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Clutch Problem Second time Fixing

Old 02-24-2008, 12:49 PM
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girwin1123
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Default Clutch Problem Second time Fixing

This is the second time I have replaced the clutch in this helicopter. It is growing old.. I have spent more time fixing it then flying it.. I have posted some pics here and I need help. It appears that the clutch is engaging and sliding the clutch lining up causing it to burn the fan assembly. It would make since that there is some play in the clutch shoes causing it to do this. When I put the assembly on the crankshaft of the engine I tightened it up as tight as I could humanaly do so. Yes I also put locktite on the bolt also..

You can see in the pics how the lining has moved up and left a groove in the fan. The clutch shoes have also sprung. By the way it has never been crashed. Anyone who can offer some help I would be greatful beyond belief............... I almost forgot when I bought the clutch it came with the lining in it, is this factory installed with JB Weld? It was bought from tower hobbies.
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Old 02-24-2008, 04:47 PM
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racer-RCU
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Default RE: Clutch Problem Second time Fixing

for some reason im thinking that back when i had bought my hawk i read somewhere that you should glue the lining in. someone else will probably pop in here and correct me if im wrong.
Old 02-24-2008, 07:53 PM
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wak86
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Default RE: Clutch Problem Second time Fixing

yaaa....your problem same like me..i hvae replace 3 times for the clucth
Old 02-24-2008, 09:12 PM
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syclic
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Default RE: Clutch Problem Second time Fixing

When you screw the clutch down onto the crankshaft, how do you secure the crankshaft from turning while you do so?

What seems to be happening is that the clutch is unscrewing and allowing the clutch bell to move up into the fan.

P.S. from the pictures it is obvios that your clutch shoes are "sprung" and needs replacing.
Old 02-25-2008, 08:19 PM
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girwin1123
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Default RE: Clutch Problem Second time Fixing

I took the back of the engine cover off and used a crankshaft lock. Now that I think about it I placed the clutch on and then applied locktite to the bolt and then screwed it on. I think when my new clutch comes I will apply thread lock to the whole crankshaft threads maybe that would do it. I ordered a new clutch,fan and clutch shoes so I will give it one more shot.
Old 02-25-2008, 09:06 PM
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syclic
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Default RE: Clutch Problem Second time Fixing

Yes, you must locktite the clutch threads to the shaft and also the prop nut threads.
Old 03-01-2008, 06:58 PM
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girwin1123
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Default RE: Clutch Problem Second time Fixing

Alright here we go again. Put the new clutch shoes housing and fan on. All new stuff. Locktited the whole thing let it dry for 24 hours. Put it on so tight you would need to get a crowbar to get it off. Ran and flew the heli for a half and hour. Burning plastic smell when I was done samething that happened before. It was coming from the clutch. Took it apart checcked it it looks ok..... Is that normal for it to smell like burning plastic?
Old 03-02-2008, 02:16 AM
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jamesc43
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Default RE: Clutch Problem Second time Fixing


Here is my input for what it is worth. I recall that having to use JB weld to glue the
clutch lining into the bell housing. It almost sounds like your idle is to high causing the
clutch to ungage to early. You clutch shoes are sprung from heat build up while being
engaged. The rotor blades should want to freewheel when the engine is running.

My first heli was a Hawk. I burned the clutch up while it on it's side in my back yard.
I tried to fly it after that but it was never the same. I was trying to learn to hiover and
was watching black crap fall out from under while it hivered bearly off the ground. When
I shut it down and it had cooled, the entire clutch was melted together.

I have several sets of instructions for Hawks and most describe how to set up the
clutch and I never had a problem.
Old 03-02-2008, 09:44 AM
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girwin1123
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Default RE: Clutch Problem Second time Fixing

The idle is really slow to the point of where the engine wants to cut off. The blades dont move and free wheel. But what you said is what happened the last time. The clutch comes with the lining already glued in. I am thinking maybe the head speed is to low in a hover putting way to much stress on the clutch.. Any though on that?
Old 03-02-2008, 04:06 PM
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Default RE: Clutch Problem Second time Fixing


That is possible I guess.

Something you should also look at when you assemble the clutch is the spacing
between the shoes and the clutch material. I do not have any specs on the spacing
but it should be close to rubbing.

Do you know your pitches at the various flying points and throttle settings? What
head speed do you get at those settings? What blades are you flying?

I've built three or four Hawks over the years and I've never had a clutch problem except
the one I mentioned above. That one was self induced.
Old 06-11-2008, 01:25 AM
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wldcwbypilot
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Default RE: Clutch Problem Second time Fixing

I learned about clutchs from old school guys. I always do a quick burn in and the head revoltions when your idle is set right should be so slow it just barely moves.
Old 06-18-2008, 06:02 PM
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Default RE: Clutch Problem Second time Fixing

i have a K-50 which is still a century heli anyhow i burnt out 3 clutches one was a hot start (my fault idle up 1 ) another was low head speed a (again my fault) and the last one was the clutch come loose and bound up ... i did a clutch, and fan upgrade with all aluminum and now i have no more trouble. also the motor is running way cooler than when it was stock
Old 10-25-2008, 03:39 PM
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mtwister
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Default RE: Clutch Problem Second time Fixing

Guys, also remember to use some sand paper (fine) on the new clutch lining and slightly scuff a new clutch. If you leave them smooth they will slip and burn up.
Old 10-25-2008, 06:42 PM
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Mutt
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Default RE: Clutch Problem Second time Fixing

are you using the spacer like your supposed to? thats the only thing I can think of. all of my hawks the clutches are 3 or 4 yer old and never a issue.
Old 11-06-2008, 07:12 PM
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Mutt
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Default RE: Clutch Problem Second time Fixing

I am thinking maybe the head speed is to low in a hover putting way to much stress on the clutch.. Any though on that?
No that wont cause it. I run headspeeds of 1400 on some of my helis. Sounds like your not using the right spacer on the crank and not tightening it up enough. I have 3 helis with the same clutches in them from over 3 years ago and all centurys.
Old 11-07-2008, 01:18 AM
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rotordoc
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Default RE: Clutch Problem Second time Fixing

Hey guys - did you know you are answering to a question from the initial poster who started and last posted in this thread in JUNE?
Old 11-07-2008, 07:28 AM
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Default RE: Clutch Problem Second time Fixing

so and your point? he never posted he figured it out either.
Old 11-07-2008, 11:24 PM
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rotordoc
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Default RE: Clutch Problem Second time Fixing

Good point Mutt - That seems to happen very often on these forums.

I would be niice if everyone came back and posted an explanation of what it was when they solve the problem.

I too have never had any clutch problems with any of my Hawks or Ravens. I personally think they have the best system I have ever seen (and I have a lot of experience with many different heli designs over the years.

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