Pull String Helicopter

UPDATED: v2 - complete rework. Different starter and propeller designUPDATED: v1.1 with open string hole - for more accessible string change and eliminating the need of the fifth threaded insert.This toys is designed to be more durable than the usual $1-2 toys you can find everywhere, therefore 608 bearing and threaded inserts are needed.There are also 3 different sizes of propellers (S, M, L)Parts needed for assembly:1pcs 608 bearing5pcs threaded inserts M3x5mm4pcs M3 screws1pcs rubber band (I