McDonnell Douglas F-4E USAF Phantom II airplane model. The F-4E is essentially an F-4D with improved J79-GE-17 engines (900 lbs. more static sea level thrust each) and a M61A1 "Vulcan" 20mm cannon. Operational experience gained in Vietnam had a direct influence on the addition of the cannon. The air-to-air missile fire-to-hit ratios were low and air combat usually degenerated to subsonic 'dogfighting' where the F-4 was at a decided disadvantage when flying against more maneuverable enemy aircraft (MiG 17 and MiG 21). The hydraulically powered wing-folding mechanism and the emergency ram-air turbine were removed to save weight and a seventh fuel cell was added. The addition of self-sealing fuel tanks starting with block 41 aircraft lowered the fuel capacity by 139 gallons, but provided much better combat survivability.
McDonnell Douglas produced 5,057 F-4's of which 1370 were F-4E's. Mitsubishi received 11 F-4 kits and built 127 of their F-4EJ's under license bringing the total to 5,195 airframes. The USAF ordered 993 -E models, but more than 100 were diverted or direct delivered to other nations. The F-4 was flown by the USAF, US Navy, US Marine Corps, United Kingdom, Australia, Japan, South Korea, Israel, Germany, Spain, Iran, Turkey, Greece, and Egypt.