Ok, I'll take your word for it, but whatever the calculations, we got a max flight time of 6.5 seconds. I'm very pleased with that.

I still think 200ft was a reasonable estimate. Next time I will try for a max range and actually measure it (pace it).

200ft is an estimate, but we didn't measure it. I'm pretty sure that it's not an over estimate. Here are some figures... We fired our best vertical shot with a flight time of 6.5 seconds (This almost blew the base plate right out of the bottom can). Ignoring air resistance (I know :roll:) this would...

45 seconds may sound like too much gas, but it isn't. We tested it from 10 seconds through to 80 seconds. 60 was the most powerful, but it kept popping seems and blowing the back out, which meant replacing the bottom can. 45 was still powerful, but didn't wreck the cannon, plus we could still hear a...

I posted this in materials section, so apologies if you've already seen it, but here is a cannon made from cans and duct tape. A simple design that is surprisingly effective. It launches footballs over 200ft. When fired vertically it has achieved 6.5 second flight times. Build time: 15 mins. Cost: $...

... oh and it takes 15 mins to make, if you're quick, but earplugs would have been a good idea.

DWV? Does it come in a diameter that will accommodate a football?

The cans were free, why would I buy plastic pipe?

Plus if it fails it tends to fail safely at the duct tape seams, and you can always experiment with combustion chamber and barrel length. It's easy to replace dented sections too.

Can anyone beat my cheapness?

It launches a football over 200 feet, cost $5 for the duct tape. The cans were free. I already had the propane blow torch...

Enjoy!

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