Minimum %N1 thrust on takeoffs

Hi pilots! Is there minimum thrust (% N1) for takeoff?
If so, what is the N1% minimum thrust of the Boeing 77W and 789?

Help me please!

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I always use 100% N1, but I don’t think there is a “minimum”.

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Normal N1 is about 90 to 95%. I don’t believe there is a minimum, unless you want to crash.

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Don’t quote me on this, but I think it depends on your specific V1 speed.

This should be a competition demonstrating who has the lowest N1

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“Flaps 30°…V1, rotate”

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“ V1, Rotaté”

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You really are asking a question that will rightfully have a wide range of answers. This is due to take off thrust being determed by the FMC when data such as runway length, condition, wind, airport altitude, temperature/dew point, and aircraft weight/COG is inputed. There is no set N1 that fits every situation. For instance hot and high airports can have heavier aircraft exceed 100% N1 on initial takeoff, sea level altitude and cold air and a light load can have a dramatically reduced take off thrust.

You answer probably lies looking at RL pilot accounts for those aircraft and published flight manuels too. I wouldnt trust the recommendations of most people on here when it comes to recommended thrust setting.

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I believe for most aircraft, the thrust won’t be de-rated to below 75% N1. However it doesn’t typically get that low.

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After nearly 5000 landings (and roughly the same amount of takeoffs) I still struggle with this very thing: %N1.

Clearly applying full-throttle always is not only not the answer; it’s also not needed and not in any way close to real life.

But…with the risk of over-complicating things or even asking dumb questions…what does this %N1 really indicate? Is it throttle or thrust only? Does it take aircraft weight, or perhaps even runway length into account?

My experience is that if I set my throttle to just under 100%N1 (which is not 100% throttle!!), I always seem to liftoff after 2/3 of the runway, not matter how heavy my aircraft. The science behind this, I honestly don’t know.

Perhaps we can get more this is how the %N1-thing works answers, instead of the I set me throttle to x% answers?

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The idea behind derated takeoffs is to use as much of the runway as is safely possible. Why? Engines are very expensive. The less stress you put them though, the longer they’ll last. And then there’s also the benefits of producing less noise and burning less fuel.

“The fee is the same whether you use 5,000ft or 12,000ft of the runway. May as well use it all!”

As for how much power to use, that will vary wildly between airplanes, load, atmospheric conditions, the runway and obstacles, procedural requirements, etc. Refer to USA007’s reply a few posts above this. There are also situations where derated takeoffs are not permitted.

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i feel a good way to judge takeoff N1, is to stabilise engines at 40 kt IAS, and slowly acceleration to 90 N1, with increases in thrust inputted before 100kts IAS, if needed

After I have seen so many videos on ECAM display no matter IRL or Xplane 11.
To sum up:

For Boeing normally apply 89%-98% N1 like 737s 787s, 747’s sometimes could be 101%N1

For Airbus normally apply 85%-95% N1 for almost all airbus family. No need to apply 98%N1 unless you are taking off at London City airport with more than 80%load

PS. this is just what I do

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%N1 is referring to the outer fan of the engine (the Part most visible looking into the engine from the front). Not sure unfortunately what 100%N1 is exactly taken from, but N1 is referring to the first stage of the engine, the outer fan.

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It all depends on weight, temperature, winds, runway length, if it’s a high elevated airfield… depends on so many things. Anywhere from 80%-100% N1. Pilots never go over 100% N1.

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You’re right in the ballpark for the Airbus A32X family Allen. With a heavy A321 I’ll use 95% (93-94 for a heavy A320) when the loads are light it’s more like 87.5-89%

These thrust levels depending on your weight will hold V2+15 at about 12.5-15° of pitch on your initial climb out

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Thank you very much!

Thanks for your coment!

You’re welcome @Wesley77X

We did a video on proper takeoff procedures a while back here it is-take a look-many people get messed up into thinking there’s a vertical speed target (aka “VS LOCK”) on initial takeoff-there isn’t-it’s all about pitch and speed.

Doesn’t really get into N1 much-but shows how you need X% N1 to maintain the speed at Y° of pitch

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Go arounds though?