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Date: Thu, 03 Aug 2006 11:13:36 -0400
From: Ernest Christley <echristley@nc.rr.com>
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To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Fw: AeroElectric-List: Alternator failure quits engine
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Ed Anderson wrote:

> Here is a story failure mode of an alternative engine on another list  
> that I found interesting.  I rather doubt that stuck belts would cause 
> a rotary to stop - although if at idle rpm, it just might.  I recall 
> one of rotary flyer who had a bolt jam the water pump pulley, but this 
> caused both belts to jump off the water pump pulley.  No coolant 
> circulating, but pilot made it back to the airfield, had to make a 
> go-a-round due to conflicting traffic, but landed safely.  Engine was 
> toast but still running when he shut it down.
>
> Ed
>
>>
>> The cause and subsequent sequence of events has now been established.
>>
>> Alternator bearing seizure initiated dual rubber v-belt slip at the
>> crankshaft
>> pulley.
>> In 2-3 seconds 50 cruise hp turned both rubber belts into smoke and
>> vulcanised
>> them instead of driving the now freewheeling prop (no flywheel effect to
>> snap
>> belts).
>>
>> The alternator was switched off immediately but to no benefit since its
>> load was
>> not the issue.
>>
>> So instead of the crankshaft pulley driving the alternator, the 
>> alternator
>> now
>> seized was now driving the engine to a stop! A relatively minor 
>> accessory
>> failure
>> had initiated a cascade of events equivalent or even worse than a major
>> engine
>> failure.
>

This sounds strange, Ed.  A couple of slipping belts stopped the engine? 
Is that possible?


-- 
         ,|"|"|,              Ernest Christley       |
----===<{{(oQo)}}>===----    Dyke Delta Builder      |
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