However, various valves have been adopted to deliver ... moving parts makes it easier to produce, and the parts also move slower compared to piston engines, making rotary engines more reliable ...

[Ben] created a piston valve for this cannon that can be built with parts sourced from your local home supply store. Anyone can build this thing, and everyone should. Instead of using a ball valve ...

One of the tricky parts of engineering in the physical ... pressurize an intermediate chamber. As the piston retracts, the ball closes the inlet valve, the outlet valve of the intermediate chamber ...