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Hi Mark,
Didn't meant to create any alarm about my "O" ring
comments. If you are using the TES "O" rings then I think you can rest
comfortable with any reasonable engine temp. My TES "O" rings were
compromised by the extreme localized heating of the rotor/apex piece rubbing
against the side housing (not the due to any defect of the "O" ring) -
you could see that the O ring was shrunken adjacent to the hot spot but "proud"
to the housing the rest of the way around.
Your temp profile seems normal to me. I was
joking about adding the cup of air, I simply find that after 2-3 flights the
system simple does not appear to have any air in it. My theory is that the
air gets heated and expelled through the radiator cap into my overflow tank,
whereupon it is replaced by coolant flowing back into the system. After a
few flights, I started to get the "immediate" increase in coolant pressure upon
startup - but, once the engine is warmed it settles back down to under 10
psi.
I've flow it this way for over 250 hours with no ill
effects that I can detect.
Ed
----- Original Message -----
Sent: Tuesday, June 28, 2005 9:18
AM
Subject: [FlyRotary] Re: Coolant
Leak
Hi
Ed,
I haven’t paid real
close attention to my coolant pressures up to now. Not seeing anything
“unusual”, I typically focus on other stuff. Best I recall, my coolant
pressure starts at 0 and gradually increases. I have not noticed any
quick rise immediately following startup. But then, the coolant pressure
sensor is locate at the thermostat housing (no thermostat). So, I’m
measuring coolant pressures between the block and radiator. The highest
pressure I recall seeing so far is about 24psi after running for 20-30 minutes
and temps are in the 212 degree range. I have to admit that I’ve been
ignorant and uninformed as to the need for a cup-o-air in my system and have
to this date “filled it to the brim”. I guess I need to add a cup-o-air
the first chance I get.
I don’t follow you on
the potential damage to the o-rings. The TES o-rings are supposed to be
good to 500 degrees (I let you test that theory). They’re supposed to be
good for 100 degrees over the stock o-rings, so I should have a considerably
higher margin of safety here. I would be more concerned with blowing a
radiator hose, but I’m using aluminum tubing with Wiggins type couplings, so I
don’t think I’ll be blowing them apart anytime soon. I guess the weakest
link in my system is the heater hoses. While they’re top of the line
Gates hose, I plan on changing to silicone heater hose before first
flight.
Mark
(Happy to hear you
got home safely)
From: Rotary
motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Ed Anderson
Sent: Monday, June 27, 2005 9:29
PM
To: Rotary motors in
aircraft
Subject: [FlyRotary]
Re: Coolant Leak
The phenomena which started this
thread was the immediate rise in pressure during initial start up in some
installations (mine for instance) when all air has been removed from the
coolant system. Once my engine warms up the pressure runs around 8 psi
and may climb as high as 10psi if temps are higher than 200F. It
is true that higher pressure delays the temperature that water boils at - but,
higher pressure may also work against your waterpump seal and cause leaks
(just a thought). I personally prefer to run at lower coolant pressures
since my radiator cap has a max of 21-24 psi. I suspect that while a
higher PSI may indeed delay the onset of the coolant boiling - if your engine
is that hot - you will probably have cooked something (like "O" rings
{:>)).
----- Original Message -----
Sent: Monday,
June 27, 2005 10:07 AM
Subject:
[FlyRotary] Re: Coolant Leak
Ed,
Not to stir the
swirl pot, but I thought that it was decided some time back that higher
pressures were better than lower pressures. The higher pressures are
supposed provide more margin of safety before a boil-over occurs, permitting
a thinner ethylene-glycol solution and enabling the engine to tolerate
higher temps before experiencing catastrophic boiling. So, I’m
wondering where this leaves us. Is it better to run at low (7-8 psi)
pressures, or high (28-30psi) pressures?
Mark S.
I agree, Al, inquiring minds
at least like a plausible hypothesis and I think the discussion has led to
that. Perhaps I'll leave the "cup" of air, just for peace of mind
{:>)
Ed
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