If this is blowing the warm combustion gases into the cabin, plenty of
drawback. The combustion products are primarily carbon dioxide and water
vapor. Lots of water vapor. The moisture can fog all the windows, or
create frost on the inside of the windows if it is below freezing. OK on
the engine, bad in the cabin.


"dave" wrote in message
. ..
Another thread made me think about using the portable propane heater I use
in my garage to preheat my airplane. It's the standard metal tube type
with the fan from Home Depot or Lowes. I've seen people simply attach a
flex duct to the end of this type heater and blow the hot air into the
cabin - poor man's red dragon. Any drawbacks?
Thanks
Dave