Originally Posted by
RansS9
*Warning* PPL *Warning*
Help.
If Vso is the stall speed str and level in the relevant landing configuration isnt this a 1G condition ? (I assume the test pilot isn't attempting a flick roll entry!!)
Why is Vsr a better or correct 1G stall?
Yours confused (as always) TIM
The old stall speed standard (Vso) corresponds to the demonstrated minimum speed in the stall manoeuvre. In practice the 'g' was not maintained at precisely 1.000, and usually was a little below that at the point of minimum speed. So it wasn't, in fact, 1 'g' stall speed - more like a 0.95'g' speed in fact.
The new methodology requires correction for the load factor being below 1'g' in a typical demonstration. So Vsr (or Vs1g as it was once known) will be about 5% higher than Vso (or Vsmin, to give it one of its older names), for the same aircraft and similar manoeuvre.
So Vref based on Vsr is 1.23*Vsr, and if you substitute that "about 5%" factor you get 1.23*1.05*Vso which is about 1.30Vso (technically it's 1.2915, but I did say "about") - just like zzuf says, about the same value.