FAA Powerplant Written Practice Test

What component typically drives a supercharger?

1. Intake manifold

2. Gear train from the crankshaft

3. Battery power

4. Fuel system

The correct answer is: Gear train from the crankshaft

A supercharger is a mechanically-driven device that compresses incoming air into the engine to increase its power output. The typical method of driving a supercharger is through a gear train connected to the crankshaft. This connection allows the supercharger to draw power directly from the engine, making it effective in enhancing engine performance by forcing more air into the combustion chamber, thus allowing for more fuel to be combusted. The gear train arrangement ensures that the supercharger's operation is synchronized with the engine speed, meaning as the engine accelerates, the supercharger increases its air intake pressure proportionally, which is crucial for maximizing the efficiency and overall performance of the engine. This mechanical aspect distinguishes superchargers from turbochargers, which are driven by exhaust gases. In contrast, an intake manifold distributes the air-fuel mixture to the cylinders but does not power the supercharger. Battery power is irrelevant in this context, as superchargers do not operate off electrical power; this is more associated with electric superchargers or devices like electric fans. The fuel system's purpose is to supply fuel to the engine, not to drive the supercharger. Thus, the gear train from the crankshaft is the definitive answer.