Metal tail rotor grip play

[BgSkyFlyr]

I just got a new metal tail rotor assembly one grip as no play pulling on it holding the hub the other side has significantly more play and can wiggle it around in all directions. I would say its almost 1mm worth. I checked all the washers and bearings they are all the same diameter and thickness. Everything is installed and greased correctly. Has anyone had issues like this and how much play is acceptable? Thanks

[Andy from Sandy]

Under normal circumstances I would say the one with no play is the problem one. Does it feel at all notchy. It could well be that the radial bearing hasn't seated properly.

1mm on this size model seems a bit excessive. I would expect a bit of play. If you take the grip off can you see if the bolt does all the way up against the washer tightly?

Are the radial bearings the correct thickness. EDIT: Okay, I see you checked this already.

Is both sides of the hub the same? What happens if you swap the grips around?

[BgSkyFlyr]

Originally Posted by Andy from Sandy

Under normal circumstances I would say the one with no play is the problem one. Does it feel at all notchy. It could well be that the radial bearing hasn't seated properly.

1mm on this size model seems a bit excessive. I would expect a bit of play. If you take the grip off can you see if the bolt does all the way up against the washer tightly?

Are the radial bearings the correct thickness. EDIT: Okay, I see you checked this already.

Is both sides of the hub the same? What happens if you swap the grips around?

No gritty feeling bearings feel nice and smooth I will try swapping the grips around and double check diameters/thickness. I am at work now so may be a while before posting results thanks!

[HeliLust]

If one side of the grip hub has some play because it's too long, carefully file a little bit away. Be careful not to go to far though because once you do its ruined.

I usually don't worry too much if there is some play there though unless it's excessive and excessive can be very subjective. One thing to remember is that once spun up there is a lot of force trying to pull the grips outward. I think I have read somewhere that it can be on the order of 100+ lbs. The play becomes a moot point once under load.

This trick also works with feathering shafts to take some play out of main grips too. Once again though, once spun up to speed does it matter? I think it's more important that under load there is no binding in the bearings.

[BgSkyFlyr]

Originally Posted by HeliLust

If one side of the grip hub has some play because it's too long, carefully file a little bit away. Be careful not to go to far though because once you do its ruined.

I usually don't worry too much if there is some play there though unless it's excessive and excessive can be very subjective. One thing to remember is that once spun up there is a lot of force trying to pull the grips outward. I think I have read somewhere that it can be on the order of 100+ lbs. The play becomes a moot point once under load.

This trick also works with feathering shafts to take some play out of main grips too. Once again though, once spun up to speed does it matter? I think it's more important that under load there is no binding in the bearings.

Great thanks for the info makes sense with the centrifugal force pulling them out and keeping them straight. On the filing you are meaning at the end of the hub shaft where the screw goes right?

[HeliLust]

Yep, that's exactly what I'm talking about. Like I said just be careful, it's pretty easy to go to far.

[BgSkyFlyr]

Originally Posted by HeliLust

Yep, that's exactly what I'm talking about. Like I said just be careful, it's pretty easy to go to far.

Thanks I will post my results tomorrow, take care

[BgSkyFlyr]

So my 1mm was actually .28mm, seemed alot more, used some 400 grit and it did not take much but, now there is no play and everything is smooth.

[HeliLust]

Good to hear! Make sure you don't go to crazy with the loctite, less is more. You will probably want to do the same process again after a few flights when everything seats down tight if your picky.

[Andy from Sandy]

The only thing I mention when there is no play is if there is now a load on the bearings. To me that little bit of play is okay.

As HeliLust stated when spun up is when the system works and not until. If you could find an old Hirobo Sceadu you would think the tail grips were broken it had so much play but it worked great.

[Number]

As long as the bearings are all the same type, installed in the same order, and installed properly, that means they're balanced and it doesn't matter how much play they have, because as HeliLust mentioned they will fling out in flight and all play will be gone.

The Blade 700X had even more and it flew just fine because all the bearings were the same on each side and when they flung out, they were exactly the same spacing from center and it was balanced.

7:55

Blade 700 X - James Haley - Designer Walkthrough (10 min 31 sec)

Now, if you say forgot a .5mm shim and that was causing play, that would be an issue. But a little play is not inherently bad in tail grips.

[BgSkyFlyr]

Yes there is a very small amount of play they are not totally tight might be say the width of a piece of paper now, that was how the tighter side was and I was ok with that, but the looser side had significantly more, so now both sides are equal in "end play" if you will. Thanks again for all the help, this has been very informative for me.

[BgSkyFlyr]

[QUOTE=Number;7236359]As long as the bearings are all the same type, installed in the same order, and installed properly, that means they're balanced and it doesn't matter how much play they have, because as HeliLust mentioned they will fling out in flight and all play will be gone.

The Blade 700X had even more and it flew just fine because all the bearings were the same on each side and when they flung out, they were exactly the same spacing from center and it was balanced.


Interesting aspect on that tail, makes sence, only thing with mine they were unequal and that is what concerned me.