FAA Powerplant Written Practice Test

In a piston engine with a supercharger, where does the supercharger typically receive its operational power?

1. From the ignition system

2. From a gear train connected to the crankshaft

3. From battery power

4. From the engine oil system

The correct answer is: From a gear train connected to the crankshaft

In a piston engine with a supercharger, the supercharger typically receives its operational power from a gear train connected to the crankshaft. This connection ensures that the supercharger is mechanically linked to the engine, allowing it to utilize the engine's rotational energy to compress the intake air. As the engine runs, the crankshaft turns the supercharger via the gear train, enabling the supercharger to increase the pressure of the air entering the engine's cylinders. This boost in air pressure enhances the engine's performance by allowing it to burn more fuel, resulting in increased power output. The design of using a gear train is essential because it synchronizes the operation of the supercharger with the engine's speed, ensuring optimal performance across various engine RPMs. Other sources of power mentioned, such as the ignition system or battery power, do not provide the necessary mechanical energy required for the supercharging process, while the engine oil system primarily serves lubrication needs and does not directly power the supercharger.