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Ron’s HeliProz South . Century Helicopter . RC-Direct

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e-Align T-REX 450-500-600 > T-REX 450 Tail Doesn't Hold
 
 
cassat
Veteran
Location: Alberta,Canada

Well, after a little crash when the ground went up and hit the heli,
I replaced all the parts plus upgraded to some metal also.
The gyro took a pretty good bash from the flybar, so I was
certain the gyro was toast. I went out with fresh packs and
could get it to stabilize but the tail would always swing. Had
a stiff breeze and kept the nose into the wind but kept adding
rudder trim. Hmmm...I thought something else is off here. Sure
enough, I forgot to check the belt drive for tension....was
totally loosened off! Pre-flight checks, yep add that one
05-08-2008 04:29 AM
 
 
Swoop
Veteran
Location: Newark, DE USA

Assuming from your gallery this is a 401, you should never be adding rudder trim while its in HH mode. The gyro will see these trims as small rudder inputs and your tail will constantly drift. Are you sure your in HH mode? Red light should be solid.

If after you initialize it in HH mode, with no rudder trim added, it still drifts: its probably a vibration. Did you check your tail shaft? (for straightness) Mainshaft?
05-08-2008 01:04 PM
 
 
cassat
Veteran
Location: Alberta,Canada

No, don't assume anything.
I was in rate mode trying to trim the tail.
Just trying to help anybody else that has the problem.
05-08-2008 01:24 PM
 
 
thelane
Senior Heliman
Location: Edmonton, Alberta Canada

Hey Cassat, funny you should post this. I had EXACTLY the same crash I just finished rebuilding and added an all metal head. My gyro took a good smack from the flybar right across the dials.

Yesterday was the first time I hovered it since and it seems to fly fine, but a little wag, only when I give it some throttle I believe. I have not checked it over yet, but I will check this out.

Thanks for the post.

~Lane

JR Vibe 50, Hawk Pro, T-Rex 450, BCX and DX7
05-08-2008 01:36 PM
 
 
Swoop
Veteran
Location: Newark, DE USA

Got ya, makes perfect sense now.
05-08-2008 01:57 PM
 
 
Drunk Monk
rrProfessor
Location: Preston, UK

Quote 
The gyro will see these trims as small rudder inputs and your tail will constantly drift.
Unless you read the manual and put it in/out HH 3 times to program the gyro with the new neutral position. I do that till I'm sure all is working right before adjusting it in rate mode.


Stephen

I only open my mouth to change feet.....
05-08-2008 02:01 PM
 
 
cassat
Veteran
Location: Alberta,Canada

Oh well, tightened the belt and still goes crazy. Time for new gyro.
Also installed a new blue main gear, but have to adjust gear mesh again since the esc gets a little warm.

Drunk Monk I am aware of the instruction for the 401 but this is a 240.
05-08-2008 08:13 PM
 
 
Drunk Monk
rrProfessor
Location: Preston, UK

My comment was aimed at swoop

What limit setting and gain do you have on the gyro? Try moving it in or out a hole on the servo arm and adjust the gain. I run a 240 on my trex and have had quite a bit of trouble getting it right. Think mine is on the third hole out on a 9650


Stephen

I only open my mouth to change feet.....
05-08-2008 08:27 PM
 
 
cassat
Veteran
Location: Alberta,Canada

Ok. NP. I have mine in closer to servo center . The other thing was the rudder stick seems like it has too much sensitivity when I try and lift off whether my expo is at 0 or -25
05-09-2008 01:30 AM
 
 
Drunk Monk
rrProfessor
Location: Preston, UK

What is your limit and gain set at and what tx are you using?


Stephen

I only open my mouth to change feet.....
05-09-2008 10:25 AM
 
 
cassat
Veteran
Location: Alberta,Canada

I use Futaba 7CHP and tried everything but the gyro is toast. So
I installed a Telebee until my 401 shows up.
05-10-2008 01:29 AM
 
 
cassat
Veteran
Location: Alberta,Canada

What I Found Out

Well, I found out that the tail belt drive gear was loose on the shaft!! Things got better with gyro gain after replacing that. But then ,
my pitch setting were all out to lunch after installing new links.
05-13-2008 06:49 AM
 
 
1 page278 viewsPOST REPLY
MTA Hobbies . MRC/Altech Marketing USA . HeliDirect

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e-Align T-REX 450-500-600 > T-REX 450 Tail Doesn't Hold
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