They built a balanced piston valve. Very heavy-duty steel, they've run it as high as 500psi. The barrel is evacuated before the shot. There's a nice shadowgraph image of the shock wave from the supersonic baseball.
Discussion of the concept:
The shock waves start here:
Re: Supersonic baseball cannon on 'Smarter Every Day'
Posted: Tue Sep 22, 2020 9:41 pm
by Moonbogg
I saw that video. It's completely awesome! It's the ultimate pneumatic cannon and pushes the performance to the extreme by doing a variety of special things to get there. I loved it. I wonder how a hybrid cannon would do. I'm thinking a simpler and cheaper hybrid could be made that would out perform the pneumatic. I wonder why they don't explore that route. They have focused on pneumatic cannons with evacuated barrels. Maybe for legal reasons? If that were the case, they wouldn't have made a combustion spudgun video, which they did. I say they up their game and build a simple, beautiful, sexy looking piston hyrbid cannon out of heat treated 4140 at around 200kpsi yield and bust loose at around 20X.
Re: Supersonic baseball cannon on 'Smarter Every Day'
It's the ultimate pneumatic cannon and pushes the performance to the extreme by doing a variety of special things to get there.
I wonder why they didn't go with a burst disk. Much simpler to engineer and arguably has an edge in performance.
I wonder how a hybrid cannon would do. I'm thinking a simpler and cheaper hybrid could be made that would out perform the pneumatic. I wonder why they don't explore that route. They have focused on pneumatic cannons with evacuated barrels. Maybe for legal reasons?
There's a certain joy in achieving certain milestones purely with compressed air I suppose. Hybrids are almost "cheating" if the goal is to go supersonic.