Has anyone used the NPG+ coolant in an aircraft? What are the pros
and cons?
NPG+ is standard
issue in the 912S, and perhaps the 912 also. If I'm not
mistaken, Dave Leonard is running NPG+ now, and I'm running
NPG-R.
The
Evan's marketing folks can give you way more pros than I can
think of, but I do think it's working very well. The
primary benefit is the fact that it's native boiling point is in
the 375F range, so you don't have to worry about a cascade effect of boil
over if you unexpectedly run hot, lose pressure, etc.
It's also not
supposed to be subject to localized boiling around hot spots in the
engine. Evan's claims this as a big benefit, but others, such as Tracy,
think this boiling helps remove heat. It's a bit more
environmentally friendly too, so it won't hurt the rats in John's
hanger.
The high
boiling temp means that you don't need to run a pressurized system, which
is my favorite part. There's less stress on the system, and any leak
that occurs, will be much slower (initially) than if there was pressure.
I added an air separator tank, with a level sensor inside, so if I
get a leak, I'll know about it before it gets to the level of the top of the
engine. That was the best detection method I could think
of.
The down side is
the cost, and the fact that it doesn't transfer heat as effectively as
traditional EG/water mix. Your temps will almost certainly go up some,
but at least you won't boil over.
If the oil temp is below 180
F but the coolant is above 220F, is this detrimental to the 13B??
Define "above"
:-) I don't think there's anything harmful about 220F, or a bit
over that for coolant, since cars do it all the time. I believe the
power will be reduced a bit at those temps though, and perhaps there will be
more wear on the engine. I've heard that, but can't say if
it's significant, or even true.
Cheers,
Rusty
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I don't know what "above" is because I've never run WOT at low altitudes
long enough to find out.
Boy am I confused about local boiling. Thought that yes maybe cool
momentarily while it initiates, but if a film stays in place that the heat
transfer goes to zip and damage to parts occur.
I like your idea about no pressure and measuring coolant level for
leaks.
What is the difference between R and +.
TIA,
Bernie