Apologies for previous version- since my printer is not big enough to print and check!
You can see why I have changed the design
This should work, and I have tried to make it fit the design better...
Still too big for me to print, so if anyone does, I would appreciate feedback!
I have to say, since I have just crashed my Phantom 4 despite all the bells and whistles, the props were completely usable- so you may not need this except for stopping destruction!