What does Vr represent in takeoff performance?

In the context of takeoff performance, Vr represents the rotation speed. This is a critical speed during the takeoff phase of flight, as it indicates when the pilot is required to pull back on the control yoke to raise the aircraft's nose and initiate the climb. The rotation speed is determined during the aircraft's performance calculations and is essential for ensuring that the airplane achieves adequate lift needed to take off safely.

Understanding Vr is crucial for pilots as it affects the safety and efficiency of the takeoff. It is not merely the speed at which the aircraft begins to climb but specifically the speed at which the pilot should rotate the aircraft to make this transition. This choice is central to effective flight operations and reflects an understanding of aircraft performance characteristics during takeoff.