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ZSOFN
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Thrust Settings For Most Modern Airliners

Sun Dec 16, 2007 6:50 pm

Hi all,

I actually posted something similar to this a couple of years ago, but with mixed success. I'm looking for thrust data for a number of modern airliners; primarily takeoff data but also climb and cruise if possible.

I realise that there are a huge raft of variables that affect things like FLEX / derate etc, but really I'm looking for ballpark figures, and let's say based on the aircraft being at MTOW, sea level, and average daytime temperature (22°C let's say). If you have anything different, that's fine too

The aircraft are:


    Airbus
    - A300-600
    - A319 / A320 / A321
    - A330 (all variants)
    - A340 (all variants)
    - A380-800 RR (I accept this may be harder to come by!)

    Boeing
    - 737-700 / -800 / -900
    - 747-400 (all engines)
    - 767-300ER (all engines)
    - 777 (all variants)


I know this sounds like a tall order, but really it's more of a wish-list; if anyone has any data on the above aircraft, please chime in!

[Edited 2007-12-16 11:06:13]
 
HAL
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RE: Thrust Settings For Most Modern Airliners

Mon Dec 17, 2007 4:53 pm

If an airliner is taking off at MTOW, it will be using max power. So all you have to do is look at the max engine output for the various types of aircraft/engine combinations and you'll get your numbers. In over a decade of airline flying, I've never taken off at MTOW while using flex/reduced power, so the question really doesn't have much meaning if you're looking for a 'ballpark' figure. Climb thrust figures are essentially the same for any climb, depending on outside temperature, no matter what the takeoff weight is. Those figures however aren't readily available anywhere in my manuals. And cruise thrust will vary immensely depending on weight, temperature, and altitude. I don't think there could be a valid ballpark figure for that.

HAL
One smooth landing is skill. Two in a row is luck. Three in a row and someone is lying.
 
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ThrottleHold
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RE: Thrust Settings For Most Modern Airliners

Mon Dec 17, 2007 7:09 pm



Quoting HAL (Reply 1):
If an airliner is taking off at MTOW, it will be using max power.

I have done several MTOW take-offs using FLEX thrust.
 
flyf15
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RE: Thrust Settings For Most Modern Airliners

Mon Dec 17, 2007 7:21 pm

Are you looking for, say, N1% thrust settings? Thats how we set our thrust in the CRJ....

We have large tables in our performance manuals to determine these numbers base on temperature, altitude, etc. For takeoff, climb, and max cruise, 99% of the time we set thrust based off of the FMS's computation and associated thrust carats on the N1 gauges. For all other stages of flight, we set thrust as required to maintain the desired airspeed or climb/descent rate.

But, for a general idea... here you go... just general ranges off the top of my head (for the CRJ-200):

Takeoff (max t/o power): 91-94% N1
Takeoff (flex thrust): 85-88% N1
Climb: 92-96% N1 (subtract 3-4% N1 if anti-ice in use)
Cruise (max): 93-95% N1
Cruise (normal): 88-91% N1
Cruise (long range): 84-87% N1
Descent (3 deg): 50-60% N1
Descent (idle): 35-45% N1
Approach (light/fully configured): 58-62% N1
Approach (heavy/fully configured): 64-68% N1
 
wilco737
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RE: Thrust Settings For Most Modern Airliners

Mon Dec 17, 2007 7:53 pm



Quoting ThrottleHold (Reply 2):
I have done several MTOW take-offs using FLEX thrust.

So did I! In the 737, not in the MD11F anymore...

In the MD11F we usually have everything between 90% (full flex) up to 110% (full power). depends on the weather, airport, weight, terrain etc etc...

WILCO737 (MD11F)
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PhilSquares
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RE: Thrust Settings For Most Modern Airliners

Mon Dec 17, 2007 11:36 pm



Quoting HAL (Reply 1):
If an airliner is taking off at MTOW, it will be using max power.

Not on the 744! Most takeoffs have some degree of reduced thrust, either a full TO and an assumed temp or a TO1 and assumed temp.

The problem with the original question that the OP doesn't realise is there is a runway issue. Taking off from KJFK is much different than it would be taking off out of DUB. Not only will you have a wide range of TO thrust settings but you will have a very broad range of V speeds.
Fly fast, live slow
 
pilotboi
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RE: Thrust Settings For Most Modern Airliners

Tue Dec 18, 2007 2:43 am



Quoting ZSOFN (Thread starter):
average daytime temperature (22°C let's say)

Most published numbers you're gunna find are probably based on ISO Standard - so 15 C.
 
