McDonnell Phantom production development

The Phantom F4H-1F (F-4A), F4H-1 (F-4B), F-4G (I) & F-4N

The initial XF4H-1 prototype performed its first flights with J79-GE-3 engines, but was then refitted with J79-GE-2s and finally J79-GE-2As, providing 46.0 kN (4,695 kgp / 10,350 lbf) dry thrust and 71.8 kN (7,325 kgp / 16,150 lbf) afterburning thrust each.

The 19th aircraft built replaced the AN/APQ-50 radar set with the evolved AN/APQ-72, which had a larger antenna that required fit of a new and bigger nose. This gave the Phantom a "droopy nose" appearance that made it look even more awkward, and also dictated a new canopy scheme. Earlier aircraft had a canopy that was flush with the aircraft's spine, but with the 19th aircraft and every other Phantom ever built, the cockpit was raised and bulged to give a better view over the big nose. Forward visibility was still not the best and rearward visibility was terrible, though the raised cockpit did improve the view to the back a bit.

The 46th aircraft introduced fully-rated J79-GE-8 engines with 48.5 kN (4,945 kgp / 10,900 lbf) dry thrust and 75.6 kN (7,710 kgp / 17,000 lbf) afterburning thrust each, along with minor modifications to the engine installation.

In March 1961, the first 45 Phantoms, following the two XF4H-1 prototypes, were retroactively given the new designation of "F4H-1F", while the others in this series retained the F4H-1 designation. The F4H-1Fs were all evaluation and test aircraft; none of them ever reached operational service.

Full-production F4H-1s were in service with the US Navy and Marine Corps by 1962. In September of that year, the US military adopted a tri-service aircraft designation scheme, and the F4H-1F became the "F-4A" and the F4H-1 became the "F-4B". A total of 649 F-4Bs were built from 1961 into 1967.

Of total F-4B production, 12 were built with an AN/ASW-21 datalink for an automatic carrier landing system, along with an "automatic approach compensation (AAC)" system that performed automatic throttle control on carrier approaches to ensure constant speed. These aircraft were designated "F-4G", with the first flying in March 1963. The new electronics gear was fitted in a compartment in the upper forward fuselage created by chopping off an edge of the forward fuselage fuel cell.

The F-4Gs went through operational evaluation in Southeast Asia in 1965:1966. They were then returned to the F-4B specification, suggesting that the AAC system was not judged successful, but the F-4G designation would be "recycled" in a later Phantom variant. The new avionics compartment was carried on to other variants.

Between 1972 and 1974, 226 Navy and Marine F-4Bs were put through an update program with structural strengthening, new wiring, 30 kilowatt electrical power generators, and new avionics. The updated aircraft were known as "F-4Ns".

The Phantom F-4C & F-4D

Robert S. McNamara, US secretary of defense in the Kennedy and Johnson Administrations, was very enthusiastic about "commonality" between the different US armed services. He wanted the services to adopt common equipment to reduce acquisition, logistical, and training costs. In 1961, the word came down that the USAF should evaluate the Navy Phantom. The Navy loaned what would eventually be a total of 29 F-4Bs for the evaluation.

Such attempts to enforce commonality didn't always work out well, partly due to interservice rivalries, plus the fact that the services really did sometimes have clearly different needs and requirements. The Phantom proved to be an extraordinary exception. The evaluation showed the Air Force that the Phantom, even though it carried the weight of additional gear required for carrier operations, was a match or more for existing Air Force fighters. The USAF would eventually acquire over twice as many Phantoms as the Navy and Marine Corps combined.

In the spring of 1962, the USAF decided to adopt the Phantom, under the initial designation of "F-110A Spectre", which was applied to the loaned Navy F-4Bs then being evaluated by the Air Force. A USAF-optimized variant actually went into service as the "F-4C", retaining the Navy Phantom name, with the first example of the variant flying on 27 May 1963. 563 were built into 1966.

