In an axial flow jet engine, N1 represents the rotational speed of the low-speed spool. This spool includes the fan, the low-pressure compressor, and the low-pressure turbine, all linked by a concentric shaft. For many jet engines, N1 serves as the main indicator of engine thrust. This is an alternative to the Engine Pressure Ratio (EPR), which is used in other engine types. Understanding N1 is crucial for those interested in aviation and jet engine performance.
