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HIROBO Turbulence - SDX - Freya - Sceadu > Lama clutch slipping
 
 
Bell Bloke
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Lama 30 sized heli clutch is slipping, have checked it and there seems to be no sign of wear or burning. Any ideas?
06-24-2005 Over year old.
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Dr Lodge
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Location: Guildford, Surrey - UK

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What's the clearance between the clutch shoe and liner? Assuming the shoes are slipping on the liner, I would guess either the gap is too large or for some reason you're trying to put more torque through it than it can handle.

Another reason would be if the clutch assembly is not rotating fast enough - what's the gearing compared with standard?

Vibe 90, Vibe 50, Vigor CS x2,
Dyna-x, Knight 503D, Logo 10,
TRex 500, Furion, Gaui EP200
06-24-2005 Over year old.
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Al Magaloff
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Location: 12,199 Posts- Enough Time Wasted. See Ya!

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Also, if you are trying to run an abnormally low head speed for a more scale look.
06-24-2005 Over year old.
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Bell Bloke
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Guys you are absolutely right the head speed is too slow with a bit too much pitch. Also the blades are very over sized. So basically too much torque trough the clutch. However I like the effect of all of the above, and so need to modify the clutch. If I ground it away very carefully at the pivot point it would come in earlier and with more force, good idea or bad idea. Or can I uprate it on this model. The only thing is that slow turning scale blades are a must. The Bell 47 has no clutch so no problem but I do like the whirring spool up on the Lama and this would be lost if I adopted the same system, however it may be my only real option.
06-24-2005 Over year old.
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Dr Lodge
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Location: Guildford, Surrey - UK

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Quote 
If I ground it away very carefully at the pivot point it would come in earlier and with more force, good idea or bad idea


Bad idea for two reasons:
a) it will weaken the clutch and it'll be prone to failure. You'd be better off replacing the lining so there is almost zero gap.
b) I think you'll still have the same problem due to insufficient centrifugal (or is it centripetal) force as the surface area is the limiting factor.

Two options for resolving this:
- change the gear ratio so the motor/clutch assembly is moving faster.
- modify the clutch so that it operates less like a clutch and gives a more direct drive eg replace the liner and pack it out so the clutch is a stiff push fit into the bell. If it still slips like this you'll have to think how you can make a solid connection up from the engine - perhaps weld a couple of locating pins on the top of the clutch that would engage into holes drilled into the top of the clutch bell?

Vibe 90, Vibe 50, Vigor CS x2,
Dyna-x, Knight 503D, Logo 10,
TRex 500, Furion, Gaui EP200
06-24-2005 Over year old.
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Bell Bloke
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Right Dr Lodge, it's drill time! I will do your last option, that makes good sense to me, I shall lock the clutch solid and then it is on less thing to worry about. One of the main attractions of electric is the huge amount of torque available on tap and also with no flameouts. The clutch is just another weak link. And because I tend to fly low at slow scale speeds with a low head speed, a really successful auto is unlikely. So reliability is the priority for me. The Bell 47 has logged 39 hours with no mods or adjustments at all. Good Ol Bell!
Will let you know how I get on.
06-24-2005 Over year old.
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Bell Bloke
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Well Gents, Thankyou very much for your help, the clutch mod is perfect!!
One problem though............
Wrong diagnosis......
Bell Bloke feels a bit of an idiot!!
You never guess what it really was....
The Bloody new receiver battery!
Basically the Bell 47 runs a U-Bec and a back up battery should either fail.
Well the Lama being so new and under development has no U-Bec, but Bell Bloke in has wisdom or perhaps just being paranoid put a duel receiver battery circuit in place until the Lama was finished. However during testing Bell Bloke only connects one battery, and after a full normal charge the nickel pack was connected. This went flat over night and after a 20 min hover starved the receiver of power. The receiver then must I think go into a failsafe mode cutting the power a bit. Then when trying to determine the fault by adding more pitch the tail wags from side to side because lack of rotor speed at the tail. I thought that this was just another indication of the clutch slipping. However what it actually is, is just the bloody tail servo packing up through lack of power.
You see even with the clutch locked it was doing the same thing!
Put another new battery on and ''we have lift off!''
But now my clutch is locked, Oh well it's one less thing to go wrong.
The moral of the story, well don't assume or jump to conclusions
AND
Always have a back-up....... AND USE IT!
Thanks though Guys, for your super rapid responses.
06-24-2005 Over year old.
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HIROBO Turbulence - SDX - Freya - Sceadu > Lama clutch slipping
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