About this 3D model

You've seen the ping pong ball on Mythbusters go faster than the speed of sound and punch a hole in a ping pong bat! ... yea. thought we'd try that one at home. The DN40 pipe that I got here in New Zealand was too small for the 40mm ping pong ball. So I ended up using DN50 and of course that was too big for the ping pong ball. SOLUTION... print your own... only not a ball. A hollow shell. The design could be improved upon, its set for 0.3mm thickness wall and depending on your printer a 0.4mm thickness wall will do better. Anyway after trimming the base slightly this fits nicely in the DN50 pipe and is just perfect when the vacuum is released. AND IT LOOKS COOL. If you release the shell at a wall or hard object it will be destroyed.... and that's where the science begins... just how fast is it going?