Velocity Vector
I was thinking..
What if we just look at this in simple kinematics terms (not sure of the spelling).
We can create a table that we enter with Vr, move across to TORA and find a resultant IAS 10 second trend minimum.
OK I know this is really vague but if you run the numbers it is interesting that you get a vector that can be anything from 10kts to 40 kts.
These are minimum averages and are independant of weight or conditions. A completely different input from that used in the LPC calcs.
So I start a take off with a fugure of say 25 kts in my head as a guide for this runway/Vr combination.
Just a thought.