Speed management on take off

#1

Hi,

So, I realise that take off varies alot depending on weight, altitude, aircraft, engine power, bladi bla bla…. But there are times where my plane (say the CRJ) shoots like an arrow in the sky with N1 around 90%, whereas there’s times where a 737 or heavier takes a lot more than that… Also, and this is the important one, having watched videos on youtube, it always takes a little while for the aircraft to reach flap retraction speed (around 180-200 kts, I think).

So, I was wondering if there’s any real pilot reading this who can advise. What is the normal N1 setting for take-off, and what should the climb rate be (on average)? How can I avoid N1 going from vr (say around 140) to 200 kts in less than 10 seconds (or indeed, is that normal).

Is there a speed management app that tells me what are the V1/VR speeds for my weight, and my flap retraction speed?

Anyway, would appreciate the clarifications.

Cheers

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#2

Whilst I’m not a pilot there are some great tutorials available here on the forum in #tutorials:flight where some of the IF staff demtostrate the recommended takeoff and landing procedures for some aircraft. This should be a great place to start 🙂

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#3

As Matt said the tutorials have some fantastic visual guides so I will link the playlist from YouTube with the majority of them on, down below:

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#4

I did a post a while ago talking about this.

In real life, we takeoff and aim for 15 degrees of pitch up attitude. Then we aim to maintain a precise speed until around 1500ft, at which point we accelerate to 250 kts, retract flaps and continue on with the climb.

We initially want to maintain V2*+10 kts, when reaching 1500ft, we accelerate to 250kts by pitching down, keeping the same constant thrust. We clean up the aircraft and then pitch up again to maintain 250 knots with the same constant thrust.

V2 is the speed we maintain in case of an engine failure after takeoff to ensure climb performance is met.

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#5

@IFATC_Andrew sage of the CRJ any advice? Or do you mind if I share the info you gave me?

#6

In the CRJ tutorial isnt the N1 supposed to be around 75%

#7

Thanks. I appreciate this might be a general rule of thumb, and it might vary from plane to plane. Like @Chad_Garnett says, I can see why a CRJ should be powered at only 75% of N1, since it really T/O like a rocket and continues accelerating very quickly.

@Wilco062 - could you clarify the following:

So you’re saying that if my V2 is 150 (say), then I’d have to try and maintain 160 kts and then pitch down >1500 ft (or minimum safe altitude) and progressively start retracting flaps thereafter (clean config by >200 kts>?) How much N1 would you say I need, then (again, rule of thumb!). I tend to take it up to around 90%.

Thanks

#8

Your take off thrust is purely dependent on airframe, weight, weather and runway conditions. For larger aircraft I aim for around 85-91%N1 to accelerate and conduct my initial climb. Working a V1 of 140, Vr of 155 and V2 of 160, I continue to accelerate to 180kts and a steady climb Vs acceleration. I dont manoeuvre before hitting 220kts, making my aircraft clean between 200-210kts. I then adjust my climb rate and thrust to maintain 230kts and around 3000ft/min to climb out before dropping to 2000ft/min VS and a steady increase in speed aiming for around 300-320kts to hit M0.80 at FL280.

It is purely dependent on your aircraft and weight at that point. Hope this helps and if you have any Qs then fire away :)

#9

You got it right. As Mags said, the N1 is calculated according to weight, temperature, altimeter, and other factors and then the autothrust maintains the setting by itself…

#10

Hi there,

i can give you here an example from my last flight which was
FRA-MCO-FRA:

Take off weight: 339000 Kgs / 747367 Pound
Fuel on board : 102000 Kgs / 224871 Pound
T/O flaps : 20
T/O N1 : 95 %
V1 : 145 kts
VR : 161 kts
Flaps 10 : 186 kts
Flaps 5 : 212 kts
Flaps 1 : 231 kts
Flaps UP : 251 kts
Climb Rate : 1700 ft/min
Pitch : 12 Degrees

Then the always friendly ATC Controller tells us most of the time: High Speed approved,
so we lower the pitch to :

Climb Pitch : 10 Degrees
Climb Rate : 1500 ft/min
Accelerating to 330 kts IAS
climb power N1 : around 91%
Initial Cruise ALT : FL270

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#11

Thanks. Is there an app or software through which I can calculate my V speeds?

#12

Anyone? Cheers!

#13

Late reply but sure man

#14

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