The F-4C was very similar to the F-4B, even retaining arresting gear and folding wings, but featured a number of changes:

• J79-GE-15 engines, which were similar to the J79-GE-8 engines used on the F-4B, but were slightly uprated and used a pyrotechnic cartridge starter system, instead of an external compressed-air starting system. This allowed the F-4C to "self-start" and operate from remote airstrips with minimal ground support gear.M
• A pop-up boom-type refueling socket fitted on the spine of the aircraft behind the cockpit, replacing the F-4B's refueling probe.
• Wider-tread, low-pressure tires, better suited to the relatively gentle landings on ground airstrips, as opposed to the "smackdown" landings on carrier decks. A slight bulge had to be added to the wings to accommodate the tires.
• Dual flight controls. The height of the rear instrument panel was reduced to give the back-seater, known as a "weapons system officer (WSO)" or "whizzo" in Air Force nomenclature, a better forward view. In practice, dual controls didn't prove to be as useful as expected. The back-seater rarely had much opportunity to actually fly the aircraft. Training the back-seater to be a pilot was counterproductive, since it was more useful to train him in the best use of the radar and weapon systems, and having two pilots on board led to friction anyway.
• New avionics, including an AN/APQ-100 radar, an improved version of the F-4B's AN/APQ-72, featuring a better display system; an AN/ASN-48 INS for long-range navigation; an AN/AJB-7 bombing system; and provision for launch of radio-controlled AGM-12 Bullpup radio-guided air-to-surface missiles (ASMs).
• Provision for the carriage of two AIM-4 Falcon AAMs on the wing pylons instead of four Sidewinders. This would not prove to be a good idea either, and the Falcons would rarely be carried.

After the F-4C went to Vietnam in 1965 a number of problems emerged, including fuel leaks and poor tolerance to humidity. A field update program was implemented to address the problems.

The F-4C was followed in USAF service by the "F-4D", which performed its first flight on 9 December 1965, leading to initial service deliveries in 1966. The F-4D was the USAF's workhorse over Southeast Asia. 825 were built into 1968.

The F-4D airframe was basically the same as that of the F-4C. The primary improvements were in avionics, particularly AN/APQ-109 radar. The AN/APQ-109 was an improved, more reliable "hybrid" version of the AN/APQ-100 with solid-state components in the low-voltage sections. The F-4D also featured new attack and navigation systems, and uprated 30 kilowatt electric power generators.

Since combat experience over southeast Asia had shown the need for a gun, a 20 millimeter cannon pod designated the "SUU-16/A" was hastily introduced, to be eventually replaced by the similar but improved "SUU-23/A". The F-4D was wired for carriage of the cannon pod, and had an ASG-22 lead-computing gunsight fitted for aiming it. Apparently some F-4Cs were also retrofitted to carry cannon pods.

The AN/AAA-4 IRST was deleted in most F-4D production, since it had proven ineffective in practice. Confusingly, late production F-4Ds were fitted with the fairing used for the AN/AAA-4, but it contained elements of an AN/APR-25/26 radar warning receiver (RWR), not an infrared sensor.

The Phantom F-4E

Combat experience led to the definitive Air Force "F-4E", which performed its initial flight on 30 June 1967. The F-4E featured:

• Uprated J79-GE-17 engines, with 79.6 kN (8,120 kgp / 17,900 lbf) afterburning thrust.
• A General Electric M61A1 six-barreled 20 millimeter Gatling-type cannon on the underside of the nose, with 640 rounds of ammunition. Fit of the cannon required a new and longer nose, a modified version of the nose designed for the RF-4C reconnaissance Phantom, described in the next section.
• The cannon pod had been a big help, but it was "draggy" and tended to become misaligned on its stores pylon, making it inaccurate. The built-in cannon was a much better solution. However, early production F-4Es suffered from engine "flameouts" due to ingestion of gases expelled from the muzzle of the cannon, and to fix this problem GE quickly came up with a longer-barreled cannon, which was fitted into a longer cannon fairing with improved ventilation. This fix was refitted to earlier F-4E production.
• A solid-state AN/APQ-120 radar. The new radar was much more compact than its predecessors, allowing it to fit into the nose along with the cannon.
• Martin-Baker Mark 7 "zero-zero (zero altitude, zero speed)" ejection seats.
• A tailplane with a fixed inverted slat attached under the leading edge. The slat provided improved control authority at high angles of attack (AOA).
• A seventh fuel cell in the tail above the engine nozzles.
• Manual wing fold, instead of hydraulic fold.

The F-4E became the primary USAF variant, and was also heavily exported, as is discussed later. Including exports, 1,387 were built into 1979.

The F-4E was enhanced during and after its production. One of the particular limitations of the Phantom was that it had been designed basically as an interceptor and strike aircraft, not a dogfighter, and maneuverability had suffered as a result. The lack of maneuverability proved troublesome in combat -- in the worst case, under certain aggressive flight conditions the F-4 could go into a spin that generally required immediate ejection if the aircraft was below 3,000 meters (10,000 feet). This unpleasant behavior came as something of a nasty shock, since flying the Phantom under peacetime conditions was very straightforward, one pilot calling it "idiot-proof", and it had an admirable flight safety record.

