Friday, December 30, 2011

Mirage III, Mirage IIIE and Mirage IIICJ Jet Fighter

The delta-winged Mirage III jet fighter has been the largest succes of the post-war French aviation industry. More than 20 countries bought the Mirage III Jet Fighter, and it is still in service, now undergoing extensive modernisation programmes in South-Africa, Chili and Switzerland. One of the most elegant aircraft ever flown, the Mirage III has a large delta wing and circular intakes with shock cones. A rectangular recess under the aft fuselage can contain either a fuel tank or a rocket engine.

The driving force behind Dassault, Marcel Bloch was born in Paris on January 22, 1892. Having become aware of aviation in 1909 after he saw his first aeroplane, Bloch subsequently studied electrical engineering at the Ecole Breguet. He then enrolled in the prestigious Ecole Superieure d’Aeronautique et de Construction Mecanique (SUPAERO), which was the world’s first dedicated aerospace engineering school, in 1912-13. Whilst Bloch was there, one of his classmates was Russian Mikhail Gurevich, who later teamed up with the Artyem Mikoyan in October 1939 to create the legendary design bureau MiG.

Bloch worked in the French Aeronautics Research Laboratory during World War 1 and then established the Societe des Avions Marcel Bloch, which produced its first aircraft in 1930. Having created parts for the national aircraft industry, Bloch’s company was nationalised on January 16, 1937 and became part of the Societe Nationale de Constructions Aeronautiques de Sud-Ouest.

The occupation of France by the Germans in World War II had a devastating effect on the country’s aviation industry in general and on Bloch in particular, for he was imprisoned from October 5, 1940 until August 17, 1944, when he was transported to Buchenwald concentration camp in Germany. Having refused to cooperate with his German captors, Bloch was due to be hung, but French Communist Party activists saved him by swapping his identity with a fellow prisoner who had died just a few hours before the execution.

 Buchenwald was liberated in April 1945 and Bloch set 8 about resurrecting his aircraft business. Born a Jew, he converted to Catholicism and changed his name to Marcel Dassault (which loosely translated into the word “Tank”). Dassault had been the alias of his elder brother, French Resistance leader Gen Darius Paul Bloch, during World War II. Avions Marcel Bloch was duly renamed Avions Marcel Dassault on January 20, 1947.

Straight wings (as fitted to the American F-104 Starfighter), swept wings (as fitted to the British Lightning) and delta wing configurations were all explored by aerospace engineers in the 1950s as they strived to develop the next generation of Mach 2 capable jet fighters. Dassault decided that the delta wing configuration would best suit a French Mach 2 fighter, primarily because locally produced jet engines lacked the thrust generated by contemporary American and British powerplants. Development of the Dassault delta fighter commenced in 1951, with a production contract being received from the French government on February 27, 1952.

The IDF/AF evaluated several examples of the ten Mirage IIIA Jet Fighter pre-series fighters in France in October-November 1959 and concluded that the delta fighter was suitable for multi-role combat. However, at that time the Mirage III had only three hard-points here, the aircraft is fitted with
rocket pods under the wings. Standing in front of the jet is IDF/AF Chief Test Pilot Danny Shapira, who has just returned from a sortie. The fighter’s versatility was greatly enhanced when two more hard-points were added beneath the outer wing sections.

Dassault had realised the limitations of the lightweight interceptor early on, and in March 1956 it proposed two heavier Mirage variants. The Mirage III was a singleengined delta-winged fighter, while the Mirage IV Fighter was a larger twin-engined version that would ultimately serve with the Armeé de l’Air as a nuclear bomber. The interaction between Dassault and the Armeé de l’Air eventually generated a new operational requirement, issued on September 3, 1956, for an all-weather interceptor. The principal threat that the aircraft had been designed to oppose was a supersonic bomber cruising at altitudes between 39,000ft and 66,000ft. The projected all-weather interceptor was no longer a lightweight fighter as had originally been envisaged with the MD 550, as it now featured an integral weapon system (including radar) and more fuel. Two light interceptor features were retained, however  a rocket booster (this time only for interception profiles against targets cruising at 66,000ft) and an armament of just a single AAM.

On November 15, 1956, the Armeé de l’Air informed Dassault that both of its revised Mirage proposals had been accepted, but that the Mirage IV Jet Fighter would be modified to serve as a bomber, while the Mirage III would be developed as an all-weather interceptor. Dassault had clearly been informed of this decision well ahead of it being officially announced, for the prototype seven-ton Mirage III 001 made its first flight just 48 hours later! Powered by an interim SNECMA Atar 101G turbojet engine, the prototype’s construction had been accelerated through use of components from the second prototype of the abandoned Mirage I. Flight testing also progressed rapidly, with the speed of sound broken in level flight on just its second sortie, afterburner ignition on the third and supersonic flight (Mach 1.24) registered during the fourth hop.

The Mirage III 001 was grounded for modifications on December 20, 1957. The most important of these was the fitment of moveable shock cones, known to the French as “Mice” (Souris), within the air intakes to control the airflow into the engine. The shock cones moved forward as supersonic speed increased, thus keeping the airflow subsonic at the throat of the intake. The moveable cones kept the shock waves at their optimum velocity throughout the supersonic speed range, thus allowing the engine to produce maximum power. The modified Mirage III 001 returned to the air on April 17, 1958, and 25 days later the first pre-production Mirage IIIA01 made its maiden flight. Powered by the SNECMA Atar 09B, which was rated at 13,230lbs st with afterburner, the shock cone-equipped Mirage IIIA01 became the first European aircraft to fly faster than Mach 2 in level flight on October 24, 1958. Such performance fully justified Dassault’s selection of the delta wing configuration to compensate for the Mirage III’s lack of thrust.

Mirage IIICJ No 38 was photographed still in its French markings while en route to Israel. The aircraft has been equipped with large 1,700-litre external fuel tanks specifically for this ferry flight. The 72 Mirage IIICJs ordered by Israel were delivered from France between April 1962 and July 1964.


Post a Comment

content="KxPS6GPOk1jXixOC5uWVt4sKw8A" />