Thrust vs. Prop Pitch

[5-in-50]

It all comes down to the Lift : Drag, or also called, Thrust:Torque Ratio.

There is a particular ratio that offers the largest amount of Thrust (push forward) to the least amount of Torque (resistance/effort in turning the propeller).

Three things determine the T:T ratio. Aircraft forward speed, RPM and Blade Angle of Attack (the size of the 'bite', as mentioned in the previous post).

By increasing the RPM past the redline, you're setting a very small bite angle and causing the engine to work extra hard (more RPM) to actually produce less thrust (forward push), which is a poor T:T ratio.

For engine management (in the real world), it's better to operate at lower RPM settings because it means less engine wear and cooler operating temps.