Ranger or Exploer class
One option to attach the propeller to a motor is the 
MAS3200 MA 05 PROPELLOR ADAPTER from Master Airscrew

INCLUDES: 
     One aluminum adapter
     One 10-24x3/4" cap head screw
     One 3/16"IDx7/16"OD flat washer
     One 6-32x3/16" set screw
     One 1/16" hex wrench

Recommendations from the intertidal zone: toss the 10-24x3/4” cap head screw and replace with a longer screw cut to length (if you thread a nut on the screw before cutting, then unscrew the nut it will help clean the damaged threads).  A pantop ¾” is actually just right for many of the propellers.
Use lock tight at least blue if not red.  Eventually the electrical chemical action will bond the steel and the aluminum together.