FIM-43 Redeye

The General Dynamics FIM-43 Redeye is a man-portable surface-to-air missile system. It uses passive infrared homing to track its target. Production began in 1962 and – in anticipation of the Redeye II, which later became the FIM-92 Stinger – ended in the early 1970s (delivery of the last Redeye for the US Army was completed in July 1971) after about 85,000 rounds had been built. The Redeye was withdrawn gradually between 1982 and 1995 as the Stinger was deployed, though it remained in service with various armed forces of the world until quite recently, being supplied via the Foreign Military Sales program. It was initially banned from being sold overseas, to avoid missiles falling into the hands of terrorist organizations. However, after the export ban was lifted, the weapon was never actually used by terrorists against civil aircraft, in contrast with other MANPADS. While the Redeye and 9K32 Strela-2 (SA-7) were similar, the missiles were not identical. Nonetheless, the CIA concluded that the Soviet SA-7 had benefited from the Redeye's development.

Post-war developments
In May 1946, the War Department Equipment Board published a report on the future of infantry weapons. They called for the development of new weapons that would be the best in the world, while also being able to be separated into loads of no more than 25 lb. When considering anti-aircraft weapons, they concluded that the M45 Quadmount mounting four M2 Browning machine guns would not be capable against future high-performance aircraft. They published a new requirement for a weapon suitable for engagements between 25 and 2500 yd against targets flying up to 1000 mph.

In response, in June 1948 the United States Army Ordnance Corps began development of the "Stinger" system, essentially an updated version of the Quadmount mounting four T17 machine guns firing the more powerful 0.60 round and aimed by an automated radar system. Development on this system continued until 1951, when the requirement was extended to 14,000 ft, which could not be met by the 0.60 round. A new concept using a revolver cannon firing a new 37 mm round emerged, but proved too complex and was cancelled.

Porcupine and Octopus
At the 1950 Tripartite Conference in London, the US, UK and France agreed that the M2 would remain effective up until about 1960, but new weapons would be needed after that time. This led to development of the Porcupine and Octopus concepts in the US. Porcupine, started in 1951, was a 64-barrel rocket launcher firing salvos of 2.75 in Folding Fin Arial Rockets (FFARs) at an effective rate of 6,000 rounds per minute. The system was never built in complete form, and cancelled in February 1956. Octopus, from 1953, re-examined the .50 and .60 rounds, as well as the emerging 20 mm round based on the latter. This project also failed to deliver an operational system.

By the mid-1950s, new medium and high-altitude surface-to-air missile (SAMs) were rendering higher altitude flight increasingly dangerous, and attack aircraft were now expected to fly at low altitudes. This led to a 1954 requirement for a lightweight system able to engage targets from 0 to 1000 ft, and larger weapons that raised the ceiling to 10000 ft. In order to improve its capability in poor visibility, it was suggested that the weapon be aimed using infrared homing.

Redeye emerges
In 1955, Convair, recently purchased by General Dynamics, began examining a weapon that would fill both of these requirements. When initial studies proved promising, in January 1956 the company began an 11-month study which they named "Redeye" due to its infrared seeker. To lower prototype costs, the missile would initially be based on the unguided FFAR, which was already in widespread production. This would be turned into a missile by replacing the contact-fused warhead of the FFAR with a new seeker system and smaller 1.2 lb warhead. In production models, the motor would be modified to burn only briefly to propel it about 25 ft at low speed before firing at full thrust.

The resulting concept mockups were demonstrated to the Army and Marine Corps in November 1956. Simulations suggested that it would have an average miss distance of 4 to 8 ft, and a direct-hit probability of 0.35 to 0.40. The design proved extremely interesting, and in 1957 official requirements were formulated. This led to the Army's Redstone Arsenal receiving several unsolicited proposals for similar weapons from other companies:


 * , a crew-served partially portable surface-to-air missile system, designed by the Drone and Missile Flight Control Departmentof Sperry Gyroscope, Garden City, New York,
 * (Shoulder-Launched Antiaircraft Missile), a man-portable surface-to-air missile system, designed by the Autonetics Division of North American Aviation, Downey, California,
 * an undesignated system by Lockheed Missile Systems Division, Sunnyvale, California (Col. James E. Linka, a supervising officer with OCRD Air Defense and Missiles Division, responsible for Stinger, later recalled that Lockheed entered the competition in 1959, but no details were ever disclosed.)

