In 1956, the Air Technical and Industrial Direction of the French government launched a competition for the design of a supersonic bomber, capable of carrying the French nuclear arm, and intended to equip the Strategic Air Force Squadrons. The competition quickly narrowed down to Dassault and Sud Ouest and was won by Dassault, whose bi-sonic Mirage IIIA-based design was judged superior to the Sud Ouest SO-4060, successor to the famous Vautour N, equipped with radar but capable only of Mach 1.3.
In April 1957, Dassault were awarded a contract for the fabrication of the aircraft, designated Mirage IV. It was a two-seater, derived from the Mirage III, and was powered by twin SNECMA Atar engines, developing a thrust of 7,000 kg with reheat.
On 17 June 1959, the Mirage IV prototype 01 made its first flight, with Roland Glavany at the controls, and was used to test the type’s navigation and bombardment systems. It flew over the Bourget Air Show on Flight 3, on 20 June and achieved Mach 1,9 on its Flight 14. On Flight 33 it exceeded Mach 2. By then the exploration of its performance was almost completed, the airplane having been flown supersonically at altitudes from only 3,000 meters to 18,000 meters.
The French detonated their first nuclear weapon in February 1960. That month the Mirage IV 01 transferred to the French flight test center (CEV). It flew there from 23 February to 14 April 1960, logging 36 flights (Flight 53 to Flight 89) for a total of 125 hours. Maximum altitude achieved was 59,000 ft. Some flights were made with auxiliary fuel tanks of 2,500 liters capacity each, and some bomb dropping trials were conducted. These tests were successful in general and showed that the aircraft had a good turnover capability, allowing two to three sorties to take place per day. Only 9 minor incidents were reported during the 36 flights.
On 22 September 1960 and with Dassault test pilot René Bigand at the controls, this aircraft achieved a world speed record in a closed circuit of 1,000 km at the average speed of 1,822 kmph, including 30 minutes of flight between Mach 1.8 and 2.
Mirage IV 01 logged its Flight 139 on 1 October 1960, concluding its first phase of testing, in which the flight envelope was explored and a maximum speed of Mach 2.1 was reached. The aircraft was grounded for the installation of the complete navigation system intended for the operational Mirage IV. It flew at maximum loading on 19 December 1961 but was lost in an accident on 13 February 1963 after the right engine compressor exploded. The CEV Brétigny crew of Captain Barbe and Major Jeanjean ejected safely.
The pre-production prototypes were designated Mirage IVA, were equipped with improved engines and were used to carry out a series of special trials, in view of the operational utilization of the bomber.
Mirage IVA 02 was first flown on 12 October 1961, reaching Mach 1.9 on its first flight. It had only logged 9 flights by year’s end.
Mirage IVA 03 and 04 made their maiden flights respectively on 1 June 1962 and 23 January 1963. In December 1963, the first production Mirage IVA left the Dassault factories of Mérignac (near Bordeaux). The Mirage IVA entered service with the French Air Force in 1964.
A total of 66 Mirage IVs was built: the four prototypes and 62 production aircraft.
One Mirage IV aircraft was used to test in flight the anemometric probe intended for the Concorde 001 prototype. On 23 October 1972, this Mirage IV took off from Blagnac and was carrying out low altitude runs when both engines flamed out. The crew of Pierre Dudal and Pierre Caneil ejected safely at 200 ft and received minor injuries. The aircraft was destroyed.
– Span: 11.85 m
– Length: 23.50m
– Height: 5.65 m
– Weight: 30,000 Kg
© Henry Matthews 2012