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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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