Trex 450 Uncontrollable Pirouette Problem - RC Groups
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Aug 10, 2017, 05:55 PM
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semtevruchte's Avatar
Help!

Trex 450 Uncontrollable Pirouette Problem


So I bought a cheap clone of the Trex 450 SE V2,

Now I have everything setup correctly and already flew it without any major problems. But after some tweaking with both mechanical and electrical suddenly when I spool it up and give it pitch I already have to give it counter rudder and after I pitch it up even more it gets in an uncontrollable pirouette.

XFX Trex 450
Turnigy i10
TGZ380

So what did I do wrong?
Any help would be appreciated.

Gr. Sem
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Aug 11, 2017, 07:32 AM
Registered User
Quote:
Originally Posted by semtevruchte
So I bought a cheap clone of the Trex 450 SE V2,

Now I have everything setup correctly and already flew it without any major problems. But after some tweaking with both mechanical and electrical suddenly when I spool it up and give it pitch I already have to give it counter rudder and after I pitch it up even more it gets in an uncontrollable pirouette.

XFX Trex 450
Turnigy i10
TGZ380

So what did I do wrong?
Any help would be appreciated.

Gr. Sem
what have you changed since it was flyingfine.

uncontrollable spin is either the gyro correcting in the wrong direction or the servos reversed.

mechanically the only thing to cause an uncontrolled spin is the tail pushrod coming off or some other tail component being loose allowing the tail to be free
Aug 11, 2017, 08:07 AM
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semtevruchte's Avatar
Quote:
Originally Posted by bazsound
what have you changed since it was flyingfine.

uncontrollable spin is either the gyro correcting in the wrong direction or the servos reversed.

mechanically the only thing to cause an uncontrolled spin is the tail pushrod coming off or some other tail component being loose allowing the tail to be free
So i changed what looks to me nothing, gyro seems to compensate in the right direction I might want to go and check if reversing works.

Edit: Checked the reversing and that's not the problem, if I reverse it it becomes worse.
Last edited by semtevruchte; Aug 11, 2017 at 08:21 AM.
Aug 11, 2017, 08:21 AM
rc user
make sure your rudder trim on your Tx is zero'd or better yet disabled.
Aug 11, 2017, 08:25 AM
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semtevruchte's Avatar
Quote:
Originally Posted by pdooley
make sure your rudder trim on your Tx is zero'd or better yet disabled.
Is already on zero, only thing is I lowered the rate a bit with some expo.
Aug 11, 2017, 09:22 AM
rc user
how much tail blade pitch do you have each direction? you can fold the blades to check.
and go through the basics:
excellent video, don't mind the voice.

Tail Rotor Basics Part 1 (4 min 1 sec)
Aug 11, 2017, 06:44 PM
Registered User
which way is it spinning?
Aug 15, 2017, 07:33 AM
Registered User
semtevruchte's Avatar
Quote:
Originally Posted by bazsound
which way is it spinning?
If you look at it from the right side, clockwise.
So should be okay

Edit: Counter-clockwise of course
Last edited by semtevruchte; Aug 15, 2017 at 07:47 AM.
Aug 15, 2017, 07:46 AM
Registered User
semtevruchte's Avatar
Here are some videos,

Mechanical setup:

XFX Trex 450 V2 Mechanical Setup tail error (0 min 30 sec)


Flight 1:

Flight XFX Trex 450 V2 tail error (0 min 13 sec)



Flight 2:

XFX Trex 450 V2 tail error 2 (0 min 18 sec)



I hope this is enough.
Aug 15, 2017, 09:36 AM
rc user
your gyro is correcting the right direction, looks like you just don't have enough tail authority.
you seem to have enough pitch each direction.
did you try adjusting the gain?

if that doesn't help, it has to be a mechanical setup problem.
Aug 15, 2017, 10:15 AM
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semtevruchte's Avatar
Quote:
Originally Posted by pdooley
your gyro is correcting the right direction, looks like you just don't have enough tail authority.
you seem to have enough pitch each direction.
did you try adjusting the gain?

if that doesn't help, it has to be a mechanical setup problem.
I already bumped the gain up until the tail began to hunt, so that should be okay, so i think it has to be a mechanical problem.
Aug 15, 2017, 11:58 AM
Registered User

if you haven't already...


1 Disconnect the tail pushod.
2 Zero trims and sub trims on Tx.
3 Initialize Tx then power up heli
4 Get rudder servo lever to be at 90 degrees first by repositioning the lever then using subtrim to get exact.
5 Unplug heli and tx
6 Fiddle with tail until you have about 5 degrees right yaw with pushrod connected at 90 degrees
7 Test hover
8 Correct linkage length (or slide servo) to hover --with no trims and servo lever at 90 degrees--maybe no-hands

This will put your servo into its 'sweet spot' for quickest ccorrection either directiion.

This is just my protocol for rudder setup. -- Ignore if I am redundant or ...
Aug 15, 2017, 12:22 PM
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semtevruchte's Avatar
Quote:
Originally Posted by daveapplemotors
1 Disconnect the tail pushod.
2 Zero trims and sub trims on Tx.
3 Initialize Tx then power up heli
4 Get rudder servo lever to be at 90 degrees first by repositioning the lever then using subtrim to get exact.
5 Unplug heli and tx
6 Fiddle with tail until you have about 5 degrees right yaw with pushrod connected at 90 degrees
7 Test hover
8 Correct linkage length (or slide servo) to hover --with no trims and servo lever at 90 degrees--maybe no-hands

This will put your servo into its 'sweet spot' for quickest ccorrection either directiion.

This is just my protocol for rudder setup. -- Ignore if I am redundant or ...
Would this help?
Because even when I give it full right stick, it won't stop and it's limited by the pitch slider so I don't think it would help. What do you think?
Aug 15, 2017, 01:04 PM
rc user
but your tail blades look like they have enough travel when you did the static test.
you might want to try some swaptronics next.
Aug 15, 2017, 01:24 PM
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semtevruchte's Avatar
Quote:
Originally Posted by pdooley
but your tail blades look like they have enough travel when you did the static test.
I know that's the weird thing here, I don't get it why I can't give it enough pitch to stop the pirouette. It just seems like the blades dont give enough pitch, but I can't change this due to the pitch slider.


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