Dassault Mirage IV

Dassault Aviation
Industry	Aerospace, Defense
Founded	April 22, 1929; 97 years ago in France
Founder	Marcel Dassault
Headquarters	Saint-Cloud, France
Products	Military aircraft, including Mirage IV strategic bomber
Website	www.dassault-aviation.com

The Dassault Mirage IV represents a French supersonic strategic bomber and long-range reconnaissance aircraft developed by Dassault Aviation. It was introduced into service with the French Air Force in October 1964, playing a crucial role within France's nuclear deterrence force, known as the Force de Frappe. The Mirage IV ceased its nuclear strike mission in 1996 and was fully retired from operational use by 2005.

During the 1960s, Dassault pursued international sales opportunities, including a proposed collaboration with the British Aircraft Corporation to create a variant for the Royal Air Force, though these export plans did not come to fruition.

Origins

In the 1950s, France launched a military initiative to develop nuclear armaments and required a supersonic bomber capable of delivering such weapons. Existing French aircraft were insufficient for this purpose. In May 1956, the government outlined requirements for a supersonic bomber with aerial refueling capability, able to carry a 3-ton nuclear payload over 2,000 km without refueling. Achieving sustained supersonic speeds was particularly ambitious at that time.

The final specifications were ratified on 20 March 1957. Among competitors was Sud Aviation’s Super Vautour, but Dassault’s design, an enlarged twin-engine evolution of the Mirage III, was chosen due to its lower cost and simpler development process. Dassault secured the contract in April 1957.

The prototype Mirage IV 01 shared similarities with the Mirage IIIA but incorporated twice the wing area, two engines, triple the internal fuel capacity, and featured a novel structural design. Its length measured , with a wingspan of , and it had an approximate weight of . Advanced production methods included machined and chemically milled parts alongside titanium components.

Constructed over an 18-month period at Dassault’s Saint-Cloud facility, the prototype addressed challenges associated with sustained Mach 1.8+ flight and integration of weapon systems. Following ground trials at Melun-Villaroche, it conducted its maiden flight on 17 June 1959 piloted by General Roland Glavany.

On 19 September 1960, pilot René Bigand established a world speed record over a 1000 km circuit at 1,822 km/h (1,132 mph). Shortly after, on 23 September, another record was set over a 500 km circuit with an average speed of 1,972 km/h (1,225 mph), reaching speeds between Mach 2.08 and Mach 2.14. Testing included minor adjustments such as enlarging the tail to enhance stability.

Production

Efforts to extend operational range led to examination of a larger Mirage IVB variant equipped with two Snecma license-produced Pratt & Whitney J75 engines, featuring a wing area of 120 m² (1,290 sq ft) compared to the prototype’s 70 m² (750 sq ft), capable of Mach 2.4 speeds and a maximum takeoff weight of . This design aimed to fulfill President de Gaulle’s preference for two-way strike capabilities but was discontinued in July 1959 due to excessive costs and dependence on aerial refueling.

Instead, production focused on the medium-sized Mirage IVA, which was slightly larger than the prototype with an 839 sq ft (78 m²) wing area and approximately weight. A formal order for 50 Mirage IVA units was placed on 4 April 1960. Three prototypes were constructed between 1961 and 1963 to conduct initial test flights and simulated nuclear bombing runs by 1962. The fourth prototype reflected production standards.

Manufacturing subcontractors included Sud Aviation for wings and rear fuselage sections and Breguet Aviation for the tailfin assembly, while Dassault internally managed front fuselage construction and flight control systems. Production encountered difficulties due to France’s policy of excluding foreign suppliers to safeguard nuclear program autonomy; notably, the Mirage IV initially lacked an inertial navigation system because domestic technology had yet to mature.

The first production-standard Mirage IVA took flight on 7 December 1963, with a total of 62 units delivered between 1964 and 1968. Dassault designed the Mirage IV from inception for low-level flight operations; accordingly, the last batch of twelve aircraft ordered in November 1964 incorporated upgraded flight control systems, avionics improvements, and structural reinforcements to enhance low-altitude performance. These enhancements were subsequently retrofitted across existing aircraft.

In December 1963, Dassault introduced plans for the Mirage IV-106 variant featuring two Snecma TF106 turbofan engines, an expanded fuselage yielding a gross weight of approximately , terrain-following radar capabilities, and armament options including a French adaptation of the Douglas GAM-87 Skybolt air-launched ballistic missile. This advanced but costly model never proceeded to production.

