By the info you supplied below the only advantage we have
with our restricted flow & NPG is the pre-ignition
protection? Has this been a problem with the 13b/
Pre-Ignition
Protection? Rusty listed the various advantages of NPG, and suggested
the only drawback was the cost. I just added a few other
drawbacks. I’m not aware of any relationship between pre-ignition
and the use of NPG coolant.
I’m also not suggesting
that NPG won’t work. Just be sure that the design of the coolant
system and pump, and engine, is compatible, and it could be great.
Al G.
-------Original Message-------
Subject:
[FlyRotary] Re: NPG + use in aircraft??
Rusty; can you quantify
this statement:
How much more
does it cost?
Over here, it's about $20/gallon plus shipping, which is
considerably more than normal antifreeze, and waaaaay more than distilled
water. For cost estimates, you'd be better off to look this
up from a local supplier, or contact Evan's about price and shipping
down under.
What percentage poorer, is it in heat removal efficiency
The specific heat of
NPG at operating temp (180F) is 0.65; compared to 0.8 for 50/50
EG/water, and 1.0 for water. So about 20% poorer than EG/water and 35%
poorer than water in carrying heat per unit of volume.
The viscosity of NPG
at 180F is about 3.6 times that of EG/water, and about 10 times that of
water. Results in considerably higher pressure drop around the loop and
higher pumping power, lower flow rates. Works best in large channel
radiators, and with Evans high performance pumps.
The thermal
conductivity is lower (can’t find the data right now). I’m
guessing about 30%. Results in lower heat transfer cooefficents.
Al
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