T-rex 450 pro V2 serious tail bearing problem

[trexpro]

You can also use the Protos 500 bearings, I have done 100 flights ago and still good

[airmanthesixth]

Which ones exactly?

[trexpro]

Originally Posted by airmanthesixth

Which ones exactly?

Bearings 3x6x2,5mm.
Model: MSH51068



Bearings 2x5x2.5mm.
Model: MSH51074

[hydro_pyro]

My 450 PRO 3GX V2 was brand new in February, and I'm still running the original bearings in the tail with no problems. Perhaps most the kits with the bad batch of bearings have "sold through" by now...

[Atomic Skull]

Late last month I replaced the tail grips on my Tarot 450 Sport with Align grips to get it back in the air fast (didn't want to wait for overseas shipping). Inner races popped out within a few flights. Tarot grips never had this problem and they are the same design. Replaced the failed bearings with cheap HK bearings I had on hand and the problem has not resurfaced.

[Atomic Skull]

Originally Posted by ryem3

Could you imagine the precision of an Align 5mm thrust bearing? Or anyone's for that matter? it is just too small.

It's not.

http://www.4chobbysupply.com/servlet...Bearing/Detail

[Janosax]

Good to know, thanks for the link. But I have a question: are Pro grips really able to have trust bearings? Don't this 6 mm bearing touch the inside of the grip resulting in sticky or even impossible movement? The common design is to have two radials and one trust per grip.

[Atomic Skull]

Originally Posted by Janosax

Good to know, thanks for the link. But I have a question: are Pro grips really able to have trust bearings? Don't this 6 mm bearing touch the inside of the grip resulting in sticky or even impossible movement? The common design is to have two radials and one trust per grip.

I was only saying that the 5-6mm size range isn't too small to use a thrust bearing. It would require a redesigned grip with a 6mm outer race and an additional 3.4mm of length for the thrust bearing and washer that would go between the thrust bearing and radial bearing (3mm for the bearing, .2 for the washer, .2 for tolerance) and a redesigned hub with a longer shaft. You can't just replace the outer radial bearing with a thrust bearing, you need the outer radial bearing because a thrust bearing cannot support a radial load, same reason main blade grips have 2 radial bearings.

[Atomic Skull]

Blade 450X tail grips have thrust bearings. If Eflight can do it then Align certainly can.

[gtr3499]

I just finished putting together my align 450 pro v2 flybar kit
After blade tracking i went over it to make sure everything was right
for its first flight and i noticed i couldnt move the tail pushrod.
It was the bearings in the grips, one blade grip had locked up.
the bearings seized up
and it hasnt even left the ground.

[RCFanatic]

Just wanted to share how important it is to assemble the tail correctly. I was having the same wag issues and replaced the bearings. When I was snugging the screws I noticed one side felt 'funny' and took more torque on the screw to get the grip seated. The whole thing felt smooth on the bench and flew great...for a couple minutes...then the wag was back. Took it all back apart and sure enough, had another bad bearing and noticed the tiny washer on the screw had a tiny deformation in it. I'm thinking I got something under the head of the screw during assembly.

This time during assembly I took plenty of time checking and rechecking making sure it went together and felt perfect. Just one test hop this morning, but the tail felt the best so far and I was finally able to set the gain.

For the record, the tail that came with the kit had been loctited on one side with way too much so the bearings on that side had loctite in them. Hindsite I should have ordered new bearings right then...

[Stickey]

Ball bearings can deal with side force. Thrust bearings aren't a requirement here.

People used regular bearings in the 450 heads for years with no issues. The same bearings can deal with the much smaller forces on the tail.

Thrust bearings are nice, but not required.

To ask a different question - can the 450X tail grips/hub simply be swapped over to the 450 pro?

Originally Posted by Atomic Skull

I was only saying that the 5-6mm size range isn't too small to use a thrust bearing. It would require a redesigned grip with a 6mm outer race and an additional 3.4mm of length for the thrust bearing and washer that would go between the thrust bearing and radial bearing (3mm for the bearing, .2 for the washer, .2 for tolerance) and a redesigned hub with a longer shaft. You can't just replace the outer radial bearing with a thrust bearing, you need the outer radial bearing because a thrust bearing cannot support a radial load, same reason main blade grips have 2 radial bearings.

[kiwianaBrad]

Sportv2 tail bearing has been destroyed

ill say it again this will be my last align product due to experience with this crap and other sorts

[waqr]

I have well over 100 flights with my Pro (clone but with Align tail assembly) without any issues. I too had this problem in the beginning but I just replaced the crappy Align bearings with some cheaper but much better ones and now it works flawlessly!

Also remember not to tighten the screws to hard on the bearings. Just make sure to use plenty of loctite (that you put inside the grip holder and NOT on the screws) and just tighten them enough so that the grips doesn't have any axial play and spinns freely

[RedOctobyr]

Originally Posted by Stickey

To ask a different question - can the 450X tail grips/hub simply be swapped over to the 450 pro?

This seems like an excellent question. I don't think I've really seen an answer to it, though.

I saw a mention that a shaft size was different, maybe the tail rotor shaft? I'm not sure.

Regardless, it seems like an interesting thing to find out for certain. If Blade fit thrust bearings in there, perhaps those bearings, if not the grips themselves, could somehow be put into Pro service?

[Stickey]

Understand Align doesn't make the bearings. They do need a better supplier, but they don't make these in house.

Mine went and I replaced them with some bearings of the same size as the stock non-align units that were in stock from Helidirect.