Export proposals

In 1963, Australia began searching for a successor to its Royal Australian Air Force English Electric Canberra bombers after the Indonesian Air Force introduced missile-equipped Tupolev Tu-16 bombers. Dassault suggested a Mirage IVA variant powered by Rolls-Royce Avon engines. Australian Air Marshal Frederick Scherger had evaluated the IVA in 1961 due to its established operational history, but ultimately the General Dynamics F-111C was chosen over the IVA and other alternatives.

After the British TSR-2 program was canceled in 1965, Hawker Siddeley proposed the Buccaneer S.2, the United States offered the F-111K, and Dassault in collaboration with BAC put forward the Mirage IV* or Mirage IVS (with "S" denoting Spey engines). This model featured more powerful Rolls-Royce Spey turbofan engines delivering total thrust of , a fuselage deepened by , an approximate forward extension of , and a maximum weight of . It incorporated avionics originally intended for the TSR-2, although BAC preferred to use the French Antilope radar system. Production was planned to be shared between Dassault and BAC, but the final assembly site had not been decided before the project was rejected. The Mirage IV* was designed to carry up to of bombs.

Reportedly, the Mirage IV* fulfilled most Royal Air Force requirements except for runway length and was said to slightly surpass the F-111's speed while offering a comparable range. Cost estimates were £2.321 million per aircraft for an order of 50 units or £2.067 million per unit for 110 aircraft, making it less expensive than the F-111K. However, RAF assessments indicated necessary modifications for improved low-level performance, including airframe reinforcement and updated cockpit glazing to enhance visibility. Despite lengthening the fuselage, range deficiencies remained. BAC criticized the British evaluation as "relatively superficial," whereas RAF pilots commended its handling at low altitudes. Some UK officials doubted its ability to operate from unprepared airstrips and regarded the F-111 as superior in that respect. Bill Gunston pointed out that low-level missions had been planned since 1963 and regularly conducted from 1965 onward, arguing that operating from rough fields was not essential for strategic bombers.

Ultimately, a combination of political and technical considerations resulted in favoring the F-111K (which was later canceled) and abandoning the Spey-powered Mirage IV* project.

BAC and Dassault had intended to market the Mirage IV* both domestically and internationally to countries such as India and potentially Israel. The absence of a British order effectively terminated these export possibilities. Some analysts believe this rejection dampened French enthusiasm for Anglo-French aerospace collaboration.

Design

The Mirage IV shares many design elements and visual similarities with the Mirage III fighter, featuring a tailless delta wing configuration and a single vertical fin with a squared-off top. However, its wing is considerably thinner to optimize high-speed performance, possessing a thickness-to-chord ratio of only 3.8% at the root and 3.2% at the tip—among Europe’s thinnest at that time. Although smaller than medium bombers proposed for similar roles, the Mirage IV weighed approximately three times as much as the Mirage III.

It is powered by two Snecma Atar turbojet engines equipped with intake half-cone shock diffusers ("souris") that adjust according to speed, enabling supersonic flight up to Mach 2.2 at altitude, limited by airframe temperature constraints. The Atar engines feature enhanced airflow and overspeed capabilities (up to 8,700 rpm) to provide increased thrust during high-altitude supersonic operation. Production models incorporated variable geometry nozzles that automatically adjusted based on descent rate and airspeed.

With an internal fuel capacity of 14,000 litres (3,700 US gallons) stored in integral wing tanks and fuselage compartments, the Mirage IV’s range was limited without aerial refueling. A built-in refueling probe facilitated in-flight refueling—crucial for missions reaching Soviet borders given its fuel consumption and afterburner usage. In nuclear conflict scenarios, surviving aircraft were expected to divert to neutral airfields rather than return to potentially destroyed home bases.

The crew comprised two members seated in tandem cockpits under separate clamshell canopies. Avionics—including bombing and navigation radar housed within an oblique radome beneath the fuselage—were primarily supplied by Thomson-CSF, Dassault, and SFENA; one key component was the Marconi-built AD.2300 doppler radar. A ventral periscope enabled bomb aiming from the navigator’s station.

Each wing featured two pylons: inner pylons typically carried large 2,500-litre drop tanks; outer pylons were fitted with ECM pods along with chaff/flare dispensers supplementing internal jamming systems. Later variants incorporated Barax NG jammer pods and BOZ expendable countermeasure dispensers. No cannon armament was installed on this aircraft type. Early Mirage IVA models included a fuselage recess beneath the engines designed to carry a single AN-11 or AN-22 nuclear bomb (yielding approximately 60 kt). Additionally, twelve solid-fuel rockets could be mounted for rocket-assisted takeoff (RATO).

