I think what needs to be added here is for the most part on the 744 F20 - V2 is the same as Vref 30 for all weights except below something like 230T, and most times F10 - V2 is 5 knots greater.
So it appears as if there is a relationship such as.
F20 V2 = Vref 30 = F10 V2+5
However an accurate computer generated RTOW V2 shows that these figures are not the same and the generic weight vs V2 vs Vref chart is conservatively rounded making it appear that the above statement is true when it's not.
The -8 V2 and Vref are so different that the generic chart is not possible and in fact we have begun removing this same chart from our 744s, as it's somewhat of a carryover from the classic where a simple chart was referred to for V2 & Vref.
Last edited by SMOC; 5th Dec 2013 at 00:19.