THE TAIWAN STRAIT, SEPTEMBER 24, 1958. Nine years after the end of the Chinese Civil War, when the island of Taiwan officially became the sovereign Republic of China, its air force squared off in a dogfight against the People’s Republic of China—the government of mainland China, which intended to bring Taiwan and its people under communist control.
Twelve U.S. F-86F Sabre fighters serving the Republic of China quickly mobilized to defend Taiwan from 12 Chinese MiG-17 fighters departing from the mainland. The MiGs, which Chinese President Mao Zedong sent to test Taiwanese defenses, could fly faster and higher than the aging Sabres, making them difficult to intercept. Nothing, not even the superior training of the Taiwanese pilots, could make up for that. And both sides knew it.
The People’s Liberation Army (PLA) Air Force MiGs darted above the Republic of China Air Force (ROCAF) Sabres, safely out of range of their M3 .50-caliber machine guns. The MiG pilots observed puffs of smoke as rockets flew off the wings of the Sabres, and wondered why the Sabre pilots were bothering to fire notoriously inaccurate aerial rockets. That is, until the rockets began corkscrewing inexorably toward their own planes, as if guided by some unseen hand.
In a matter of moments, six of the 12 MiGs were sent crashing into the waters of the Taiwan Strait. The remaining jets hightailed it back to the mainland, one unknowingly carrying a secret passenger: an unexploded Sidewinder missile, one of the world’s first infrared guided air-to-air missiles.
IN 1945, A RAGTAG GROUP OF ENGINEERS at the Inyokern, California-based Naval Ordnance Test Station was conducting research on an obscure new technology: lead-sulfide proximity fuses. Because the fuses were sensitive to heat, lead physicist William B. McLean saw the potential for a new kind of missile guidance system. His team—derisively known as “McLean’s Hobby Shop,” due to the perception of their work as wasting time and effort—would toil in the heat of the California desert on the secret missile project for the next nine years.
By 1950, the United States had entered the Korean War. The U.S. Navy flew some of the first air missions against invading North Korean forces, and quickly discovered Soviet-made MiG-15 fighters outclassed its F9F Panther jet fighters. The MiG was a better fighter than the Panther by almost every performance metric, including speed and maneuverability; it was only the experience of Navy pilots, many of whom were veterans of World War II, that prevented serious losses.
Stung by its lackluster performance in the air, the Navy looked for something that would give it an edge if the Cold War with the Soviet Union turned hot. One obvious solution was something the Germans had invented during World War II: the air-to air-missile, a weapon that fighter jets lob at other aircraft. The U.S. already had rockets, but no systems in place to guide those rockets and their warheads toward a target.
McLean’s team invented a solution. By the mid-1950s, the team had placed a spinning parabolic mirror, known as a Cassegrain reflector, behind a transparent glass dome in the nose of a five-inch aerial rocket. Moving at 4,200 rotations per minute, the spinning mirror reflected onto a second mirror, constantly projecting a 25-degree view of the area in front of the lead-sulfide detector. The distance of a hot object from the axis of spin guided the missile along the correct angle, and enough corrections would leave the missile at a zero-degree angle from the axis of spin—aiming it directly at the infrared source.
McLean christened this groundbreaking missile the “Sidewinder” after a poisonous snake found in the Mojave Desert adjacent to China Lake. And the name was quite apt: like the missile, the Sidewinder snake detects targets using infrared thermal radiation. And according to legend, the name also refers to the Sidewinder snake’s distinctive tracks left in the desert sand—similar to the corkscrewing motions of the missile in flight. Later designated AIM-9B, the missile had a three-mile range, far outranging existing guns, and a ten-pound fragmentation warhead with an effective blast radius of 30 feet.
In 1956, the Sidewinder went to sea, secretly deployed aboard carrier-based fighter jets for the first time; the U.S. Navy publicly revealed the missile’s existence a year later. “It’s like having a six-foot reach on the other fellow in a boxing bout,” Navy Lt. Cmdr. C.A. Tierney bragged at the time. The missiles gave the Navy fighters a theoretical edge—one that would become reality just a year later.
In 1958, the U.S. supplied the Republic of China Air Force with F-86 Sabre fighters, the same fighter jets the U.S. Air Force deployed during the Korean War. At the same time, the Soviet Union supplied its ally, China, with MiG-15s, which had also flown during the Korean War. The Soviets had also provided an improved version, the MiG-17F, which threatened to outclass the Sabres. If the Chinese planes outfought American planes in the sky, it would be a major propaganda coup that would send the Pentagon reeling.
“The PLA’s fighter was faster and could fly higher, and the situation was extremely dire for ROCAF’s pilots and Taiwan itself,” Joe Coles, an aviation blogger and author of The Hush Kit Book of Warplanes Volumes 1 and 2, tells Popular Mechanics.
The United States responded with a secret program, Project Black Magic, to turn the tables on the MiG-17F. The U.S., Coles explained, fitted Sabre fighters with AIM-9 Sidewinders. The missile allowed ROCAF fighters to launch their missiles at the higher flying enemy fighters at ranges beyond traditional guns and cannons and then turn away.
BACK AT BASE AFTER THE DOGFIGHT over the Taiwan Strait, the surviving Chinese pilots climbed out of their MiGs, stunned at their losses. They were baffled by the maneuvering rockets that had shot down half their force, but quickly solved the puzzle when they saw the Sidewinder embedded in one of their surviving jets.