Beginning in 1972, twelve aircraft were converted into Mirage IVR reconnaissance versions equipped with CT52 pods containing either low- or high-altitude camera systems or infrared line scanners; these systems relied on older wet-film technology. The CT52 pods saw operational deployment during missions in Chad in September 1974.

During the 1980s, eighteen Mirage IVs were upgraded with centerline pylons and associated equipment enabling carriage of the nuclear Air-Sol Moyenne Portée (ASMP) stand-off missile. While theoretically capable of carrying up to six large conventional bombs by sacrificing drop tanks and ECM pods, such configurations were seldom utilized.

Introduction and early operations

The French Air Force began receiving Mirage IV aircraft in February 1964, achieving operational status for the first squadron by 1 October that year. Ultimately, the bomber fleet expanded to nine squadrons, each consisting of four aircraft paired to operate with one carrying a nuclear weapon and the other serving as a buddy refueling tanker. These squadrons were organized into three wings stationed at separate airbases to reduce vulnerability during strikes. The units were:

Following the establishment of an autonomous nuclear deterrent force known as the Force de Dissuassion or Force de frappe, France exited NATO's integrated military command structure in 1966. President De Gaulle regarded the Mirage IV fleet as essential to maintaining national sovereignty and an independent nuclear deterrent. From 1964 until 1971, the Mirage IV stood as France’s exclusive nuclear delivery platform, each aircraft equipped with a 60-kiloton warhead.

The alert roster maintained 36 Mirage IVs: twelve airborne, twelve on immediate four-minute ground alert, and twelve on a 45-minute standby, all armed with operational nuclear devices. These were supplemented by 26 reserve planes kept ready for deployment. Within its first ten years, the fleet amassed over 200,000 flight hours and performed roughly 40,000 aerial refueling operations—activities that accounted for nearly 44% of the French Air Force’s spare parts consumption.

The Mirage IVA was tasked with striking key Soviet urban centers and military installations; its aerial refueling capability enabled missions targeting Moscow, Murmansk, and cities in Ukraine from French territory. Brigadier General Pierre Marie Gallois of the Armée de l'air encapsulated its strategic concept: "France is not a prize worthy of ten Russian cities."

To facilitate these refueling operations, France acquired fourteen Boeing C-135F tankers from the United States. Typically, Mirage IVAs operated in pairs: one bomber armed with nuclear ordnance escorted by a tanker-equipped companion providing mid-air refueling support. Some mission profiles reportedly involved one-way sorties without plans for crew return—a contentious aspect during development.

Training responsibilities for both flight and ground personnel were centralized under Strategic Air Forces Command 328 in Bordeaux. Initially, modified Nord Noratlas aircraft outfitted with Mirage IV avionics served navigator instruction needs; these were eventually replaced by specially adapted Dassault Falcon 20 jets featuring advanced avionics from the Mirage IVP variant.

Transition and upgrades

At first, the Mirage IV executed high-altitude attack runs at speeds near Mach 1.85, engaging targets up to approximately 3,500 kilometers away. By the late 1960s, growing surface-to-air missile threats necessitated adaptations for low-level penetration tactics, resulting in reduced top speed to around 1,100 km/h and diminished combat radius. By 1963 most missions were planned for low-altitude flight profiles. By 1964, training flights routinely occurred at altitudes near 200 feet without terrain-following radar assistance, increasing pilot workload and exposure to atmospheric turbulence.

To improve survivability against potential strikes, the French Air Force dispersed its Mirage IVs across austere airstrips during the 1960s; constructing hardened shelters was deemed cost-prohibitive. By the following decade, vulnerability to advanced air defenses rendered delivery of gravity bombs such as the AN-11 or AN-22 impractical. Consequently, France shifted strategic emphasis toward land-based S2 missile systems and submarine-launched M2 ballistic missiles. This transition led to the deactivation of one Mirage IV wing in 1976 due to attrition.

In 1973 plans called for maintaining a force of forty Mirage IVs as France’s primary nuclear deterrent into the 1980s with ongoing modernization efforts. By 1975 all aircraft adopted a green and grey camouflage scheme. In response to declining effectiveness of free-fall nuclear bombs, development commenced in 1979 on the ASMP stand-off missile—capable of ranges up to 400 kilometers and equipped with either a 150 or 300 kiloton warhead. Test firings from Mirage IV platforms took place between 1981 and 1983.

