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Date: Thu, 08 Mar 2012 15:38:06 -0500
From: Ernest Christley <echristley@att.net>
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To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Engine cooling
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Chris Barber wrote:
>
> Just some data points for discussion. PLEASE if you know some stuff tha=
t
> is rotary specific, or just wrong, CHIME IN!!
>=20
> =20
>=20
> Chris
>=20
> Houston
>=20
> =20
>=20
> Cooling Guidelines for V8 Engines in Aircraft
> by Bud Warren and Phyllis Ridings
>=20
> After much thought, Bud decided to install a thermostat in the LS1
> engine of the Ravin 500 to do some test flying. During cold weather the=

> resulting engine temps have remained stable at 190=B0F at cruise, and
> near 200=B0F during climb out; just about what we see during the warm
> months of the year. This has corrected the check engine light coming on=

> due to the engine remaining in warm up mode.=20

This approach makes me nervous.  It doesn't hit us much here in the south=
ern US, but things get colder as we move north.
 When it is freezing on the ground, it's very easy to get REALLY cold tem=
ps at altitude.   If it is 0*F on the ground,
then the rule of thumb says that it will be -40* at altitude.

The problem described is that the engine isn't able to produce enough hea=
t to warm the water with the amount of -40*F
air that is rushing through.  The prescription given is to force the wate=
r to stay in the engine longer.  This
necessarily means that the water will stay in the radiator longer. Now th=
e thermostat opens even less, because what it
pulls from the radiator is ice water.  At some point, the water gets real=
ly hard in the radiator and stops flowing
altogether.  The there is no flow from the engine to melt it.  The engine=
 water keep recirculating and it eventually
overheats.

The Mack truck I bought in the late 80's had a shutter arrangement in fro=
nt that would close when it got to cold and
block airflow through the radiator.  I think a thin aluminum panel, possi=
bly controlled by a push-pull cable from the
cockpit, that slid in to partially block the radiator would be a much saf=
er solution.  It would also alleviate the
concern over broken thermostats.  The panel would require minimal support=
, as it could simply lay flat against the
radiator face.