How does the Constant Speed Unit (CSU) maintain the propeller speed at 1700 RPM?

The Constant Speed Unit (CSU) maintaind the propeller speed at a specific RPM, such as 1700 RPM, primarily through the use of oil. The CSU works by controlling the angle of the propeller blades to adjust for varying engine conditions and maintain the desired RPM.

When the engine speed increases, the CSU senses this change and causes the blades to change pitch to a flatter angle, which reduces the load on the engine and prevents over-revving. Conversely, if the engine speed decreases, the CSU adjusts the blades to a steeper pitch to increase resistance, helping the engine maintain the set RPM. This adjustment is achieved by using oil pressure generated by the engine itself. The use of oil allows for smooth and efficient control of propeller pitch and, consequently, propeller speed.

In this context, while fuel, electronic signals, and hydraulic pressure might play roles in other systems or components within the aircraft, it is specifically the oil that is critical for the function of the CSU in maintaining propeller speed.