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V speeds – Velocity-speeds

V Speeds 737V-speeds or Velocity-speeds are standard terms used to define airspeeds / performance speeds in a wide variety of operating conditions which are important or useful to the operation of aircraft

The actual speeds represented by these designations are true airspeeds specific to a particular model of aircraft, and are expressed in terms of the aircraft’s indicated airspeed, so that pilots may use them directly, without having to apply correction factors.

Aircraft configuration and operating conditions affects “V” Speeds. Runway conditions, pressure altitude, temperature, aircraft weight, aircraft configuration and settings  (such as flap and landing gear settings) all may impact the relevant Velocity setting.

 

The most common V-speeds are often defined by a particular government’s aviation regulations. In the United States, these are defined in title 14 of the United States Code of Federal Regulations, In Canada, the regulatory body, Transport Canada, defines 26 commonly-used V-speeds in their Aeronautical Information Manual (AIM)

V- Speed Relationships

Here’s some common V Speed relationships:

  • V1 must always be >VMCG,
  • • VR must always be ≥V1, >VMCA
  • • VLO must always be ≥VR, >VMCA, >VS, >VMU
  • • V2 must always be >VMCA, >VS, >VR

 

V-speed designator Description
V1 Maximum speed during takeoff at which a pilot can safely stop the aircraft without leaving the runway. This is also the minimum speed that allows the pilot to safely continue (to V2 takeoff) even if a critical engine failure occurs (between V1 and V2).
V2 Takeoff safety speed.
V2min Minimum takeoff safety speed.
V3 Flap retraction speed.
VA Design maneuvering speed, also known as the “Speed for maximum control deflection.” This is the speed above which it is unwise to make full application of any single flight control (or “pull to the stops”) as it may generate a force greater than the aircraft’s structural limitations.
VB Design speed for maximum gust intensity.
VC Design cruising speed, also known as the optimum cruise speed, is the most efficient speed in terms of distance, speed and fuel usage.
VD Design diving speed.
VDF Demonstrated flight diving speed.
VEF The speed at which the critical engine is assumed to fail during takeoff.
VF Designed flap speed.
VFC Maximum speed for stability characteristics.
VFE Maximum flap extended speed.
VFTO Final takeoff speed.
VH Maximum speed in level flight at maximum continuous power.
VLE Maximum landing gear extended speed. This is the maximum speed at which it is safe to fly a retractable gear aircraft with the landing gear extended.
VLO Maximum landing gear operating speed. This is the maximum speed at which it is safe to extend or retract the landing gear on a retractable gear aircraft.
VLOF Lift-off speed.
VMC Minimum control speed with Critical engine inoperative.
VMO Maximum operating limit speed
VMU Minimum unstick speed.
VNE Never exceed speed.
VNO Maximum structural cruising speed or maximum speed for normal operations
VR Rotation speed. The speed at which the airplane’s nosewheel leaves the ground.
VRef Landing reference speed or threshold crossing speed.
VS Stall speed or minimum steady flight speed for which the aircraft is still controllable.
VS0 Stall speed or minimum flight speed in landing configuration.
VS1 Stall speed or minimum steady flight speed for which the aircraft is still controllable in a specific configuration.
VSR Reference stall speed.
VSR0 Reference stall speed in landing configuration.
VSR1 Reference stall speed in a specific configuration.
VSW Speed at which the stall warning will occur.
VTOSS Category A rotorcraft takeoff safety speed.
VX Speed that will allow for best angle of climb.
VY Speed that will allow for the best rate of climb.

 

 Other V-speeds

Some of these V-speeds are specific to particular types of aircraft and are not defined by government regulations.

V-speed designator Description
VBE Best endurance speed – the speed that gives the greatest airborne time for fuel consumed. This may be used when there is reason to remain aloft for an extended period, such as waiting for a forecast improvement in weather on the ground.
VBG Best power-off glide speed – the speed that provides maximum lift-to-drag ratio and thus the greatest gliding distance available.
Vclmax Max coefficient of lift speed
Vdmin Minimum drag
Vg Best glide speed
Vfto Final takeoff speed
Vimd Minimum drag
Vimp Minimum power
VLLO Maximum landing light operating speed – for aircraft with retractable landing lights.
Vmbe Maximum brake energy speed
Vmd Minimum drag
Vmca Minimum control speed in the air – the minimum airspeed at which the aircraft is directionally controllable in flight with one engine inoperative and takeoff power on the operative engine(s). Aircraft certification standards specify the most critical engine becoming inoperative and its propeller windmilling (propeller unfeathered), not more than a 5 degree bank towards the operative engine, takeoff power on the operative engine(s), landing gear up, flaps in the takeoff position, and center of gravity in the most unfavorable position. In the USA Vmca is defined at FAR Part 23.149 for normal category and commuter category airplanes; and Part 25.149 for transport category airplanes.
Vmcg Minimum control speed on the ground – the minimum airspeed at which the aircraft is directionally controllable during acceleration along the runway with one engine inoperative, takeoff power on the operative engine(s), and with nose wheel steering assumed inoperative.
Vmcl Minimum control speed in the air in an approach or landing configuration with one engine inoperative.
Vme Max endurance
Vmin Minimum speed for instrument flight (IFR) for helicopters
Vmp Minimum power
Vmr Max range
Vnd Max structural cruising speed
Vp Aquaplaning speed
VPD Maximum speed at which whole-aircraft parachute deployment has been demonstrated
Vra Rough air speed (turbulence penetration speed).
VSL stall speed in a specific configuration
Vs1g stall speed at maximum lift coefficient
Vsse Safe single engine speed[
Vt Threshold speed
Vtocs Take-off climbout speed (helicopters)
Vtos Minimum speed for a positive rate of climb with one engine inoperative
Vtmax Max threshold speed
VXSE Best angle of climb speed with a single operating engine in a light, twin-engine aircraft – the speed that provides the most altitude gain per unit of horizontal distance following an engine failure.
VYSE Best rate of climb speed with a single operating engine in a light, twin-engine aircraft – the speed that provides the most altitude gain per unit of time following an engine failure.
VZRC Zero rate of climb speed in a twin-engine aircraft[13]
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