Water Rocket Parts for 0.5L Polar Seltzer Bottle

Part of the Marimo Labs Open Access Water Rocketry Project

More info here: https://marimolabs.com/water-rocket-launcher
Launcher is here: https://www.printables.com/model/86434-water-rocket-launcher

Water rocket kit for Polar Seltzer 0.5L bottles

This is an alpha prototype of attachments to convert the Polar Seltzer-brand 0.5L plastic bottle into a water rocket. It is a proof-of-concept for a modular system of payloads and fins for water rocketry that provides the durability, repeatability, and extensibility required for a STEM-education platform. No adhesives are required.

Documentation is scarce, nomenclature is inconsistent, tolerances are variable, and optimal printing settings are not determined. But if you're up for trying something, here you are!

Parts

Nosecones: D66 (66mm diameter nominal), in 50 and 100mm long versions. FYI. Mass is a greater factor than shape. Print in TPU for safety and durability. Bayonet-lock onto the mount.

Payload (nosecone) mount: D66-P5 (5 petaloid base). Print from TPU to allow flex; press-on fit to Polar Seltzer-brand 0.5L bottle; also fits San Pellegrino 0.5L PET bottle. 

Rail Mount: 66D PLR05. Fits PS and SP bottles. Print from PETG with attention to cooling, as the overhangs tend to curl and cause parts to detach from the bed. PLA print ok too, with usual caveats about softening when warm.

Fin: L50-14sqcm (50mm rail length, area 14sqcm) and L55-21 (55mm rail length, area 21sqcm). Slide onto Rail Mount.

RM Retainer: Print from TPU. Flexible “crown” that holds the Rail Mount on the bottle and provides space for Clamps to engage with the bottle flange.

Recommended Print Settings

TBD; please share your testing with different filaments.

For rigid parts, generally PETG; 1 wall; 15% infill, cubic; top pattern concentric, higher cooling to avoid edge curling

For TPU parts, 1 wall, 15% infill, cubic; whatever optimizations are needed to deal with stringing and surface blemishes.