How does the Nf governor regulate the propeller speed below 1853 RPM?

The Nf governor regulates the propeller speed below 1853 RPM primarily through adjustments to fuel flow. This is achieved by the governor sensing the speed of the propeller and then modulating the fuel delivery to the engine to maintain the desired RPM. When the propeller speed decreases below the set point, the governor reduces the fuel flow to decrease engine power, which subsequently helps stabilize the propeller speed.

Other potential methods of regulation such as hydraulic flow or mechanical adjustments may be involved in the overall operation of the propulsion system, but the critical function for managing the propeller speed, particularly during operations below a specific RPM limit, is the precise control of the fuel flow to adjust the engine power output. This coupling between propeller speed and fuel management is essential for maintaining optimal performance and adherence to operational limits.