November 17 / Dassault Mirage III first flight

Dassault Mirage III

The Dassault Mirage III is a family of single/dual-seat, single-engine, fighter aircraft developed and manufactured by French aircraft company Dassault Aviation. It was the first Western European combat aircraft to exceed Mach 2 in horizontal flight, a feat which was achieved on 24 October 1958.

In 1952, the French government issued its specification, calling for a lightweight, all-weather interceptor. Amongst the respondents were Dassault with their design, initially known as the Mirage I. Following favourable flight testing held over the course of 1954, in which speeds of up to Mach 1.6 were attained, it was decided that a larger follow-on aircraft would be required to bear the necessary equipment and payloads. An enlarged Mirage II proposal was considered, as well as MD 610 Cavalier (3 versions), but was discarded in favour of a further-developed design, powered by the newly developed Snecma Atar afterburning turbojet engine, designated as the Mirage III. In October 1960, the first major production model, designated as the Mirage IIIC, performed its maiden flight. Initial operational deliveries of this model commenced in July 1961; a total of 95 Mirage IIICs were obtained by the French Air Force. The Mirage IIIC was rapidly followed by numerous other variants.

Development

Origins

The Mirage III family has its origins within a series of studies conducted by the French Defence Ministry which had commenced in 1952. At the time, several nations had taken an interest in the prospects of a light fighter, which had been motivated by combat experiences acquired during the Korean War, specifically the Soviet-built Mikoyan-Gurevich MiG-15 jet-propelled fighter aircraft which had drawn considerable attention internationally. Western nations were keen to explore the performance of a relatively uncomplicated and heavily armed jet-powered swept wing fighter, inspired by the rapid advances in aircraft capabilities that had been made by the Soviet Union. France was one of the quickest governments of several nations, including the United Kingdom (resulting in the Folland Gnat), the United States (leading to the Douglas A-4 Skyhawk), and Italy (which became the Fiat G.91), to embark on encouraging the development of such an aircraft.

In 1952, the French government issued its specification, calling for a lightweight, all-weather interceptor, capable of climbing to 18,000 meters (59,100 ft) in 6 minutes along with the ability to reach Mach 1.3 in level flight. Three separate French manufacturers decided to respond to the specification, these being Dassault Aviation, Sud-Est, and Sud-Ouest, offering the MD.550 Delta, SE.212 Durandal and SO.9000 Trident, respectively. Dassault's submission, which became known as the MD.550 Delta, was a diminutive and sleek-appearing aircraft that was principally powered by a pair of 9.61 kN (2,160 lbf) Armstrong Siddeley MD30R Viper afterburning turbojet engines (built under licence by Dassault); atypically, the design also featured provisions for the installation of a secondary propulsion system in the form of a SEPR-built 66 liquid-fuel rocket engine, capable of providing boost thrust of 4.7 kN (1,100 lbf).

The Mirage III incorporated various new design principles, such as the transonic area rule concept, where changes to an aircraft's cross-section were made as gradual as possible, resulting in the famous "wasp waist" configuration of many supersonic fighters. Similar to its Mirage I predecessor, the Mirage III had provision for a booster rocket engine. On 17 November 1956, the prototype Mirage III perform its first flight. During its 10th flight, it was recorded as having attained a speed of Mach 1.52 at one point. During the course of the flight test programme, the prototype was fitted with a pair of manually-operated intake half-cone shock diffusers, known as souris ("mice"), which could be moved forward as the Mach number increased. This achieved a reduction in inlet pressure losses by ensuring the fuselage oblique shock remained outside the intake lip. Reportedly, their addition enabled an increased speed of Mach 1.65 to be reached, while use of the supplemental SEPR 66 rocket (as fitted to the Mirage I) had allowed for a speed of Mach 1.8 to be reached in September 1957.

