V-speeds

Standard reference airspeeds for an aircraft, each written with a V and a subscript. Common ones are:

• Vr: rotate speed, where you lift the nose for takeoff
• Vx and Vy: best-angle and best-rate-of-climb speeds
• Vso and Vs1: stall speed in landing configuration and clean (bottom of the white and of the green arc)
• Vfe: maximum speed with flaps extended (top of the white arc)
• Vno: maximum structural cruising speed (top of the green arc)
• Vne: never-exceed speed, the red line on the airspeed indicator
• Va: manoeuvring speed, the fastest at which full control inputs are safe

They all come from the aircraft’s flight manual and are usually given as indicated airspeeds in knots.