Is this a ruined clutch liner?

[marked23]

After an auto, I reset the throttle hold switch without flipping out of idle-up. Vroom!

It went full throttle and a few seconds later (I was slow to react), the sound changed and the blades stopped spinning up. I gave it a rest for a few seconds and tried to spin-up again. The blades started spinning, but did not come up to full speed. I heard a awful metal-on-metal scraping sound, so I cut it off and went home... presuming I ripped the liner out of my clutch.

After tearing it down, the liner doesn't look too bad. But I've never seen a ruined liner.

Is this a ruined clutch liner?

Is this a ruined clutch shoe?

Thanks,

-Mark

[marked23]

The liner diameter is 1.486.
The shoe diameter is 1.474.

That's a difference of .012. Which means the gap on one side is .006

Those are good numbers right? So why did it not spin up?

-Mark

[Russ McC]

Mark,

You did not do it any favor but it seems like I have run some that looked like that with no problem. Make darn sure that the liner is still attached securely to the bell if it is and your clearance is right and it sounds like it is then maybe your auto sprag clutch broke loose in your main gear, give it a look.

[marked23]

I hold the blades still, Then turn the main gear one way... It spins. Then the other way, it stops. I even gave it a good hard tug. No aparent slipping.

Is there a better test?

Also, the liner looks like it never came unglued. It's in there solid.

-Mark

[Russ McC]

Mark,

There are only two places you can loose your power to the blades, your clutch or the auto hub, with out being there and looking myself I can’t make the call. You know the clutch is somewhat hammered so send it in to Min Air for repair, they are reasonable in price and then you will know it is good. If it still does not spin up then send in your auto hub. Also they see this stuff a hundred times a day so a quick call to them might clear this up quick, you could also send your auto hub with the clutch so they can check both.

[kthane]

looks smoked, blued, blown out and everything else to me, time to upgrade to the 90 clutch.. Unless you already got it.

[pgcopter]

I agree with Russ and the sprag bearing. There are 2 small set screws that hold the sprag bearing. Try snuging those up a little, only takes a few seconds and you don't need to take anything apart. I know the sound your talking about, heard it on mine. And the problem was the sprag bearing.

[marked23]

kthane,
This is the clutch that came with a Fury Extreme. Is that the 90 one? or is that the same clutch that was used on the 60? I didn't upgrade to HD or anything. What's the part number for the upgrade?

pgcopter,
It doesn't appear to be slipping when I try to move it by hand. Did you notice that when you saw this effect on yours? How do I know how far to snug up the screws?

-Mark

[kthane]

http://www.ronlund.com/Merchant2/merchant.mv?Screen=PROD&Store_Code=heli&Product_Code=MA121-20

http://www.ronlund.com/Merchant2/merchant.mv?Screen=PROD&Store_Code=heli&Product_Code=MA121-22

[pgcopter]

Yes it was very hard to make it slip by hand. I would try about a 1/4 turn on each set screw. That should be enough to atleast let you know if thats whats slipping.

[Dr.Ben]

I don't know if any of you have ever seen the sleeve that's inside the auto hub and which the set screws bottom out on. Before it's installed, the factory places two flats on it at 180d intervals to receive the set screws. If the set screws loosened up and the sleeve broke free (it's green loctited into the hub), the alignment on those flats will be lost. Simply snugging up those screws wouldn't guarantee against future slippage.

Ben Minor

[DavidH]

The clearance between the clutch and the clutch liner are on the upper end of specs. I would prefer it to be about .008 total or .004 clearance gap.
From looking at the pictures, the lining appears to be glazed from too much heat. The clutch is blued from too much heat. I would think the liner and the clutch need to be replaced.
I can't tell from looking at the pictures if you have the larger HD clutch and bell.
The stock clutch is 38 mm across, if you have the HD clutch it will larger than 38 mm across the clutch.
The HD clutch was only started being put in the Extreme kits around the first of 2005.

David

[marked23]

I flew it today.

I scraped the glazing off of the clutch liner with a knife.
I removed the main-gear assembly and inspected the sprague bearing.
I snugged down the set-screws on the sprague bearing.

It just flew.

I think Dr.Ben is on to something. My sprague bearing might have slipped within the housing. Should I be able to see the flats through the set-screw hole? Can this be repaired?

I'm going to buy the HD clutch and a new sprague housing/bearing. Then this should be sorted, whatever it was.

-Mark

[DavidH]

Don't believe you will be able to see the flats on the sleeve thru the 3mm set screw holes.
That clutch and clutch liner did not get over heated from the sprag slipping in the auto rotation hub.

If your going to get an HD clutch, that is easy to install yourself if you have the right tools.
No need to buy a new sprag bearing or housing, it is either working or it isn't working. If the sleeve has slipped in the auto rotation hub. All that it needs is disassembled and the sleeve loctited . Place the flats on the sleeve where the set screws will contact that area.

David