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I know generally it is about 170mph. But what is the actual speed in mph that an airliner has to reach before it takeoff's.

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closed as unclear what you're asking by David Richerby, Federico, mins, vasin1987, Dave Sep 11 '15 at 14:43

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    $\begingroup$ could you define "typical"? is an empty 737 typical? or is a fully loaded 380? $\endgroup$ – Federico Sep 11 '15 at 5:49
  • $\begingroup$ @Federico With passengers on it taking off from an airport. $\endgroup$ – Ethan Sep 11 '15 at 5:51
  • $\begingroup$ @Ethan Still, what is a typical passenger airliner? A 737? An A380? An ATR-72? A CRJ-100? What airport? The air's much denser in the middle of winter at JFK than in the middle of summer at Denver, for example. $\endgroup$ – David Richerby Sep 11 '15 at 9:23
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    $\begingroup$ You may search for Vr or V rotate online. This is the name of the speed at which the rotation is initiated and the nose leaves the ground, the aircraft is airborne just after Vr. You'll see that Vr varies a lot, even for the same aircraft with the same engines. $\endgroup$ – mins Sep 11 '15 at 11:18
  • $\begingroup$ You are asking a general question on airliners in general and state what the general answer is. What do you expect as an answer? $\endgroup$ – Mayou36 Nov 23 '16 at 9:38
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It depends on what type of an airliner you are talking about. Even then, take off or rotation speed in every flight is different. Pilots need to consider many variables like air density, aircraft gross weight, lift coefficient (aerodynamics of the plane), and aircraft configuration (flap or slat position, as applicable), according to Wikipedia. This is a few examples from the Aerospaceweb.org,

  • Boeing 737 at 100,000 lb, rotation speed is 150 mph / 130 KIAS.
  • Airbus A320 at 155,000 lb, rotation speed is 170 mph / 150 KIAS.
  • Boeing 747 at 800,000 lb, rotation speed is 180 mph / 155 KIAS.

Each plane has a set of calculations which pilots use to determine a specific speed (V1, VR - rotation, and V2) for each flight. Modern airliners come equipped with their own software and/or computer designed for this purpose.

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  • $\begingroup$ What about for an a380 $\endgroup$ – Ethan Sep 11 '15 at 5:56
  • $\begingroup$ I'm not sure about this plane. Each version of the A380 has slightly different take off speed. Many links on the internet say around 150 knot, but I can't find any reliable source yet. $\endgroup$ – TBBT Sep 11 '15 at 6:03
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    $\begingroup$ The answer can only ever be typical since exactly the same aircraft, wth exactly the same load, can have different speeds on different days or at a different airport or even on different runways at the same airport. $\endgroup$ – Simon Sep 11 '15 at 6:47
  • $\begingroup$ I should add that assuming the same weight, the biggest factors are the pressure altitude, temperature and required obstacle clearance although the latter is not a consideration at most commercial airports. $\endgroup$ – Simon Sep 11 '15 at 7:58
  • $\begingroup$ For the A380, related video on Youtube: Airbus A380 Take-off Time. $\endgroup$ – mins Sep 11 '15 at 13:55

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