What is an Aircraft Supercharger? How Does it Work?

Aircraft superchargers are an important part of aircraft engines. As an aircraft reaches higher altitudes, there is less air pressure and air density, so a piston engine no longer is enough to power the aircraft. That’s where superchargers come in. Superchargers are engine-driven air pumps or compressors that provide compressed air to the engine, which then provide additional pressure to allow the piston engine to produce more power. A normal piston engine cannot have a manifold pressure higher than atmospheric pressure on its own, but with a supercharger, we can increase the pressure inside manifold by 30 “Hg.

This is especially useful to aircraft engines as air density is about 50% that of sea level or less at high altitudes. Superchargers could supply air to the engine at the same density at an altitude of 18,000 ft. as at sea level. The addition of a supercharger to a system doesn’t change much. The supercharger is placed between the fuel metering device and the intake manifold and driven by the engine through a gear train at one, two, or variable speeds. Superchargers also can have one or more stages, each of which provides an increase in pressure. They may be classified by their number of stages and their speeds.

For example, single-stage, single-speed superchargers, also known as sea-level superchargers, use a single gear-driven impeller to increase the power produced by an engine at all altitudes. Single-stage, two-speed superchargers use a single impeller that can operate at two-speed settings, low blower, and high blower. When the aircraft takes off, the aircraft supercharger is in the low blower, but when the aircraft reaches a certain altitude, power is reduced, and the supercharger is switched to the high blower. Then the throttle is reset to the desired manifold pressure, and the flight is maintained.