As Paul Suh indicated, the Energy-Maneuverability calculations that Col. John Boyd, USAF, developed in the early 60’s quantified why certain aircraft dumped more energy during their maneuvers and required more thrust to regain said energy.

While the Phantom was a workhorse, it shared the same faults as the Century-series fighters. High thrust married with high weight and payloads gave them good straight-line speed, but made them lousy in the corners. It’d be like racing the Formula 1 tour in a 1965 Ford Mustang.