McDonnell YF4H-1 Phantom II

The McDonnell Phantom was one of the most successful postwar fighters. It was the second most prolific American jet fighter to be built, outnumbered only by the North American Sabre. Total US production was 5057, with another 138 being built under license in Japan. The Phantom was in continuous production for 20 years (from 1959 until 1979). During the Vietnam War, 72 Phantoms were coming off the production line every month.

Although initially designed as an interceptor and later used primarily in the air-to-ground strike role, the Phantom proved to be surprisingly successful in the air-to-air role when the correct tactics were used. USAF, Navy, and Marine Corps Phantom IIs achieved 277 air-to-air combat victories in Vietnam. In service with the Israel Defense Forces/Air Force, the Phantom claimed 116 air-to-air victories in various conflicts between Israel and its Arab neighbors.

The Phantom served with the United States Air Force, the United States Navy, and the United States Marine Corps. Overseas, it served with the air forces of Australia, Egypt, the Federal Republic of Germany, Greece, Iran, Israel, Japan, South Korea, Spain, and Turkey. In addition, it served for many years with the Royal Navy and the Royal Air Force of the United Kingdom. The Phantom is now in the twilight of its career, and is no longer in active service with the US armed forces, currently operating with the air forces of Iran, South Korea, and Turkey

The Phantom was the first naval fighter to dispense totally with cannon armament. It was the first fighter that was able to identify, intercept and destroy any target that came into range of its radar without having to rely on ground control. It was the first fighter originally designed solely as a carrier-based fighter to be ordered by the USAF. It was the first fighter to have computer-controlled air inlets for optimum airflow to the engines. Finally, it was the first aircraft to be flown simultaneously by both the Navy's Blue Angels and the Air Force's Thunderbirds flight demonstration teams.

The design of what was eventually to emerge as the McDonnell F-4 Phantom began in August of 1953. The McDonnell design team was headed by Herman Barkley. Initially, the goal of the team was to extend the production life of the F3H Demon single-seat carrier-based fighter by boosting its performance and improving its versatility.

Several quite different design concepts emerged, all of them being informally designated by the company as F3H-X since they were all viewed as a natural follow-on to the F3H Demon.

The first of these preliminary designs was the F3H-C or the "Super Demon". The F3H-C was to be powered by a single Wright J67 turbojet and was to be capable of reaching Mach 1.69 at high altitude. The J67 was a license-built version of the British-built Bristol Olympus turbojet engine, and was untried and unproven at the time.

The F3H-E project (also known as Model 98A by the company) was similarly powered, but dispensed with the nose-high attitude of the Demon and stood level on a tricycle undercarriage. It had a 45-degree swept wing of 450 square feet in area. In the event, the J67 engine never did materialize as a realistic powerplant for American aircraft.

The Model 98B (F3H-G) project was to be powered by a pair of Wright J65-W-2 (or W-4) turbojets rated at 7800 lb.s.t. each. The twin-engined configuration was attractive to many in the Navy, because of the increased amount of safety it offered over a single-engined aircraft. The engines were to be fed by a pair of side-mounted air intakes. A low-mounted swept wing and an all-flying straight tailplane were to be used. This wing was slightly larger than that of the F3H-E, with a 530-square foot area. The fuselage was to be designed in conformance with the area rule, in order that minimum transonic drag be achieved.

The F3H-G aircraft was to be equipped with an Aero 11B fire control system and an AN/APQ-150 radar. Armament was to consist of four 20-mm cannon, but provision for a retractable pack carrying 56 two-inch FFAR rockets was also proposed. A heavy load of bombs and fuel tanks could be carried on up to nine external stores stations (four under each wing and one underneath the fuselage). A maximum speed of Mach 1.52 was envisaged.

The J65 was a license-built version of the British-designed Armstrong Siddeley Sapphire engine, and was already in production at the time. Although at that time the Navy was experiencing a good deal of trouble with the J65 engine installed in its North American FJ-3 Fury single-engined fighter, the McDonnell team fully expected that these problems would be resolved by the time that their F3H-G proposal was ready for production.

The F3H-H was similar in overall configuration to the F3H-G, but was to be powered by a pair of higher-thrust General Electric J79 turbojets. The J79 was at that time a new and untried engine. Assuming that the J79 performed as promised, a maximum speed of Mach 1.97 was envisaged.

