> > 100% ethylene glycol cools WORSE than 50/50 EG/water mix.

There is a LOT of snake oil out there.   I am not saying that NPG is
snake oil, really haven't looked into it, but it is likely not optimum

for

cooling engines designed for EG/water 50/50 mix.

Bill Freeman

Take another look at all the charts on this subject I have uploaded
recently.

Paul Lamar

Ed Anderson wrote:

I guesss, I don't understand this search for a different coolant medium.
So far as I know, no commonly available liquid has a higher specific heat
value than water.  Even mixing antifreeze with water effectively lowers the
amount of heat the coolant can absorb as anitfreeze does not have as high a
specific heat value as water.  So regardless of the boiling temp of the
cooling liquid, if the specific heat value is lower then less heat is
transported from the metal into the liquid per unit volume. While a higher
boiling temp does permit more heat to be transfered to the cooling medium
before it boils, this does not necessarily mean that it transfers heat more
efficiently than water.  There may be some applications where the higher
boiling temperature is critical, but for ours?? What am I missing??

Ed Anderson

You are missing nothing.  You are absolutely right.  The reason for EG/water is
primarily for freeze protection and secondarily (more important now than
30 yrs ago) for corrosion protection, plus a lube function for the water pump
seal.  Distilled water is a great coolant, but it will corrode the heck out
of stuff,
esp a mix of metals like a typical cooling system.  When the radiator was thick
brass and the block thick cast iron, and engines lasted 50,000 miles to the
junkyard, water alone was fine except in winter.  With paper thin aluminum
rads, cast iron blocks, aluminum heads and who knows what else in the mix,
we really need a lot of corrosion inhibitors.  Use distilled water in making up
your EG/water mix to minimize "lime" plate out on the cooling surfaces.

Bill Freeman
Long EZ builder & pilot
BSME, MSME
EAA Technical Counselor

 
The AirCraft Rotary Engine NewsLetter.              Powered by Linux.
ACRE NL web site.
http://home.earthlink.net/~rotaryeng/            http://www.linux.org