old post but I usually pry the foam out of broken props to put in ones missing it, but probably can use foam from an FPV drone search for fpv foam example , pretty cheap 50 pcs $3, trim to fit, sticky side in
I see some cable release drop systems on ebay now 2024. search inspire 1 or 2 drop or fishing drop system. Personally I don't like the LED activated ones, difficult to use. the leg raise with switch seems easier
responding to this old post, I have replaced many center assemblies. the gear on the motor just slips on the shaft, there is no set screw . its pressed on there and eventually spins instead of grabbing. New center assemblies $249 used about $150 if you can find one. I bought the gear...