Dan Youngquist wrote:

Have you experimented with blowing the heat in the cowl inlets and
letting the coldest air inside the cowl come out the bottom? Seems like
it would heat much faster that way since you'd be exhausting the coldest
air instead of the warmest air.

I got my best results by inserting the heat duct in the air gap at the bottom of
my cowl and allowing the air to exhaust out the cowl inlets. When I inserted the
heat duct in the cowl inlets, the top of the cowl got uncomfortably hot fairly
soon. All the warm air stayed up at the top and the cold air stayed down around
the crankcase.

Perhaps if the cowl inlets were sealed around the heat duct it might work
better, but I think it would not.

George Patterson
Coffee is only a way of stealing time that should by rights belong to
your slightly older self.