So here is my 1/50 dollar:
By definition VR is the speed where you initiate rotation as to arrive at V2 at 35ft. Regardless of all the other numbers/weights/heights/regulations, you are supposed to get to V2 at 35ft so if you have selected a derated takeoff power setting you will rotate at a higher speed because you will have less power to accelerate to V2 while climbing to 35 feet (as far as I know your climb angle should be the same for a derated takeoff per 1st segment climb requirements, but I could be wrong). I think this is what CCA said in post #4.
I don't think VMCA is a factor here, according to the numbers below provided by Jammed (I assume TO2 is the derated number for Boeing, I am stuck on brand A) a TO thrust/MAX T/O has a lower V1/VR than TO2/derated T/O. If it was a VMCA issue you would want more speed before taking it in the air at MAX T/O.
FMC Flap 20 TO thrust: V1:136 Vr:150 V2:165
FMC Flap 20 TO2 Thrust: V1:143 Vr:154 V2:165
As far as
"Guys, please wake Up. This is basic performance. And the type of aircraft is irrelevant in this matter."
is concerned, I really don't think your second post added any more information to the discussion at hand than the first............
I think Intruder types faster than I do!
Last edited by hans brinker; 20th Apr 2015 at 02:45.
Reason: spelling