Originally Posted by
watchyourairspeed
G'day gc 2750,
The previous posts have missed the target. 
According to Airbus F-COM 3.04.10
VS or Stalling speed, it is not displayed. Moreover, for a conventional A/c, the reference stall speed, VSmin is based on a load factor that is less than 1g. This gives a stall speed that is lower than than the stall speed at 1g.
All operating speeds are expressed as functions of this speed (for instance VREF = 1.3 VSmin). Because A/c of the A320 family have a low speed protection featute (alpha limit) that the flight crew can not override, the airworthiness authorities have reconsidered the definition of stall speed for these A/c.
All operating speeds must be referenced to a speed that can be demonstrated by flight test. The speed is designated as VS1g. Airworthiness authorities have agreed that a factor of .94 represents the relationship between VS1g for A/c of the A320 family and VSmin for conventional A/c types. As a result tha authorities allow A/c of the A320 family to use the following factors:
V2 = 1.2 * .94 VS1g = 1.13 VS1g
VREF = 1.3 * .94 VS1g = 1.23 VS1g
FCOM concludes by saying that the A319,320,321 hav exactly the same maneuver margin that a conventional A/c would have at its reference speeds.
Saying that it stalls at 80kts or between 108 and 110 is somehow inacurate. 
My two cents about it.
Safe flying,
WYA
Actually, Vs1g isn't a unique concept for A320-family, nor the various factors associated with it. It's the *new* way of considering stall speeds, and was applied optionally for about a decade or more, before becoming (recently) enshrined as the standard approach - any new (non grandfathered) Part 25 a/c will be "vs1g" aircraft.
And in any case, whether you use Vs1g or Vsmin as the way to define the stall speed, you still have to stall the a/c to know what they are. So the A320 family still has a stall speed, and it's perfectly valid to discuss it as a stall speed. Only when you get into the fine details of scheduling operational speeds is anyone going to care if it's a Vsmin or Vs1g speed.
Oh, and whatever Airbus might claim, Vs1g/Vsmin difference have nothing to do with "conventional vs FBW" or whatever it is they are alluding to. It's simply a different way of certifying the same aircraft. (ONly thing is, I bet Airbus couldn't have got decent numbers the Vsmin route ...)