Hi All,
First a word of caution. I'm not an engineer and don't have
any specialist knowledge. What I have to say may well be ( and probably is )
a load of old rubbish. Having said that, I'll press on anyway.
The problem seems to arise when the engine kicks back on
start up. The poor little starter motor turning one way meets the engine
violently kicking back the other. The location for this titanic conflict is
the sprag clutch - no wonder it can't cope. The higher output starter spins
the engine so fast that there is plenty of inertia to carry it over the
compression, whenever ignition takes place. This is how it feels anyway.
I agree that the higher power starter will put greater
torque into the clutch, but I suspect the increased forces are relatively
small compared to those involved in meeting a backfiring engine. I shudder
to think what it would feel like to have a kick back against the high power
starter.
Cheers, Paddy Clarke
ps. I hope this message doesn't appear twice - we had a power cut just as it
was being sent!
----- Original Message -----
From: "Ami McFadyean" <ami@mcfadyean.freeserve.co.uk>
Subject: Re: Europa-List: Rotax starting - 912S
<ami@mcfadyean.freeserve.co.uk>
>
> How is it that the higher power starter motor does not put a higher load
on
> the sprag clutch, which would lead to the earlier demise of the clutch?
This
> assumes that the clutch is the victim rather than the cause, which seems
to
> be the case.Or is it that the violent starting (and the 'standard' but
less
> violent stopping) is the sole cause?
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