... Training is in full gear making sure we're ready to fly the NEO when it finally gets here. So I've already completed the differences training course.
The one thing that stands out is the max EGT for engine start. On a CEO it is 635 C. On a NEO max EGT is 1018 C - a significant difference
I guess one day I will eventually get to fly it. Since we started taking deliveries of 321s last year, I have been seeing more and more flight time in a 321 compared to before last year where I only saw the 321 only once, right after completing training and I never saw another one. ...
So nice You became one of us and to have You here, nkpilot!
I see You mention EGT temperature difference You have noticed, but I am not so sure the word is here about two equivalent measurements ...
... just a brief introduction. A limiting factor in a gas turbine engine is the temperature of the turbine section that must be monitored closely to prevent overheating of the turbine blades and the other exhaust section components. One common way of monitoring the temperature of a turbine section is with an EGT gauge.
EGT is an engine operating limit used to monitor overall engine operating conditions.
The variations of
EGT (exhaust gas temperatures) systems bear different names, and based on the location of the temperature sensors. Common turbine temperature sensing gauges include the turbine inlet temperature (
TIT) gauge, turbine outlet temperature (
TOT) gauge, interstage turbine temperature (
ITT) gauge and turbine gas temperature gauge (
TGT) gauge.
Since the whole
Spirit Airlines´
Airbus A320ceo aircraft family fleet (29
Airbus A319-132,
45
Airbus A320-232 and 15
Airbus A321-231)
is powered by
V2500 engines, the temperature You mention (635 °C) is the one measured at engine´s ´
station 4.9´, at the 5-stage
LPT section´s exit and this is
Turbine Outlet Temperature (TOT). The other temperature You mention (1018 °C) is related to the future
NK´s
Airbus A320-271N aircraft powered by twin
PW1100G-JM´s geared turbofan engine. This temperature is measured on the other position, and this is not Turbine Outlet Temperature but
Interstage Turbine Temperature or
Indicated Turbine Temperatures (You can see that in the PW1100G-JM engine certification sheet) in between 2-stage
HPT and 3-stage
LPT engine´s sections and this is where it comes from such a difference in the temperatures You have mentioned...
... Comparing the data of the most powerful engine that is recently installed on the
Airbus A320-271N aircraft,
PW1127G-JM geared turbofan (fan diameter: 2.057 mm / 81,0 in; eng. architecture: F]G[3LPC-8HPC ^ 2HPT-3LPT), rated at 120,43 kN / 12.280 kgf / 27.075 lbf, to those of the most powerful engines installed on the
A320ceo aircraft:
CFM56-5B4 twin-shaft turbofan (fan diameter: 1.735 mm / 68,3 in; eng. architecture: F+4LPC-9HPC ^ 1HPT-4LPT) rated at 120,10 kN / 12.247 kgf / 27.000 lbf, applied on
Airbus A320-214 and
V2527-A5 twin-shaft turbofan (fan diameter: 1.613 mm / 63,5 in; eng. architecture: F+4LPC-10HPC ^ 2HPT-5LPT), rated at 110,31 kN / 11.248 kgf / 24.800 lbf and applied on
Airbus A320-232, we can come to conclusion that the
PW1100G-JM engine´s core is a lot faster than those of the
CFM56 and
V2500 engines.
The
PW1127G-JM´s
HP shaft´s maximal speed -
N2 (22.300 rpm) is 49,2% higher than the one of the
IAE V2527-A5 engine (14.950 rpm -
100%) and 46,9% higher than the max. rotational speed of the
CFM56-5B4 engine HP´s shaft (15.183 rpm -
105%).
Regarding their
LP shaft´s speeds -
N1, the one of the
PW1100G-JM engine (10.047 rpm) is 77,8% higher than the rotational speed of the
IAE V2527-A5 LP´s shaft (5.650 rpm -
100%) and 93,2% higher than the LP shaft´s speed of the
CFM56-5B4 engine (5.200 rpm -
104%).
When we get to those engines´ fan´s rotational speeds, the story is quite different and it actually shows the whole point of the geared turbofan engine´s background. While the circumferential fans´speeds of the
V2527-A5 (477 m/s) and
CFM56-5B4 (472 m/s) are pretty much the same, the rotational speed of the
PW1127G-JM engine´s fan, connected through the
1:3,0625 ratio gearbox to the LP shaft, is only 353 m/s...
Regarding
LEAP‐1A26 twin-shaft turbofan engine, aimed for
Airbus A320-251N aircraft (fan diameter: 1.981,2 mm / 78,0 in; eng. architecture: F+3LPC-10HPC ^ 2HPT-7LPT), rated at 120,64 kN / 12.302 kgf / 27.120 lbf, its HP shaft´s speed,
N2, is 19.391 rpm -
116,5% (15% lower than the speed of the
PW1127G-JM´s
N2 - 22.300 rpm) and LP shaft´s speeds speed,
N1, is 3.894 rpm -
101% (158% lower than the speed of
PW1127G-JM´s N1 speed - 10.047 rpm). Fan´s rotational speed of
LEAP‐1A26 engine is 404 m/s, 14,4% higher than the rotational speed of the
PW1127G-JM engine´s fan - 353 m/s.
Otherwise, the geared turbofan engine is not a new concept. The
British Aerospace BAe 146, a regional airliner that first flew in 1981, and was produced till 2002, was fitted with four
Textron Lycoming ALF 502R-5 geared turbofan engines. The
Bombardier Challenger 600s originally were fitted with the
ALF 502L geared turbofans. The
TFE731, a geared turbofan engine, first ran in 1970, and its variants power popular airplanes such as the
Learjet 35,
Learjet 40,
Learjet 45 and
Learjet 55,
Dassault Falcon 900DX,
Hawker 800,
Hawker 850XP and
Hawker 900XP as and a few
Cessna Citations...
Nice regards
mfranjic
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A320N aircraft with the: 
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