Harrison Young wrote:

What is the worst corrosion anyone has seen in the aluminum
parts of a
rotary engine out there? I'm thinking of the case where someone
(automotive
use here) didn't maintain their cooling system with inhibitors,
or ran many
years with just tap water in the radiator. Has anyone seen
corrosion bad
enough to potentially "break-through" the wall of a combustion
chamber?

Harrison Young

I have never seen anything really bad except in a water pump
housing
and that was probably caused by cavitation due to low coolant
level
rather than corrosion.

Inside the rotor housing develop a thick coating which probably
reduces the heat transfer to the coolant. These are from Perry's
engine he got out of a junk yard, installed it as it was and flew
for 650 hours or so as I recall. This is the worst I have seen
most of
my
other half dozen rotor housings are in better shape. They all have
this coating to a lessor extent and other colors.

Paul Lamar

I fly a lot Paul, but I haven't reached that level of hours yet.
Total hours are approaching 450 after almost 5 years of flying the
rotary. I had 165 flight hours and 30 ground test hours on the
122,000 mile junkyard engine when it needed to be overhauled,
because the coolant orings started leaking. Which you think was
related to the tension bolt breaking.

--
Perry Mick
http://www.ductedfan.com

Sorry about getting the hours wrong. It sure looked like the broken
tension bolt 
caused the O-ring leak. Other than the O-ring leak the rotor housings
were
still in great shape. Looked like there were many more hours left in
that
engine if it were not for the direct drive thrust bearing wear.

For the new guys make sure your tension bolts have a spiral of red
RTV around them before you put them in. This damps the resonant
vibrations
that lead to broken tension bolts. If your engine is already built you
can take the bolts out in the proper order one at a time, apply
the red RTV, replace it and torque it to specs.

Paul Lamar
 
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