This is an “acorn” style prop-adapter for our 10gm brushless motors. Fits a 1.8-2.0mm motor shaft. The diameter of the prop shaft is 3mm. The length of the threaded part of the prop shaft is 1cm. This is a collet-style adapter which attaches by tightening the nut (the nut has a hole in the tip) – no grub screw.
This is suitable for 3″ and 4″ props. We also have a slightly larger prop adapter for larger props available.
The picture below shows the hub with a 4″ propeller mounted to a 10-gm brushless motor (the props and motors are available separately). The “acorn”-style hub looks realistic for typical warbird models.