In 1950, Marcel Dassault produced the first French transonic aircraft, the MD 452, based on the fuselage of the MD 450 Ouragan, equipped with a thinner wing.
Using the experience from the Ouragan’s first flights, Marcel Dassault managed to use a pre-production plane to improve its aerodynamic features. On February 11, 1950, he signed a contract to design and build thin-section wings that could fit an MD 450 Ouragan’s fuselage. The MD 452, later renamed Mystère, was thus born.
The fuselage of the Ouragan was altered in the central compartment to receive a different wing, much more swept back (30° instead of 14°) and with reduced relative thickness ratio, such that transonic phenomena would not be encountered until the aircraft reached much higher velocity. The empennages with the unchanged layout above the rear fuselage were homogeneously modified. The Mystère II was equipped with the first serial servo-control units manufactured in France (designed and built especially in Saint-Cloud by Dassault).
The prototype Mystère II 01 (with a Rolls Royce Nene jet engine) first flew out of Istres on February 23, 1951 with Kostia Rozanoff at the helm.
This new model’s climb rate and maximum speed were considerably better than the Ouragan’s. In the early 1950s, transonic flight was an achievement in itself. No French aircraft, however, had yet broken the speed barrier. Kostia Rozanoff tried, and was indeed under the impression his plane had broken the barrier, but the famous boom was never heard. In October 1952, three American pilots flew the Mystère II.
The second and third prototypes with the Tay engine known as the Mystère II A flew on April 5 and July 2,1952, respectively. The Mystère II n°4 served as a flying test-bed for the Snecma Atar 101 C and 101 D engine. It first flew on December, 1952, piloted by Charles Monier.
On October 28, Major Marion Davis flew n° 03. As opposed to French pilots, he knew the secret to directing the sound towards the public, and the much-anticipated boom was heard. Commander Roger Carpentier from the flight test center was the first Frenchman to officially break the sound barrier on December 12, 1952, in Brétigny. Jacqueline Auriol was the first woman to do so, on August 15, 1953, in the cockpit of a Mystère II.
On January 15, 1953, 150 Mystère II C aircraft (Atar engine, symmetrical wing and two 30- mm cannons) were ordered by the French Air force. The first production model flew on October 1, 1954, piloted by Georges Brian. The 150th was delivered in January 1957. In July, the Mystère II C entered into service in the Air Force at the Creil Wing, simultaneously with the Mystère IV. He was retrieved the same year, replaced by the latter.
The French Air Force was demanding a night fighter derived from the Ouragan. On February 18, 1950, Marcel Dassault signed a contract to provide a night fighter, the MB 451. This two-seater was equipped with nose-cone radar, which meant that lateral air intakes would be required. To test the new air intakes, the front of the Ouragan n°11 was modified. The aircraft, under the new name MD 450-30 L, first flew at Melun-Villaroche on January 24, 1952, with Charles Monier at the controls. The increase in weight combined with the absence of radar motivated the Corporation to focus its efforts on a more advanced model from the same range, the MD 453 Mystère III or Mystère de Nuit (Night Mystère).
An amendment clause, dated July 18, 1951, canceled the straight-wing MD 451 in favor of the MD 453, with its swept-back wing.
The MD 453 was derived from the MD 452 Mystère II. What made it different from the 452 was its greater sweepback angle (32° as against 30°), its thinner wing (8% as against 9%) and its air intake with lateral inlets (due to the frontal position of the radar antenna). It was a tandem two-seater equipped with Rolls-Royce Tay engine and 30-mm cannons. The Mystère de Nuit first flew on July 18, 1952, at Melun-Villaroche, piloted by Kostia Rozanoff.
Plans for serial production were never realized, mainly due to the lack of radar, and growing interest in the more sophisticated Mystère IV N and the Vautour N. The aircraft finished its working life as a flying test-bed for SNCASO’s ejection seats.