Originally Posted by syncnzflying

Sportv2 tail bearing has been destroyed

ill say it again this will be my last align product due to experience with this crap and other sorts

[ryem3]

I had major tail control problems for a long time. Couldn't figure out what it was. My main issue was that the tail couldn't hold against the rotor. I would go into idle up and the heli would piro. I found that my BeastX endpoints would shift after I spooled it up. Once, I found that the boom slipped. I pinned the boom after that. I had a boom slip so hard it ripped my screw through the part of the boom block even after I pinned it.

I replaced my tail grip bearings. Tried a totally different tail grip set. Switched the tail servo.

I think the endpoint was resetting because my motor was crap. Worked on this for a LONG time. Finally figured out a fancy Neu motor was just crap. Replaced it with a Scorpion and it fixed the problem.

Also had a tail servo issue. I thought I could fix the problem with a different tail servo. Turns out the 3500 I replaced it with was JUNK! It couldn't generate the torque to move the tail out under heavy load, i.e. idle up. Finally checked the torque generated by the servo and it was really weak. I guess the motor is shot because the gears are not stripped. Replaced it with the orginal 9257, which actually was never the problem and seemed totally fine.

Also noted that my tail shaft was VERY SLIGHTLY out of round. Not enough to notice, even on close examination. But I believe at super high RPM, the out of round end increased the force necessary to move the slider out by so much that the tail servo just couldn't do it. Replaced the tail shaft.

So, between replacing the tail shaft, new motor, and going back to a servo that actually works, the 450 finally flies perfectly. I'm really happy with it. Only shows that a tail problem may not be the tail grip bearings or the FBL system.

Hope those suggestions help you.

[Atomic Skull]

Originally Posted by Stickey

Ball bearings can deal with side force. Thrust bearings aren't a requirement here.

People used regular bearings in the 450 heads for years with no issues. The same bearings can deal with the much smaller forces on the tail.

Thrust bearings are nice, but not required.

To ask a different question - can the 450X tail grips/hub simply be swapped over to the 450 pro?

I was wondering the same thing. The grips use ball links instead of screwing directly to the pitch control arms but they look like M2 holes. The pitch control arms are the opposite configuration from the Align, the arms hug the metal T arm that attaches to the bearing holder instead of the other way around so you can't use those and the bearing holder is a completely different design than what Align uses and isn't compatible. You might be able to use the metal T arm and bushing with an Align bearing holder but I couldn't say for sure without actually having both pieces. If the tail shaft is the same diameter I can't see a reason why you couldn't use the hub and grips and just attach the grips to the control arms with collar screws like the Align grips. If not that then the whole tail assembly could probably be used on a 450 Pro if you converted it to belt drive (and would be a drop in replacement on a Sport)

[Atomic Skull]

Originally Posted by waqr

I have well over 100 flights with my Pro (clone but with Align tail assembly) without any issues. I too had this problem in the beginning but I just replaced the crappy Align bearings with some cheaper but much better ones and now it works flawlessly!

Same thing happened to me. I replaced the tail grips on my Tarot 450 Sport with Align and they didn't last 2 flights. Replaced those bearings with cheap $1.25 per pack of 4 Hobbyking bearings and no problems for well over 100 flights now.

Originally Posted by Stickey

Understand Align doesn't make the bearings. They do need a better supplier, but they don't make these in house.

Mine went and I replaced them with some bearings of the same size as the stock non-align units that were in stock from Helidirect.

It still reflects badly on Align's supposed "quality" when they ship bearings that don't last more than a few flights while supposedly inferior clones are shipping with better quality bearings than the actual Align kits. People will only drink the kool-aid for so long with clone makers like Tarot approaching the quality of the Align kits and actually surpassing them in a few areas. (The coupling nuts in the Align 450 Sport's boom holder are horrible, the Tarot bolts are actually better, though the best ones I found were actually the brass WinRC ones)

[RedOctobyr]

Originally Posted by Atomic Skull

I was wondering the same thing. The grips use ball links instead of screwing directly to the pitch control arms but they look like M2 holes. The pitch control arms are the opposite configuration from the Align, the arms hug the metal T arm that attaches to the bearing holder instead of the other way around so you can't use those and the bearing holder is a completely different design than what Align uses and isn't compatible. You might be able to use the metal T arm and bushing with an Align bearing holder but I couldn't say for sure without actually having both pieces. If the tail shaft is the same diameter I can't see a reason why you couldn't use the hub and grips and just attach the grips to the control arms with collar screws like the Align grips. If not that then the whole tail assembly could probably be used on a 450 Pro if you converted it to belt drive (and would be a drop in replacement on a Sport)

I'm working on doing this at the moment. The tail shafts are different diameters where the tail hub mounts to the shaft (450 X's is larger). I had to make a custom bushing to slip over the Pro tail shaft. But using the bushing, the 450 X tail hub mounts OK to the Pro shaft. And the Align links seem to mount OK to the 450 X blade grips (screwed on directly, like Align does, vs using balls). I'm using the 450 X grips and tail hub, with Align pitch slider (with links and collar screws), tail shaft, and tail rotors.

I oriented the 450 X grips so you can still do the "grip flip" mod. From a quick check, it appeared that you may lose a bit of maximum tail pitch, with the 450 X grips. But due to the height of the thrust bearings, the grips also mount the tail rotors about 0.23" further apart than stock, so you have located the tail blades a bit further out and therefore have a larger rotor diameter (with more swept area, and higher tip speed). That might help offset the pitch change.

It *looks* like it will work. But I'm down for repairs at the moment, so I haven't gotten to try it yet. Once I can try it, I'll post how it goes.