"Breaking the Barrier" The Sidewinder was prone to losing lock from simple effects like sun glare or ground heat radiation... and the early Sparrows weren't much better. The F-4 was also prone to systems malfunctions, it's radar and fire-control systems were twitchy to say the least... and without an on-board gun, the only choice was to use speed and power to try and dictate the terms of the engagement in a way that you could use the missiles to your advantage. About 1/2 the time either radio or fire-control was out on the F-4's, but at least the pilots knew they could get out of dodge fast if they needed to... About the only advantage an F-4 had in Vietnam was power... In combat you could light the burners to use that power to escape any opponent more maneuverable than you were. In dog-fights against MiG-17's this was about your best option... you could gain distance and try for a favorable shot... "Shoot and scoot" in layman's terms. Pilots could use the raw power and speed of the F-4 to dictate the terms of an engagement and allow them to get missile shots from outside of an enemy fighters gun range... Here an F-4 punches through the sound barrier to break out of a MiG trap... F-4B Phantom, MiG-17 and special effects props by me. Rendered in DS 4.7