Big John wrote in message . ..
Andre

Didn't think about the automobile 'boom boxes' that move your car
sideways when they go by.

There must be some of the amps and heavy duty speakers around if you
look, as a give away from wrecked cars or on Internet. Could build a
mock up and set on ground by your bird and start and run engine and
let someone walk away and see how far the sound can be heard over
engine.

Check ye local pawnshop. Being a guitarist, I drop in from time to
time just to see what's hangin'. There always seems to be a good
selection of automotive subwoofers and power amps. Rather than a
cassette tape, why not record to MP3? The MP3 players are lighter and
have no moving parts. Plus, you have random access to many different
sound tracks, not just a machine gun. For example, you might record a
75mm Howitzer (when you want to play at being a B-25H pilot), a
'bombs-away' whistle/kaboom to wake up the neighbors, various engine
sounds (for example, a B-36 on takeoff from the CD available at
http://www.b-36peacemakermuseum.org/ or
http://www.cowtown.net/proweb/lastb36/), sonic boom, etc.