During the early stages of the Vietnam War, the US Air Force lost numerous aircraft to the highly lethal air defenses of North Vietnam. The very first US aircraft lost to a Soviet-built SA-2 Guideline Surface-to-air missile was a USAF F-4C Phantom II. It was July 24, 1965, the world had been re-introduced to the SAM and the US Air Force had a big problem. A few days later a meeting between US Air Force officials and industry representatives were set up, kicking off what was to become the "Wild Weasel" project.
An SA-2 SAM missile couldn't guide itself onto its target. Instead, a ground radar tracking the targeted aircraft directed the missile towards its calculated impact point. The idea behind the Wild Weasel project was simplicity itself; shut down the radars. That's what the US Air Force set out to do.
In the project, one important thing was lacking, and that thing was time. This lead to the first Wild Weasel aircraft being field-tested under combat conditions, and it naturally had a serious impact on aicrew longevity. However, the lessons learned were all-important to later refinement of equipment and tactics.
The aircraft chosen for the Wild Weasel mission was the two-seat F-100F Super Sabre. In the front was the pilot, and in the back was an Electronic Warfare Officer (EWO), handling the equipment for detecting and tracking enemy radars. It was equipped with a Radar Homing and Warning signal analysis system (RHAW) for detecting the Soviet SA-2 SAM Fan Song radar. The RHAW system was originally developed for the U-2 spy plane. The Wild Weasel concept was as simple as it was dangerous; the F-100s teamed up with a flight of F-105 Thunderchiefs, creating a so-called hunter-killer pack. The F-100F Wild Weasel aircraft (the hunter) would identify and track the enemy radar by exposing itself to it, attacking it with 2.75 inch rockets and guns. To finish off the entire SAM site, the Thuds (the killers) would bring their weapons to bear on the radar, directed by the Wild Weasel aircraft.
Wild Weasel I
In November 1965, F-100F Super Sabres started operating as Wild Weasel's out of Korat Royal Thai Air Force Base in Thailand. Their missions codenamed Iron Hand were dangerous and demanding, luring enemy air defenses to fire so that their companion F-105 Thunderchiefs could attack them.
The first Wild Weasel SAM kill happened near Phu To northwest of Hanoi, December 22, 1965, 22 days after the first Wild Weasel mission was flown and two days after the first Wild Weasel crew was lost to a SAM missile. Flying out of Korat RTAFB, flight "Spruce" consisting of one F-100F Super Sabre and four F-105G Thunderchiefs, attacked and destroyed a SAM site with rockets and guns. A painting commemorating this event is on permament display in the United States Air Force Museum in Dayton, Ohio.
Wild Weasel II and III
In July 1966 the F-100Fs days as a Wild Weasel were over. It was decided to configure the two-seat F-105F Thunderchief for the Wild Weasel role instead. The crews that had survived the F-100 Wild Weasel missions were flown back to the United States to train the next batch of Wild Weasel crews. With the newer aircraft and the time to train, Wild Weasels became a much more capable force. Following equipment upgrades and enhancements, the F-105F evolved into the F-105G Wild Weasel III. Both Thud Weasel variants used the AGM-78 Standard and AGM-45 Shrike missiles as well as M117 iron bombs, 2.75 inch FFAR rockets and 20 mm guns for the destructive part of the job.
Two units flew the Wild Weasel F-105; 355th Tactical Fighter Wing (TFW) at Takhli RTAFB and 388th TFW at Korat RTAFB, both in Thailand.
Wild Weasel IV
When the F-105F began to be replaced with the F-105G, the former was gutted of its radar detecting and tracking equipment. In 1972 a fleet of F-4C Phantoms IIs were fitted with this equipment, becoming Wild Weasel IV aircraft. The reasoning behind using Phantoms were simply that there were not enough Thuds to fulfill the increasing number of missions. At the beginning of their Wild Weasel career, Phantoms were kept to South Vietnam, but towards the end of the conflict they too were sent "downtown" - into the heavily defended area around Hanoi.
Wild Weasel V
Once the Vietnam War ended the USAF had plenty of time to design and test Wild Weasel aircraft and electronics. The E variant of the Phantom II were modified to become the Wild Weasel V. The specially designed equipment inside the F-4E was combined with the AGM-88 HARM High-speed Anti Radiation Missile to create a Weasel that would last until its retirement in March 1996.
When the last F-4 Phantom II Wild Weasel had left for the boneyard or foreign military sales, the USAF needed a new aircraft to fill the gap. What they ended up with was regarded as a sour deal for many in the Wild Weasel community; an F-16C (nicknamed "Viper") with a HARM Targeting System (HTS), AGM-88 HARM missiles and an ALQ-119 jamming pod. Its official mission designation is SEAD (Suppression of Enemy Air Defenses), but the Wild Weasel term seems to have planted itself firmly in the minds of the people in the anti air-defense community. It's designated F-16CJ, and is arguably less of a Weasel than the Phantom.
"The Encyclopaedia of modern Air Warfare Vol.2", Aerospace Publishing Ltd.