My co-worker and I made an acetylene cannon once.
Put a tennis ball in it.
After we figured out the best way to ignite it (arc welding stick at a hole near the bottom) the thing went off with a ten foot flame shooting out the front.
Tennis ball landed on top of a 5 story building about 600 feet away
I did something similar.
I used to go caving - back in the day when you used carbide lamps.
A 3-4 foot piece of pipe - open at both ends.
A wet towel on ground, a touch hole near the bottom, a wire shield to keep the ball from sliding all the way to the towel.
Toss in chunk of carbide, then the ball.
Timing was iffy due to needing the right ratio of gas to air in the pipe.
Then balls went REALLY high all right!
(I’ve no idea where to get Calcium Carbide these days...)