Conceived as a supersonic tactical nuclear attack aircraft, the F-105 was plagued with design and maintenance problems in its early days and gained the uncomplimentary nickname "Thud" as a result. But most of these difficulties were ironed out by the time the 'D' models rolled off the assembly lines, and it was the F-105D that gained a reputation for rugged endurance in the skies over Vietnam where it was put into use as a conventional attack aircraft and carried out more strikes than any other US aircraft in theater. It also suffered more losses.