The Model 98F was the photographic reconnaissance version of the Model 98C.

Models 98C and D were to be fitted respectively with delta and straight wings, and were to be powered either by a pair of Wright J65s or two J79s.

The Model 98E (F3H-J) was to have been similar to Models 98C and D, but with a larger and thinner delta wing.

Herman Barkley's design team decided that the Model 98B with its twin J65s offered the best potential and they abandoned work on all the other configurations. A full-sized mockup of the Model 98B (F3H-G) was built. The company hedged its bets by designing the right side of the mockup for a J79 engine and the left for a J65.

On September 19, 1953, McDonnell submitted its Model 98B project to the Navy's Bureau of Aeronautics (BuAer) in the form of an unsolicited proposal. Since the Navy as yet had no official requirement for such an aircraft, McDonnell tried to cover all bases by developing interchangeable single- and two-seat noses that could be accommodated to widely different roles. Noses were designed that could carry search radars, missile fire-control systems, mapping radars, cameras, or electronic reconnaissance equipment.

Although the Navy was favorably impressed by the Model 98B proposal, the Grumman XF9F-9 Tiger and the Vought XF8U-1 Crusader which had been ordered respectively in April and June of 1953 appeared to satisfy all the Navy's immediate requirements for supersonic fighters. Nevertheless, the Navy encouraged McDonnell to rework its design into a single-seat, twin-engined all-weather attack aircraft to compete against designs being worked on by Grumman and North American.

McDonnell submitted a formal development proposal for the F3H-G/H to the Navy in August of 1954. The Navy responded in October of 1954 by issuing a letter of intent for two prototypes and a static test aircraft. The Navy assigned the designation AH-1 to the project, reflecting its intended ground attack mission. The AH-1 was to have no less then eleven weapons pylons. Armament was to consist of four 20-mm cannon.

On December 14, 1954, the multirole mission of the aircraft was formally abandoned by the Navy, and McDonnell was requested to rework the proposal as an all-weather interceptor. McDonnell was instructed to remove the cannon and all hardpoints except for a centerline pylon for a 600-US gallon fuel tank. In addition, troughs were to be added for four Raytheon Sparrow semi-active radar homing air-to-air missiles. A Raytheon-designed APQ-50 radar was added, this installation being essentially that installed in the F3H-2 Demon. A second seat was added to accommodate a radar operator.

On April 15, 1955, in a formal letter from the BuAer to the Commander of Naval Operations, the J79 engine was formally adopted, and all work on the J65-powered version was dropped.

On May 26, 1955, after further review of Navy requirements, the BuAer requested that the designers complete the two prototypes (BuNos 142259 and 142260) as two-seat all-weather fighters carrying an entirely missile-based armament. On June 23, 1955, the designation was changed to YF4H-1, a fighter designation. A day later, McDonnell issued a new model number for the project--98Q.

This factory designation was to be short-lived, since when a contract for 18 airframes beginning with 2 flight test prototypes and a static test article was signed on June 24, it was for the Model 89R with a modified APQ-50 I/J-band radar with a 24-inch dish which was to be compatible with the Sparrow III semi-active radar homing missile. This order was changed to Model 98S shortly thereafter, the changed designation indicating the provision of the capability of handling the infrared homing Sidewinder missile in addition to the radar-homing Sparrow.

On July 25, 1955, the Navy and the manufacturer agreed to a detailed list of specifications for the YF4H-1. The aircraft was to be capable of staying on patrol for up to two hours at a time at a distance of up to 250 nautical miles from its carriers and was to be able to remain in the air for at least three hours without midair refuelling. At the same time, the go-ahead for the F4H project was confirmed, with a formal contract being written for the two previously-ordered prototypes but also for five pre-production aircraft (BuNos 143388 to 143392).

The YF4H-1 mockup was inspected between November 17 and 23, 1955. The twin J79 afterburning turbojets were to be mounted in the lower portions of the fuselage and fed by fixed-geometry cheek air intakes. The primary armament was to be four Sparrow III radar-guided missiles mounted in semi-submerged slots beneath the fuselage. No provision was made for the mounting of cannon.

