Mirage IV Strategic Bomber

The Suez crisis in October 1956 prompted France to look into setting up a “strategic intervention force”, equipped with nuclear weapons. Soon after General Charles de Gaulle came into office, in June 1958, he said France was to single-handedly develop what he called its “dissuasion of aggression” weapon. The scheme involved an aircraft first, and a ballistic missile later. In fact, besides the scale effect, the air-friction heating is very different. The Mirage IV was chosen. Whereas the Mirage III could only withstand Mach 2 for a few minutes, the Mirage IV needed to hold that speed for much longer than the 20 or so minutes required for the temperature to stabilize throughout the outer structure and inner casings housing the equipment, petrol and hydraulic liquid.

Every component, therefore, needed to undergo a full thermal assessment. French equipment manufacturers fulfilled virtually all the requirements.

The bomber’s specifications were jointly defined by government authorities and Dassault staff, and cleared on March 20, 1957.

The Mirage IV 01 was an experimental prototype designed to discover the problems inherent in sustained supersonic flight. The general appearance of Mirage IV 01 was very like that of the Mirage III A with respect to its surface area, engine configuration and empty weight. It nevertheless carried three times more internal fuel. Manufacture, at the Saint-Cloud factory, lasted 18 months. It left the factory at the end of 1958 for final adjustments at the Melun-Villaroche base before proceeding to flight tests.

Although its aerodynamic specifications were very similar to those of the Mirage III, its structure, layout and equipments demanded specific developments. Temperature differences during rapid acceleration or deceleration imposed constraints which had to be taken into account when determining the dimensions. The Snecma Atar 9 B jet engines – 13,200 lb of thrust with reheat – were identical to those of the Mirage III A which first flew in May of 1958, a full year before the Mirage IV. The Mirage IV was the first French aircraft to incorporate one-way electronic flight controls for pitch and roll
The bomb carrier was to be a bomber aircraft.
A second aircraft for electronic reconnaissance and offensive jamming was to prepare the way for the bombers and accompany the bombing raid. On May 5, 1959, three pre-production Mirage IV Bs were ordered, of which the first was scheduled to fly before July 1, 1961. Mirage IV 01 was now considered as a small scale prototype for the development of the navigation and bombardment system. In September 1959, the desire to avoid constructing a foreign aeroengine under license for the propulsion of the Strategic Nuclear Force led to the adoption of a smaller, less expensive aircraft, the Mirage IV A. This was the end of the Mirage IV B program.

Source - Dassault Aviation