Tail pitch links - how much to tighten?

[marked23]

On a Fury Extreme:

When installing the pitch links (#0859-16), I noticed that if I tighten the screws (#0049) until they stop, the pitch slider binds against the tail output shaft.

Even though the pitch link bearings still rotate freely, somehow having the screw fully tightened causes the pitch slider to not slide freely.

What's that about? Have others seen this?

Dare I back-off the screws until it seems right?

-Mark

[bighands3d]

you can back off the screws till smooth I don't think you'll will have a Problem. I belive I had to do the same thing.

now I think your talking about the screws in the grips. Right. If not just use some ol Red loctite on the nuts for the slider. and loosen them till smooth.

[marked23]

I'm talking about those tiny screws (#0049) that go through the figure-8 looking things that have two bearings in them. If I tighten them firmly, not overtight, the slider binds. So now I have them just down until the screw stops.

I have a healthy dose of blue loctite on the inboard screws and also plenty of CA on the outboard ones.

Should I do-over the inboard ones with red?

-Mark

[bighands3d]

NO they will be fine I just use blue on mine as well. Just as long as the system is freely. You don't want a sticky tail system makes for an ugly gyro operation.

[DavidH]

Mark,
Are you sure you have everything assembled correctly. Tightening the bolts on the ball bearing links as tight as you can get them should not cause the pitch slider to bind.

Do you have the links orientated the correct direction. The flange of the bearing should face outward towards the bolt on both the pitch slider and the tail blade grip.

I would think you have the links installed correctly on the pitch yoke. The link goes on the side of the yoke that does not have the hex cutout for the nut.

David

[EricLarson]

I agree with David, something does not sound quite right.

[marked23]

There is no way to put this together and get the screws on the wrong side. The angles just don't work any other way. So that part of the assembly has to be right. Yes, the flange side of the bearing faces the screw head.

What if my tail-hub is out of spec? It could be too long or too short. Or one or more tail grips out of spec?

Yes, looking at it now, it appears that one of the links is at exactly 90deg, the other is on at the slightest angle that would suggest that the tail-hub is too short, or that the grip is imperfect. I bet I could get that straight by shaving just a tad off of the end of the grip.

Is that something to try?

-Mark

[Bonsai]

Mark check and make sure that you have the screws in the dogbone (the piece with the bearings in it) in the same screw holes in the tail blade grips...there are 2 holes there and you may have one in the inner hole and the other in the outer hole causing the assy to bind...just a thought....
Dean

[marked23]

They are definately in the right holes. I just re-did them last night. Instructions in hand. Even so, that shouldn't change the angle of the dogbone.

This is really a drag (pun intended). :D

-Mark

[marked23]

I rebuilt the whole tail tonight. I took the opportunity to disassemble, regrease, and re-assemble the thrust bearings... yup that was ok.

I reassembled the dogbone bearings. This time I tightened the grip end down screwdriver tight (not wrench tight) with CA. For the yoke end, I used red loctite and left those screws just a tad loose. The red loctite set quickly and I expect I'll never move those again.

The feel now is much better than before, but it is still a dampened smooth movement, not floppy at all. It it supposed to be so easily moved as to feel floppy?

I'm taking this to Richland, WA next weekend. I'll have Russ or Doc look it over.

-Mark

[kthane]

having the little links flipped over the wrong way will cause the problem you describe. I know this cause a guy I fly with (won't mention names :-)) had his flipped the wrong way on his ION! The head of the little allen screws should be on the bearing flange side. :shock: Posting a picture might help. :smokin: