No, it was a little forward of that. Think of the temperatures. What is
stainless steel melting point ?
And if the heat came from the inside, why is not burned right through ?
Karl
>From: "Duncan & Ami McFadyean" <ami@mcfadyean.freeserve.co.uk>
>Reply-To: europa-list@matronics.com
>To: <europa-list@matronics.com>
>Subject: Re: Europa-List: Melting silencer
>Date: Mon, 7 May 2007 20:52:44 +0100
>
><ami@mcfadyean.freeserve.co.uk>
>
>Was the "heat-stressing" opposite where one of the header pipes goes in to
>the silencer i.e. where hot gases directly from the end of the header pipe
>would impinge internally?
>
>Duncan McF.
>----- Original Message ----- From: "Karl Heindl" <kheindl@msn.com>
>To: <europa-list@matronics.com>
>Sent: Monday, May 07, 2007 2:17 PM
>Subject: Europa-List: Melting silencer
>
>
>>
>>
>>
>>The mod 72 has one good side benefit, it gives us the chance for a real
>>close inspection of the back of the engine and underneath. I had to remove
>>the silencer for better access to the firewall and two bottom frame bolts.
>>Here is what I discovered :
>>The bottom of the silencer , starboard side, an oval area of 30x90mm was
>>badly pitted with strong signs of having melted. The aluminum duct
>>directly underneath is similarly affected. I tapped the affected area with
>>a hammer to look for any weakness, but it appears to be still okay. The
>>aluminum is paper thin and needs to be patched.
>>
>>My installation is a standard 912S fwf kit with stainless exhaust system
>>and Singleton firewall. I never experienced any temperatures (according to
>>the EIS) above the permissable ranges. The EGT probes are on the exhaust
>>stubs of cylinders 3 and 4. I never noticed anything unusual.
>>There is no other heat damage. The coolant pipe directly behind it to the
>>radiator shows no sign of anything unusual.
>>
>>My questions are:
>>
>>Has anyone ever experienced or heard of anything like this before ? What
>>could be the possible cause ? What is the melting point of stainless steel
>>?
>>
>>There is no direct fresh air to the bottom of the engine. Some time ago I
>>had taped off the starboard NACA duct, as it was supposedly designed for
>>the 914. There was no detrimental effect to the engine temperatures. I
>>have now opened up the precut flap in the starboard side of the alu duct,
>>which will divert some fresh air to the silencer. (I believe this flap was
>>also designed for the 914).
>>
>>One very long shot : Could there be any electrical sparking between the
>>two surfaces, acting like a capacitor ? I just don't see how those high
>>temperatures could come from the exhaust gases without also burning the
>>outside of the fuselage etc.
>>
>>I wonder if anyone knows. And any help greatly appreciated.
>>
>>Karl
>>
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>
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