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Although exhaust wrapping is fairly commom and effective it does create
some risks.  I recall an old article in the Lancair Network News where a
section of the exhaust pipe failed and fell onto the lower cowl preventing
a  normal nose gear extension.  In this particular installation the pipes
had been wrapped and could not have been inspected for cracks.  The exhaust
pipes should be inspected for cracks periodically and of course wrapping
would make this dificult or  impossible.

I used instead a high performance ceramic coating which the race car
drivers use to keep heat in the pipes.  HPC, Inc. did the coating for me
(about $200) and I was happy with the results although I don't have any
data to absolutely say that it made any difference.  HPC use to be at SLC?
(801) 262-6807 or (405) 682-2220 in Oklahoma City.  I suspect that wrapping
is more effective though.

Another very effective method is to use heat shields where needed.  One
method is to simply use Al or SS tape applied to the engine cowl where the
pipes are  too close.  I found too close to be within about 1 1/2 inch.
Another method is to instal fiberfax sandwitched between AL sheet and the
cowl.  These adjustments in my case were done after observing cowl hot
spots near the exhausts which caused discoloration of the paint on the
inside of my cowl.  If the cowl gets too hot it will cause the paint on the
exterior to fail as well.  

Jim
Lancair Network News