I get it that I don't fly those and the "rules" have existed for a long time and the "work".
But do they?
There are 3 important speeds needed when taking off: V1, VR and V2.
Before I continue with this I'll digress slightly to when I was doing/trying to do the BAK.
You are flying a plane at an airport and are going to take off. You need to know these things:
1 - QNH
2 - Temperature
3 - Wind speed and strength
4 - TODA
5 - TODR
6 - TOW
Ok, so QNH and Temperature, fair enough.
TOW - Take Off WEIGHT. Again: Fair enough.
TODA - Take Off Distance AVAILABLE
TODR - Take Off Distance REQUIRED
The QNH, wind, temperature and TOW go through a table to give you your TODR.
That has to be less than the TODA, or you will run out of runway. Kinda obvious.
You can't take off on a 1,000 foot runway if you need more than 1,000 feet to take off.
So, that is fairly self explanatory.
But now things get interesting for me.... V1, VR and V2.
V1 - Above this speed you MUST take off. (Confusing for reasons to which I shall address soon)
VR - This is the speed at which you "rotate" the plane. That is: You take off.
V2 - Minimum climb out speed needed. If you are slower than this: you are not going to continue flying.
So, let's break this down a bit more:
Your plane weighs... 500Kg.
The wind is still. (Just to keep things simple)
Your TODR is.... 800M (Arbitrary/random number)
The runway is 1000M long.
You get to the start of the runway and start your take off roll.
And this is where it all falls apart for me.
Let's say your V1 = 80 and VR = 100.
You set off down the runway and the entire runway is ahead of you - good.
You continue down the runway getting faster and faster... and faster.
You get 800M down the runway but haven't got to VR speed (let alone V1 speed) and slam on the brakes.
Where is your stopping distance required calculated?
You are in a plane doing - say 70 kts - 800M down a 1,000M runway and decide to abort the take off.
The STOPPING DISTANCE REQUIRED (I just made that term up now) is.... 300M.
Guess what is going to happen.
Problem as I see it:
V1 is misleading.
V1 should be replaced by a P1 - Point1 which indicates: YOU MUST BE FLYING BY NOW OR YOU WILL NOT STOP BY THE END OF THE RUNWAY!
Also the fact that VR > V1 is also weird/strange/confusing.
You have a "gap" between when you can take off and when you must take off.
Surley VR should be LESS THAN V1, or more correctly: P1
And P1 is a point on the runway where if you reach it and are not flying, you MUST ABORT AND STOP.
So the take off would be more like, you start (at the start) and accelerate down the runway.
If you get to P1 before you get to VR, you abort the take off. The remaining runway distance is enough for you to stop.
All things being good: You get to VR well before P1 and you are flying before you get to P1 on the runway.
And - of course - P1 will vary from plane to plane and with different conditions. Temperature, wind, etc.
Yes, it is more complicated to work out and "way back then" it may have been too difficult to calculate.
But now, with computers coming out of every hole in "everything".... that isn't too difficult to do.
So really looking back at the V1, VR and V2 speeds, and their association that:
V1 < VR < V2 is really problematic.
VR < V1 for starters.
V2 and VR.... well.... I'm not sure.
Thoughts?
Who can help me get my head around why these are called what they are called and why.