Dassault Mirage IV

https://en.wikipedia.org/wiki/Dassault_Mirage_IV

The Dassault Mirage IV was a French jet-propelled supersonic strategic bomber
and deep-reconnaissance aircraft. Developed by Dassault Aviation, the aircraft
entered service with the French Air Force in October 1964. For many years it was
a vital part of the nuclear triad of the Force de Frappe, France's nuclear
deterrent striking force. The Mirage IV was retired from the nuclear strike role
in 1996, and the type was entirely retired from operational service in 2005.

During the 1960s, there were plans of export sales for the Mirage IV; in one
proposal, Dassault would have entered a partnership with the British Aircraft
Corporation to jointly produce a Mirage IV variant for the Royal Air Force and
potentially for other export customers, but this project did not come to
fruition. The Mirage IV was ultimately not adopted by any other operators beyond
the French Air Force.

Origins

During the 1950s, France embarked on an extensive military program to produce
nuclear weapons; however, it was acknowledged that existing French aircraft were
unsuitable for the task of delivering the weapons. Thus, the development of a
supersonic bomber designed to carry out the delivery mission started in 1956 as
a part of the wider development of France's independent nuclear deterrent. In
May 1956, the Guy Mollet government drew up a specification for an
aerially-refuelable supersonic bomber capable of carrying a 3-metric-ton,
5.2-metre-long nuclear bomb 2,000 km (without aerial refuelling). According to
aviation authors Bill Gunston and Peter Gilchrist, the specification's inclusion
of supersonic speed was "surprising" to many at the time.

The final specifications, jointly defined by government authorities and Dassault
staff, were approved on 20 March 1957. Sud Aviation and Nord Aviation both
submitted competing proposals, both based on existing aircraft; Sud Aviation
proposed the Super Vautour, a stretched Sud Aviation Vautour with 47 kilonewtons
(10,500 lbf) thrust Atar engines and a combat radius of 2,700 kilometres (1,700
mi) at Mach 0.9. Dassault's proposal for what became the Mirage IV was chosen on
the basis of lower cost and anticipated simpler development, being based upon a
proposed early 1956 twin-engined night-fighter derived from the Dassault Mirage
III fighter and the unbuilt Mirage II interceptor. In April 1957, Dassault were
informed that they had won the design competition.

Dassault's resulting prototype, dubbed Mirage IV 01, looked a lot like the
Mirage IIIA, even though it had double the wing surface, two engines instead of
one, and twice the unladen weight. The Mirage IV also carried three times more
internal fuel than the Mirage III. The aircraft's aerodynamic features were very
similar to the III's but required an entirely new structure and layout. This
prototype was 20 metres (67 ft) long, had a 11 metres (37 ft) wingspan, 62
square metres (670 sq ft) of wing area, and weighed approximately 25,000
kilograms (55,000 lb). It was considerably more advanced than the Mirage III,
incorporating new features such as machined and chem-milled planks, tapered
sheets, a small amount of titanium, and integral fuel tanks in many locations
including the leading portion of the tailfin.

The Mirage IV is powered by two Snecma Atar turbojets, fed by two air intakes on
either side of the fuselage that had intake half-cone shock diffusers, known as
souris ("mice"), which were moved forward as speed increased to trim the inlet
for the shock wave angle. It can reach high supersonic speeds: the aircraft is
redlined at Mach 2.2 at altitude because of airframe temperature restrictions,
although it is capable of higher speeds. While broadly similar to the model used
on the Mirage III, the Atar engine had a greater airflow and an elevated
overspeed limit from 8,400 rpm to 8,700 rpm for greater thrust during high
altitude supersonic flight. While the first Mirage IV prototype was fitted with
double-eyelid engine nozzles, production aircraft featured a complicated
variable geometry nozzle that automatically varied in response to the descent
rate and airspeed.

The aircraft has 14,000 litres (3,700 gal (US)) of internal fuel, and its
engines are quite thirsty, especially when the afterburner is active. Fuel was
contained within integral tanks within the wings, as well as a double-skinned
section of the fuselage between and outboard of the inlet ducts, underneath the
ducts and engines, and forward of the main spar of the tail fin; this provided a
total internal capacity of 6,400 kilograms (14,000 lb). A refueling probe is
built into the nose; aerial refuelling was often necessary in operations as the
Mirage IV only had the fuel capacity, even with external drop tanks, to reach
the Soviet Union's borders, thus refuelling was required to allow for a 'round
trip'. In the event of nuclear war between the major powers, it was thought that
there would be little point in having the fuel to return as the host air bases
would have been destroyed; instead, surviving Mirage IVs would have diverted to
land at bases in nearby neutral countries following the delivery of their
ordnance.

