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EMB-145 thrust settings

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Yank McCobb said:
Have you flown a large number of jets from which you can draw this conclusion?

Don't need to, it's just a basic fact of the physics involved. A given FF will always yield the same speed no matter the temp or altitude. N1, N2, etc... all change depending on your alt and temp for a given speed. Do you disagree?
 
PCL_128 said:
Don't need to, it's just a basic fact of the physics involved. A given FF will always yield the same speed no matter the temp or altitude. N1, N2, etc... all change depending on your alt and temp for a given speed. Do you disagree?

Sure do. It's a good ballpark figure for maneuvering-type speeds (200-250, for example), but for higher IAS there's quite a bit of difference. For example in our aforementioned E145, it takes around 1900pph/side to maintain 315 kias in the low-mid teens, whereas that number decreases to 1500-1600 in the mid-twenties (before the mach number becomes limiting, depending on temp). YMMV

For the OP, if you're looking for 220 and want to use the N1, try~63 percent at lower altitudes, this'll at least get you into the ballpark.
 
PCL_128 said:
Don't need to, it's just a basic fact of the physics involved. A given FF will always yield the same speed no matter the temp or altitude. N1, N2, etc... all change depending on your alt and temp for a given speed. Do you disagree?

Even in a descent, climb, gear down, flaps down in different increments, in a turn, icing, etc....??
 
Nova said:
Even in a descent, climb, gear down, flaps down in different increments, in a turn, icing, etc....??

Sorry, should have specified level flight for a given configuration. Throwing out gear and flaps will obviously change the situation.
 
It's really not as complicated as everybody's trying to make it.

If you're slow, push 'em up. If you're fast, pull 'em back. If the resulting change is too much, split the difference; if it's not enough, move 'em a little more.
 
aewanabe said:
For example in our aforementioned E145, it takes around 1900pph/side to maintain 315 kias in the low-mid teens, whereas that number decreases to 1500-1600 in the mid-twenties (before the mach number becomes limiting, depending on temp).

I can't imagine this being the case in level flight. In a climb, absolutely. The FF will decrease as alt increases while you maintain a given speed in the climb. In the CRJ you will start out with a FF of around 2200/side when you accelerate to 290 at 10k. By the time you get into the 20s, that number has dropped to around 1700 or so. On the other hand, 1350/side will always maintain 290 kts in level flight in the CRJ no matter what altitude you're at as long as you're clean. It might vary by 50-75/side depending on the individual airframe and different weights, but not by more than that.
 
FlamingFUPA said:
jeezuz, didn't take long for a thread with usefull suggestions to turn into a pissing contest
Huh? Seems like it's been pretty civilized to me!

And T-Gates, you are right about the trend vectors. One of my instructors taught us to "pinch" the trend vector between the airspeed pointer and the target speed, i.e.as the tip of the trend vector reaches the target speed, gradually add or reduce power so that the tip of the trend vector stays touching the target speed, and the vector shrinks down to nothing as the airspeed pointer reaches the target speed.

Sounds more complicated than it really is, but that's my best explanation.

LAXSaabdude.
 
LAXSaabdude said:
Huh? Seems like it's been pretty civilized to me!

And T-Gates, you are right about the trend vectors. One of my instructors taught us to "pinch" the trend vector between the airspeed pointer and the target speed, i.e.as the tip of the trend vector reaches the target speed, gradually add or reduce power so that the tip of the trend vector stays touching the target speed, and the vector shrinks down to nothing as the airspeed pointer reaches the target speed.

Sounds more complicated than it really is, but that's my best explanation.

LAXSaabdude.
Works great for both AS and Alt. After that a little fine tun'n as needed.
 

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