How does the blade cuff (a fairing of suitable airfoil shape used to cover the shanks of propeller blades in order to reduce the aerodynamic losses) help cool the engine?
The cuff is used to change the pitch of the blades (or to create an airfoil when there is none) near the spinner. The cuff increases the airflow near the engine cooling intakes. The cuff is large, and larger at the blade root because the linear speed in this area is very small compared to the tip. Lockheed P3 Orion
North American P-51 Mustang, cuffed vs uncuffed
Awesome photo by Allan Grant/LIFE Magazine, via This Day in Aviation
Joe De Bona and Jimmy Stewart with Thunderbird, their P-51C Mustang racer, April 1949. Placed on the ramp in front of the airplane is equipment that has been removed or replaced. Note the four “cuffed” Hamilton Standard propeller blades along the right side of the photograph. They have been replaced with un-cuffed and polished Hamilton Standard “paddle” blades.