I think the article is concerned about the time between when the aircraft is going too fast to stop on the runway, but still too slow to take off.
“I think the article is concerned about the time between when the aircraft is going too fast to stop on the runway, but still too slow to take off.”
If you read down into the blog post, this is discussed extensively with numerous informative links and Youtubes provided.
From the blog link:
What is V1?
According to Wikipedia V1 is the critical engine failure recognition speed or takeoff decision speed. It is the decision speed nominated by the pilot which satisfies all safety rules, and above which the takeoff will continue even if an engine fails. The speed will vary between aircraft types and also due to aircraft weight, runway length, wing flap setting, engine thrust used, runway surface contamination and other factors.
What is VR?
Per Wikipedia VR is rotation speed, the speed at which the aircrafts nose wheel leaves the ground. When the aircraft reaches VR, the pilot pulls back on the yoke causing the nose of the aircraft to rotate upwards and causing the wing and flap takeoff configuration to generate lift sufficient to raise the aircraft off the runway.
Why does the RKZ begin way down the runway at V1 and not back at the beginning of the runway?
In the event of a terrorist attack on the engines of an aircraft during take-off, if the attack were to occur while accelerating at any speed below V1, the pilots should be able to abandon the takeoff safely by rejecting the takeoff.