F-4E Phantom II
The F-4E, which took off on its maiden flight on June 30th 1967, became the leading Phantom model, with 1,389 planes built. The first F-4E was delivered to the Air Force in October 1967. The Air National Guard received its first F-4E in 1985, the Air Force Reserve in 1987. This model, with an additional fuselage fuel tank, leading-edge slats for increased maneuverability, and an improved engine, also has an internally mounted 20mm multibarrel gun with improved fire-control system. The F-4E, which was equipped with leading-edge maneuvering slats and weapons and radar controls that were optimized for dogfighting, vastly improved the Phantom's air-to-air capabilities. Nevertheless, the Phantom's ultimate 3:1 kill ratio over the MiGs fell far short of the impressive advantage enjoyed by the Air Force in Korea.
The F-4E was different from earlier models in that it has an integral cannon, as well as improved systems that give it an added edge in air-to-air and air-to-ground operations. Since conventional wisdom held that the combination of high-speed and sophisticated systems would eliminate classic close-in dogfighting, the Navy's F-4B and the Air Force's F-4C and -D fighters were not configured with internally mounted guns. Such wisdom proved false in the skies over southeast Asia where restrictive engagement rules required visual identification of the enemy before missiles could be launched and where nimble MiG-17, -19, and -21 fighters proved they could hold their own against the more powerful but less maneuverable F-4s in the kind of close-in "knife fights" that remained a part of air-to-air combat. During the first few years of the Vietnam conflict, the US found itself engaging enemy aircraft such as the MiG-17 and MiG-19 that were relatively agile and could easily out-maneuver the heavier US aircraft (F-4 and F-105) that had been designed without requirements for close dogfighting or close weapons such as a gun. Initial tactics used by US pilots to try and turn with enemy aircraft had been relatively unsuccessful, and it had become apparent that missiles in use at that time were relatively unreliable at long ranges. Pilot training and revised tactics were ultimately employed to blunt the threat and use US aircraft to an advantage, but the lack of maneuverability and a gun for close-in combat became issues for the Air Force -- solved by the F-4E.
North Vietnam took advantage of the bombing halt ordered by President Johnson in late 1968 to rebuild its air force (NVNAF) and prepare its ground forces (NVA) to invade the south. In late March 1972, NVA units crossed the border into South Vietnam and sent the defenders reeling in disarray. On 8 May, President Nixon halted peace negotiations and authorized the USAF to strike targets in the heart of North Vietnam, which were now defended by over 200 MiGs flown by well-trained pilots. During Operation Linebacker I, USAF fighter aircrews made the defending MiG pilots pay dearly. From May through mid-October, the NVNAF lost at least 40 MiGs in air battles with USAF Phantoms.
The return of close-in air-to-air combat during Vietnam unfortunately exposed a deficiency in the flying characteristics of the F-4. During hard turns to engage or escape enemy aircraft, pilots began to fly the F-4 at high angles of attack where they experienced a marked deterioration in lateral-directional stability and control characteristics. Inadvertent loss of lateral-directional control and spin entries occurred, with an alarming number of accidents and losses of crew and aircraft during training and combat. McDonnell Douglas became interested in wing modifications for the F-4 that would improve buffet onset and increase lift and turning performance, while retaining satisfactory characteristics for approach and landing. Candidate configurations included the use of wing leading-edge flaps, leading-edge camber, trailing-edge flaps, and other devices; however, the most effective modification was a two-position leading-edge slat. Two slats were mounted on the leading edge of each wing panel in place of the earlier leading-edge flap. The inner slat was fully retractable at high speeds, but the outer slat remained deployed in both the cruise and high-lift con-figurations. With the slats deployed, the F-4 could make tighter turns, and approach speeds were also reduced by a significant amount. Another benefit of this modification was a dramatic improvement in the lateral-directional handling characteristics and spin resistance at high angles of attack. The slat configuration was evaluated during flight tests (known as Project Agile Eagle) of a modified F-4 test aircraft with extremely impressive results. The wing leading-edge slats were incorporated on all F-4E aircraft built during and after 1972. Later, the Navy received a slat equipped version of the aircraft known as the F-4S.
