450 Main shaft bearing play.

[Bruno]

I have been flying my Trex 450 sport V2 (which I built about 3 weeks ago ) about 10 batteries worth. I noticed a bit of play with the top main shaft bearing. The bird is very stable in the air/hover with no shakes. I am not doing any 3D.
Question: the shaft barely moves a mm, what determines definite need to replace the bearing?

 

[Westy]

If it flies beautifully and you have no issues with its characteristics ... that if fine. Bearings do need some play to work. if they start getting noisy or you start getting vibes or wobbling in the head time to replace them.

Keep and eye on them and give them a bit of oil love occasionally and you should have happy days!

 

[pvolcko]

I think on the sport models there is a collar that rides on top of that top bearing. If you have up/down play on the main shaft, loosen the set screw in the collar, and while pulling up on the head assembly and pushing the collar down to the bearing, tighten it up again. Make sure to put a dab of loctite on the set screw before doing this, so it will stay in place. It doesn't have to be pushed down with a lot of pressure, but remove the up play in the shaft and then lightly push the collar down to rest against the bearing and tighten the set screw. Should remove any play you have.

Also, in the collar has a conical side and a flat side, make sure that collar has the conical end pointing down toward the bearing.

If no collar and just a "bump" in the main shaft, there should be shims available to place between the bearing and the fat spot in the main shaft to remove play.

If you don't remove the play it won't be the end of the world, but over time you will cause some damage to the shaft bearings and possibly cause them to prematurely fail.

 

[Bruno]

I think on the sport models there is a collar that rides on top of that top bearing. If you have up/down play on the main shaft, loosen the set screw in the collar, and while pulling up on the head assembly and pushing the collar down to the bearing, tighten it up again. Make sure to put a dab of loctite on the set screw before doing this, so it will stay in place. It doesn't have to be pushed down with a lot of pressure, but remove the up play in the shaft and then lightly push the collar down to rest against the bearing and tighten the set screw. Should remove any play you have.

Also, in the collar has a conical side and a flat side, make sure that collar has the conical end pointing down toward the bearing.

If no collar and just a "bump" in the main shaft, there should be shims available to place between the bearing and the fat spot in the main shaft to remove play.

If you don't remove the play it won't be the end of the world, but over time you will cause some damage to the shaft bearings and possibly cause them to prematurely fail.

Good to know. I am familiar with both systems. Mine (V2) actually has the "bump" on the main shaft.
The play I have is lateral not verticle. However, probably just normal tolerance unless it results with shaft wobble.
I will keep an eye on it. Thanks.

 

[pvolcko]

Sorry, misunderstood. That kind of play is actually a little more concerning to me. In my (limited) experience I haven't really seen any play like that unless I've crashed and the bearing was damaged. In my case by a shaft bending right inside the bearing interface. Def keep an eye on it. Could probably develop a nasty vibration if it got too free.

 

[coolgabsi]

a bit of play wont hurt anything.. make a video if you can show us what you see.. being softer metal, that happens sometimes. what that will cause is your bearing life gets reduced. they get gritty faster... I dont think there needs to be any play in the bearing seating.. they need to sit just snug.. not press fitted.. but snug..

how to get rid of it... green bearing seating loctite.. teny tiny drops of it.. it is STRONG! and flows fast.. make sure not to get any in the bearing just on the outer race.. and that should hold it steady.. make sure they are aligned right when you use it

 

[Bruno]

a bit of play wont hurt anything.. make a video if you can show us what you see.. being softer metal, that happens sometimes. what that will cause is your bearing life gets reduced. they get gritty faster... I dont think there needs to be any play in the bearing seating.. they need to sit just snug.. not press fitted.. but snug..

how to get rid of it... green bearing seating loctite.. teny tiny drops of it.. it is STRONG! and flows fast.. make sure not to get any in the bearing just on the outer race.. and that should hold it steady.. make sure they are aligned right when you use it

The bearing sits snug in the bearing block. The play is within the bearing itself between the outer and inner race. I checked my Trex pro V2 which I may have flown 5 times (waiting to get better with the sport) and the upper main shaft bearing has the same amount of play.

 

[coolgabsi]

take the bearing out then and check for grittiness.. and you probably need to replace that... before putting the new one in check the main shaft alignment with bearing blocks.. main shaft is supposed to slide in and out without any friction through the inner race.. .. any friction.. and that could mean that the bearing blocks are misaligned and it is causing un equal wear.. and yes 5 flights are enough ..

or beairing going bad.. one way or the other.. if that ceases at a point.. there is a LOT of destruction that can take place..

 

[Bruno]

take the bearing out then and check for grittiness.. and you probably need to replace that... before putting the new one in check the main shaft alignment with bearing blocks.. main shaft is supposed to slide in and out without any friction through the inner race.. .. any friction.. and that could mean that the bearing blocks are misaligned and it is causing un equal wear.. and yes 5 flights are enough ..

or beairing going bad.. one way or the other.. if that ceases at a point.. there is a LOT of destruction that can take place..

Warning understood. I tried to video the movement and it was too minimal to detect on video. I remember making sure the blocks were aligned during the build. I will of course double check.

However, do the main shaft bearings typically develop a minimal amount of play during use?

 

[Bruno]

OK...so, I examined a brand new align shaft (h450a2at) and a brand new pack of Align 5X11X5 bearings (4). Sliped the bearings onto the shaft one at a time. Each bearing had a minimal amount of inner race torque-type (if that makes sence) play and minimal amount of tolerance/play between the shaft and inner race consistent with the amount of play I detecetd with the installed system. Seems this is a typical amount of tolerance. I spun the installed main shaft carefully and was not able to detect and friction/gritty movement. It was smooth as butter.

 

[coolgabsi]

Then you are good


If it was too small for the camera to pick up lol that's pretty small.

Fly safe!! have fun!