As a former "Four Fanned Trash Can" pilot with about 750 hours in type, I never heard the reasoning for the prop shape. I do know the Orion (P-3) had high-speed props and they were round tipped. The H model Herk could outrun an A-10 down low so to call it slow is really a relative assessment. I do know the dadblamed props ate tons of torque generated by the motor: 19,600 inch-pounds comes to mind (19,600 pounds hung from a 1 inch fulcrum). During flight test in the late 50's the flight test pilots never discovered the power on stall speed. They quit at 45 degrees nose high saying, "You don't pay us enough to go higher."
PT
