I think a better comparison is a car heater. It utilizes the
antifreeze and operates below boiling temperatures. I would think that
the oil temps would be greater than the water temps.

I would assume that at some point the oil will be hot enough to flow
through the oil cooler and not bypass the oil cooler.

So as long as fresh air is used to cool the oil cooler, the heat could
be directed into the cabin with an air bypass on the egress side of
the oil cooler. Or a second oil cooler could be installed in the cabin
with a heater box that could open or close an air vent.

I agree with the concern of running the air past the muffler. For that
reason I disconnect the air duct from the muffler to the heater
system. In the areas that I fly it does not get cold.

Exhaust heaters are beyond my margins for safety.

Steve


On Wed, 27 Oct 2004 09:17:19 -0400, Todd Pattist
wrote:

(Ulrich Neumann) wrote:

Not quite so, Ian. The oil cooler would always be cooling the oil,
just what you do with the warm air downstream from it is the issue. A
simple vane valve diverts the warm air either into the cabine or out
into the atmosphere. Simple and light-weight!

Not so simple or light. Oil runs at a far lower max temp
than exhaust. It's also far more viscous, especially when
cold. To get comparable heat transfer you would need to
provide much more surface area than an exhaust muff. That
means more weight. You'd probably need to run the oil
through a heat exchanger, which means forcing viscous oil
through small diameter heat exchanger tubes. Of course, you
can't do that until the oil is hot, so you'd probably need a
bypass system and you've got to be careful not to block up
the heat exchanger tubes, stop oil flow and blow the
engine.

Todd Pattist - "WH" Ventus C
(Remove DONTSPAMME from address to email reply.)