust the linkage so your blades are centered and make sure they are correcting in the right directionk

+1

Blade alignment

Fold tail blades towards each other, they should be aligned. If not, adjust linkage or if boom mounted, slide servo on boom till they do.

For rudder input:

On rate mode, once blades are aligned with each other, align rotor hub with boom, blades horizontal, fold rear blade 90° up pointing to the sky, put/observe heli tail in, move rudder stick left and right, the blade should do the same. Rudder stick left input moves blade left & vice versa.

For gyro correction:

On heading hold or AVCS mode (same thing) Use same method as rudder input BUT, this time move heli nose to the left and the up blade should move to the right.

Remove main blades, set heli on a lazy susan, old turntable or bar stool for testing without the risk of an imminent crash. FB can use the fb weights and paddles for load, just a bit. If FBL do not run motor excessively without blade load.

Hope this helps some