Va
Maneuvering speed
Vb
Design speed "maximum gas intensity
Vc
Crusing speed
Vd
Design diving speed
VDF/MDF
demonstrated flight diving speed
Vef
Critical engine is assumed to fail during take off
Vf
Flap speed
Vfc/Mfc
Maximum speed for stability characteristics
Vfe
Maximum flap extended speed
Vfto
Final take off speed
Vh
Maximum speed in level flight with maximum continuos power
Vle
Maximum landing gear extended
Vlo
Maximum landing gear operating speed
Vlof
lift-off speed
Vmc
minimum control speed with critical engine inoperative
Vmo/Mmo
maximum operating limit speed
Vmu
minimum unstick speed
Vne
never exceed speed
Vno
maximum structural cruising speed
Vr
rotation speed
Vref
reference landing speed
Vs
stalling speed/ minimum steady flight speed "airplane is controllable
Vso
stalling speed/ minimum steady flight speed "landing configuration
Vs1
stalling speed/ minimum steady flight speed "specific configuration
Vsr
reference stall speed
Vsro
reference stall speed in the "landing configuration
Vsr1
reference stall speed in "specific configuration
Vsw
speed at which onset of natural or artificial warning occurs
Vtoss
take off safety speed "category A rotorcraft
Vx
speed for best "angle of climb'
Vy
speed for best "rate of climb
V1
Decision speed" maximum speed in take off which "pilot must take the first action" (e.g. apply brakes, reduce thrust, deploy speed brakes) "stop the airplane with acceleration stop distance."
minimum speed for take off and achieve the require height.
V2
takeoff safety speed
V2min
minimum takeoff safety speed.
VFR
visual flight rules
VHF
very high frequency
VOR
very high omnirange station
VORTAC
collocated VOR & TACAN