Received-SPF: none
 receiver=logan.com; client-ip=68.230.241.28; envelope-from=daveleonard@cox.net
From: "DaveLeonard" <daveleonard@cox.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Subject: RE: [FlyRotary] Re: Switching to Evans NPG+
Date: Mon, 17 Jan 2005 15:18:45 -0800
Message-ID: <PIEMJLCHGPKMFMDHBKMLKEHNCPAA.daveleonard@cox.net>
MIME-Version: 1.0
Content-Type: text/plain;
	charset="iso-8859-1"
Content-Transfer-Encoding: 7bit
Importance: Normal
In-Reply-To: <list-610732@logan.com>

Thanks Marv, that is a good data point.  I'm sure it is true that if the
coolant is 250, the coolant o-rings in the rotary will be quite a bit hotter
than that....

I have more or less committed to giving it a try.  At this point I am trying
to decide upon a safe redline...  Pineapple racing (rotary) uses 250-260.
After hearing your story I might start at 240 and see how things go...

Dave Leonard

> HI dave,
>
> Just a data point for you to consider....
>
> I've been working on this Eagle540 V8 powered Lancair IVP for the
> last several
> years.  When we received the engine we installed it, put coolant
> in it (50/50
> anti-freeze/water) and started to run it in order to work the
> bugs out of the
> instrumentation.  During a call to the engineer who designed the
> motor he went
> apoplectic when he heard that we were running 50/50 coolant/water
> in there, as
> the engine has a magnesium intake manifold and may well suffer
> from corrosion
> from the water.  We drained it and replaced it with Evans NPG+.  This was
> about a year or so ago.  At that time the folks at Evans also
> suggested to Ted
> (owner of this Lancair) that since this coolant was so superior and has
> hundreds of proponents running it in their race cars and other
> vehicles, that
> 250*F coolant temps are just fine.
>
> Fast forward to now.....
>
> One time during the most recent testing phase, when we were
> working our way up
> to full power, Ted let the coolant temp (on the hot side, coming
> out of the
> engine to the thermostat housing and on to the radiator) rise to abou 240
> degrees.  I saw a couple puffs of black smoke from one of the
> exhausts, Ted
> saw a cloud of something fly over the top of the cockpit, and so
> shut down.
>  We had coolant on the outside of the engine, at the front on the
> gearbox,
> about 4 feet away from the coolant overflow bottle.  It looked
> like we sprung
> a leak between the intake manifold and the head on the right side of the
> engine.  I pulled the mamifold, found a kinked o-ring, replaced
> it, put things
> back together and tried again.  More coolant outside... bummer.
> Tried dealing
> with the manifold once again and during the next test discovered
> that the leak
> was coming from the right head gasket.  Replaced it and went back to
> testing... new leak from the left head gasket, or more likely
> just another one
> that we didn't see when the right leak happened.  When Ted got it
> up to 240 he
> managed to blow both head gaskets.  That's not the worst of it...
> the internal
> metal temps of the engine had to be considerably higher than the
> 240* we were
> seeing on the coolant, as when we pulled the left head we found cylinder
> scoring, and perhaps even evidence of a couple broken rings in
> there... the
> engine is being removed from the aircraft and being sent to the local
> pro-stock engine builder for a complete bottom end tear down,
> inspection, and
> replacement of damaged parts... rebalance, etc, etc......
>
> The moral of the story is that the folks at Evans might know
> everything there
> is to know about the chemistry of their product but they don't
> know everything
> about the metallurgy of every engine their product might be used
> in.  While I
> understand the argument that there's only a relatively small difference
> between 200* and 240*, the heat load that the metal parts are
> seeing can be
> far greater.  Other components may suffer as well.  Before you go
> merrily on
> your way, convinced that 250* is ok for your rotary you might want to ask
> yourself this question:  If that's the case, how come everybody
> sets their
> redline at 210 or thereabouts?  We already know that water has a higher
> specific heat carrying capacity than other checmicals, so why is
> it ok to pump
> more heat into something that doesn't work as well as water?
>
> Don't get me wrong, you might be perfectly ok setting your
> redline with NPG+
> at 250.  Then again, you might not, and wind up going down the
> same road we
> are with this monster V8.  Personally, I'd rather see you make the
> water/anti-freeze system work... higher temps could well take certain
> components right over the edge, and who needs that aggravation?
>
>   <Marv>
>