Engine Pressure Ratio
“How does the ratio of outgoing and incoming air pressure affect the performance of a jet engine?”
The difference in air pressure across the entrance and exit of a jet engine is what allows a jet to fly. The greater this pressure, the better the performance. To get a standard metric for this, we can take the outlet pressure and divide it by the inlet. The greater the number, the better the performance. This is why the Engine Pressure Ratio is so important.