The Sidewinder Story
By 2nd Lt. Taylor Couch, History Division, U.S. Marine Corps
Following World War II, the Department of Defense (DoD) developed all-weather air-to-air missiles designed to intercept and destroy Soviet bombers. The Navy and Air Force funded the semi-active radar-guided Sparrow and Falcon weapons programs.
However, a physicist with a penchant for simplicity saw the radar-guided missiles as overly complicated. Dr. William B. McLean pioneered infrared technology and persevered in constructing the most successful air-air missile ever developed, the AIM-9 Sidewinder, despite the misgivings of the DoD.
Working as head of the Aviation Ordnance Division at the Naval Weapons Center at China Lake, Calif., Dr. McLean believed the ultimate air-to-air solution involved infrared technology, using heat detection rather than radar for guidance. Semi active radar required terminal guidance, with the pilot following the missile until impact. With heat detection, the missile could be guided internally, or ‘fire-and-forget.’ Although infrared technology was theoretically complicated, the missile itself was simple.
It had nine moving parts, and according to McLean’s assistant, Howard A. Wilcox, “had the mechanical complexity of a small washing machine combined with a table radio.” In a 1956 shootout with the Air Force’s Falcon missile, the Sidewinder downed both target drones while the Falcon never left the launcher. After six days of tinkering, the Air Force conceded.
Prevailing wisdom in the defense community was that infrared detection, for all of its advantages, would always be limited to fair weather. Because of this belief, the DoD refused to fund such a program. From 1947, when McLean conceived the project, until 1951 when the Bureau of Ordnance officially recognized it, McLean siphoned money from ongoing Naval Weapons Center projects and worked after hours to experiment.
The Sidewinder project did not officially exist until 1951 when the Bureau of Ordnance, satisfied with the potential demonstrated at China Lake, allocated $3.5 million for its development. The obscurity of the Sidewinder in its early stages led to a unique design atmosphere, where the designers held complete creative control without bureaucratic interference. In contrast, the AIM-7 Sparrow was built under rigid oversight, with resources devoted to meeting predetermined Navy specifications.
The Sidewinder joined the fleet in 1956, and its first battle test came in the second Formosa Strait crisis in 1958. Chinese Nationalists downed four Chinese communist MiGs with the AIM-9B version. It would be less successful in Vietnam, with a 47 percent failure rate, but still out performed the Sparrow III’s 66 percent failure rate. The Sidewinder was almost twice as effective.
In Operation Rolling Thunder, from 1965 to 1968, the AIM-9B and AIM-9D killed 16 percent as compared to 8 percent of the AIM-7 Sparrow III. The Sidewinder numbers improved, as later versions made the seeker more sensitive. In the Falklands Conflict, the British firing AIM-9Ls, recorded 18 kills in 26 attempts for a 69 percent kill ratio.
The Sidewinder continues fleet service with the AIM-9X, introduced in 2003. Block II upgrades to the AIM-9X include the Lock-on After Launch capability, that with the proper equipment allows for 360 degree engagements. It is carried by all major strike fighter platforms of the U.S. Navy, Marine Corps and Air Force.