Staff Writer (Updated: 5/18/2016):
Founded in 1929 by Marcel Dassault (born as Marcel Bloch) and based in Paris, France, the Dassault Aviation concern emerged from the devastation of World War 2 (1939-1935) to become one of the leading aviation companies of Europe. In 1952, the French government required a new, lightweight supersonic interceptor to counter the threat posed by Soviet nuclear-capable bombers and fighters. Dassault responded with their "Mystere-Delta 550" (M.D.550) concept which utilized a single-seat, twin-engine, delta-wing planform with single vertical tail fin. Power for the aircraft was served through 2 x British Armstrong Siddeley MD30R Viper afterburning turbojet engines backed by a rocket thruster. The M.D.550 achieved first flight on June 25th, 1955.
The M.D.550 product then evolved to become the "Mirage I" concept with a revised wing surface. This model achieved first flight in November of 1956 and set a maximum speed mark of Mach 1.6. While promising from a performance stand point, the Mirage I was not a realistic military-minded product which was intended to carry internal cannon, a useful fuel store, onboard interception radar and external missiles. As such Dassault moved on the slightly larger "Mirage II" concept though this was eventually given up for good with the dimensionally larger "Mirage III" design being furthered.
Based on the wartime German BMW 003 series turbojet, French manufacturer SNECMA developed its in-house Atar 101G-1 turbojet and a single installation of this system would power the new Mirage III airframe. The airframe retained the delta-wing planform seen in earlier prototypes and the single vertical tail fin with seating for one pilot. The fuselage was very slim and dart-like in its design approach, making maximum use of aerodynamics to achieve the projected Mach 2 speeds for the French interceptor. The Atar engine developed some 9,700lbs of thrust and offered afterburning for short bursts of concentrated speed. First flight of a Mirage III prototype was claimed on November 17th, 1956 while a tenth test flight netted a maximum speed of Mach 1.5. Testing indicated turbulent airflow along the two half-moon intakes aspirating the Atar engine so adjustable shock cones were added to each opening. In this revised configuration, the Mirage III reached a speed of Mach 1.8.
Impressed with the new Dassault product, the French government moved on ordering the type for service and this begat the "Mirage IIIA" preproduction designation. Aircraft would be outfitted with the SNECMA Atar 09B turbojet engine of 13,228lbs thrust. The fuselage was extended slightly to house the Thomson Cyrano air intercept radar system and a drag chute was added to reduce runway roll upon landing. First flight of a Mirage IIIA aircraft was in May of 1958 and the model eventually clocked a maximum speed of Mach 2.2 - fulfilling the French government's high speed request while also becoming the first European aircraft to exceed Mach 2 in level flight.