What is N1 and N2 in a jet engine?
N1 and N2 express the rotational speed of turbine engines as a percentage of the maximum normal operating RPM. N1 is the speed of the low pressure spool and serves as the primary power setting, and N2 is the speed of the high pressure spool which indicates if aircraft systems have sufficient power. The N1 Indicator is a cockpit gauge which presents the rotational speed of the low pressure (low speed) engine spool, a speed that is referred to as N1. The gauge is usually calibrated in percent RPM based on an engine manufacturer defined rotational speed that corresponds to 100%.In an axial flow jet engine, N1 refers to the rotational speed of the low speed spool which consists of the fan, the low pressure compressor and the low pressure turbine, all of which are connected by a concentric shaft.The N3 Indicator is a cockpit gauge which presents the rotational speed of the high pressure (high speed) engine spool in a three spool jet engine such as the Rolls Royce RB211. The speed of this spool is referred to as N3.
What is N2 or N3?
N3: Intermediate level: It’s a bridge level where Japanese language proficiency reaches a professional level, ideal for communication in both the office and daily life. N2: Upper intermediate level: It’s a pre-advanced level where candidates can communicate with Japanese native speakers with relative ease. Even though the great majority of potential employers prefer candidates with a level of Japanese language proficiency between N2 and N1, it is not impossible to get work if you have a command of the Japanese language at the N3 level.