Staff Writer (Updated: 5/18/2016):
Design on the Mirage IV was derived fro the Mirage III development, detailed elsewhere on this site. The Mirage IV was larger than its predecessor and fitted with two powerplants instead of the traditional Dassault arrangement of a single engine. The aircraft would have to be capable of sustained high-level, high-speed flight with long range abilities. The first prototype IV, based on an abandoned twin-engine night fighter once in development, flew in 1959. Several pre-production aircraft would soon follow by 1961 as larger overall designs fitted with Atar 9C 14,110lb turbojet engines. It would be these preproduction models that would become the main Mirage IV production models in use.
The Mirage IV was of a basic delta-wing design with a single rudder at rear. The crew of two sat in tandem in the long and narrow fuselage. Wings were of the low-mounted monoplane type and the nuclear ordnance - when carried - sat in a recessed under-fuselage position. Power was provided by two SNECMA-brand engines with applicable reheat capability. At any rate, the sleek-looking Mirage IV was quick to provide high-speed results thanks to its overall design, dimensions and power.
The Mirage IV was ordered as the IVA model series. This system offered up a center-fuselage provision for a single An22 60-kiloton nuclear freefall bomb, to which 62 examples were produced. From this lot, 12 aircraft were set aside and reconfigured as the IVR strategic reconnaissance model with additional and specialized equipment. Additionally, 19 IVA models were converted to a "missile carrier" variant that allowed for the handling and firing of ASMP nuclear-tipped stand-off missile weapons in the low-level penetration combat role.
By the end of the Cold War, the need for such nuclear-capable systems was becoming less and less. As a result, the Mirage IVA's were disbanded from their nuclear strategic roles while only the Mirage IVR reconnaissance series stayed on to continue service with French forces. The Mirage IV nevertheless fulfilled a very vital role to the French people, offering up a nuclear deterrent through the later stages of the Cold War that would keep the Soviet Bloc at bay for decades.