The Grumman F-14 Tomcat

One of the mainstays of US Navy fleet defense in the late 20th century was the Grumman "F-14 Tomcat", a twin-engine interceptor armed with long-range Phoenix air-to-air missiles. The Tomcat is being phased out of Navy service, having also been pressed into the reconnaissance and, as the "Bombcat", strike roles. This document provides a history and description of the F-14.

Grumman F14 Tomcat origins

In the late 1950s, the US Navy was interested in obtaining an interceptor to protect carrier battle groups from adversary strike aircraft, and the Douglas company proposed an aircraft named the "F6D-1 Missileer". The Missileer was to carry advanced radar and eight big Bendix "AAM-M-10 Eagle" long-range air-to-air missiles (AAMs) to knock down intruders at distances of up to 205 kilometers (110 NMI), before they could get close enough to be a real threat.

The whole idea was at least a bit ahead of its time and the development program didn't go well. The Missileer itself began to look unpromising, since it was envisioned as a lumbering "missile truck" that would not be capable of close-in dogfighting, and the Eagle missile program faltered as well. The Missileer was cancelled in December 1960. However, the work on the advanced radar was not abandoned, and the Navy still retained a requirement for a fleet-defense interceptor.

In the early 1960s, American Defense Secretary Robert S. McNamara wanted to promote commonality of equipment between the different branches of the US armed services, and he believed that the Navy requirement for a fleet-defense interceptor could be filled with a navalized version of the Air Force's "variable geometry" or "swing-wing" General Dynamics F-111A tactical fighter. Few thought this was a good idea since the F-111 was a big, heavy machine, not all that adaptable to carrier operation, but McNamara insisted.

The Navy never became very enthusiastic about the "F-111B", as their variant was designated. The initial prototype performed its initial flight on 18 May 1965, with flight trials leading to a Navy report in October 1965 that concluded the F-111B was highly unsatisfactory. Attempts were made to fix the problems, but it was impossible. Congress cut funds in May 1968, work was halted in July, and the program was formally axed in December, after the construction of a total of seven F-111B prototypes and evaluation aircraft.

The Grumman company had actually been responsible for developing the F-111B as a subcontractor for General Dynamics. In January 1966, following the highly negative Navy report on the F-111B, at the Navy's request Grumman began work on a set of designs for a more effective carrier-based interceptor, with the company designation of "G-303", derived from their F-111B work. Grumman submitted their finalist proposals to the Navy in October 1967.

In July 1968, when the F-111B was clearly dead, the Navy began a new competition for a fleet defense interceptor under the "VFX" program. Grumman submitted the G-303 against proposals from North American, LTV, General Dynamics, and McDonnell Douglas. Grumman, which tended to have a leg up in any competition for the Navy since the company had been supplying highly satisfactory aircraft to the service for decades, won the award in January 1969. The project was assigned high priority; the Navy was worried about new Soviet threat aircraft like the MiG-25 Foxbat, and the decade of delays in fielding an improved fighter that had piled up from the cancelled Missileer and F-111B programs left the admirals very worried.

A mockup of the definitive G-303 concept was inspected by Navy officials in the spring of 1969. Although some of the earlier concepts had featured fixed wings, the mockup used swing wings. An initial development contract for six prototype and evaluation "YF-14A Tomcats", as the type was designated, was awarded to Grumman that same year. Incidentally, the name "Tomcat" was selected partly to in tribute to Navy Admirals Thomas Connolly and Thomas Moorer; Connolly was such a strong supporter of the program that the aircraft was referred to as "Tom's Cat", and the name stuck. The contract was later modified to fund twelve YF-14As. Development went forward under Grumman program manager Mike Pelehach.

The initial prototype F-14A performed its first flight on 21 December 1970, with company test pilots William "Bob" Miller and Robert Smythe in the cockpit. It was a short hop with the wings left in the forward position. The second flight was on 30 December 1970, when the prototype suffered a catastrophic hydraulic systems failure. Both Miller and Smythe ejected safely from just above the treetops, but of course the aircraft was completely destroyed.

The second prototype made its first flight on 24 May 1971 and the program moved swiftly after that, though there were serious cost overruns, as well as a few more accidents:

• The number-five prototype was lost on 20 June 1973 during a Sparrow missile stores separation trial, both crew ejecting safely. This mishap led to a story that the aircraft had shot itself down with its own AAM, but it was a typical stores-release accident, with the missile pitching up after release and damaging the aircraft, leading to its loss. This is precisely why stores-release trials are conducted, and the accident led to the fit of more powerful pyrotechnic cartridges to eject the missile.
• The tenth prototype was lost on 29 June 1973 in a crash that killed Bob Miller, who had been fortunately flying with no back-seater.