At first, Chinese engineers tried to reverse-engineer the Sidewinder on their own. But their own technology, lagging decades behind the United States, stymied their efforts. They transferred the missile to the Soviet Union with the understanding that Moscow would share whatever secrets it uncovered with its allies in Beijing. The Soviet government sent the Sidewinder to the Toporov OKB missile design bureau, instructing the engineers involved to make an exact copy.
The Sidewinder had caught the USSR unawares. The Soviet air-to-air missile program had thus far produced only the Vympel K-5, a short-range beam-riding missile that “required the launching aircraft to maintain its relative orientation toward the target for the entire duration of the missile’s flight.” At best, this made it suitable for engaging slow-moving, lumbering bombers; at worst, it was wholly unsuitable for fighter-on-fighter air combat.
Theft of military secrets was fairly common at the time, especially given the prospect of the Cold War turning violent at any moment. Both sides sought to lie, cheat, and steal their way to any possible military advantage, though America’s technological lead typically meant secrets flowed from the West to the East. For example, the Soviet Union relied on nuclear secrets provided by physicist Klaus Fuchs, a veteran of the Manhattan Project, to produce its own nuclear bomb. Lacking an intercontinental delivery system for their bombs, the Soviets also copied a B-29 Stratofortress interned in Siberia during World War II, going so far as to copy holes in the fuselage without any understanding of what they actually did.
But according to Coles, none of these thefts changed aerial warfare quite like Russia’s copying of the Sidewinder missile.
“The recovered missile was one of the biggest technology windfalls in air warfare,” Coles explains, which enabled mainland China to arm itself with far better missiles than it previously had. Both the Warsaw Pact—a collective defense treaty among the Soviet Union and seven other Central and Eastern European Soviet satellite states—and Chinese air forces had numbers, but NATO’s lead in missile technology evened things out. Now, thanks to just one Sidewinder, the Communist bloc had both numbers and technology—a formidable combination that threatened to tilt the balance of air power.
Soviet engineers marveled not only at the Sidewinder’s effectiveness, but also at its simplicity of design, which bordered on elegance. One engineer, Gennadiy Sokolovskiy, later called it a “university offering a course in missile construction technology which has upgraded our engineering education and updated our approach to production of future missiles.”
By 1960, the Soviet Union had completed its reverse-engineering effort, resulting in the K-13 missile (NATO designation: AA-2 “Atoll”). It became the main short-range missile among the Soviet and Warsaw Pact Air Forces; Soviet client states including Cuba and Vietnam; and India and Pakistan. China called their version the PL-2.
The year 1969 saw an improved version of the AIM-9B enter service with the German Air Force. Known as the AIM-9B-FGW Mod.2, it featured improvements such as “solid-state electronics, carbon-dioxide seeker cooling, a new nose dome and better optical filtering.” The result was an improved missile with a more sensitive infrared seeker that was less likely to confuse the ground, a cloud, or the sun for enemy aircraft.
Of course, the Soviets would want this new Sidewinder, too—and they would get their hands on it in the most unbelievable way.
IN 1967, WEST GERMAN ARCHITECT MANFRED RAMMINGER was on a trade mission trip to the USSR; he was recruited to work for the KGB, the Soviet Union’s primary internal security agency. The KGB ordered Ramminger to concentrate his espionage activities on the German Air Force, known as the Luftwaffe—the first operator of the new AIM-9B FGW Mod.2.
One night in 1968, he broke into Neuberg Air Base; the KGB had recruited a German pilot to hand over a map of the base to Ramminger. The spy, his driver, and the pilot stole a live Sidewinder and rolled the missile down the runway in a wheelbarrow to Ramminger’s Mercedes sedan. The nine-foot missile didn’t fit in the car, so the spies-turned-thieves punched out the rear window and drove off after concealing the warhead and forward control fins with a blanket.
Ramminger brought the missile home, had a custom crate built to transport it, and air-mailed it to the KGB. The shipping cost was $483.88, and the missile took ten days to reach its destination. For his efforts, Ramminger was paid $81,000 (over $700,000 today).
A West German court later arrested and convicted Ramminger and his associates with treason, espionage, and grand larceny. The three were sentenced to between three to four years in prison.
Although the USSR got its hands on a fully functional AIM-9B FGW Mod.2, it’s not clear how much the Soviets and their allies benefited from the missile. In 1973, a new version of their Sidewinder copy, the K-13M, went into service. The only improvement the two missiles had in common was the use of compressed gas to cool the infrared seeker head. The German missile’s use of solid-state electronics was likely delayed in the Soviet Union, as the Soviets were years behind the West in microchip design and fabrication technology. The Soviet Union never caught up in the field of microprocessors, and even today Russian weapons found in Ukraine use a vast number of Western microchips to make up for a lack of domestic capability.
The Sidewinder missile has a storied legacy as one of the most successful missiles of all time with a lifetime tally of 270 kills as of 2021. And the missile continues to rack up kills: the U.S. used the latest AIM-9X version in 2023 to shoot down a Chinese spy balloon, and this year the Air Force F-15E Strike Eagles used it to shoot down Houthi drones.
The air-to-air missile arms race the Sidewinder kicked off seven decades ago endures to this day—with renewed implications as the threat of armed confrontation with Russia and China loom over Washington. Moscow and Beijing are likely still trying to steal America’s best-kept defense secrets, but today they’re much more likely to be carted away on a flash drive than in a wheelbarrow.
Kyle Mizokami is a writer on defense and security issues and has been at Popular Mechanics since 2015. If it involves explosions or projectiles, he's generally in favor of it. Kyle’s articles have appeared at The Daily Beast, U.S. Naval Institute News, The Diplomat, Foreign Policy, Combat Aircraft Monthly, VICE News, and others. He lives in San Francisco.