In response to the maneuverability problems, a program named "Agile Eagle" was initiated, in which the Phantom was fitted with various experimental aerodynamic modifications. The solution in the end was to fit the wing with leading-edge slats, which extended automatically when the aircraft's AOA exceeded six degrees, and retracted when the AOA went back to four degrees. Installation of the slats required removal of the BLC system.

The leading-edge slats were introduced into F-4Es beginning in mid-1972 and were retrofitted to older aircraft. Beginning the next year, 1973, F-4Es went through a structural strengthening program after an F-4E was lost due to a wing structural failure.

The Northrop "Target Identification System Electro-Optical (TISEO)" camera system was also introduced in late F-4E production, being retrofitted to older aircraft as well. TISEO involved a steerable, stabilized telescopic camera mounted on the left wing, and was used primarily to inspect targets before engaging them. TISEO imagery was displayed on the WSO's radarscope. The camera could be slaved to the AN/APQ-120 radar, and apparently there was an upgrade that allowed it to be linked to the navigation system to target flight checkpoints as well. Of course, it was a daylight / clear-weather only system. Most export F-4Es were not fitted with TISEO.

Phantom F-4J, F-4S & Oddballs

The Navy and Marines procured a variant similar to the F-4E, designated the "F-4J", with the following improvements:

• Some new features like those of the F-4E, such as Martin-Baker Mark 7 zero-zero ejection seats; the slatted tailplane; and the number-7 fuel cell. The M61 cannon was not fitted, and in fact no production Navy or USMC Phantoms would ever have built-in gun armament.
• Uprated J79-GE-10 engines, comparable to the F-4E's J79-GE-17 but without cartridge starting.
• Strengthened airframe and landing gear, with Air-Force style tires.
• New avionics, including an AN/AWG-10 fire control system with AN/APG-59 radar; an AN/AJB-7 bombing system; an AN/ASW-25 data-link for automatic carrier landings, developed as a follow-up from the F-4G experiments; and an AN/APR-32 RWR. The AN/APG-59 was a particular step forward, as it was a solid-state system with multi-mode operation and "look-down" capabilities, allowing it to pick low-altitude targets out of ground clutter.
• An uprated 30 kilowatt electric power generation system.

Three F-4Bs were rebuilt as "YF-4J" prototypes, with the first prototype performing its initial flight on 27 May 1966. 522 new-build F-4Js were manufactured into 1972, following the prototype conversions. A special version of the F-4J was proposed for the USMC but not built, incorporating an enhanced fire-control system and F-4E-style leading-edge maneuvering slats.

Incidentally, the "F-4F" was a specialized Phantom variant flown only by the German Luftwaffe, discussed in a later chapter, while the "F-4H" designation was not used since it might cause confusion with the old "F4H" designation. The "F-4I" designation wasn't used either, since it could be misinterpreted as "F-41".

Beginning in 1978 248 F-4Js were brought up to "F-4S" standards, with structural strengthening; leading-edge slats; a substantially updated AN/AWG-10A radar set and other new avionics; and uprated J79-GE-10B engines, which also featured improvements to eliminate the tendency of the J79 to leave behind a dirty smoke trail, a liability in combat. Fit of the leading-edge slats required removal of the BLC system.

There were also some unusual or unbuilt Phantom variants. The 226th Phantom built was used as an experimental platform. It started life as an F-4B, to be reconfigured as the prototype for several Phantom variants. In 1972, it was given a fly-by-wire (FBW) control system, and was later given canard foreplanes. This aircraft was retired and donated to the US Air Force Museum in Dayton, Ohio, in 1978.

In the late 1970s, McDonnell Douglas proposed an air superiority variant of the F-4E designated the "F-4T" that would have deleted all gear needed for ground attack. Nothing came of the notion.

The most dramatic proposed modification of the Phantom was a "swing wing" or "variable geometry" derivative of the F-4J, designated the "F-4 (FVS)", promoted in the mid-1960s by McDonnell. The wings would be shoulder-mounted and would be able to sweep from 23 to 75.5 degrees. The Navy was very leery of this idea, since the service wanted a new fighter instead of an updated version of an older one, and lobbied for the Grumman F-14 Tomcat instead.

The Phantom RF-4C, RF-4B, & RF-4E

Although the Air Force had some entirely understandable resistance to having a Navy fighter forced on them, after adopting the Phantom the USAF quickly became very enthusiastic about the type. Shortly after ordering their first production Phantom fighters, the service decided to acquire a reconnaissance variant to replace to their current McDonnell RF-101 Voodoo. The "recce" (pronounced "rekky") Phantom was originally designated the "RF-110A", but was redesignated "RF-4C" in September 1962.