Starting in 1973, F-4E's were fitted with target-identification systems for long-range visual identification of airborne or ground targets. Each system is basically a television camera with a zoom lens to aid in positive identification, and a system called Pave Tack, which provided day and night all-weather capability to acquire, track and designate ground targets for laser, infrared and electro-optically guided weapons. Another change was a digital intercept computer that includes launch computations for all AIM-9 Sidewinder and AIM-7 Sparrow air-to-air missiles. Additionally, on F-4E/G models, the digital ARN-101 navigation system replaced the LN-12 inertial navigation system.
The Israeli Air Force [IAF] expressed interest in buying Phantoms in 1965, when they were the most advanced airplane in service, anywhere. The Americans refused this, but agreed to sell Israel Skyhawks. Only in January of 1968, after massive pressure was applied at the highest diplomatic levels, did the Americans relent. The IAF, which at that time preferred single-seat aircraft, considered having a single seat version of the Phantom designed exclusively for it. The idea was abandoned when it was realized that giving up the second crewman would prevent full utilization of the Phantom's excellent potential. It was decided to purchase the tandem seat E model which was in development at the time. At the IAF's initiative, an internal cannon was included - the first time a Phantom model included a cannon. On 05 September 1969 the first quartet of Phantoms, nicknamed 'Kurnas' ('Sledgehammer') landed on Israeli soil.
In 1980 the IAF embarked upon the initial planning phase of the project for upgrading the Kurnas. On 15 July 1987 the first prototype of the improved plane took off. It was dubbed the Kurnas 2000. Kurnas 2000, which entered service in the IAF on 09 April 1989, was different from the original Phantom mostly in its avionics. The conversion plan included replacing the plane's original radar with a new one. Norden, an American company, developed the APG-76 radar especially for this purpose - and according to the IAF's specifications. This radar, considered to be the best of its kind, uses advanced technologies that were originally developed for the US Navy's future attack plane, the A-12 Avenger II - a project that has since been cancelled. McDonnell Douglas and the Israeli Aircraft Industries had both considered replacing the J79's with Pratt & Whitney PW1120. The IAI experimentally installed the new engines in a Phantom, and its performance was markedly enhanced, in terms of cruise speed and range.
New features included in the F-4E were a General Electric Vulcan armament system (M61A1, 20 mm gun) mounted in the aircraft's nose; AN/APQ 120C fire control system; two J-79-GE-17 turbojet engines (17,900 lb thrust with afterburner); and slotted stabilator. Also (beginning with the 1972 productions), leading edge slats (LES); and fittings for mounting armorplate over certain aircraft systems and armor on the rear of the fuselage.
Basic development in 1964 followed the 17 June completion by the Air Force of a DOD directed study. It probed the known limitations of the F-4C and yet to be flown F-4D. It covered every facet of the tactical mission and as requested the cost effectiveness of various means to improve air to air, all weather, and low altitude performance. The study's chief recommendations were: (1) delete installation of an infrared search and track set (the gain would not justify the cost); (2) substitute the cheaper and more versatile Hughes AIM-4D infrared Falcon for the Navy (Philco developed) AIM-9D Sidewinder; (3) do without data link equipment (too costly for limited tactical use); and (4) defer any final decision until the coherent on receive doppler system (CORDS) was tested: If CORDS did not work, give up the whole project and end the F-4 program with the forthcoming F-4D.
A Navy LC in late July 1966 and a Navy fixed price contract in August started the FEE procurement, as requested by the Air Force. Ensuing fixed price and incentive contracts were issued by the Navy until fiscal year 1973, when the Air Force took over. It then ordered 76 more F-4Es for the FMS and another 48 for itself.
Hughes successfully flight tested the CORDS in February 1965. However, the system soon became so erratic that McDonnell (the prime contractor) had to put off Hughes's production contract. Programmed for the 35th F-4E, CORDS would at best appear on the 120th.
Immediately accepted by the Air Force, this first F-4E was neither a prototype nor a typical production. It had udergone contractor conducted Category I tests since April, and was tagged for continued testing. Yet, it was not actually a test aircraft, being accounted for as the first F-4E production.
Although TAC had only received a first few F-4Es, testing began at the Neliis Fighter Weapon Center on 23 October. Soon afterwards, the 33d Wing at Eglin (TAC's first FEE combat unit) got its initial aircraft.
