The F-4X Phantom II is a proposed F-4E Phantom II variant that was never built in the real world. However, it exists in the Strangereal universe of Ace Combat.
F-4X was a project to create an F-4 Phantom II capable of performing photographic reconnaissance at higher speed and altitude than a MiG-25 Foxbat. For this purpose, the F-4 was modified in various manners enabling it to reach a top speed of Mach 3 and a supercruise speed of Mach 2:
Two conformal tanks containing de-mineralized water were fitted to the top of the fuselage engine fairings. The water would be used for cooling compressor air, increasing total mass flow through the engine and adding more oxidizer to the afterburner. This increased the J79 turbojets' thrust by 50%.
A water injection switch was added to the cockpit.
The cockpit enclosure was remanufactured using polycarbonate to withstand frictional heating at Mach 3.
The air intakes were redesigned to be larger, with a new internal plate and air bleed system.
The tail area was increased, and the control surfaces were modified to be bigger.
The radar was removed and replaced with a smaller version of the HIAC-1 LOROP reconnaissance camera.
While testing proved successful, no actual F-4X was built due to fears it may have used funding intended for the F-15 Eagle, the F-4's own successor as an air superiority fighter.
However, in Ace Combat 5, the F-4X does not have different intakes to the F-4E and F-4G and cannot reach speeds of Mach 3. It is also equipped with a radar instead of the HIAC-1, as seen by the fact that it can carry and release guided weapons like the other F-4s.
"Advanced F-4E derivative originally developed as a reconnaissance aircraft. It was quickly deployed as an air superiority fighter after engine enhancements resulted in a 150% thrust increase."
The Osean color of the F-4X (Hill Grey II paint scheme), if not the aircraft itself, was used in the reveal trailer of Ace Combat Zero: The Belkan War by the secondary members of the Silber Squadron.
During the development of Ace Combat 5: The Unsung War, the F-4X had the reporting name of "Super Phantom". An unused line of AWACS Thunderhead in the game's files would have led him to utter the name in the event of an F-4X kill - similar lines for other aircraft were recorded, but were unused in the final release.[1]
References
↑Ace Combat 5: The Unsung War (2004) AWACS Thunderhead: "Super Phantom shot down!"