The Phantom was adapted to the reconnaissance role through fit of a new forward fuselage to carry cameras and other reconnaissance gear. Initial flight of the first of two "YRF-4C" prototypes was on 8 August 1963. 505 RF-4Cs, including the two prototypes, were built into 1974.

The cameras were fitted in a new nose that stretched the aircraft's length by 84 centimeters (33 inches). The wing-mounted pitot tube was moved to the nose from the leading edge of the tailfin as well, resulting in a total increase in length of 147 centimeters (57.8 inches). As noted, a modified version of this nose was fitted to the F-4E to accommodate the M61 cannon, and resulted in the same increase in length.

The RF-4C's nose featured three camera "stations" that could be configured by ground crews with different camera fits:

• "Station 1", or the "forward camera station" was just under the radome and stared forward at an angle. It could accommodate a KS-87 or KS-72 camera.
• "Station 2" was behind station 1, and included a camera port staring downward, as well as camera ports staring off to each side. It could accommodate various combinations of KS-72, KS-87, or panoramic KA-56 cameras in vertical or oblique (angled to the side) mountings.
• "Station 3" was behind station 2, and included two vertical ports. It could accommodate a KA-91 or KA-55A high-altitude panoramic camera; dual KS-87s with different focal lengths; or KC-1A, KC-1B, or T-11 mapping cameras.

In addition to the cameras, the RF-4C carried electronic reconnaissance gear, as well as systems to support the reconnaissance mission:

• A Goodyear AN/APQ-102 "side looking airborne radar (SLAR)" that shot radar beams out to the sides of the aircraft and recorded the echoes on a long film strip, giving an all-weather view of the terrain alongside the aircraft's flight path.
• The AN/APQ-102 also had a "moving target indicator (MTI)" capability that picked out any vehicle moving at more than 9.25 KPH (5.75 MPH or 5 knots) perpendicular to the aircraft's flight path, highlighting the target on the film strip. The SLAR was mounted under the pilot's position, with the SLAR antennas fitted unobtrusively into the fuselage at that location, forward of the engine intake ramps.
• An AN/AAS-18 infrared line scanner was mounted under the back-seat position and stared out of the belly vertically. It recorded infrared imagery on a film strip to provide a thermal map of the terrain below the aircraft's flight path.
• An AN/ALR-17 "radar homing and warning system (RHAWS)" that located, identified, and targeted adversary radar stations, marking them on film imagery. RHAW antennas were mounted on either side of station 1 and on the wingtips.
• An "auxiliary data annotation set (ADAS)" that marked camera film with such useful data as date & time, radar and barometric altitude, latitude & longitude, heading, pitch, roll, drift angle, and unit identification.
• Two photoflash cartridge dispensers were fitted underneath the fuselage at the tail for night photography.
• The RF-4C could also be fitted with electronic intelligence (ELINT) systems carried in pods on stores pylons.

The RF-4C was not intended as an active combat aircraft. Fire control systems were deleted; the recesses for Sparrow missiles under the fuselage were faired over, since the RF-4C didn't have the radar to guide the Sparrows; and the pilot's weapons sight was replaced by an LA-313 optical viewfinder to help target camera shots.

Instead of an AN/APQ-100 radar set, the RF-4C was fitted with a more compact Texas Instruments AN/APQ-99 forward-looking radar set, intended to support air navigation instead of combat. The AN/APQ-99 provided a ground mapping capability, along with terrain-following and terrain-avoidance modes. The RF-4C also featured an improved AN/ASN-56 INS, and a long-range HF communications system.

Although in Air Force terminology the back-seater was still known as WSO, as the RF-4C didn't have any weapons, he was more often known simply as the "navigator".

Following the Vietnam War, USAF RF-4Cs were given various upgrades to keep them up to date, the most important being fit of the AN/ALQ-125 ELINT system.

The RF-4C's nose and reconnaissance gear was fitted to the F-4B airframe to yield the "RF-4B" for the US Marine Corps, with initial flight on 12 March 1965, leading to operational introduction in May 1965. The equipment fit differed slightly from the RF-4C's in that the station 2 cameras could be rotated in flight.

