Raptor 90SE Clutch Slipping

[Rocket Man]

Hope someone can help me. I just did a couple of test hovers with my new R90SE.

On the plus side, the OS 91 starts easy and seems to run great.

The down side is the clutch is slipping badly. I pulled the engine and checked everything against the directions. There is no shim between the clutch and the fan hub and everything is lined up fine.

But the engine had to be revved almost to hover speed before the blades even started rotating. Once they came up to speed, the heli lifted off and hovered okay. But a minute later, I noticed that I was at FULL throttle and the machine was settling back to the deck. :(

Anyone have this problem? Got a solution? Should I shim up the clutch?

I'm using the stock clutch, stock bell, 11/91 gears, OS 91 C-spec, TT 710 blades, and Cool Power 30 percent.

Thanks.

[alexander]

oil or grease on the liner maybe? Improper shoe clearance is the other thing that will cause the same symptom.

Stephen

[ClayK]

You verify the throttle linkage?

You verify throttle curves?

I have to ask these things, not sure how much flying or setup you've done.

There are a couple of us local, including me, if you need someone to take a peek just let me know.

[bgjames111]

wasn't a problem on mine, but I remember about a year ago people were having this issue, most just bought a new liner and reinstalled.

[Rocket Man]

You verify the throttle linkage?

You verify throttle curves?

I have to ask these things, not sure how much flying or setup you've done.

There are a couple of us local, including me, if you need someone to take a peek just let me know.

Clay,

Thanks for the offer. I have been flying helis off and on since 1981 and now realize I am simply addicted. I've tried to kick the habit a couple of times (ran out of hobby money) but always come back.

The throttle and pitch curves are the ones I've copied from Ray Hostetler over the years (3/4 throttle hover, etc.) even though I'm too old and not good enough for 3D.

I'm thinking I got contamination in the liner. I scraped a layer of waxy build up off and tried again with no joy. I'm not sure if brake cleaner will work and may just suck it up and replace the liner.

My LHS is Hobby Hanger. Let me know if you hang out there, too.

Thanks.

[Mike C]

I did maiden on mine a few weeks ago ,,,would revvvvvv way up before the clutch would catch.
It has gotten much better after 6 or 7 tanks.

If you scrapped the liner down no doubt it will slip,, Gap was too large on mine.

Most of the time if you run with too large of a gap ,,won't be long till the clutch breaks. ( I don't expect the stock one to last with that large gap)

[ClayK]

Yeah, I've been going to Hobby Hangar for 15+ years. I use to race cars at their old location (the red brick building near the post office). I grew up in Chantilly. John Rohland is out that way and so is Dennis.

I try to get out to that shop whenever I can. Hard to lately, been flying locally and working.

[Turbo Dave]

Dont wait for it to break! Mine smashed inflight and vibrated that hard it almost made the collective tray unscrew itself, not to mention smashing the fan and clutch bell aswell!...Metal everywhere


Put a QuickUK 3D clutch in...they are slightly larger and engage earlier.

Fixed mine anyway.

[Rocket Man]

Put a QuickUK 3D clutch in...they are slightly larger and engage earlier.



I might do that.

I pulled everything down. The clutch bell was full of oily residue, which may explain the slippage. I cleaned everything off with brake cleaner, then went ahead and changed the clutch liner.

I checked the gap: .015. That's right at the edge of what's recommended, so I'll give it a try.

It was too doggone cold to fly today - weather is supposed to warm up to 50 tomorrow.

Thanks for your tips.

[frankg11]

My question is where is the oil comming from? Did you contaminate it during assembly? Might want to track that down, or you may repeat the process.

[Mike C]

Dont wait for it to break! Mine smashed inflight and vibrated that hard it almost made the collective tray unscrew itself, not to mention smashing the fan and clutch bell aswell!...Metal everywhere


Put a QuickUK 3D clutch in...they are slightly larger and engage earlier.

Fixed mine anyway.

I've had a few break ,,,Never on the bench :dontknow

I havn't had any explode :shock: Maybe I should change the clutch .
The clutch and bell?
Or just the Quick clutch?

[Rocket Man]

The clutch problem has been solved and the heli flies great.

After tearing the machine down two times, I finally decided it wasn't the oil - it was the clearance. I talked with one of the local experts and he agreed that his machine gets drippy with oil after a flight (we both use Cool Power 30 percent) and he always finds some in the clutch bell. He suggested that I shim up the liner so it's tighter.

I did this and now have .007 clearance around the clutch (vs. the stock .015). Fired her up and the results were fantastic. The clutch still does not grab at low idle, but spools up immediately. FWIW - I did buy a Quick UK clutch as suggested, but it miked out exactly the same size as the stock TT unit (1.782"). I'll keep it as a spare.

Thanks to all you guys for your advice and suggestions. For a while, I was really disappointed that I spent so much time, effort, and money on this machine. I always thought my Raptor 50 was the best heli I ever owned, but this 90SE is bigger, faster, and stronger. To watch it fly yesterday was priceless. :D :D

Ron

[hrosee]

What did you use for a shim??

I had the same problem. Put in a new lining and it's a lot better but still not like I would like.


The clutch problem has been solved and the heli flies great.

After tearing the machine down two times, I finally decided it wasn't the oil - it was the clearance. I talked with one of the local experts and he agreed that his machine gets drippy with oil after a flight (we both use Cool Power 30 percent) and he always finds some in the clutch bell. He suggested that I shim up the liner so it's tighter.

I did this and now have .007 clearance around the clutch (vs. the stock .015). Fired her up and the results were fantastic. The clutch still does not grab at low idle, but spools up immediately. FWIW - I did buy a Quick UK clutch as suggested, but it miked out exactly the same size as the stock TT unit (1.782"). I'll keep it as a spare.

Thanks to all you guys for your advice and suggestions. For a while, I was really disappointed that I spent so much time, effort, and money on this machine. I always thought my Raptor 50 was the best heli I ever owned, but this 90SE is bigger, faster, and stronger. To watch it fly yesterday was priceless. :D :D

Ron

[Rocket Man]

What did you use for a shim??

I had the same problem. Put in a new lining and it's a lot better but still not like I would like.


I used brass shim stock - .002"

The key part for me was to measure the thickness of the tape I put around the clutch (.006) and I only used a single layer. Between the brass shim stock and the epoxy, I got a nice snug, consistent fit.

It took a couple tries before I got the spacing I liked. Now I know what works best for me, so I don't expect more problems with the clutch.

Ron