Subject: thermostats
From: ACRE NL
Date: 8/13/2001, 10:11 PM


Paul Lamar wrote:

Come to think of it I did not see any -4 bleeds on Power Sports engine
from the front of the block (PSRU end) to the pressure can.
Perhaps when they changed the rad to a single pass from a double
pass they inadvertently got all the air out of the system and it started
cooling better. Things like that can really fool you.

Come to thing of it if you don't have a bleed like this the rotary engine will
build its own [vapor] pocket in this part of the engine block while the
airplane is in a climb . That is because  the water inlet and
outlet to the block are located no higher than the rest of
the block. When it is tilted up in a climb it is generating
an [vapor] pocket in the front of the block due to normal nucleate
boiling. Not to mention an out and out boiling steam pocket.

Russell Kent wrote:

[ Nitpick mode = ON ]
Paul,
True nucleate boiling won't cause an "air pocket".  Actually, nothing but
entrailed air can cause an air pocket.  It is possible to have full-tilt boiling
cause a steam pocket, however.  Of course, if you have full-tilt boiling (not
nucleate), then you're seconds away from much bigger issues...

But you are correct in stating that the highest point in the block needs to have a
bleed line.

Russell Kent

I think Heinz Heisler disagrees with you. He calls it "vapor" in
them tiny bubbles and they go to the air space at
the top of the system.

Paul Lamar

It is definitely water vapor that Heisler is writing about, not air vapor.  No where is
there mention of air in the attachment.  How can the heat transfer processes between the
coolant and metal surfaces create a mixture of nitrogen and oxygen gases?

Scott

I changed the original text to read vapor guys. I stand corrected.

Sheesssss what nit pickers :-) The result is the same. A vapor pocket 
does not cool any better than an air pocket. That was supposed to be the point:-)

Paul Lamar
 
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