Propeller Launcher

This propeller launcher works with any propeller with a 5.5 mm square hole at its base. I've found Meister Edel ‘s Toroidal propeller to be the best. Here’s a link to it: https://makerworld.com/en/models/76740-toroidal-propeller-dupio-4-strong-flying-copter-to#profileId-113441. Some assembly and superglue required.