The North Vietnamese Army had not been idle while the Weasels were forming--U.S. air losses had been heavy. With the help of Russia and China, the NVA had developed a system of coordinated and layered air defenses that could be supplied and expanded at will, since President Lyndon Johnson had ordered that North Vietnamese harbors and rail links into China be off-limits to U.S. forces. NVA air defense depended on SAMs to dominate the medium to high altitudes, which caused the fighters, in their dive to elude missiles, to fly into a waiting hail of AAA, much of it radar-guided and accurate. The AAA became thicker the lower the altitude, and below 4,500 feet it became more lethal than the SAMs themselves. The plan was simple: Drive the attackers down into the lethal envelope, where they would be destroyed.
By December, the small cadre of Wild Weasel crews began checking out their equipment and devising tactics for their first missions. The crews flew orientation flights along the North Vietnamese border and became familiar with the various electronic signatures of NVA radar. When the Huns did head north, they accompanied strike packages to targets selected by the air staff. Intelligence about the location of SAMs wasn't always accurate, since the sites were mobile and could be broken down and moved in four to six hours. Wild Weasel missions were code-named Iron Hand.
As the Weasels flew, field engineers from ATI and North American were back on the ramp at Korat, working alongside Air Force crew chiefs and technicians under primitive conditions and dealing with constant changes to equipment and installation of subsystems. "We got into the field where they're changing engines out all the time and the wiring was deteriorating really badly," says ATI's Mel Klemmick, who was sent to Thailand in 1965 for a tour that was to last 30 to 90 days but ended up stretching for two years. "Towards the end they were really falling apart. For example, you use commercial-grade coaxial cable for the rear antennas running right on the tops of those engines where the afterburners were. And particularly when they started flying the 100s out in front of the F-105s, those poor guys were in afterburner all the time."
Because they often worked in concert with faster F-105s and F-4 Phantoms, even by the time the Weasels arrived in Thailand it was clear a more capable airframe was needed. Both the Thunderchief and the Phantom were logical choices, but the Phantom was a much more complicated machine: With twin engines, multi-role mission capability, and an extensive array of weapons to carry, it was much more densely packed with wiring, cables, and systems. Just finding space for the Weasel equipment was a challenge. Once the systems were installed, technicians discovered incompatibilities with the Phantom's existing electronics. Because of its difficult development and a string of intervening cease fires in Vietnam, the first F-4C Wild Weasels wouldn't reach Korat until 1972.
The conversion of the Thunderchief was much more successful and was to result in the most storied Wild Weasel airframe, and one that would fly the most missions in Vietnam. By January 1966, the first modified F-105F, with essentially the same equipment as the F-100F, made its first flight. The big Thunderchief had come out of the shop with its 20-mm Gatling gun still in the nose and the added ability to launch a new air-to-ground missile that fed on radar beams, the AGM-45 Shrike, a weapon that was partly based on the AIM-7 Sparrow air-to-air missile but had a Texas Instruments seeker head that locked on to ground-based radar sources. The Shrike was eventually carried by other U.S. Air Force aircraft, and was used by Navy radar suppression aircraft, including A-6 Intruders and A-4 Skyhawks; its appearance marked the beginning of more widespread SAM supression and offensive capability for a host of aircraft operating in Vietnam.
By May 1966, ten F-105Fs were on the ramp at Korat, bolstering the battered EF-100F contingent. The Thuds were flying sorties by early June, led by experienced crews in F-100Fs. When the Huns were withdrawn in July, they had proven the new system worked, pioneered a new mission, and destroyed nine SAM sites.
In mid July, the first Thud Weasels arrived at Takhli Air Base in Thailand. The air war was heating up at an incredible pace, and within six weeks, five Weasels had been lost and the sixth was too badly damaged to fly again. Operation over the north reached a long bloody plateau from late 1966 through early 1968. In 1967 alone, 26 Wild Weasel aircraft and 42 crew members--the equivalent of an entire squadron--were shot down. The losses prompted a reexamination of whether Weasel operations should be continued at all.
The surviving crews from the first deployment were sent to Nellis Air Force Base in Nevada to set up a Wild Weasel prep school that would provide new crews with instruction on the Vector IV equipment and 10 missions in the F-105F, some of them flown against dummy SAM radar sites. But for Wild Weasel crews, the best lessons were learned in combat. The training gave crewmen the basics of operating the equipment and included classwork on SAM radar and tactics, as well as simulated missions flown against the radar simulator. "We could learn how they operated, but actually seeing how they turn on, and seeing [a SAM] fire off and go by you [in combat] is another experience," says former F-105 backseater David Brog. "But [the school] prepared us and we were trained by guys who had been there already."
The crews experimented freely and developed their own tactics, even as their onboard equipment was continually modified. One of the more successful maneuvers against SAMs was developed by Takhli-based Weasels, who began forming teams made up of two pairs of aircraft: One tempted a SAM to fire, which revealed the site for the other pair to attack. This was a favorite trick of Leo Thorsness and his EWO Harold Johnson, a tactic they called "trolling." Thorsness also pioneered the lofted delivery--a sharp pull-up during launch of the Shrike that added as much as 20 miles to the nominal range of the missile. Thorsness and Johnson flew 92 Wild Weasel missions, one of which earned Thorsness the Medal of Honor and Johnson the Air Force Cross, but the two were shot down by a MiG in 1967 and spent the rest of the war as prisoners in Hanoi.
As tactics were developed in the air, field modifications to the Wild Weasel systems continued on the ground. A key weakness of the equipment was that if several SAM sites were displayed on the scope and the light that signaled a launch was illuminated, there was no way to know which site had fired and from which direction the SAM was coming. "I heard the crews complaining about that," says Weldon Bauman, who in 1967 was a junior enlisted technician at Takhli. "And I thought Well, if I knew more about the signal, then maybe we could do something about it." Bauman became a Wild Weasel legend for devising a system similar to Bob Klemic's but that sidestepped cumbersome and lengthy procurement procedures and could be hot-wired into the aircraft in the field immediately. But to do it, he first needed access to sensitive data about the nature of SAM site radar emissions, and after convincing an EWO to escort him into the intelligence section, he got the information he needed. "I sat down and got the real-time data--the same day then was real time," Bauman says. "I found out what they were seeing and then went back and designed a circuitand it worked." When activated, Bauman's modification cleared the scope of all information except for a blip that indicated the launching site. Tom Wilson, a former F-105 EWO, marveled at Bauman's ingenuity and his modesty. "This kid had two stripes, and he was so damn smart it was unreal," Wilson says. "When I asked him how he came up with the mod, he said, "It was real easy. Just three little parts wired into the line for the scope, and a switch, and it was done.' "