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Good discussion on that link Michael. Although I noticed one of the posters
referred to 30% glycol mix as 70%. Making it quite confusing.
Over the years, I've encountered pilots who've done good job of measuring
Evans vs. glycol temperatures. We would expect them to have 20% higher temps,
but usually find 15% or so. I'm always intrigued when the occasional person
describes that Evans reduced their temp. It defies physics. But when you think
about it, it's possible that person started out with trapped air in system. When
converting to Evans, he may have eliminated that trapped air. Thus sees much
improved cooling. That's my best guess. That and pareidolia.
-al wick
----- Original Message -----
Sent: Friday, October 11, 2013 4:16
PM
Subject: [FlyRotary] Re: waterless
coolant?
Al:
I did a bit more digging on the
stuff and came up with this which makes the same point.
Michael Silvius
Scarborough, Maine
----- Original Message -----
Sent: Friday, October 11, 2013 10:33
AM
Subject: [FlyRotary] Re: waterless
coolant?
I've researched this product thoroughly and used to do fluid heat
transfer experiments in my occupation. If you drained all the fluid in your
radiator, replaced it with 100% antifreeze (normal ethylene glycol) you'd
have identical boiling point and heat transfer characteristics to Evans
product. So you could operate zero pressure, as it wouldn't boil over until
it reached 392F.
Unfortunately both Evans and 100% glycol have very low heat transfer
coefficient (.66). They are both insulators, so all things being equal, you
have to increase your radiator area by 30% to achieve the same engine
operating temperature. Compared to running with 30% glycol mix, that's quite
a penalty.
Ethylene glycol is substantially superior to Evans, as you can tune
it's efficiency by adding water. For example, it you decide to operate with
more efficient 50/50 mix, the heat transfer coefficient jumps from .66 to
.86. You get to reduce your radiator size a lot, yet still have 230F boiling
point.
Evans has a great propaganda web site, a lot of people get sucked in.
It's one of those rare products that has zero redeeming value. Far inferior
to glycol. Yet I bet it will continue to sell for decades.
-al wick
----- Original Message -----
Sent: Thursday, October 10, 2013
11:15 AM
Subject: [FlyRotary] Re: waterless
coolant?
You might want to check what happens to the viscosity of this fluid
at lower temperatures. Its been a while, but as I recall this
fluid turns into heavy syrup at lower temps. You can visualize
your water pump churning (cavitating) in a void of this fluid at low
temperatures while not moving any through your cooling system.
The fluid next to the rotors would undoubtedly get hot -while
that in the radiator and water pump may act as a (Temporary) plug to
coolant flow – until the heated fluid explosively forces the issue.
I tried finding the viscosity charts they used to have on the site,
but could not find it.
My impression when I looked into this fluid back a few years ago, was
that this heavy viscosity at low temps was probably not much of a draw
back compared to the benefits in a racing motor – heated garage,
summer temps, etc. But, might be a different story for aircraft
application.
Ed
Edward
L. Anderson
Anderson Electronic Enterprises LLC
305 Reefton
Road
Weddington, NC
28104
http://www.andersonee.com
http://www.eicommander.com
Sent: Thursday, October 10, 2013 1:05 PM
Subject: [FlyRotary] Re: waterless coolant?
This
appears interesting. I looked at the website and was unable to find
the heat capacity of the fluid. The higher boiling temp may not be
helpful if the heat capacity is such that you need a large delta T to
transfer the same amount of heat as a water-based
system.
One
must also consider the effect of the higher operating temperature on
engine oils. At some temperature, oil loses its lubrication
ability. I don’t know what that temp is but assume it is different
for different oils. Just because the coolant allows higher operating
temperatures, doesn’t mean one should do that.
Gordon
C. Alling, Jr., PE
President
acumen
Engineering/Analysis,
Inc.
540-786-2200
www.acumen-ea.com
From: Rotary motors
in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of
Michael Silvius
Sent: Thursday, October 10, 2013 1:19
PM
To: Rotary motors in aircraft
Subject: [FlyRotary]
waterless coolant?
While on the subject of
cooling, I am curious if anyone has tried the waterless coolant? Seems to
offer some advantages, namely higher boiling boint and low pressure, is
there any reason it should not be used in our
aplication?
No virus found in this
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