450 450 pro 3gx spinning out of control

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Bruno

Member
Trex 450 PRO, V2, 3GX, AR6210, Satellite, DX6i. I have flown this heli dozens of times in same location as below without any electronic issues.

The issue: Really frustrated!!!! :whining:

FLIGHT A: .... I was flying the heli and in a hover she just started spinning clockwise. Crash/landed. Upon examination the rotor grip linkage broke off the grip. I thought perhaps it had come loose and broke causing the spinning.

Took my time and rebuilt the heli. Changed tail grip bearings since they seemed a bit sticky and all the other expected parts: boom, main bearing, main shaft, etc.

Checked all 3GX functions, tail compensation, tail command direction, set tail limits, blade pitch/0 pitch, blade tracking...all perfect.

FLIGHT B: Take her out (just for a hover) a few minutes ago.

Hovers perfect, effortlessly. 10 feet off the ground, do one pirouette...hover no problem...second pirouette hover...no problem (10 feet off the ground, between buildings, virtually no wind).

I decide to check for tail hold for gyro gain so I give it a slight right rudder command...then it happens...she starts spinning clockwise. Crash land with throttle hold. :puke:

Examination: bent main shaft, radius arm popped off swash ball. I check the tail and no sticking. I immediately think the radius arm popped off causing the problem but that doesn't make sense. When she was spinning she maintained a level/horizontal orientation.

Please let me know what this may be.

I hate typing this (cause I don't want biased assessments but) ....Is it the 3GX? How could I rule out the 3GX?
 
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Tony

Tony

Staff member
I would first be looking at the tail gears. I know you said spinning clockwise, but gears, or drivetrain is where I would start. If that doesn't fix the issue, then it's time to look at other things. Make sure your tail blades are spinning in the correct direction (if this is a belt tail). The blade, when at the VERY rear of the heli, should be going down, trying to pick the back of the helicopter up.

If that is correct, then I would start looking at the 3GX. What version are you running? If 4.0, then back it down to 2.1 and try that. You will have to completely go through all setups again, but I would suggest this anyway. Sometimes, resetting the model in your Tx, and resetting the settings in your 3GX cures a lot of issues.
 
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Bruno

Member
Tony said:
I would first be looking at the tail gears. I know you said spinning clockwise, but gears, or drivetrain is where I would start. If that doesn't fix the issue, then it's time to look at other things. Make sure your tail blades are spinning in the correct direction (if this is a belt tail). The blade, when at the VERY rear of the heli, should be going down, trying to pick the back of the helicopter up.

If that is correct, then I would start looking at the 3GX. What version are you running? If 4.0, then back it down to 2.1 and try that. You will have to completely go through all setups again, but I would suggest this anyway. Sometimes, resetting the model in your Tx, and resetting the settings in your 3GX cures a lot of issues.
Click to expand...


This heli has a TT. Correction direction was compensating with counter movement.

I am running the stock 3GX version 1.2.
Should I upload the upgrade? Which version?
Should I go with an AR7200 like with my other birds?

Thank you for any help..
 
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pvolcko

Well-Known Member
I'd re-re-re-check the tail servo direction and correction directions. It is very easy to get it confused. I very nearly flew my gob 700 with it incorrectly set despite having checked it on the bench twice and on the ground pre-flight once. I did one last check before flight and realized I had it all wrong. I somehow doubt the 3GX would cause this blatant an issue. All the negatives I've heard on it have been tilts to the right or left, especially if left sitting on the ground a bit past spin up. Nothing as drastic as uncontrollable piros.
 
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Bruno

Member
I have checked and rechecked (after watching Lee's video to maintain sanity) and correction direction and servo movement are correct with leading edge of tail rotor moving counter/opposite direction of rotation input. I have rebuilt the mechanics of the heli. I am considering upgrading the 3GX V1.2 to the 3.1 version and going through the entire setup of the 3GX. I will go through entire 3GX Setup regardless of firmware version.

As an aside, my AR7200 seems so more simple with setup when considering the 3GX software programming.

I dread the thought of having to reference multiple threads just to configure 3.1.

Someone please tell me it's virtually simple to upgrade to 3.1.

Thanks. Happy Holidays!!
 
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Tony

Tony

Staff member
upgrading to 3.1 is very simple. just remember that 3.1 HATES to be on the ground. You MUST get it in the air quickly.

If you need to know how to upgrade the firmware, click on articles > 3GX Setup. At the bottom of that page, there is an upgrade video. It says 3.0, but 3.1 will work as will any other firmware. It's all the same process.
 
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Bruno

Member
Tony said:
upgrading to 3.1 is very simple. just remember that 3.1 HATES to be on the ground. You MUST get it in the air quickly.

If you need to know how to upgrade the firmware, click on articles > 3GX Setup. At the bottom of that page, there is an upgrade video. It says 3.0, but 3.1 will work as will any other firmware. It's all the same process.
Click to expand...

IMHO. I had no issues (prior to what I describe above) with 3GX V1.2.

Should I upgrade to 3.1? What are the advantages?

Should I run through the DIR and give her another test with V1.2 since it seems the consensus is it was NOT the 3GX even though I was not able to find the cause of the spinning?

Thanks.
 
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