Linked Questions

0 votes
1 answer
6k views

What is significance of N1 and N2 in Jet engine? [duplicate]

Why N1 Low pressure compressor RPM and N2 High Pressure compressor RPM are monitored in jet engines ? Why specifically compressor RPM rather than turbine RPM ? What do N1 and N2 signify in terms of ...
  • 514
1 vote
0 answers
185 views

Is N1 and N2 and any N speed the revolutions per second for the rotor blades of compressors? [duplicate]

For example the Airbus A350 has three N speeds I think is called Nucelle speed and N1 is for the fan or LP compressor, N2 is for the IP compressor and N3 is for the HP compressor. Even on the Airbus ...
23 votes
10 answers
9k views

Why are all engines identical in typical commercial airplanes?

I come from the IT world where redundancy is in place to cover several cases, among other: a statistical failure of a device (so we use more of them expecting that the event is independent) a rogue ...
  • 526
15 votes
3 answers
5k views

How do pilots set the exact amount of thrust needed for a reduced power takeoff?

I know jet-powered airplanes very rarely use 100% available power for takeoff, and most often reduce power to increase engine life. How does a pilot set thrust to an exact level? The airplanes I'm ...
  • 375
14 votes
2 answers
3k views

How much thrust is lost due to the bleed air system?

I've read that bleeding air for the pneumatic system from the engine core can produce important losses in thrust, and also rising the fuel consumption too. Today this problem is worse, with the more ...
  • 2,066
15 votes
3 answers
11k views

Regarding N1 and N2, what does the "N" stand for?

I initially phrased this question in a comment to another question regarding what N1 and N2 mean, hoping it would be that sort of low-hanging fruit that is easily answerable and not worth a proper ...
  • 3,675
3 votes
1 answer
1k views

What is the meaning of T/O Thrust => TRQ / N1 in a flight log?

I work at a software company which builds record-keeping software for aviation. What is the meaning of TRQ / N1 in a flight log, under a ...
  • 163
0 votes
1 answer
873 views

How are jet engine RPM cycles used to monitor LCF life?

Can someone please define what are N1 and N2 throttle cycles? These are used to keep track of the accumulated low cycle fatigue (LCF) life of rotating components. But I cannot find an exact definition ...
2 votes
1 answer
481 views

Turbo-fan idle at high speeds, will air speed up fan speed?

If N1 idle is 30%, will flying idle at very high speeds force the fan to go higher than 30%? (for example idle while descending fast) And if no, why not?
  • 1,731
1 vote
1 answer
221 views

Why would an F16 battery make a buzzing sound?

According to this YouTube Video I heard the mechanism that moved the canopy, and then I heard a small buzzing sound. The video description says that it is spooling something, but I don't know what ...