The success of the Mirage III prototype resulted in an order for 10 pre-production Mirage IIIA fighters. Although the type had initially conceived of as an interceptor, the batch had been ordered with the intention of using them to develop the type for additional roles as well. The Mirage IIIA were almost 2 meters longer than the Mirage III prototype, had an enlarged wing of 17.3 per cent greater area, a chord reduced to 4.5 per cent, and an Atar 09B turbojet capable of generating afterburning thrust of up to 58.9 kN (13,200 lbf). The SEPR 841 rocket engine was also retained. The Mirage IIIA was also fitted with a Thomson-CSF-built Cyrano Ibis air intercept radar, operational-standard avionics, and a drag chute to shorten its landing roll.

In May 1958, the first Mirage IIIA conducted its first flight. On 24 October of that year, this aircraft achieved a top speed of Mach 2.2 during one of its test flights, thus becoming the first Western European aircraft to exceed Mach 2 in level flight. In December 1959, the tenth and final Mirage IIIA was rolled out; the last six pre-production aircraft were largely representative of the subsequent initial production standard. The test regime involved a wide variety of tasks, including the evaluation of the newer SEPR 841 rocket motor, various underwing drop tanks, and other major systems. One Mirage IIIA was powered by a Rolls-Royce Avon 67 engine capable of generating 71.1 kN (16,000 lbf) of thrust, to serve as a test model for Australian evaluation, which was given the Mirage IIIO designation. This variant flew in February 1961, but the Avon powerplant was ultimately not adopted on production aircraft.

The basic layout of the MD.550 Delta featured a tailless delta configuration, possessing a 5 per cent thickness (ratio of airfoil thickness to length) and 60° sweep, complete with a large vertical stabilizer and rudder. However, the tailless delta configuration imposed a number of limitations, including the lack of a horizontal stabilizer, which meant that conventional flaps could not be used; this resulted in a relatively long takeoff run and a high landing speed. The delta wing itself limits manoeuvrability and suffers from buffeting at low altitudes due to the large wing area and resulting low wing loading. However, the delta is a simple design, easy to construct and relatively robust while providing generous amounts of internal volume in the wing for fuel tankage and being capable of achieving high speeds when flown in a straight line.

British aviation author Derek Wood observed that there was "a striking resemblance" between the MD.550 Delta and the British Fairey Delta 2, an experimental aircraft that first flew three months later, on 6 October 1954, and which set a new world speed record on 1 March 1956. During the latter stages of testing of the Fairy Delta 2 in October and November 1956, the FD2 performed 47 low-level supersonic test flights from Cazaux Air Base, Bordeaux, in France. Dassault engineers observed these trials and obtained additional data on the performance and flight characteristics of delta wing aircraft. The Delta 2 confirmed Dassault's theories and provided additional supporting evidence for the viability of the Mirage III development.

Mirage IIIC and Mirage IIIB

The first major production model, the Mirage IIIC, first flew in October 1960. The IIIC was largely similar to the earlier IIIA, being less than a half meter longer and featuring a full operational fit. The Mirage IIIC was a single-seat interceptor, with an Atar 09B turbojet engine, featuring an eyelid-type variable exhaust. The Mirage IIIC was armed with a twin 30 mm DEFA cannon fitted in the belly with the gun ports under the air intakes. Early production Mirage IIICs had three stores pylons, one under the fuselage and one under each wing; another outboard pylon was soon added to each wing, for a total of five, excluding a sleek supersonic tank which also had bomb-carrying capacity. The outboard pylon was intended to carry an AIM-9B Sidewinder air-to-air missile, later replaced by the Matra R550 Magic and was also armed with the radar-guided Matra R530 Missile on the centre line pylon.

A total of 95 Mirage IIICs were obtained by the French Air Force, with initial operational deliveries in July 1961. The Mirage IIIC remained in service with the AdA until 1988.

