[Ref CAD 385]
Vr is the Rotation Speed
Vr – the speed at which the pilot initiates action to raise the nose gear off the ground, during the acceleration to V2 at a height of 35 ft.
Minimum Unstick Speed, Vmu – the calibrated airspeed at and above which the aeroplane can safely lift off the ground, and continue the take-off.
Vlof is the calibrated airspeed at which the aeroplane first becomes airborne.
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