T-rex 450 pro V2 serious tail bearing problem

[yosemite]

Here are my bearings after not even 40 flights. This tail is from a new Trex 450 Pro V2 kit. I put the tail on my older 450 heli thinking it would be "Better". Yesterday the tail started wagging like crazy so i went through the whole tail (except the tail blade grips!) and replaced a bunch of parts, even ordered a new tail servo!


I also noticed that there was all this play in the V2 tail gear case which took several shims.

Stuck my old trusty tail back on and my 450 is way quieter and the tail so smooth.

Beware of this new V2 tail!

[michael88997]

R y'all all using old tails to fix the broken bearings? Hopefully align will fix the issue

[DesJardins]

I have to replace my main grip bearings, they look like the tail bearings people are posting.
Only started set-up hovers and after a few hovers the main blade grip was wobble city, dang

[Mac796]

Just put my tail of my old 450 pro on it. Problem gone.

[DiggityDan]

Originally Posted by Mac796

Just put my tail of my old 450 pro on it. Problem gone.

good to hear. i wanted to do this right off the bat and was curious if it was ok. Can i use just the tail grips from my pro v1? or the whole tail?

[jbrown287]

For the people using bocas....do you have part numbers by chance.

[nopotential]

i have had some tail wag issues. it seemed like every time i would fly i had to adjust the gain it was driving me nuts. saw this thread, checked my bearings and they are wasted. just wanted to say thanks for saving me the crash. got some on order from boca.

2x5x2.5 = mr52-zz
3x6x2.5 = mr63-zz

[jbrown287]

Well Im looking at bocas site and wondering what he differences are in a couple that seem to be identical. Can someone please explain......

http://www.bocabearings.com/search.a...thOperator=%3d

MR52-ZZ vs MF52-ZZ

I would have figured the ceramic ball bearing they offer would be top of the line....am I wrong?

[Mac796]

I don't think its the bearings. I think there is a bad batch of grips. If you just go for replacing the bearings. I think were asking for trouble. I might be wrong. But I tried 3 sets of bearings with the same problem. When I put my old pro tail on it was cured.

[Mac796]

Diggity dan . I used just the grips. I think the whole tail will work. Mine was the v1

[tdrnmartin]

Originally Posted by jbrown287

Well Im looking at bocas site and wondering what he differences are in a couple that seem to be identical. Can someone please explain......

http://www.bocabearings.com/search.a...thOperator=%3d

MR52-ZZ vs MF52-ZZ

I would have figured the ceramic ball bearing they offer would be top of the line....am I wrong?

The difference is that the MF version has a flange on one side of the bearing where the MR doesn't. If you go to the spec tab for each type, there is a diagram that shows the difference.

[trexpro]

Originally Posted by nopotential

i have had some tail wag issues. it seemed like every time i would fly i had to adjust the gain it was driving me nuts. saw this thread, checked my bearings and they are wasted. just wanted to say thanks for saving me the crash. got some on order from boca.

2x5x2.5 = mr52-zz
3x6x2.5 = mr63-zz

you're welcome

[trexpro]

Note that the problem is not in the blade grips itself but is really a bad batch of bearings imo! The V2 tail is the same as the V1. Note that if you replace the tail blade grip bearings that you dont turn the screws too tight,and be absolutely convinced that there is no play between the blade grips and the tail rotor hub and that you can turn/rotate the grips without feeling the bearings (if you can feel the axial load on the bearing,than you have turn the screws too tight), let the loctite do the job, but watch out that no loctite touches the bearings!

Note: Too much axial load on a radial bearing which is as small as this, is asking for trouble (as due to incorrect assembly)

[michael88997]

That could be escalating the problem, I know a lot of people really wrench down on these small helis. I just bearly tighten til their snug and let the blue magic do the rest... Never had a loose screw or stripped one... I just got my v2 yesterday so I guess I'll find out on my bearing soon lol

[trexpro]

I just bearly tighten til their snug and let the blue magic do the rest

Hi Michael,

that is the way to do it

[wkma7six]

Add me to the list as one of my outer bearings failed on my 3gx V2 also. Not good for Align. The other remaining intact bearing that I pulled out was pretty rough and gritty also. Heli is brand new on maiden flight when I got this strange vibe with bad tail response. Luckily I have some spares from other heli's with the same dimensions. The newer ones I replaced them with have less slop and very smooth. Let's see how long these will last.

[JoeW]

I had one go on my maiden... Actually, I still haven't maidened it, I thought the hub was bent at first so I replaced the whole assembly. It was binding so bad i naturally assumed the hub was bent somehow. I confused me that i didnt pick up on that on the bench. When I took apart the original, I was surprised to see it was just a bad bearing.

I got 2 sets of replacements and plan to maiden it tomorrow.

[lankey]

Strange. I torque down quite hard on the tail grips, same as I do with the main grips. No axial load resulting from this and butter smooth rotation.

Never had a problem after nearly 150 flights. Still, not the best designed tail IMO!

[wkma7six]

I can torque down on mine too and no issues with the grips rotating freely, but after the vibes and lack of tail response, I saw that one of the blade grips had started to pull away from the hub and I knew what was wrong. This time, I believe it was a faulty or weak bearing with terrible tolerances. The other "good" remaining bearing had a lot of slop in it after I pulled them both for replacement. This tells me that the inner race, ball, and outer race have poor tolerance standards, and something or everything could be undersized allowing them to pull away from each other like that. It could be possible that the metals are too soft also, but Align spec'd out a bad bearing from something that handles such a high axial load.

[highlightshadow]

Is this issue something i should be concerned about as a new (ordered the kit at the weekend) owner?

I've ordered some MHS / Protos bearings to use instead of the align ones but opinion still seems divided here as to whether its bearing / installation / design problem

Right now i'm still beginner so not yet worrying about tail blowing out on hard moves (won't be for a long time) but still like to know i've got something mechanically sound at least