The FEE testing program was extensive and unconventional. Category I started on the ground in April 1967. It formally ended in August 1968 but lingered through December 1969. Category II, initiated in November 1967, was completed in June 1968, with follow on tests extending through May 1970. Category III (officially called combat evaluation) was expedited because of the aircraft's urgent need in Southeast Asia. For the same reason, these tests began in November 1967, concurrent with the beginning of Category II (a not too common procedure). TAC cut short the F-4E combat evaluation in July 1968, as the aircraft's oversea deployment became imminent. Also, the lack of modified engines (to cure demonstrated stalls and flameouts) made further testing meaningless. All told, testing showed that the F-4E excelled the F-4D. Despite failings, the new J-79-GE-17 turbojet seemed basically sound. The aircraft's inside gun worked well. Still, flight testing of the few early APQ-120s available pinpointed deficiencies. Most likely, the problems turned up by the F-4E evaluation would hamper the plane for a time in actual combat.
Although still needed, CORDS failed to work out. Headquarters USAF cancelled it on 3 January and directed fresh effort towards an F-4E look down capability without major modification of radar and fire control. The Air Force forbade any production commitment until the new component had definitively proved itself. Further, in May 1968, the Air Force stopped the installation of the trouble ridden APS-107, flown by the RHAW-F-4Ds. F-4Es already equipped would be retrofitted with the APR-36/37, which would be on forthcoming F-4Es.
These F-4Es (18 by January 1969) were the first of many sent to Southeast Asia. To meet PACAF's most urgent requirements, they were fitted with Skyspot radar beacons, together with the APX-76 and strike/documentation camera systems. Special modifications let them carry more ECM pods at the same time. They could also fire AIM-9B Sidewinders as well as the AIM-4D Falcons and AIM-7 Sparrows (both provided during production). However, the target identification system approved for 4 of the first F-4Es was missing. By mid 1971 only 72 F-4Es were in SEA- the deployment program having slipped. Meanwhile, a few F-4Es went to Europe, first appearing on USAFE inventory in July 1969.
Early F-4Es (beginning with those going overseas) were modified to prevent engine stalls and flameouts. Yet engine problems of all sorts remained. Like previous F-4s, the Es delivered through November 1969-before necessary changes reached the production lines had to be modified to avoid engine bay fires. Moreover, the J-79-17 at first did not live up to its billing. The new engine could not exceed 2.15 Mach by mid 1970-the Air Force citing General Electric for not reaching the specified 2.24 Mach. Meanwhile, engines remained hard to obtain. In the summer of 1969, engine failure rate rose, while engine life expectancy declined to 608 hours. A 4 month strike in October did not help matters. Depot stocks sunk so low that TAC raided assets at McDill to deploy an Eglin squadron to SEA on time. Ensuing progress was short lived. In early 1972, just before the Constant Guard F-4 deployments, spare engines were again scarce; engine overhaul money limited. Another problem also loomed. Engine stalls appeared likely as LES equipped F-4Es (delivered after April) began flying at lower speed and higher attack angle. Finally (despite several years of effort by G.E., the Navy, and the Air Force), engine smoke trails in every model of the F-4 persisted alerting the enemy from miles away.
Early F-4Es had no or incomplete AN/APQ-120 fire control systems. Even tough the APQ-120 passed through several modifications, it was still imperfect in late 1972. Aerospace ground equipment for both the new APQ-120 and the M-61AI gun was initially short. Then, too, troubles existed in several new missiles and in the overall FEE weapon systems. In January 1969, the Air Force began to correct deficiencies arising when the AIM-7E Sparrow was combined with any model of the F-4. Its project to mate AIM7F missiles with the F-4E had made little headway by December 1972. On the other hand, the Air Force had modified the AIM-9B Sidewinder and shipped the first newly configured AIM-9Es to SEA in early 1969. These missiles were used by all F-4s, as were the AGM-45A Shrike antiradiation missiles (retrofitted with improved warheads and new rocket motors).
The F-4, by 1 January 1972, ranked second to the F-105 in SEA combat losses-362 (all models), most of them downed by the enemy. Later, in F-4Es alone, the Air Force lost eight in 2 months of intensive combat.
By 30 January, F-4 strength in SEA stood at only 11 squadrons-8 in Thailand, 3 in South Vietnam. Massive North Vietnamese attacks, on the heels of the United States withdrawal, swiftly brought back US air power (a move that later proved to be both successful and crucial). In the Constant Guard I deployment, F-4Es were among the first to depart from the United States. The 334th and 336th squadrons of TAC's 4th Tactical Fighter Wing left Seymour Johnson AFB, N. C., in early April. Under Constant Guard II, the Homestead based 308th TFS and the 58th TFS from Eglin departed Florida later in the month. These Constant Guard I and II F-4Es went to Thailand-36 each to Ubon and Udorn. Alternately flying day and night missions, the FEE squadrons struck enemy targets around the clock. By 30 June they had lost 8 aircraft.
