To save costs, the new vertical take-off aircraft was built on the prototype of the Mirage III-001. Later, the experimental project was named the Mirage Balzac V.
According to the concept of the project, the Mirage Balzac V was a tailless low-mounted wing aircraft, similar in appearance to other aircraft in the Mirage fighter family.
To install the lift engine, the fuselage had to be rearranged to increase the area of the central part of the fuselage. The air intakes were located above the fuselage, covered with movable flaps. To control in level flight, they retained the standard cable and rigid wiring from the Mirage-3.
Balzac V had a length of 13.1 m (43 ft 0 in), wingspan of 7.3 m (23 ft 11 in), height of 4.6 m (15 ft 1 in). It had an empty weight of 6.1 tons, and a maximum take-off weight of 7 tons. By design, the Balzac V could reach a maximum speed of Mach 2. In the tests, it only reached 1,100 km/h.
To perform take-off, the pilot had to start the main engine, after which the lifting engines were started using compressed air. By increasing the thrust of the lifting unit, the aircraft had to rise to a height of at least 30 m, and then horizontal acceleration was allowed. At a speed of 300 km/h it was possible to retract the chassis and turn off the lifting motors.
Project Mirage Balzac V was ready by the end of 1961. In January 1962, a prototype began being assembled at the Dassault plant. The aircraft was ready in May and the first ground tests were conducted in July.
On October 12, 1962, the first takeoff took place at Milan-Villaros airport. The flights resumed only in March 1963, with flight tests of horizontal take-offs and landings. On March 18, a vertical takeoff was performed for the first time, followed by a transition to horizontal flight and landing like a normal airplane.
On January 10, 1964, in a test, the plane capsized and crashed, killing the pilot. Undeterred, they decided to restore the damaged plane, which took about a year. On February 2, 1965, test flights resumed. Over the following months, another 65 flights were made with vertical and horizontal takeoff and landing methods.
On October 8, 1965, another test flight took place, with US pilot Philip Neal. While taking off vertically at an altitude of approximately 50 m, the plane suddenly lost control and began to fall. The pilot tried to escape, but the parachute was not high enough to deploy, he was killed and the plane was severely damaged.