Part layout.
Drilling end cap.
Bike valve cut.
Inside end cap.
Assembly.
Dish soap bottle cap. This is taller than a soda bottle cap leaving enough threads for tightening after a 3/4″ gasket is fitted.
Hole for nozzle.
Gardena nozzle.
Threaded body removed.
Placed inside bottle cap.
Base plate.
Leveling feet.
Base assembled.
Launcher on base.
Guide rods added.
Some details worth noting:
– tennis balls on bottles as nosecones to make them front-heavy
– straws on bottles for guided vertical launching
– strings attached with collars on the Gardena connectors for remote triggering
– abort valves for releasing pressure in case something goes wrong
– non-return valve to minimize water in the launcher and also for keeping the bike valve dry
– holes in the base for fixing the launcher on the ground with tent stakes