The two-man crew, pilot and navigator, were seated in tandem cockpits, each
housed under separate clamshell canopies. A bombing/navigation radar is housed
within an oblique-facing radome underneath the fuselage between the intakes and
aft of the cockpit; much of the Mirage IV's onboard avionics systems, such as
the radar communications, navigational instrumentation, and bombing equipment,
were produced by Thomson-CSF. Other avionics elements were provided by Dassault
itself and SFENA; one of the only major subsystems not of French origin onboard
was the Marconi-built AD.2300 doppler radar. Free-falling munitions could also
be aimed using a ventral blister-mounted periscope from the navigator's
position.



Role
Supersonic strategic bomber

National origin
France

Manufacturer
Dassault Aviation

First flight
17 June 1959

Introduction
1 October 1964

Retired
1996 all bomber variants
2005 all reconnaissance variants

Status
Retired

Primary user
French Air Force

Produced
1963–1968

Number built
62 + 4 prototypes

Developed from
Dassault Mirage III

The primary objectives of the Mirage IVA force were major Soviet cities and
bases. With aerial refueling], the plane was able to attack Moscow, Murmansk or
various Ukrainian cities when sortieing from French bases. A justification of
the Mirage IV given by Armée de l'air Brigadier General Pierre Marie Gallois, an
architect of the French nuclear deterrent, was that: "France is not a prize
worthy of ten Russian cities".

In order to refuel the Mirage IVA fleet, France purchased 14 (12 plus 2 spares)
U.S. Boeing C-135F tankers. Mirage IVAs also often operated in pairs, with one
aircraft carrying a weapon and the other carrying fuel tanks and a buddy
refueling pack, allowing it to refuel its partner en route to the target. Even
so, some sources state that some of the mission profiles envisioned were
actually one-way, with the crew having no chance of returning after bombing a
Soviet city. The inability for the Mirage IV to return after missions had been a
point of controversy during the aircraft's early development.

Both flight and grounds crews received training principally by Strategic Air
Forces Command 328, stationed at Bordeaux. Several Nord Noratlas were specially
modified, having received the Mirage IV's radar, control consoles, and
additional electrical generators, for the purpose of training navigators; these
were later replaced by a pair of customised Dassault Falcon 20 outfitted with
much of the Mirage IVP's avionics.

Phase-Out

On 31 July 1996, the Mirage IVP was formally retired in its bomber capacity, the
nuclear mission having been transferred from the Mirage IV to the newer Dassault
Mirage 2000N. EB 2/91 was disbanded and EB 1/91 was redesignated Escadron de
Reconnaissance Stratégique (Strategic Reconnaissance Squadron), using five
remaining Mirage IVPs based at Mont-de-Marsan; the remaining aircraft were
stored at Chateaudun. In the reconnaissance role, the Mirage IVP has seen
service over Bosnia, Iraq, Kosovo and Afghanistan.

ES 1/91 Gascogne's surviving Mirage IVPs were retired in 2005 and are conserved
and stored at the Centre d'Instruction Forces Aériennes Stratégiques (CIFAS) at
Bordeaux Mérignac. The retirement of all reconnaissance-configured Mirage IVPs
in 2005 meant that the French Air Force's Mirage F1CRs were for some time the
only aircraft capable of carrying out aerial reconnaissance missions. The long
term replacement for the Mirage IVP was Mirage 2000N aircraft outfitted with a
modern PRNG Pod de Reconnaissance Nouvelle Génération (New Generation
Reconnaissance Pod), equipped with digital camera equipment.

The Mirage IV had been popular with its crews, who found it enjoyable to fly. In
addition, it required surprisingly little maintenance considering its age and
complexity.

Specifications (Mirage IVA)

General characteristics
Crew: 2 (pilot & navigator/bombardier)
Length: 23.49 m (77 ft 1 in)
Wingspan: 11.85 m (38 ft 11 in)
Height: 5.4 m (17 ft 9 in)
Wing area: 78 m2 (840 sq ft)
Airfoil: root: 3.8%; tip: 3.2%
Empty weight: 14,500 kg (31,967 lb)
Gross weight: 31,600 kg (69,666 lb)
Max takeoff weight: 33,475 kg (73,800 lb)
Powerplant: 2 × SNECMA Atar 9K-50 afterburning turbojet engines, 49.03 kN
(11,020 lbf) thrust each dry, 70.61 kN (15,870 lbf) with afterburner

Performance
Maximum speed: 2,340 km/h (1,450 mph, 1,260 kn) at 13,125 m (43,061 ft)
Maximum speed: Mach 2.2
Combat range: 1,240 km (770 mi, 670 nmi)
Ferry range: 4,000 km (2,500 mi, 2,200 nmi)
Service ceiling: 20,000 m (66,000 ft)
Time to altitude: 11,000 m (36,089 ft) in 4 min 15 sec

Armament

Bombs:

1× AN-11 free-fall nuclear bomb or
1× AN-22 free-fall nuclear bomb or
1× Air-Sol Moyenne Portée nuclear missile (Mirage IVP)
16× 454 kg (1,000 lb) free-fall conventional bombs

Avionics

Thomson-CSF navigation radar
Doppler navigation
CT-52 sensor pod for strategic reconnaissance



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