This is a 1.5m zagi with a pressure vessel clamped to the fuse.
The vessel is filled half with water
and then pumped to 14 bar
The front of the vessel has a parachute.
When the pressure drops the clamps release the fuselage
and the parachute deploys
and the launch begins
The thrust at 14 bar was calculated at around 100kgs
The vessel is carbon fibre made in house.