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 (production for the US Army continued until 1969. Afterwards, production was extended until 1973 to fulfill export orders) 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 The Redeye was withdrawn gradually between 1982 and 1995 as the Stinger was deployed, though it remained in service with various armed forces of the world until quite recently,^[when?] 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.

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 pounds (11 kg). 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 2,500 yards (23 and 2,300 m) against targets flying up to 1,000 miles per hour (1,600 km/h).

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 feet (4,300 m), 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.

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-inch (7.0 cm) Folding-Fin Aerial 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 1,000 ft (300 m), and larger weapons that raised the ceiling to 10,000 ft (3,000 m). In order to improve its capability in poor visibility, it was suggested that the weapon be aimed using infrared homing.

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-pound (0.54 kg) warhead. Convair's prototype initially used a miniaturized version of the AIM-9 Sidewinder seeker and was small, weighing 14.5 lb (6.6 kg), a gripstock/launch tube weighing 3.2 lb (1.5 kg). The overall weight of the prototype was 18.2 lb (8.3 kg), while unit cost was initially estimated at $700 (equivalent to $8,096 in 2024) compared to about $3000 (equivalent to $34,696 in 2024) for a Sidewinder missile.

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 feet (1.2 to 2.4 m), 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:

The competing designs were rejected for being too heavy, while US Army engineers deemed that while the Redeye design was the most promising, it also needed further substantial studies on the IR seeker before development could begin. They also concluded that improvements on the IR seeker (and subsequent weight increase) were necessary for the system to perform as claimed on the proposal. Convair objected to the Army evaluation, stating that it already performed exhaustive research in private, while the United States Marine Corps were more enthusiastic about the Redeye and insisted that the weapon was ready for development, offering an initial funding of $1 million (equivalent to $242.88 million in 2024) to accelerate the program.