[Drew68]

Squirt a good blast of lighter fluid in the bottom hole and shake it vigorously for a few seconds.

We used starter fluid. The tennis balls went a little farther than 10-20 yards.

[Spruce]

We once tried our knowledge of this technology with an old, metal globe of the earth. In a basement. Squirted it full of a LOT of fluid, shook it well, match....BOOM!

We got stunned.

The two sections flew away from us or we could have been decapitated. The northern hemisphere spun on the floor in flames as we shook it off.

Friends mom came running down the stairs in a panic. She thought we killed ourselves.

Ahhh, youth.

[Charles Martel]

We used starter fluid. The tennis balls went a little farther than 10-20 yards.

Yes, starting ether was a better propellant - and it even came with that tube extension like WD-40, which perfectly fit the cannon's touch hole.