The competing designs were based on various US air-to-air missiles, adapted for ground use and scaled-down to be operated by hand and launched from a disposable tube. The lead that Convair had over these weapons was unapproachable, and their proposal was strongly supported by the Marines, who pressed the Army to begin development. They also suggested that the system would suffer from a number of issues during development related to the airframe and seeker, but felt that these were not enough to hold up development.

On 14 April 1958, the development contract was released and Convair was awarded a contract to start development of the system.

Testing
The original design consisted of a simple tube with a clip-on grip system. The operator would simply point the tube in the general direction of the target, and fire when he heard the seeker make its "growl" sound, indicating it was locked onto the target. In May 1958 six unguided launches were conducted by US Marines at Twentynine Palms proving ground and Camp Pendleton, California, to assess human factors and ergonomics of the new weapon, as well as a trooper's capability to aim and launch a missile from the shoulder safely and accurately towards an imaginary target. In June 1958 the flight test phase of the feasibility demonstration program began.

In July 1959 the development project began, in March 1960, the advanced test rounds were fired. Launches from a launch tube followed in May 1961, with a shoulder launch occurring in 1961. Technical problems prevented the missile entering full production: The missile did not live up to its specifications, being slower, less maneuverable and less accurate. During the testing, substantial use was made of the Atlantic Research MQR-16 Gunrunner expendable target missile.

Deficiencies and shortcomings were experienced during the system development phase—mainly seeker inability to discriminate target against cloudy background or in a heavy clutter environment, coupled with absence of night operation capability and inability to engage head-on targets—which were never resolved (eventually leading to the Stinger development). Consequently, several other unsolicited proposals competed with the Redeye in the early 1960s. These included both guided (engaging target using techniques other than infrared homing) and unguided (directionally-controlled) missile systems.

Limited production began as XM41 Redeye Block I. The missile was designated XMIM-43A in June 1963. Block I systems were then evaluated between 1965 and 1966.



Block II systems designated XM41E1 began development in 1964, the missile being designated XMIM-43B. The missiles were delivered in April 1966, and included a new gas-cooled infrared detector cell, a slightly redesigned launcher and an improved warhead.

In 1965 to 1966 General Dynamics developed the final Redeye Block III configuration, designated at first XM41E2 with XFIM-43C missiles. The missiles retained the seeker from the Block II missile, but included a new rocket motor, warhead and fuze. The launcher now had an XM-62 open sight and upgraded electronics. The new missile could turn at up to 3g. The missile achieved a kill probability against F9F tactical drones travelling at 430 kn at an altitude of 100 m of 0.51. From this it was calculated that the kill probability versus a Mikoyan-Gurevich MiG-21 at similar altitude would be 0.403, and 0.53 against helicopters (specifically the Mil Mi-6 and US H-13 and H-21). Kill probability against larger propeller driven aircraft like the Antonov An-12 was estimated at 0.43. Production of the Block III systems began in May 1967. In 1968 Block III was declared operational.

History
Fifty Redeye systems were delivered to the mujahideen by the United States during the Soviet–Afghan War in 1984, where they were used to shoot down aircraft including several Sukhoi Su-25 jets, as well as Mil Mi-24 and Mi-8 helicopters. By November 1986 it had largely been replaced by the dramatically more successful FIM-92 Stinger missiles.

All Redeye missiles were numbered and inventorized by the US Army Missile Command to prevent them from disappearance or otherwise unnoticed losses. No Redeye missiles were reported lost or stolen from the Army inventory, but losses occurred after Redeyes were supplied to foreign troops. This happened first in Belgium in January 1974, causing a strengthening of security measures in the major West European and British airports.

The Redeye was known as Hamlet in Danish service and as RBS 69 in Swedish service.

Redeye missiles provided to the FDN by the US were also used by the Nicaraguan "Contras" to shoot down at least four Soviet Mil Mi-8 helicopters during the Nicaraguan Revolution.