A contract awarded in July 1984 upgraded eighteen Mirage IVA aircraft to carry ASMP missiles; these modified versions were designated Mirage IVP (Penetration). Enhancements included installation of a deep centerline pylon capable of mounting either the ASMP missile or CT52 reconnaissance pod, replacement of radar and electronic systems with modernized equipment, along with updates to navigation instruments, flight controls, and cockpit ergonomics. The inaugural Mirage IVP flew in October 1982 and returned to active service by May 1986.

In August 1985 France proposed deploying Mirage IVPs at bases within West Germany—a notable shift in nuclear posture policy. Nevertheless, French authorities historically regarded basing nuclear aircraft on allied soil as risky due to concerns over possible hostility following an attack.

Phase-Out

The Mirage IVP officially concluded its bomber service on 31 July 1996, with the nuclear strike responsibility shifting to the more advanced Dassault Mirage 2000N. Following this transition, EB 2/91 was dissolved, while EB 1/91 was rebranded as ERS 1/91 (Escadron de Reconnaissance Stratégique), continuing operations with the remaining five Mirage IVPs stationed at Mont-de-Marsan. Additional units were placed in storage at Chateaudun. In its reconnaissance capacity, the Mirage IVP was deployed over conflict zones including Bosnia, Iraq, Kosovo, and Afghanistan.

The last Mirage IVPs of ES 1/91 Gascogne were withdrawn from active duty in 2005 and are now preserved at the Centre d'Instruction Forces Aériennes Stratégiques (CIFAS) located in Bordeaux Mérignac. After their retirement, the French Air Force relied temporarily on the Mirage F1CRs as their sole aerial reconnaissance platform. The long-term successor is the Mirage 2000N outfitted with a cutting-edge PRNG Pod de Reconnaissance Nouvelle Génération (New Generation Reconnaissance Pod), which incorporates advanced digital imaging technology.

Aircrews appreciated the Mirage IV for its pleasant flight characteristics and relatively modest maintenance demands, especially considering its age and technical sophistication.

Operators

French Air Force

Mirage IV A

Mirage IV A s/n:2-AB exhibited at the Musée de l'air et de l'espace Paris-Le Bourget
Mirage IV A s/n:4-AC located at Rochefort airbase
Mirage IV A s/n:6-AG displayed in Savigny-les-Beaune
Mirage IV A s/n:9-AH preserved at the Musée de l'Air et de l'Espace, Paris-Le Bourget; notable for having deployed live nuclear ordnance during the Tamouré series
Mirage IV A s/n:16-AO stationed at St Dizier airbase
Mirage IV A s/n:18-AQ part of the collection at Savigny-les-Beaune Museum
Mirage IV A s/n:31-BC displayed at Musée Européen de l'Aviation de Chasse
Mirage IV A s/n:32-BE exhibited at Orange airbase
Mirage IV A s/n:43-BP on display at Mont-de-Marsan Air Base
Mirage IV A s/n:45-BR, previously shown at the Paris Science Museum, transferred to the Yorkshire Air Museum in 2016; arrived March 2017

Mirage IV P

Mirage IV P 1 "AP" showcased at Châteaudun Air Base within the CANOPEE Museum
Mirage IV P 11-AJ positioned at Bordeaux airbase
Mirage IV P 23-AV located at Cazaux airbase
Mirage IV P 25-AX part of Musée de l'Epopée et de l'Industrie Aéronautique's collection
Mirage IV P 26-AY exhibited by Ailes Anciennes Toulouse
Mirage IV P 28-BA displayed at Musée de l'Aviation Clément Ader
Mirage IV P 29-BB presented at Avord airbase in flight stance with retracted landing gear and support attached to engine nozzle
Mirage IV P 36 "BI" on display at Istres airbase
Mirage IV P 59 "CF" exhibited at Creil airbase
Mirage IV P 61 "CH" part of St Dizier Aero retro Museum's collection
Mirage IV P 62 "CI" preserved at Musée de l'Air et de l'Espace, Paris-Le Bourget

External links

Mirage IV information and photos by Yves Fauconnier (French)
Mirage IV data from former Forces Aériennes Stratégiques website (French)
AirForceWorld.com Mirage IV bomber page (English)