VR speed is the speed during takeoff at which the pilot initiates rotation by gently pulling back on the control column, causing the aircraft's nose to lift off the runway.
Based on the provided reference, VR is the specific airspeed reached during the takeoff roll. At this speed, the pilot performs the action of gently pulling back on the control column. This maneuver is known as "rotation," and its purpose is to raise the aircraft's nose, increasing the angle of attack on the wings to generate enough lift for the aircraft to become airborne shortly thereafter (at or above the VLOF - Lift-Off Speed).
For commercial aircraft, the exact value of VR is not a fixed number. It is a dynamic speed that is calculated before each takeoff. The reference highlights that VR varies depending on several critical factors:
- Aircraft Weight: A heavier aircraft requires more lift and therefore a higher speed to rotate effectively.
- Aircraft Configuration: Settings such as flap position affect the wing's lift characteristics, influencing the necessary rotation speed.
- Environmental Factors:
- Weather: Wind (especially headwinds) and temperature affect air density and aircraft performance.
- Runway Conditions: Factors like runway slope and surface condition (wet, dry) can influence acceleration and lift requirements.
Pilots and flight crews calculate the appropriate VR speed for each specific takeoff using performance charts, flight computers, or electronic flight bags (EFBs), taking all these variables into account to ensure a safe and efficient liftoff.
