Definition
In a turbine engine, the ratio of the air pressure leaving the compressor to the air pressure entering the compressor. It is a measure of how much the compressor squeezes the incoming air before it reaches the combustion section.
Plain English
It tells you how much harder the air is being squeezed by the time it leaves the compressor compared to when it first came in. A higher ratio means the air has been packed tighter.
Context Anchor
Seen in turbine engine discussions, especially when describing how the engine compresses air before adding fuel and burning it.
Derivation
From Latin 'comprimere' (to press together) and 'ratio' (a calculated relationship between two numbers). Together: the relationship between the pressure pressed in and the pressure pressed out.
Why Pilots Care
Higher compressor ratios improve engine efficiency and thrust at altitude, directly influencing climb performance, cruise speed, and fuel planning.
Grounding Statement
A compressor ratio of 20:1 means the air leaves the compressor twenty times denser in pressure than when it entered.
Intuition Check
Do not confuse compressor ratio with the physical size of the compressor or how fast it spins. It is a pressure comparison: air pressure after the compressor compared with air pressure before it.
Example Sentence 1
Modern turbofan engines achieve a high compressor ratio, which contributes to their fuel efficiency at cruise altitude.
Example Sentence 2
During preflight study, the student compared compressor ratios between two turbine engines to understand differences in fuel burn.