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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