HAL
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RE: Thrust Settings For Most Modern Airliners

Tue Dec 18, 2007 7:11 am

Ouch! OK, I stand corrected! However, I do have to wonder about this Phil;

Quoting PhilSquares (Reply 5):
Not on the 744! Most takeoffs have some degree of reduced thrust, either a full TO and an assumed temp or a TO1 and assumed temp.

How do you get full takeoff power while using an assumed temp? From what I've learned in my ground schools, if you're using assumed temp, you're reducing power.

I do see that if you're on a really long runway with cold temps you could do a reduced power T/O, even with MTOW, but it's just something that I haven't seen in my career.

HAL
One smooth landing is skill. Two in a row is luck. Three in a row and someone is lying.
 
PhilSquares
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RE: Thrust Settings For Most Modern Airliners

Tue Dec 18, 2007 7:45 am



Quoting HAL (Reply 7):
ow do you get full takeoff power while using an assumed temp? From what I've learned in my ground schools, if you're using assumed temp, you're reducing power.

The PWs have TO2 (20% reduction), TO1(8% reduction) and TO (FULL THRUST), from there you can do an assumed temp. For example, TO 52 assumed, the full TO EPR will be about 1.51 SL and 15C, while the assumed (52C) would be about 1.38.

Quoting HAL (Reply 7):
I do see that if you're on a really long runway with cold temps you could do a reduced power T/O, even with MTOW, but it's just something that I haven't seen in my career.

It doesn't even take really long runways and cold temps to accomplish that. As I originally wrote, on most takeoffs there is some reduction. It's not that uncommon at all.
Fly fast, live slow
 
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ZSOFN
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RE: Thrust Settings For Most Modern Airliners

Tue Dec 18, 2007 11:40 pm

Thanks, this is really interesting, folks. Sorry I should have been more clear; I was indeed looking for N1 speeds. I fully appreciate that ball-park figures aren't always appropriate; predominantly I need them for takeoff settings; generally speaking for those types I listed it's a question of closer to 100+ N1% or closer to 90% (assuming standard / minimum FLEX).
 
2H4
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RE: Thrust Settings For Most Modern Airliners

Tue Dec 18, 2007 11:49 pm



Quoting Flyf15 (Reply 3):
Approach (light/fully configured): 58-62% N1
Approach (heavy/fully configured): 64-68% N1

I wonder what these numbers were for the Concorde...

Also, I notice that nobody's taken the "Conveyor Thrust" adjustments into account for conveyor belt operations.

2H4
Intentionally Left Blank
 
HAL
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RE: Thrust Settings For Most Modern Airliners

Wed Dec 19, 2007 8:01 am

Phil et. al.,

I agree that the vast majority of our takeoffs are at reduced thrust, normally using an assumed temp off of full TO power. (At Hawaiian, we don't use TO1 or TO2. I don't know why, but we don't). I was just referring to the thread opener when he used an assumption of the aircraft being at Max Takeoff weight. I believed this to mean at maximum structural T/O weight (i.e. the numbers we all memorize from the limitations section). I've only done a few that way in the 767 - HNL to SYD against strong winds comes to mind - where we were loaded up with fuel, passengers & cargo, and blasted off the longest available runway using Max T/O power - no assumed temp available. If the original poster is looking for max thrust in such a situation - it's in the book for each type of engine. However if he's looking for N1 numbers - that can vary greatly depending on temperature and altitude, even for constant 'max thrust' settings.

HAL
One smooth landing is skill. Two in a row is luck. Three in a row and someone is lying.
 
PhilSquares
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RE: Thrust Settings For Most Modern Airliners

Wed Dec 19, 2007 8:22 am



Quoting HAL (Reply 11):
I agree that the vast majority of our takeoffs are at reduced thrust, normally using an assumed temp off of full TO power. (At Hawaiian, we don't use TO1 or TO2. I don't know why, but we don't). I was just referring to the thread opener when he used an assumption of the aircraft being at Max Takeoff weight. I believed this to mean at maximum structural T/O weight (i.e. the numbers we all memorize from the limitations section).

I understand what you are saying. However, on the 744 at MTOW (Structural), it's not uncommon to use something other than full rated thrust. The aircraft is normally over-powered even at 400tons.

Quoting ZSOFN (Reply 9):
Thanks, this is really interesting, folks. Sorry I should have been more clear; I was indeed looking for N1 speeds.

FYI, PW and RR don't use N1 for thrust settings, they use EPR.
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