At the same time, the Navy authorized Vought to build two prototypes of the single-seat, single-engined F8U-3 Crusader III to compete with the F4H-1. In reality, the aircraft should have been designated F9U, and it should have been Crusader II rather than Crusader III.

After much wind-tunnel testing, it was found that the new McDonnell fighter would encounter severe stability problems at high speeds and would as a result probably be limited to speeds below Mach 2. In order to correct these problems, several important changes had to made. One of these was the application of 23 degrees of anhedral to the all-flying tailplane, which became known as a *stabilator*. This gave the necessary degree of stability but still left the tailplane free of the jet exhaust. Another change was to the outer wing panels. The center section of the wing had originally been envisaged as a single unit spanning 27 feet from wing fold to wing fold. It was decided to give the outer (folding) panels twelve degrees of dihedral, and a dog-tooth leading edge was fitted. Another change was to the air intakes. The intakes had originally had a fixed geometry, but it was now decided to fit movable ramps to the sides of the air intakes. These ramps could be adjusted in flight to admit the optimal airflow to the engines at various speeds and angles of attack. These changes took time to incorporate in the design, and initial structural release was not authorized until December 31, 1956.

In the meantime, on December 19, 1956, the Navy ordered 11 more F4H-1s (BuNos 145307/145317). These were to be the first full production aircraft.

In August of 1957, the modified APQ-50 was dropped for the Phantom, and Westinghouse was given the go-ahead to develop a new system which was initially called the Aero 1A, but later renamed APQ-72. However, the system would not be ready for the first prototypes, which retained the APQ-50.

The first YF4H-1 was to have been powered by a pair of General Electric J79-GE-8 engines, but delays in their development led to the substitution of a pair of 14,800 lb.s.t. afterburning J79-GE-3A engines on loan from the Air Force. The first F4H-1 was a proof-of-concept aircraft and was not equipped with radar and was not wired for missile firings. However, four dummy Sparrow missiles were carried in their ventral underfuselage recesses. Ballast was provided in place of the AN/APG-50 airborne intercept radar that was to be carried. The tandem cockpits were covered by a canopy that was flush with the top of the fuselage. However, on the first YF4H-1, only the pilot's cockpit was provisioned, with the rear radar operator's position being filled with test instrumentation.

The YF4H-1 was fitted with wing leading edge flaps which extended from the wingtip all the way inward to about one-quarter span. They were in two segments, divided by the wing folding point. These would droop downward at low speed to provide additional lift at low speeds.

The wing leading edges as well as the flaps were all blown by high-pressure air bled from the engine compressors, which produced a sheet of air which helped to keep airflow attached at high angles of attack.

Five-degree fixed air intake ramps were fitted. Flush NACA-type inlets were mounted on the lower sides of the forward fuselage just behind the radome to feed ram air into the air-conditioning system which cooled the electronics.

The trailing edge of the horizontal main wing was divided into two, the inboard surface being a flap and the outboard being a "flaperon". The "flaperon" was a sort of aileron which could be moved down only, not up. Immediately ahead of each was a large spoiler. To roll to the left, the pilot would push the right flaperon down and the left spoiler up. A complex pattern of large perforations was applied to the spoilers which were mounted on the upper wing trailing edges ahead of the flaps and just inboard of the wing folding points. The aircraft had no ailerons in the conventional sense, with control being provided by spoilers and downward flaperons only. The outer wing panels were canted up by twelve degrees and had no control surfaces except for the hinged (drooping) leading edge. The stabilators had a 23 1/4 degree anhedral, and provided all of the pitch control.

The YF4H-1 prototype made its maiden flight on May 27, 1958, taking off from Lambert-St. Louis Municipal Airport with McDonnell test pilot Robert C. Little at the controls. On the first flight, the nose gear door would not close, there were difficulties with the hydraulic system, and there were problems with the engines. Consequently, the flight had to be cut short, but the aircraft landed safely. The right engine was replaced and the air inlet ramps were repositioned at 4 degrees. On the second flight on May 29, the nose landing gear door still would not close. However, on the third and fourth flights on May 31 and June 2, things went better and the aircraft flew at speeds of Mach 1.30 to 1.68.

