This is the Master Airscrew 13x8 3-Blade Pusher Propeller.
FEATURES: Constructed of glass filled nylon for strength and durability
Scale look and true pitch
Accurately balanced to create a greater thrust at lower RPM
SPECS: Diameter: 13" (33cm)
Pitch: 8" (20cm)
COMMENTS: The general rule for converting a 2 blade prop to a 3 blade is to
subtract 1" from Diameter OR subtract 1 from Pitch.
Pusher propellers are designed for airplanes that have the engine
facing backwards in the rear of the plane, PUSHING the airplane
PER MASTER AIRSCREW: All 3- and 4-blade props are balanced
dynamically at the factory prior to drilling. The mounting holes
are then drilled slightly off center, if required, to properly
balance the propeller. As such, the mounting hole may be slightly
off center. Master Airscrew assures us this is perfectly normal
and will not cause problems during use.