The Armée de l'Air also placed an order for a two-seat Mirage IIIB operational trainer. Performing its first flight on 21 October 1959, it was developed in parallel with the Mirage IIIC. The fuselage was stretched about a meter (3 ft 3.5 in), while both cannons were removed to accommodate the second seat. The IIIB lacked radar and provision for the SEPR rocket was also deleted, although it could carry external stores if desired. The AdA ordered 63 Mirage IIIBs (including the prototype), including five Mirage IIIB-1 trials aircraft, ten Mirage IIIB-2(RV) inflight refuelling trainers with dummy nose probes, used for training Mirage IVA bomber pilots, and 20 Mirage IIIBEs, with the engine and some other features of the multi-role Mirage IIIE. One Mirage IIIB was fitted with a fly-by-wire flight control system in the mid-1970s and redesignated Mirage IIIB-SV (Stabilité Variable), it was used as a testbed for the system in the later Mirage 2000.

Flight testing

On 25 June 1954, the first prototype of the MD.550 Delta, without afterburning engines or rocket motor and with an unusually large vertical stabilizer, conducted its maiden flight. In this configuration, it was able to attain a maximum speed of Mach 1.15. Following initial flights, it received a redesign that involved the vertical stabilizer being reduced in size along with the installation of afterburners and a rocket motor; it was at this point that the aircraft was renamed as the Mirage I. In late 1954, the prototype attained a recorded speed of Mach 1.3 in level flight without rocket assistance, as well as reaching Mach 1.6 when using the rocket motor. According to aviation author John F. Brindley, testing of the Mirage I and prototypes of the rival Trident and Durandal designs had demonstrated the limitations of the light fighter concept, namely limitations on both endurance and equipment/payload capacity. The small size of the Mirage I restricted its armament to a single air-to-air missile, and it was decided during flight trials that the aircraft was too small for the carriage of a useful armament. Following the completion of flying trials, the Mirage I prototype was eventually scrapped.

Dassault was keen to produce a successor to the Mirage I prototype; at one point, the firm was considering the production of an enlarged version, known as the Mirage II, which would have been furnished with a pair of Turbomeca Gabizo turbojet engines. However, the Mirage II ultimately remained unbuilt as it was bypassed for an even more ambitious design, being 30 per cent heavier than the original Mirage I, powered by the newly developed Snecma Atar afterburning turbojet engine, capable of generating up to 43.2 kN (9,700 lbf) of thrust. The Atar was an axial-flow turbojet design, having been derived from the German Second World War-era BMW 003 engine. The new Atar-equipped fighter design received the name Mirage III. There was also an even larger heavy fighter design drafted, referred to as the Mirage IV. A decisive factor had been interest from the French military, who had made its favour for the Mirage III proposal known to the company.

The Mirage III was produced in large numbers for both the French Air Force and a wide number of export customers. Prominent overseas operators of the fighter included Argentina, Australia, South Africa, Pakistan and Israel, as well as a number of non-aligned nations. Often considered to be a second-generation fighter aircraft, the Mirage III experienced a lengthy service life with several of these operators; for some time, the type remained a fairly manoeuvrable aircraft and an effective opponent when engaged in close-range dogfighting. During its service with the French Air Force, the Mirage III was normally armed with assorted air-to-ground ordnance or R.550 Magic air-to-air missiles. Its design proved to be relatively versatile, allowing the fighter model to have been readily adapted to serve in a variety of roles, including trainer, reconnaissance and ground-attack versions, along with several more extensive derivatives of the aircraft, including the Dassault Mirage 5, Dassault Mirage IIIV and Atlas Cheetah. Some operators have undertaken extensive modification and upgrade programmes of their flights, such as Project ROSE of the Pakistan Air Force.

