Calculating takeoff speeds
By Murray Bourne, 18 Nov 2009
You are the pilot of a jet roaring down the runway approaching takeoff speed. Suddenly an emergency buzzer goes off, indicating a critical loss of oil pressure in one of the engines.
Do you keep accelerating, or do you try to stop the aircraft and stay on the ground?
Before a pilot begins the takeoff run, (s)he needs to know some important decision speeds. These include:
- VR - rotation speed, or the speed where the pilot pulls back on the control yoke and the front wheel leaves the ground
- V1 - takeoff decision speed, or the speed where the pilot is committed to go. It is safer to take off, rather than try to stop
- VRef - threshhold reference speed decision speed, or the speed crossing the runway threshhold, just before landing
Some of these are fixed for the aircraft type, while others depend on many variables, altitude, temperature, airplane configuration, weight, braking energy, and engine type. [See more on V Speeds.]
The following article is a "real-world math tutorial" from Kidwaresoftware.com:
Computing Airplane Takeoff Speeds (See the link towards the bottom - it's a zipped MS Word file. Update: The doc file is no longer available from that site.)
This article from Airbus may be of interest: Understanding Takeoff Speeds
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