The Air Force decided to go ahead with Pave Spike in May, having made sure in 1972 that the program's technical problems would not disrupt SEA operations. Pave Spike, estimated to cost $81 million, called for Westinghouse to produce 156 (AN/ASQ-153) pods, and for modification of 317 aircraft (106 F-4Ds and 211 F-4Es). These modified aircraft and pods would provide a selfcontained day tracking and laser target designator for delivery of laser guided weapons. Another long range project had been launched in April 1973. It would improve the structure of all F-4s and RF-4Cs (late F-4Es productions were excluded, their structural integrity requirements being covered by the Leading Edge Slat Program). The structural improvement program (prompted by the January loss of an early F-4E) would cost $5 million, but it would stretch the aircraft's service life from 3,000 to at least 4,500 hours. The Air Force figured the structural modifications would begin in May 1974 (upon delivery of the first kits) and end in June 1977. The work would be done during regular depot maintenance.
There were two other configurations of the F-4E. The F-4F, flown by the Federal German Luftwaffe; and F-4E (J), being produced for the Japanese Air Self Defense Forces.
In June 1972, the Air Force expected to receive the last of its 740 F-4Es in December 1974. Additional procurement (48 in FY 73, and 24 in FY 74) changed all this. Now, the USAF portion of F-4E production would most probably end with acceptance of the 812th aircraft, due for delivery in the spring of 1976. An upturn in F-4E sales also promised to extend FMS production by several years.
734 F-4Es were accepted; against 812 ordered and funded
The Air Force accepted one F-4E in FY 67, 145 in FY 68, 242 in FY 69,186 in FY 70, 105 in FY 71, 25 in FY 72 (December 1971 through May 1972), and 30 in FY 73 (all during the first 6 months of 1973).
The F-4E had a flyaway Cost Per Production Aircraft of $2.4 million-airframe, $1,662,000; engines (installed), $393,000; electronics, $299,000; ordnance, $8,000; armament, $111,000.
R&D costs amounted to $22,700-cumulative through mid 1973 and included in the F-4E's flyaway cost.
Of 734 F-4Es accepted by mid 1973, 614 remained, with 78 still due. There were 438 F-4Es in 22 squadrons. Ten of these units served overseas mostly with the USAFE. The Air Force planned to use F-4Es a long time. However, F-15s (also by McDonnell Douglas) might replace some F-4Es after 1975.
While few F-4s were funded under the MAP (18 in FY 69), many went to the FMS-mostly F-4Es, some slightly modified. The F-4F program, estimated at $750 million, fell under the latter category. It would give the Luftwaffe 175 F-4Fs. The first 2 were to be delivered in August 1973 at Jever AB, West Germany, by the Air Force's 2d Aircraft Delivery Group. As for the F-4E (J), it was also a modified E to be used solely for air defense. Twelve of the 128 F-4E (J) interceptors due by 1980 were operational in mid 1973. Meanwhile, stateside production of FMS F-4Es grew. As of 30 June, the Air Force had accepted a total of 89 F-4Es for Israel and 36 for Iran. Delivery of F-4Es to Greece was set for April 1974; to Turkey, later in the year.
As planned since early 1967, the Air Force re-equipped its aerial demonstration team with F-4Es during the summer of 1969. The Thunderbirds expected almost the impossible of their aircraft. Structural cracks quickly developed, requiring reinforcement of the outer wing panels. F-4Es also took part in Red Baron II, a 2-year project begun in mid 1968. It would compare the merits of USAF planes with what was known of current or programmed Soviet aircraft.
Under Peace Reef devised in April 1970, after Australia deferred acceptance of 24 F-111Cs-the Air Force leased that country 24 F4Es. The first six were delivered on 9 September, after the Air Force furnished ground equipment and a 1 year supply of spares. The last of the 24 leased F-4Es were returned by Australia in June 1973.
The NATO dual based, FEE equipped 4th TFW was the first to receive the new AGM 65 Maverick (initially flight tested by an F-4D). By 30 June, 24 of the wing's F-4Es were fitted to carry the missile, and aircrew training was underway.
|Join the GlobalSecurity.org mailing list|