Initial deliveries of production Tomcats to the Navy took place in October 1972, with the aircraft arriving at Naval Air Station (NAS) Miramar in California.

The Grumman F-14A Tomcat described

The F-14A was a big aircraft, with tandem seating for a pilot in front and radar intercept officer (RIO) in back on Martin-Baker GRU-7A "zero-zero (zero speed, zero altitude)" ejection seats. The cockpit layouts were specialized for the pilot and RIO, and had little duplication. The aircrew sat under a clamshell canopy that hinged open from the back. Field of view from the cockpit was said to be very good. The aircrew got into the cockpit on fold-out steps mounted on the forward fuselage.

The variable-geometry wing scheme incorporated a number of advanced features. One was the fit of "glove vanes", which were small triangular foreplanes mounted in the wing gloves that were automatically extended at high speeds as the main wings were swept back, compensating for any change in aircraft pitch caused by the change in wing geometry.

The wing sweep was controlled by a "Mach sweep programmer" that automatically moved the wings through the range of 20 degrees to 68 degrees sweep, as dictated by flight requirements. The pilot could also set the sweep manually, and could select a special 55-degree mode for ground attack. The wings could be set back 75 degrees to an "oversweep" position, overlapping the horizontal tailplane, for carrier-deck storage.

The wings featured spoilers to improve maneuverability, plus full-span trailing-edge flaps and leading-edge slats to improve low-speed handling. The inboard flaps were of course disabled when wing sweep blocked their movement. The spoiler position could be tweaked by a thumbwheel on the pilot's control stick during landing approach to adjust speed and angle of descent without requiring a change in aircraft attitude, a scheme known as "Direct Lift Control (DLC)".

The tail assembly featured "all moving" slab tailplanes, with differential action for roll control, and twin outward-canted tailfins; some early concepts had featured a large single tailfin. There were also twin ventral fins. The mockup had featured long ventral fins that folded to the outside for landing, but in practice the ventral fins were fixed. There were hydraulically-operated speed brakes on the top and bottom of the rear fuselage forward of the engine exhausts.

The F-14A followed in the Grumman tradition of building rugged aircraft. It was built primarily of aircraft aluminum alloy and titanium, with selective use of graphite-epoxy composite assemblies. The aircraft was initially powered by twin Pratt & Whitney (P&W) TF30-P-412 turbofans with 54.9 kN (5,600 kgp / 12,350 lbf) dry thrust and 93 kN (9,480 kgp / 20,900 lbf) afterburning thrust each. The TF30 was one of the items inherited from the F-111B.

The engines were fitted in separate housings underneath the fuselage. The major rationale for this configuration was that it ensured adequate airflow to the engines, which had been a major problem for the F-111. It also gave maintenance crews direct access to the engines and made engine replacement easier, though it had a few drawbacks as well. Each engine had a wedge-style inlet with a variable ramp in the throat, and was canted slightly away from the fuselage. A single external tank with a capacity of 1,011 liters (267 US gallons) could be carried under each engine pod. A retractable inflight refueling probe was fitted to the right side of the nose.

The main single-wheel landing gear retracted forward into the wing gloves, rotating 90 degrees to lie flat. The steerable nose gear had twin wheels, a catapult hookup, and retracted forward as well. There was a stinger-type arresting hook on the belly between the engine exhausts.

The Tomcat's distinctive weapon was the big Hughes "AIM-54 Phoenix" AAM. with a range of 200 kilometers (125 miles) and a fully active radar seeker, which allowed the missile to perform its terminal-phase attack on a target without requiring that the Tomcat keep the target "illuminated" with radar. In principle, it gave the Tomcat the ability to destroy intruders at very long range.

The Phoenix was another item inherited from the F-111B, and was the ultimate evolution of the Hughes Falcon series of AAMs. It owed something to the Hughes "GAR-9" missile developed for the experimental Lockheed YF-12A interceptor version of the SR-71 Blackbird. In principle, the Tomcat, which was the only aircraft to ever carry the Phoenix operationally, could carry six Phoenix missiles, with four carried in the fuselage "tunnel" between the engines and two on wing pylons.

