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From: "Ed Anderson" <eanderson@carolina.rr.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Subject: Fw: AeroElectric-List: Alternator failure quits engine
Date: Thu, 3 Aug 2006 07:36:01 -0400
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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

> --------------------------------------------------------------------------------
>
> Our recently rebuilt Europa G-BWCV is again in pieces after we put only 30
> more
> flying hrs on this engine to add to the 50hrs it had done in the hands of
> the
> previous owner.
>
> We had just received the new full permit to fly when recently, heading for
> Lundy
> Island just South of Bristol Docks , the cockpit filled with smoke as if a
> smoke
> bomb had gone off and the engine stopped! I could not discern whether the
> smoke
> was electrical in origin but assumed as the engine had stopped it had to
> be.
>
> 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.
>
> Ofcourse this should not happen should it?
>
> Little did I know I had become an involuntary test pilot!!!!!!!with an
> observer!!!!!
>
> The idea of a re-start attempt was not surprisingly quickly rejected.
> However, as
> I now know it would obviously have been a futile exercise, the engine
> stopped
> from 50hp running  so the starter did not have a chance.
>
> Two other aspects of this incident made for an extremely high workload.
>
> 1. I had to switch off all electrics to prevent any further risk of smoke
> (if
> only to be able to see out for a forced landing) or worse still fire. This
> meant
> I lost the electric trim.
>
> This may appear a small thing but believe me, this meant the constant use
> of one
> hand flying the stick without feel and as a consequence one eye glued to
> the ASI.
> A workload I did not need at this time. Mechanical trim would have helped
> enormously.
>
> Try your practice forced landings in cruise trim to see what I mean. "It
> could be
> you."
>
> 2. The other aspect which is a little more difficult to practice was the
> free
> wheeling prop. All practice forced landings to date had been with the
> engine at
> idle as is usual. In this condition increasing speed, by diving, increases
> engine
> rpm so the sprag clutch is effectively connecting engine and propeller
> like any
> other engine.
> When the engine stopped, I was quickly aware of an abnormally high rate of
> descent. The prop ran away like a wind generator in hurricane, the feel of
> the
> stick was abnormal due to the out of trim load and I think also the
> braking
> effect on the airflow over the tail.of the prop now in drag parachute
> mode.
>
> The location was far from ideal for a forced landing and with the high
> rate of
> descent meaning short time for descent we could easily have come off far
> worse
> especially since the area was well populated with power lines of different
> sizes
> forcing a late rejection of the primary field selection.
>
> Having taken the diagonal in anticipation of the limited field size We hit
> the
> far hedge in a 290 meter  30+ Celcius almost max gross with wind light and
> variable as the sea breeze was backing up the Severn valley. The near
> hedge
> incidentally was a 6 foot steep bank from a wide drainage canal. This,
> coupled
> with the unusual deck angle in the glide which only got worse of course
> when I
> put the coupled gear and flap down on the Mono, requiring an unusually
> long
> duration flare as if landing up hill, put our aiming point considerably
> before
> the actual touch down point so we were going to hit the hedge. The last
> trick I
> had up my sleeve from my cross country gliding days was to drop the gear
> in order
> to minimise the ground roll. This in retrospect, although it did no such
> thing,
> probably stopped us flipping upside down. I never considered applying the
> brake
> but the wheel just keeps turning judging by our grass marks.Which
> fortunately I
> was able to pace out having vacated the aircraft.
>
> I am giving a talk to Gloucester strut about the Europa rebuild and now
> have a
> new chapter.
>
> It is in the Aeros flying club building next Tuesday at 07.30 pm and would
> welcome anyone especially Subaru owners to come along.
>
> I still like the Subaru engine and would be happy to fly it again once
> this
> single point failure has been addressed. If the Europa flies again it will
> be
> called hedgehog!
>
>
>
>
>
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