The Mirage III has been used in active combat roles in multiple conflicts by a number of operators. The Israeli Air Force was perhaps the most prolific operator of the fighter outside of France itself; Israel deployed their Mirage IIIs in both the Six-Day War, where it was used as both an air superiority and strike aircraft, and the Yom Kippur War, during which it was used exclusively in air-to-air combat in conjunction with the IAI Nesher, an Israeli-built derivative of the Mirage 5. Ace of aces Giora Epstein achieved all of his kills flying either the Mirage III or the Nesher. During the South African Border War, the Mirage III formed the bulk of the South African Air Force's fleet, comprising a cluster of Mirage IIICZ interceptors, Mirage IIIEZ fighter-bombers and Mirage IIIRZ reconnaissance fighters; following the introduction of the newer Mirage F1, the type was dedicated to secondary roles in the conflict, such as daytime interception, base security, reconnaissance and training. The Argentine Air Force used the Mirage IIIEA during the Falklands War, but their lack of an aerial refuelling capability limited the aircraft's usefulness in the conflict. Even using drop tanks, the Mirages only had an endurance of five minutes within the combat area around the British fleet.

Mirage IIIE

While the initial Mirage IIIC model was heading towards quantity production, Dassault turned its attention towards the development of a multirole/strike variant of the aircraft. Efforts in this direction would eventually materialized in the form of the single-seat Mirage IIIE; a two-seat trainer variant of the aircraft was also developed, designated as the Mirage IIID. On 5 April 1961, the first of a batch of three prototypes performed its first flight.

The Mirage IIIE considerably differed from the earlier Mirage IIIC interceptor. In terms of its airframe, the aircraft possessed a 300 mm (12 in) forward fuselage extension, which had been made to increase the size of the avionics bay, located directly behind the cockpit. The stretch had also enabled its fuel capacity to be expanded, which had been deemed necessary after several pilots had criticized the Mirage IIIC for having been quite limited in terms of its range.

Many Mirage IIIEs were fitted with a British-built Marconi continuous-wave Doppler navigation radar radome on the bottom of the fuselage, underneath the cockpit; in contrast, none of the Mirage IIICs were provided with this apparatus. A similar inconsistent variation was the presence or absence of a high frequency (HF) antenna fitted as a forward extension to the vertical tailplane; on some Mirages, the leading edge of the tailplane was a straight line, while on those with the HF antenna the leading edge had a sloping extension forward. The extension appears to have been generally standard on production Mirage IIIAs and Mirage IIICs, but only appeared in some of the Mirage IIIE's export versions. The Mirage IIIE featured Thomson-CSF Cyrano II dual mode air / ground radar; a radar warning receiver (RWR) system with the antennas mounted in the vertical tailplane; and an Atar 09C engine, the latter being equipped with a petal-style variable exhaust.

On 14 January 1964, the first production Mirage IIIE was delivered to the AdA, over time, 192 aircraft were eventually delivered to that service. By 1971, this variant had become the most widely exported version of the aircraft.

Mirage IIIR

A number of dedicated reconnaissance variants of the Mirage III were developed and produced, grouped under the general designation of Mirage IIIR. These aircraft possessed a Mirage IIIE airframe but were furnished with avionics from the Mirage IIIC variant, along with a purpose-developed camera nose, which internally accommodated up to five OMERA cameras. On this variant, the radar system was removed due to a lack of available space in the nose, however, the aircraft retained the twin DEFA cannons and all compatibility with its external stores. An improved variant, designated as the Mirage IIIRD, was also developed later on; it was essentially a Mirage IIIR outfitted with an extra panoramic camera at the most forward nose position, along with the adoption of the Doppler radar and other avionics from the Mirage IIIE, and provision for carrying an infrared linescan or a Side looking airborne radar in an under-fuselage pod.

In response to interest expressed by the AdA in a reconnaissance model of the Mirage design, Dassault proceeded with the development of a pair of prototypes. On 31 October 1961, the first of these prototypes conducted its maiden flight; on 1 February 1963, it was followed by the first production-standard aircraft of the model. The AdA opted to obtain a total of 50 production Mirage IIIRs; the service later ordered a further 20 Mirage IIIRDs as well. Several export customers, most notably Switzerland, also chose to procure reconnaissance Mirages. The Mirage IIIR preceded the Mirage IIIE in operational introduction.

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