The RF-4B actually followed the F-4C into service, reversing the usual sequence of subvariant codes. The RF-4B was strictly a Marine machine; the Navy did not use the type since that service had no requirement for it, relying on the RF-8A Crusader and RA-5C Vigilante for the reconnaissance role. 46 RF-4Bs were built. The last ten were odd hybrids, with the original RF-4B nose, RF-4C fuselage and tail, and F-4J wings. In the last half of the 1970s, the RF-4Bs were given a substantial update under Project SURE, involving structural strengthening, new reconnaissance systems, a datalink, defensive countermeasures, and other avionics.

The F-4E was fitted with a recce nose to yield the "RF-4E". Initial flight of the prototype was on 15 September 1970, and 146 were built, strictly for the export market. Late production F-4Es had a modified nose that was less angular than earlier recce Phantoms. RF-4Es also had slight variations in equipment fit for their specific customers.

By this time, the Phantom was properly known as the "McDonnell Douglas" Phantom, since the two companies had merged in 1967. Three decades later, McDonnell Douglas would be bought out by Boeing, but nobody would think to call an F-4 a "Boeing Phantom".

The Phantom F-4G "Wild Weasel"

The last Phantom was rolled out of the McDonnell Douglas factory at Saint Louis on 26 October 1979, after manufacture of 5,057 of the type there, not counting 138 assembled or built in Japan, as discussed in a later chapter. However, given the widespread use of the type, that was by no means the end of the story.

One of the nasty surprises encountered by the US military in Vietnam was the effectiveness of North Vietnamese air defenses, and so developing counter-defenses was a high priority. One possible counter-defense was a "defense suppression" aircraft that could target air-defense radars and attack SAM sites, and this led to the "Wild Weasel" series of "defense-suppression" aircraft.

The original "Wild Weasel I" was a modified tandem-seat F-100F Super Sabre, but this aircraft could not keep with strike packages, and amounted to a proof-of-concept system. It was followed into service by the "Wild Weasel II", a modified F-105F Thunderchief, and then a more optimized F-105F modification, the F-105G "Wild Weasel III", which performed the burden of defense suppression over North Vietnam.

Late in the war, about 36 F-4Cs were modified to the "Wild Weasel IV" configuration, carrying radar detection and targeting systems along with the AGM-45 "Shrike" anti-radar missile (ARM), which was a Sparrow with a radar seeking head. The Wild Weasel IV conversion left something to be desired, and after the war 116 F-4Es were converted into the "Wild Weasel V" or "Advanced Wild Weasel", which was given the "vacant" designation "F-4G".

The nose cannon was deleted, with the space occupied taken up by gear for an AN/APR-38 RHAWS, with 52 antennas littered over the fuselage. Combat avionics systems were retained. The AN/APR-38 could not only locate and identify radar emitters, it could also target them for attack with ARMs, or cluster bombs and other munitions. At first, the F-4G carried the Shrike, but in the early 1980s this missile was generally replaced by the Texas Instruments AGM-88 "High Speed Anti-Radiation Missile (HARM)", more or less a scaled-up Shrike with a better seeker system. The HARM would become the F-4G's most characteristic weapon.

QF-4 Phantom Target Drones

With plenty of old Phantoms available, it is unsurprising that the type has been favored for conversion into high-performance target drones. Some F-4Bs were converted to "QF-4B" target drones and "DF-4B" drone controllers, and as later Phantom variants were removed from first-line service, they were often converted to target drones as well, collectively referred to simply as "QF-4s". The conversions cost a few million USD each.

Interestingly, some of the QF-4s retain a piloted capability. This is because test and training scenarios require a high degree of choreography to make them as realistic as possible, and so pilots have to fly the QF-4s through "dry runs" to ensure that all details are considered. The USAF refers to unpiloted flights using the acronym "NULLO (Not Utilizing Local Live Operator)", while the Navy more tidily calls them "NOLO (No Onboard Live Operator)".

Up to four QF-4s can be flown in formation during NULLO flights. The drones do not interact with each other, they are simply commanded to follow a specific moving point in space known as a "rabbit", with each aircraft maintaining a specific three-dimensional offset from the rabbit. The autopilot system on the QF-4 is very sophisticated. For example, the remote operator can land the aircraft simply by giving it a single command to land.

Although missiles used in air combat tests don't usually have combat warheads, once a QF-4 is used as actual target in exercises, its predicted lifetime is no more than four missions. The QF-4 carries a self-destruct system to destroy itself if missile damage fails to shoot it down but causes it to become a potential threat to populated areas.

While QF-4s continue to be "manufactured", they are now nearing the end of their useful lives even as targets, since they are increasingly unrepresentative of any adversary American pilots might face. A new generation of targets is now under consideration, possibly based on retired F-16A fighters.

Author: Greg Goebel