Pull Copter with grip to glue

I gifted the original version to a 6 year old boy. He had a lot of fun with it but also a hard time to get it to start. 

He mostly struggled with getting a good grip on the ring, as it is way to big for his hands. So I modeled a new grip. Further the pullring of the key was way to close to the rotor. I redesigned the key so it stays out of the rotor. 

On the version I first tried with him the gear jammed with the key. So I lengthened the part where the key fits in the gear. 

As I hadn't have any M2 I just removed the screw-holes as I glued it anyway. The angle in the picture is for gripping the device with the left hand and the key with the right, rotate before glueing for the other orientation. 

Thanks for the initial designing!