Guys,
All this fancy aerodynamics stuff is all well and good, but has nothing to do with a body moving along a surface under a constant force. This could equally be a sleek sports car, or something travelling in a vacuum.
rustle understands what I am getting at. Bringing practicalities into it, you have to be going FASTER then 0.71Vr at half way point. I find your discussion very interesting though, please continue.
Now then Flying3Greens. Sit down, give your PPL to mumsy so you can't hurt anybody, take your blinkers off and listen
The POH performance charts are the only legal means for you to know how much runway you need to get your plane off the ground given the conditions. It doesn't tell you how fast you will be going at any point on the runway between 0 and Vr.
Let me repeat. All it tells you is HOW MUCH RUNWAY DO YOU NEED.
Lets say the conditions are such that the POH says you need 3000 ft of runway and you rotate at 60knts. First decision is "is the runway 3000 ft long", that should be simple for even the most undereducated amongst us. (Then you have to consider the POH is best case, but I don't want to confuse).
Lets take the example of a 10,000ft long runway. You start rolling. If you are not at 45knts by 5,000 ft ABORT.
Lets take the example of a 5,000ft long runway. You start rolling. If you are not at 45knts by 2,500 ft ABORT.
Lets take the example of a 3,000ft long runway. You start rolling. If you are not at 45knts by 1,500 ft ABORT.
Simple stuff really. That's all I am saying. Hopefully in the case of the 10,000ft runway when the POH says you need 3,000 ft you will be airborne at 5,000ft. If you are not then something is wrong. So ABORT.
How anybody can be criticised for suggesting a rule which encourages and errs on the side of safety is beyong me. Safety is certainly not silly. Come to the Rockies and learn all about runways and performance. In the world where this really matters, people who think like you are a liability.
As for the bulldog. The only machine I know which can violate Newtons Laws is the Starship Enterprise. Just because your airspeed indicator says you are going 0knts doesn't mean you are going at 0knts. That is REAL basic stuff, and I give up. I think I will shut up too.