As the cold war intensified, F-84s would serve as testbeds for some unusual projects, including a radical solution to replace the runway with a “zero-length” launch system. The system used a booster rocket from a Matador cruise missile to fling an EF-84G from a platform into the air at a shallow angle. That system enabled the aircraft to be launched in forward wooded areas, so close air support could be made faster and more accurate. But the technique quickly proved too dangerous for the pilots so the idea was dropped.
Instead, the G model was adapted for another purpose. Taking advantage of the Thunderjet’s stability as a weapons delivery platform, the Air Force retrofitted the fighter-bombers with a low-altitude bombing system and nuclear bombs for missions against targets in the Soviet Union.
Guy Razzeto was one of the pilots trained to fly the nuclear strike mission. After the Korean War, Razzeto says, “we trained to carry ‘A’ bombs, and went to inflight refueling [in the F-84G]. We could go anywhere in the world.” Beginning in August 1953, the Strategic Air Command deployed nuclear-capable F-84s to Europe. By 1955, more than 550 fighters were equipped for the mission. These were eventually replaced by North American F-100s.
In 1949, the imaginative Kartveli turned the Thunderstreak into the XF-91 Thunderceptor by supplementing its jet engine with a cluster of rockets that were supposed to provide extra thrust for the final burst of speed during the intercept. The airplane’s most notable feature was its wings, which were much wider at their tips than at their roots, giving them increased lift but a very odd appearance. And like other fighter-interceptor designs of the time, the XF-91 had a too-brief total flight time—only 25 minutes for the Thunderceptor—making it virtually useless for U.S. border defense. It eventually lost the competition to defend the country to the F-86D Sabre, which had a far longer range; Northrop’s large, straight-winged F-89 Scorpion; Convair’s F-102 Delta Dagger and F-106 Delta Dart; and Lockheed’s F-94 Starfire, which carried a ring of air-to-air missiles in its nose. Two XF-91s were built and flight-tested 192 times over the course of five years, then retired.
Then there was the XF-84H, which served as a test platform for the Navy: By using a turbine engine to drive a massive 12-foot propeller, the XF-84H could lift off from fields as short as an aircraft carrier deck. Only two were built. While the experimental aircraft set an unbroken speed record for a propeller-driven aircraft—670 mph—its blades delivered loud, and nausea-inducing sound waves while on the ground, and the Navy dropped the idea.
Despite the dead ends, the trials did prove one thing: the Thunderjet’s versatility. That was one of the traits that made it attractive to America’s cold war allies and neutrals, including Josip Tito’s breakaway regime in Yugoslavia, which bought F-84Gs. Of the 7,524 Thunderjets that rolled out of the factory in Farmingdale, Long Island, hundreds were bought and flown by the air forces of other countries: Belgium, Denmark, France, Greece, Iran, Italy, the Netherlands, Norway, Portugal, the Republic of China (on Taiwan), Thailand, and Turkey. The last in operation, three RF-84Fs in the Greek air force, were retired in 1991.
Air Force pilots, like Razzeto, provided the schoolhouse for friendly countries and their new Thunderjets. “We went to Formosa to train [the Chinese] to fly the F-84G,” he says. “We had already converted to the F model—the swept-wing version—and they got F-84Gs through the [Military Assistance Program].”
Even with its versatility and hard-won respect firmly a part of aviation legend, it was clear to Kartveli that a successor to the F-84 was needed, so in 1951, he turned his attention to the F-105 Thunderchief, a high-speed, low-altitude nuclear bomber that drew some inspiration from the RF-84F Thunderflash—in particular its distinctive wing-root intakes. The Thunderchief would carry on the Thunderjet’s ground-pounding tradition in Vietnam.
Although the F-105 was a success, Republic was hemorrhaging money by 1965, forcing a merger with Fairchild-Hiller. That led to the closing of the plant in Farmingdale in 1988. In 1972 Fairchild-Republic met an Air Force requirement for a close air support fighter-bomber by producing the A-10 “Warthog”—dubbed the Thunderbolt II to celebrate its heritage.
“Republic proved its versatility going from the Thunderjets to the F-105, which was basically one of the fastest aircraft close to the deck,” says Ken Neubeck, a former A-10 engineer who has written books on the F-84 and other Republic aircraft. He notes that the A-10’s roots go right back to the P-47, which was also a ground attack aircraft.