V2 Scheduling
JT
I was referring to the AFM speeds. Perhaps an example would be the best way.
Assume an aircraft with TOW from 40,000lbs to 80,000lbs.
Vmca of 90kts
Vmcg of 90 kts
Vs from 80kts at 40,000lbs to 94kts at 80,000lbs.
Vmu sufficiently far below Vs that we can ignore it.
Then the 1.2Vs lower limit to V2 will be 96kts at 40,000lbs and 113kts at MTOW.
Looking at the Vmc-driven limits, the Vmca limit will be 1.1*90kts=99kts. If this were the only limit we would have a constant V2 of 99kts from 40,000lbs up to 61,000lbs or so, then increasing with stall speed up to 113kts at 80,000lbs.
But, the V1mcg limit must also be considered. Since V1 may not be less than Vef which may not be less than Vmcg (and in fact one must also add the acceleration for recognition time too), for the case shown we may have a V1 of not less than 90kts (and probably a little more, let us assume 2kts of accel, giving a V1mcg of 92kts). FAR25.107(a)
FAR25.107(e)91)(i) states that VR may not be less than V1 - assume a V1=Vr schedule.
FAR25.107(c)(2) then states that V2 may not be lower than VR "plus the speed increment attained before reaching a height of 35ft...".
We refer to this increment (at Canadair at least) as the "speed spread" and since the aircraft is often constrained by pitch rate considerations there is a finite time required. At lighter weights this means that the higher T/W accelerates the aircraft more than at heavier weights, and so the "speed spread" is greater at light weights.
One might have a situation where the speed spread was as much as 10kts, say, at the lightest weight, dropping more or less proportionally with weight.
For the numbers used here that would give a V2 at 40,000lbs of 102kts due to Vmcg limits, dropping to 97kts at MTOW say.
The combined effect of all those limits might be (apologies, I'd love to insert a sketch here, but...)
40,000lbs : V2=102kts (V1mcg limit)
45,000lbs : V2=100kts (V1mcg limit)
50,000lbs : V2=99kts (V1mcg and 1.1Vmca limits coincident)
60,000lbs : V2=99kts (1.1 Vmca limit)
61,000lbs and above : 1.2 Vs limit (from 99 to 136kts)
I haven't double checked those numbers, I will do so later - it's Saturday night!
Regarding the V2 at min being higher than at max. Yes, it was the scheduled speed - it was a consequence of unreasonably high Vmc's (both 'a' and 'g'). But it would have been very hard to respect the procedures and not get those speeds in practice. (It would also have been very bizarre)