The YF-105 completed its maiden flight at Edwards AFB in October 1955, easily exceeding Mach One even though it was powered by a J57 engine, much less powerful than its projected power plant, the J75. The D-model "Thud" added water injection to the J75 engine, along with updated avionics, attack equipment, and improved refueling features, and it first flew in June 1959. A total of 833 Thunderchiefs of all types were built, including 610 F-105Ds, and all models of the F-105 were flight tested at Edwards. During the Vietnam War, the F-105D flew 75% of all air strikes against North Vietnam during its first four years and could carry over 12,000 of ordnance, a heavier bomb load than the World War II B-17. This Thunderchief was flight-delivered to Edwards in January 1984 from its last operational assignment with the 419th Tactical Fighter Wing (USAF Reserves) at Hill AFB, UT, and it was restored in 2007 by the 412th Test Wing Surfaces Team.