If you lose a propeller in the air with a quad is the better way to crash...
I have been informed that the Maytech 13 inch carbon prop for Yuneec Q500 has been upgraded at the end of 2015. The tightening nut 2mm is deeper than former version.
This seems to be due to problems, and manufacturer changed it to makes it combine better to the Q500 motor.
Be carefull to control if the propellers fit to your Typhoon Q500 quad.
A forum post from a guy of San Jose, CA - Jan 26, 2016:
YUNEEC has changed motor thread later 2015. We are updating the threads on our cabon props now.
The carbon props for YUNEEC shippped after 15 March are all updated ones.
Maytech Electronics Co., Ltd
Tel: 86-21-56165310 Fax: 86-21-29922989 www.maytech.cn
I contacted Carolina Dronz and asked them..why the **** they are selling the old props and also asked why they didn't pull them off the shelves. Of course....haven't heard anything back as of yet...In regards to the Maytech #MTCP1303Y CF Props...FYI for you all...Thanks
Source: New Aeronaut CF Props