However, the Phoenix, nicknamed the "Buffalo" because of its size, was so heavy that a Tomcat couldn't carry six of them if the aircraft was to land on a carrier. No such restriction existed if the Tomcat was operating off a land base. Another problem with carrying six Phoenix missiles was that the drag of the two extra missiles on the wing glove pylons cut into aircraft performance and flight endurance.

In practice, a full armament load consisted usually of four Phoenix missiles on the tunnel stations, plus two AIM-9 Sparrow semi-active radar homing (SARH) medium-range AAMs and two AIM-7 Sidewinder heatseeking short-range AAMs, for a total of eight AAMs. A Sparrow and a Sidewinder were carried on a special dual rack mounted on each wing glove pylon, with a Sparrow on the bottom of the rack and a Sidewinder to the outside. This unusual configuration was used because mounting stores pylons on a swing wing is tricky and there was limited room on the wing gloves. If the Phoenix wasn't carried, there were also recesses in the fuselage tunnel for carriage of three more Sparrows.

The Phoenix and Sparrow were controlled by a Hughes AN/AWG-9 radar and the AN/AWG-15 fire control computer. The AN/AWG-9 was also inherited from the F-111B, with roots going back to the Missileer program as well as the "AN/ASG-1" radar, developed by the Air Force for the cancelled North American F-108 Rapier Mach 3 interceptor program and the Lockheed YF-12A. The AN/AWG-9 gave the Tomcat a wide-area air-surveillance capability, with a range of 160 kilometers (100 miles) or more. The radar could search while tracking 24 targets, and engage six targets simultaneously.

Early F-14As were fitted with a steerable "AN/ALR-23 Infrared Search and Track (IRST)" sensor under the nose that could be slaved to the radar or used independently. In the early 1980s, the IRST was replaced in Tomcat production with the Northrop "AN/AXX-1 Television Camera Set (TCS)", a steerable daylight video camera with a telephoto lens, and the TCS was retrofitted to the earlier F-14As. TCS allowed a Tomcat to inspect a target at long range before engaging it, at least in daylight / clear weather conditions. The inability to determine if a target was a friend or a foe had been one of the limiting factors for use of "beyond visual range (BVR)" AAMs such as the Sparrow in Vietnam.

Other stock avionics included UHF radio; identification friend or foe (IFF) transponder and interrogator; an inertial navigation system; a TACAN beacon-navigation system; an automatic direction finder; and a radar altimeter. The F-14A was originally also fitted with an AN/APR-45 radar warning receiver (RWR) system; an AN/ALQ-126 deception jammer system, with antennas in the tips of the horizontal tailplane and under the nose; and AN/ALE-39 chaff-flare dispensers, mounted under a "boattail" fixture on the end of the fuselage.

The Tomcat featured a built-in General Electric (GE) M61A1 six-barreled Gatling-type 20 millimeter cannon, with an ammunition store of 675 rounds. The cannon was fitted under the left side of the cockpit.

F-14 TARPS

The Tomcat took up the reconnaissance role early on. In 1979, the Naval Air Test Center at Patuxent River, Maryland, began development of the "Tactical Air Reconnaissance Pod System (TARPS)" for the Tomcat. TARPS was derived from a reconnaissance system developed for the LTV A-7 strike fighter but not fielded for that aircraft. The streamlined pod was about 5.18 meters (17 feet) long; weighed 794 kilograms (1,750 pounds); and included a CAI KS-87B serial frame camera in the nose, a Fairchild KA-99 panoramic camera in the midsection, and a Honeywell AN/AAD-5 infrared line scanner in the rear.

TARPS was carried on the right rear fuselage tunnel station. The pod required additional control, power, and environmental control connections, and so Tomcats had to be specially modified to carry it, with about 50 aircraft given TARPS capability. The modifications did not rule out carriage of the Phoenix on that station. The system was controlled by the RIO in the back seat who had a specialized TARPS display to observe reconnaissance data, though the pilot did have a camera on-off switch on his stick as well. AAMs could still be carried on the wing glove pylons for self-defense.

TARPS was introduced in 1980 and proved an extremely valuable, since dedicated reconnaissance aircraft like the Vought RF-8G Crusader were being phased out. TARPS was only supposed to be an interim solution, since the Navy was hoping to obtain a dedicated reconnaissance version of the McDonnell Douglas F/A-18 Hornet, but that didn't happen. The TARPS Tomcat would be a Navy firstline reconnaissance asset for the rest of the century.

Author: Greg Goebel