As kids, we found that putting a mike behind a fan created the same sound. We would record an adventure, using the sound, and just by snapping the fan frame it would sound like flak. Facing the fan and talking into the mike sounded like getting the message over the radio. After discovering that, we discovered the jet engine, it was made with a Hoover. We modified the sound with a wooden barrel and we had take offs and landings. Imagination and creativity as kids, where did it go?
.....; That's funny. What we did was took the muffler of a mower and fixed a makeshift megaphone on it to increase the roar......never understood why the neighbors disliked us...