1.  Cut a board the same size as the hub.  I just use 3/4 inch hardwood.  Drill mounting holes in the plate to attach it to the wall.  (I use 3/16" toggle bolts or simple drywall screws if mounted on a stud.)
2.  Use the propeller hub as a template to drill holes (the same size as the hub mounting holes)  in the plate.
3.  Glue dowels into the holes in the plate.  Notice the different lengths of the dowels.  This makes placing the propeller onto the mounting plate much easier. At least 2 of the dowels should extend almost the whole width of the hub.
4.  You can further secure the propeller onto the plate by drilling a small pilot hole in the top dowels, sawing along the tip of the dowel to create a saw kerf, then after attaching the plate to the wall, inserting a screw into the end of the dowel to expand it against the bolt hole on the propeller.
5.  Attach the plate to the wall.  Usually a single strong screw into a stud or a single lag bolt is sufficient.  If you are using more than one screw or bolt attach the top screw or bolt first, put the propeller onto the dowels and align the propeller horizontally before adding the second screw.  (I usually just use a single upper screw or bolt so that the prop can be adjusted horizontally if needed.)

Mounting Bracket for Wooden Propeller Display
Storage Rack for Multiple Propellers
This relatively simple rack, consisting of two posts attached to a base plate, is a convenient way to store a number of propellers when space is a concern.  Wax paper can be helpful to keep them from sticking together but is probably not necessary.

A subsequent version, shown to the right, also serves as a convenient device to hold the a propeller to be wrapped or even  varnished  (although there are rare circumstances where varnishing is recommended.)

By expanding the tip of the dowel, these screws inserted into a drill hole and kerf in the dowel hold the hub firmly against the mounting plate.