Chapter 9: Supercharging

Flashcards covering key concepts from Chapter 9: Supercharging, including naturally aspirated vs supercharged engines, compressor types, waste gates, and altitude effects.

What is the absolute ceiling?

The altitude at which an aircraft can no longer climb.

Why does naturally aspirated engine performance fall with altitude?

Air density decreases with altitude, reducing the fuel-air mixture density and engine power.

What defines a naturally aspirated engine?

An engine that draws air only from ambient air with no forced induction.

What is the purpose of a supercharger or turbocharger?

To compress intake air before entering the cylinders to compensate for reduced air density at higher altitude, maintaining more power.

In carbureted versus fuel-injected engines, what is compressed by a supercharger or turbocharger?

Carbureted: the entire fuel-air mixture is compressed; fuel-injected: only air is compressed, with fuel injected into the compressed air just before entering cylinders.

What is the critical altitude?

The altitude at which the supercharger/turbocharger can no longer maintain sea-level performance.

What is a major risk of excessive compression in a supercharged engine?

Detonation due to high temperature, causing uncontrolled burning of the fuel-air mixture.

What instrument monitors the air pressure entering each cylinder in a supercharged engine?

Manifold pressure gauge.

What is the main component of a supercharging system and how does it work?

A centrifugal compressor with an impeller and diffuser; air enters the center of the impeller, is accelerated outward, and the diffuser converts it to high-pressure air.

How is the compressor driven in a supercharger vs a turbocharger?

Supercharger: engine-driven via belts or chain; Turbocharger: driven by exhaust gas through a turbine.

What is a waste gate and what does it do?

A valve that controls the turbocharger compressor speed by diverting or allowing exhaust gases through the turbine.

What is the difference between fixed and variable waste gates?

Fixed waste gates are set before flight; variable waste gates can change position in flight (pilot-controlled or automatic).

What is altitude turbocharging (normalizing)?

An automatic setting that adjusts the waste gate to keep engine operation near sea level as high as possible.

What are the benefits and potential downsides of supercharging?

Benefits: climb faster and higher; Downsides: consumes engine power to drive the compressor and can strain or over-pressurize the engine, increasing detonation risk.

What is the inlet manifold and why is it important?

The pipes delivering compressed air to each cylinder; at very high compression, it can be damaged.

What is the relationship between waste gate settings and automatic altitude compensation?

Automatic systems adjust the waste gate to maintain sea-level-like performance at higher altitudes (normalizing).