No drawbacks at all. I've done it as you described. I took an old battery,
put it in a plastic battery case from WalMart, and bought a $20 inverter to
hook to the battery. The propane heater I used ran on 120v, and we have
little access to electricity. Since the heater only needed 120v for a
little fan, the current draw was low, and the battery-inverter thing worked
great. I got a little propane bottle, and a thing called "barbeque saver"
which allows you to refill the little bottle from a standard size tank. I
put the battery box and little propane bottle on an old folding luggage
cart, and had a portable preheater.

"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