So you want to build a combustion-powered vortex cannon that can fire a ring of air at a high speed? NightHawkInLight has posted a brilliant video that shows you how to build your very own high velocity vortex cannon. The most difficult part was building the barrel. Since metal is too difficult to bend correctly and heavy, fiber glass was used to complete the job.
As you can see in the above video, this vortex cannon can fire rings at a high speed. What do you think? How would you improve it?