V-Speeds are a common term for the different operational speeds of an aircraft.
Here are some of the most common v-speeds:
; Vs : the aircraft's stall speed in clean, or cruise configuration (gear and flaps up).
; Vso : the aircraft's stall speed in dirty, or landing configuration (gear and flaps down).
; Vx : the airspeed that provides the best angle of climb (highest altitude in shortest distance). It is typically a fairly slow speed, and is most useful for taking off over obstacles like trees.
; Vy : the airspeed that provides the best rate of climb (highest altitude in least time). It is faster than Vy, and is most useful for getting to an altitude as quickly as possible (say, to avoid icing).
; Va : the maximum airspeed for turbulence. For a typical light civilian aircraft, Va will be approximately double Vs, to ensure that the plane will stall under forces greater than 4 Gs.
; Vfe : maximum airspeed for flap extension.
; Vno : (yellow line) maximum structural cruising speed, to be exceeded only in very calm air.
; Vne : (red line) airspeed not to be exceeded under any circumstances.
Pilots of complex planes, multiengine planes, and transport planes often refer to additional v-speeds:
; V1 : critical engine failure recognition speed.
; V2 : takeoff speed.
; V2min : minimum takeoff speed.
; V3 : flap retraction speed.
; Vb : maximum gust intensity speed.
; Vc : cruise speed.
; Vd : diving speed.
; Vh : maximum level flight speed at full power.
; Vlo : maximum speed for extending the landing gear.
; Vmc : minimum controllable speed with an engine out; any slower and the control surfaces will not be able to counter asymmetric thrust.
; Vr : rotation speed, the speed to start raising the nose during the takeoff run.
; Vref : landing reference speed.
V-speeds are nearly always given as Indicated Airspeed (IAS), so that pilots can read them directly off the Airspeed Indicator.