142259 was sent out to Edwards AFB for initial flight trials. The YF4H-1 and the competing F8U-3 were put through the Navy Phase I flight evaluations at Edwards AFB, and in December of 1958 the F4H-1 was declared the winner of the contest. On December 17, 1958, McDonnell was awarded a follow-on contract for 24 more F4H-1s (BuNos 148252/148275). This brought the total production order to 45 machines.

The second YF4H-1 (BuNo 142260) flew in October of 1958. It was provided with an operable AN/APQ-50 radar and a fully-equipped rear cockpit. Variable-inlet ramps were fitted which were set at 5 degrees for the fixed portion and at ten degrees for the variable panel downstream. The aircraft was provided with unperforated spoilers, and a ram-air turbine was fitted which could be extended upward by a pneumatic ram from a compartment situated above the left intake duct. This turbine drove an emergency hydraulic pump that powered the controls in the case of an inflight emergency. An ASA-32 autopilot was provided. YF4H-1 144260 was later retrofitted with Martin-Baker Mk H5 ejector seats. In 1960, wiring was installed for the firing of the Sparrow missiles.

On July 3, 1959, the F4H-1 was officially named Phantom II in a ceremony held at the McDonnell plant in St Louis. At one time, the project manager, Don Malvern, had wanted to name it Satan, and James S. McDonnell himself had wanted to name the aircraft Mithras, after the Persian god of light. In practice, the Roman numeral II was often omitted from the name, since the original Phantom, the FH-1, had long been out of service and there was no possibility of confusion.

Following trials at Edwards AFB, the first YF4H-1 (BuNo 142259) was returned to the manufacturer in St Louis in October of 1958. It continued to be used for various flight test programs. On its 296th flight, on October 21, 1959, the aircraft suffered a failure of the aft access door of the right engine, which led to a further catastrophic failures and to the crash of the aircraft, killing test pilot Gerald "Zeke" Huelsbeck.

The Navy was anxious to publicize its newest fighter, and the second YF4H-1 (142260) was used on December 6, 1959 by Commander Lawrence E. Flint, Jr. to set a new world's altitude record of 98,560 feet. This record, set as a part of Project Top Flight, bettered the existing record of 94,658 feet, set by Major V. S. Ilyushin of the Soviet Union in a Su-T-43-1. To set this record, Commander Flint took his YF4H-1 up to 47,000 feet and a speed of Mach 2.5. He then pulled the aircraft up into an angle of attack of 45 degrees, and then climbed to 90,000 feet. He then shut down his engines and coasted up to 98,560 feet and went over the top and then began to fall back to earth. At 70,000 feet, he restarted his engines and made a normal landing.

On December 22, 1961, Marine Corps Lt.Col. Robert B. Robinson used 142260 to set a new world absolute speed record of 1606.347 mph. On his second run at an altitude of 45,000 feet over the measured 15/25 km course, Lt.Col. Robinson's Phantom was clocked at over 1700 mph. This speed run was known as Operation Skyburner. For the record attempt, 142260 was fitted with a special water/alcohol spray in the engine inlet ducts to cool the air ahead of the compressors and thus increase engine thrust.

Flying the previously-modified YF4H-1 BuNo 142260, Commander George W. Ellis set a new sustained altitude record of 66,443.8 feet.

Sources:

1. The World's Fighting Planes, William Green, Doubleday, 1964.
   
   
2. McDonnell F-4 Phantom: Spirit in the Skies. Airtime Publishing, 1992.
   
   
3. The American Fighter, Enzo Angelucci and Peter Bowers, Orion, 1987.
   
   
4. United States Military Aircraft Since 1909, Gordon Swanborough and Peter M. Bowers, Smithsonian, 1989.
   
   
5. Post-World War II Fighters: 1945-1973, Marcelle Size Knaac, Office of Air Force History, 1986.
   
   
6. The American Fighter, Enzo Angelucci and Peter Bowers, Orion, 1987.
   
   
7. The World Guide to Combat Planes, William Green, Macdonald, 1966.
   
   
8. The World's Great Attack Aircraft, Gallery, 1988.
   
   
9. E-mail from Randall Whitcomb on APQ-72 radar for Phantom.
   
   
10. E-mail from Vahe Demirjian on current F-4 users (2023)