N1/N2 Sync

MNSUpilot

MNSUpilot

Well-Known Member
Hey everyone,

Just a quick question here, I've heard a few different opinions and couldn't find anything in the archives so I figured this would be the place to find out. Is N1(fan) or N2 (turbine) engine sync typically preferred? A professor of mine that flies the B767 prefers the turbines synced whereas I have a few friends that fly corporate that have said N1 sync is best for the passengers and N2 sync is best up front for the pilots. Wasn't sure if it depends on the aircraft and/or business jet vs. airliner. Thanks in advance!
 
On the non-FADEC 767s I've flown, I've always preferred to match N1s. Less vibration and noise. The N2s are usually pretty close anyway.
 
Derg said:
Do we have the option in FADEC 76's?
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No, I think it's all N1 sync all the time. I think. Hell, I'm just happy I remember how to start the motors some days. :p

Soon enough here I'll get my hands on some 1982 model 767-200s with the JT-9s. Hoooooah!
 
The only airplanes where I could actually choose was the 88 and the 90. But the 90 was just N1 I think.

I do find myself occasionally manually synching the engines during a throttle hold descent. That RUMRUMRUM gets a little annoying after a while.
 
Derg said:
The only airplanes where I could actually choose was the 88 and the 90. But the 90 was just N1 I think.

I do find myself occasionally manually synching the engines during a throttle hold descent. That RUMRUMRUM gets a little annoying after a while.
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In the 90, Keeping it mildly out of sync puts most passengers to sleep. Just sayin
 
Thanks for the quick responses. Was a bit timid to start a thread on here, being unexperienced and all. I'm assuming the science behind it must come down to the sound waves coming from the fans/turbine? Just curious. Best regards.
 
Everyone I've flown with for the last 10 years has preferred N1. I might try the N2 if the N1 sync isn't working so well.

Nobody I know (including me) can come up with a good reason we prefer N1, it just seems to be the thing to do. My experience has been mostly Lears, and Beechjets.
 
It was not taught, but I always matched the N1s on the 145. I deadheaded enough in the far back that I got tired of WONWONWONWON.


Sent from Seat 3D
 
With the RJ, it will almost always be the N1s. On occasion you will hear a feel a vibration that is caused by the N2 splits. At that point we will just match the N2s and for some reason you never hear the N1s out of sync.
 
terdferg23 said:
In the 90, Keeping it mildly out of sync puts most passengers to sleep. Just sayin
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And that damned "Robo-Dog" hydraulic noise on the Airbus is there to entertain passengers! :)

180px-Muffit.jpg


Muffit's in the cargo bin!
 
Derg said:
And that damned "Robo-Dog" hydraulic noise on the Airbus is there to entertain passengers! :)

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Muffit's in the cargo bin!
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Speaking of passengers and airplane noises, I had someone ask me yesterday what the noise was the airplane made when everything was shut down-turns out it was the gyros spinning down. Another popular one in "those little planes" is the "wheep wheep wheep" noise the strobe power pack makes.
 
staledog said:
Nobody I know (including me) can come up with a good reason we prefer N1, it just seems to be the thing to do. My experience has been mostly Lears, and Beechjets.
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Never done anything but fan in the beechjet. Wouldn't even know if the nob went the other way..
 
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