What does Compressor Variable Geometry (CVG) provide?

• A. Best efficiency of the compressor while preserving compressor stall margin.
• B. Best efficiency of the fan while preserving fan stall margin.
• C. Maintains exhaust temperature (T5).
• D. Controls anti-ice airflow.

Answer: (C)

Compressor Variable Geometry tunes the flow through the compressor by adjusting vane angles to change the pressure ratio and mass flow the engine sees at any given operating point. By doing so, it keeps the compressor operating on its efficient part of the map while preserving stall margin, which directly influences the energy entering the turbine. That balance helps keep the turbine inlet and exhaust conditions within limits, contributing to maintaining the exhaust temperature (T5) across different throttle and altitude conditions. CVG isn’t primarily about fan efficiency or anti-ice airflow, so its main effect isn’t on those areas.