Zip Tie Launcher for Pet Bottles inspired by various online sources.

https://youtu.be/Egix7ZXbOf4

This type of launcher make clever use of zip-ties to retain the PET-bottle on the launcher while you pressurize it. The zip ties grab around the flange on top of the bottle, and a ring makes sure the zip-ties can not move out of the way. When the ring slides down, it leaves room for the zip-ties to deflect and release the grip of the bottle, witch then leaves the launcher if pressurized.

My first attempt in PLA a few years ago was flawed and leaked all over the place. I now decided to do the pressurized part much smaller, in one piece and change material to PETG, witch now seams to work fine. I kept the majority of the design and just adapted to the new smaller pressurized part, witch might explain why some parts are designed like this.

The LaunchPipe is responsible for retaining the bottle using the Zip-Ties, locating the Pet-AP_Connector witch adapts the pet bottle to a standard European Air Hose connector.

I had a lot of small ball bearings witch I made use of in the launcher base, to work as pivot points in the release cord path, to alter the direction so that a remote pull cord can be used to release the bottle.
These ball bearings might be omitted and dummies can be printed in plastic if needed.
Among the STL's are a locator that fit around the airline tube inside the launch pipe to aid retain the direction of the adapter piece. and thereby keep the pet-rocket aligned with the pipe.
A tube is fitted on top of the PET-AP_connecor pice witch prevents the water to flow down the airline, and also generates some additional launch height.
The Locking_Ring is a safety feature, that can be used to lock the launcher and prevent a premature launch. It is to be placed undert the ring to stop this from sliding down and release the rocket.

STL's are attached, but also the original fusion360 file

Parts used:

• 1pcs Rubber O-ring, od=22mm, id=17mm, th=2,5mm (part of Biltema kit Art. 86-7030, size F12)
• 16 pcs Plastic ZipTies 4,8mmx250mm(x1,3mm) (Biltema Art 61-648)
• 2 pcs BallBearing 684, 4x9x4mm (flanged in my case), can probably be replaced by plastic spacer
• 1pcs European AirLine QuickConnect for 9mm tube. (Biltema Art.15-589)
• 1pcs Schrader Bicycle valve, (od 8,5mm) (might be taken from a bicycle tube)
• some meters of pressureised airline tubing (id=9mm)
• 2pcs hose clamps, the one used in the quick connect end needs to be of a low profile type to fit into the launch tube assembly
• 1pcs tube, id=13mm (Swedish 16mm “VP-rör”, electric conduit tubing) about 300mm, that fits on top of the pet
• some small wire or simmilar to become the release wire going through the pulley in the base assembly

Other parts:

• a wooden plate to stabilize the base to the ground
• a couple of tent spikes
• a dual hand bicycle pump (With schrader fitting) preferably with a pressure gauge
• a couple meters of rope to connect to the release wire
• 1,5l to 2l pet-bottles with PCO-1881 throat, with some sort of stabilizing fin assembly attached
• ¼ to 1/3 bottle volume of water per launch