Description
The missile is fired from the M171 missile launcher. First, the seeker is cooled to operating temperature and then the operator begins to visually track the target using the sight unit on the launcher. Once the target is locked onto by the missile, a buzzer in the launcher hand grip begins vibrating, alerting the operator. The operator then presses the trigger, which fires the initial booster stage and launches the missile out of the tube at a speed of around 80 feet per second (25 m/s). As the missile leaves the tube, spring-loaded fins pop out—four stabilizing tail fins at the back of the missile, and two control surfaces at the front of the missile. Once the missile has traveled six meters, the sustainer motor ignites. The sustainer motor takes the missile to its peak velocity of Mach 1.7 in 5.8 seconds. The warhead is armed 1.2 seconds after the sustainer is ignited.

The missile's seeker is capable only of acquiring and tracking the hot exhaust of aircraft, which limits the engagements to tail-chase only, tracking the rapidly receding target. The missile's blast fragmentation warhead is triggered by an impact fuze, requiring a direct hit. As a first-generation missile it is susceptible to countermeasures, including flares and hot brick jammers. Its inability to turn at a rate greater than 3g means that it can be outmaneuvered, if detected.

Variants
During its development, the weapon underwent several major design changes. Initially, its gripstock was literally just a gripstock with grips, stock and trigger only, later evolved in a separable launch unit with optics, electronics, and battery input. Several designs had no optical sighting device; the gunner was supposed to rely on the auditory alarm when the seeker acquired the target. Those with optical sights differed one from another in shape, field of view and the magnification of their optics, and were either separable or non-separable, which in turn could be built-in or molded-in primitive mechanical sight with flashing diodes inside diopter to inform gunner of seeker's lock-on. The launch tube changed its design and shape several times, from pipelike straight-shaped one to the variable-diameter tube with a wider rear section to provide the missile with better acceleration, and back to a straight tube to prevent its explosion due to a critical pressure drop or accidental booster detonation. Canards of the basic missile design were housed within the missile body during the entire flight, coming outside only to correct the course deviation of each roll cycle and folding back within a split second, variable incidence (instead of fixed) canards were used to improve terminal guidance accuracy. The seeker also changed drastically, with multiple modifications made during the test phase, the most important of which making it cooled, increasing its discrimination capability (though extending reaction time in order to adjust its subsystems to operating temperature,) and reducing the field of view to increase the missile's capability against single engine jets. Among the design improvements made in the seeker gyro were an increased aperture to provide greater sensitivity; a new center post design for supporting the secondary mirror to improve background discrimination; a new gyro gimbal of increased rigidity; an improved lead sulfide cell, doubling its sensitivity; and an improved reticle with a reduced field of view. Unorthodox designs included the "Foxhole Redeye," which was small enough to be stored and fired from a rifleman's foxhole, and the "unitized launcher Redeye" fire-and-discard variant as a fully discardable throw-away unit with no separable elements for use with the USMC and CONARC units. All interim designs were dropped in favor of the one which was considered the best possible choice by the Army Missile Command, and mass-produced at the General Dynamics facilities within the Greater Los Angeles Area. The following is the list, featuring the basic model, designated FIM-43A and approved for production along with its derivatives:
 * Block I FIM-43/XFIM-43A/XMIM-43A
 * Block II FIM-43B/XFIM-43B/XMIM-43B – Fitted with a gas cooled seeker and improved warhead and fuse and modified launcher.
 * XFEM-43B – Experimental missile, with data logging capability
 * Block III FIM-43C/XFIM-43C – Production version; improved warhead and fuse section, and a new launcher.
 * XFEM-43C – Experimental missile, with data logging capability
 * FIM-43D – Upgraded missile, with unknown capabilities.

Former operators
Sources:

States

 * 🇦🇺 Australia
 * undefined
 * 🇹🇩 Chad
 * 🇭🇷 Croatia
 * 🇩🇰 Denmark
 * 🇸🇻 El Salvador
 * 🇬🇷 Greece
 * 🇮🇱 Israel
 * 🇯🇴 Jordan
 * 🇵🇰 Pakistan
 * 🇸🇦 Saudi Arabia
 * 🇸🇩 Sudan
 * 🇸🇪 Sweden
 * 🇹🇭 Thailand
 * 🇹🇷 Turkey
 * 🇺🇸 United States
 * West Germany
 * West Germany

Groups

 * Afghan Mujahideen
 * FAN
 * Coordination of Azawad Movements
 * Contra Guerrillas
 * FMLN