Richard Riley wrote:
that's one of the nice things about gear pumps. I'm using one for an
oil based cabin heater, I can't easily check to see if it's
reversable, but a phone call to them should answer it.

I've been toying with that idea for a while. You mean engine oil,
right? Are such things at all common? I guess what I most wonder is
why, on GA aircraft with aircooled engines, are exhaust heat muffs
and/or fuel fired heaters commonplace. Which is worse, the
possibility of CO in the cabin or hot oil in the cabin (and possible
loss of powerplant lubrication)?

Seems to me that safety/reliability issues can be addressed by using
quality parts and design. The functionality issue is maintaining the
oil at operating temp, on a cold day or fast/high cruise, when cabin
heat is most needed and the engine does not want to run hot (cowl
flaps?).

In other words, what am I missing? Thoughts anyone?