What is a supercharger in aircraft propulsion?

• A. An engine- or exhaust-driven air compressor used to provide additional pressure to the induction air so the engine can produce additional power.
• B. A device that cools the intake air to increase density altitude.
• C. A turbine-driven device that recovers exhaust energy to boost thrust.
• D. A pump that increases fuel pressure to improve engine performance.

Answer: (A)

A supercharger is a device that compresses the air going into the engine to raise its pressure and density, allowing more fuel to be burned and more power to be produced. It helps compensate for thinner air at higher altitudes, so the engine can maintain higher performance than it would with naturally aspirated intake. The compressor can be driven directly by the engine (mechanical drive) or by exhaust energy (turbine-driven), which is why you’ll see both crankshaft-driven and turbo-driven variants described as superchargers in different contexts. The key idea is forcing more air into the cylinders to boost power.

Why the other ideas don’t fit: cooling the intake air would increase air density, but the phrase about density altitude is misleading and not how a supercharger works. A turbine-driven device that boosts thrust by recovering exhaust energy describes a different propulsion approach, not increasing induction air pressure into the engine. A pump that increases fuel pressure affects fuel delivery, not the air entering the engine.