FAA Powerplant Written Practice Test

What does the prop governor cockpit control adjust?

1. Blade angle directly

2. Fuel mixture

3. Tension on the speeder spring

4. Propeller rotational speed

The correct answer is: Tension on the speeder spring

The prop governor cockpit control primarily adjusts the tension on the speeder spring within the governor mechanism. By modifying the speeder spring tension, the governor can regulate the propeller's speed response to changes in power settings and load conditions. When the pilot increases power, the prop governor works to maintain the desired RPM by adjusting the propeller blade angle. In a typical governor system, when the RPM drops below the set point, the governor allows the blades to change to a lower pitch, enabling the propeller to absorb more power and return to the desired RPM. Conversely, if RPM exceeds the set point, the governor shifts to a higher blade pitch, reducing thrust and allowing the engine to maintain the targeted speed. This mechanism is crucial for managing engine efficiency and maintaining consistent performance across various flight conditions. Understanding the relationship between the speeder spring tension and propeller speed is fundamental for pilots and maintenance personnel when it comes to ensuring propeller systems operate effectively.