Hello William,
My 912 'classic' Europa has flown for just under 600 hours and has a
very great number of take-offs and landings (higher than average),
mostly from a relatively smooth grass strip.
I have had 2, non-catastrophic exhaust failures in that time.
On the first occasion, after around 200 hours, a hole appeared in the
upper portion of the exhaust, probably related to a 'wire-wool' type
heat insulating material covering. (did it encourage condensation ?) The
insulation is now, no longer used. The engine became much noisier,
though the aircraft remained perfectly flyable. The failed pipe was
replaced.
On the second occasion, a hole appeared around 400 hours around the
'crossover' point of the exhaust downpipes and was only spotted on
inspection.
I can dig out more details, if you write me.
Alan
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-----Original Message-----
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] On Behalf Of William
Mills
Subject: Europa-List: 912 - Classic - Exhaust Pipe Fracture Survey
<combined.merchants@virgin.net>
I have recently had two stress fractures in my 912 / Classic exhaust
system. The first occurred on the outside of the last bend into the
silencer from No 2 cylinder (stb front) and the second occurred on the
outside of the first bend in the down-pipe from No 4 cylinder (stb
rear). The first was in the form of a letter "H" with the verticals
circumferential and the horizontal longitudinal. After speaking to
Andy, I had it gas welded and it has remained intact. 20 flying hours
later the second fracture occurred (fortunately less than 10 miles from
home), which blew apart and caused me to make a semi emergency down-wind
landing, because the vibration with more than 1/4 throttle was
unacceptable.
The aircraft has flown just short of 500 hours and operates from a
fairly rough farm strip. The exhaust pipes are mild steel and the box
is stainless. I would like to hear from any other owners details of any
exhaust fractures, hours flown and type of field used (i.e. hard or
grass runways etc) I know of at least one other, but there may be more.
The whole weight of the exhaust system is suspended off the down pipes
and the stub tubes off the box. The inertia when the aircraft is
bumping along rough ground is therefore considerable and I believe is
the cause of the stress fractures. For piece of mind, I have decided to
replace the whole exhaust system and having discussed the problem with
Andy, he is very kindly arranging to weld some supporting lugs to the
new silencer box so that I can provide metal straps to the crankcase and
engine mount (cross section member rigid with the crankcase) to reduce
differential movement and resulting stresses. If premature exhaust
failure due to mechanical stress is going to happen, the factory might
consider offering a mod to help support the weight of the system. I
have offered to provide details of the support system I set up for mine.
Best wishes,
William
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