Thanks for the insights. The terminal velocity suggestion makes a lot of sense. I ran the Gas Gun Design tool, and once I figured out how to correctly input the chamber data, the results from the Ballistic Calculator are reasonably close to what we measured as well as the overall flight time. Very c...

Hi: New to the forum, got lots of great ideas for my son's science fair project here. Trying now to help him interpret the results. We built a compressed air tennis ball cannon using the simplest design I could come up with based upon examples I found referenced on this site. We used a 4" PVC sectio...