Dassault MYSTERE IV
Last Revised: May 1, 2003
The "Mystere IV" was essentially a new design, a rethinking of the Mystere II rather than a modification of it. The first prototype was flown in September 1952, and was powered by a Hispano-built Rolls-Royce Tay 250 turbojet, as were the early Mystere IIA prototypes.
While it also featured the twin 30-millimeter DEFA cannon adopted for the Mystere II, the Mystere IV had a new and more robust oval-section fuselage, a thinner wing with greater sweep, and new tail surfaces. The result resembled the Mystere IIC in a general way but had cleaner lines, more in the class of the US F-86 Sabre.
There was apparently only one prototype, leading to a production contract for 225 Mystere IVAs for the Armee de l'Air. Interestingly enough, this batch of aircraft was purchased for the French by the United States as part of the NATO Military Assistance Program, though the French would purchase 100 more Mystere IVAs with their own funds.
The first production Mystere IVA flew in late May 1954, and the type entered service with the Armee de l'Air the next year, being initially deployed as an interceptor. It would also be used as ground-attack fighter in French service.
The first 50 production aircraft used the Tay 250 engine, but all following production was fitted with an uprated Tay, the Hispano-built Verdon 350, with 34.3 kN (3,500 kgp / 7,715 lbf) thrust.
The Mystere IVA had four stores pylons, with a total load capacity of 900 kilograms (2,000 pounds) of underwing stores. It appears that in typical flight configurations, two of the pylons were fitted with drop tanks while two others carried bombs or Matra 68-millimeter unguided rocket packs. As with many early jet aircraft, the Mystere IVA's range without drop tanks was pathetic.
The Mystere IVA remained in first-line service with the Armee de l'Air until the early 1960s, when it was replaced by the Mirage IIIC. It remained in service in the ground-attack role until 1975, when replaced by the SEPECAT Jaguar, and as an operational trainer until 1980, when it was replaced by the Dassault-Dornier Alpha Jet.
60 of the Verdon-powered Mystere IVAs that were ordered by the French ended up being sold to Israel, with the first batch of 24 arriving April 1956, just in time for the war over Suez in October. In the hands of skilled IAF pilots, they proved themselves more than a match for Egyptian MiG-15s. French Mystere IVAs also participated in the October 1956 war, operating from Israeli bases with an Israeli squadron number, and French pilots would also fly some of the Israeli Mystere IVAs during that war.
The remaining 36 Mystere Ivs in the batch were shipped to Israel after the 1956 war. Two squadrons of Mystere IVAs were still in Israeli service in the Six-Day War in 1967.
The Indian Air Force also bought 110 Verdon-powered Mystere IVAs. These were all new-production aircraft. First delivery was in 1957. The type was used in the close-support role during the 1965 Indo-Pakistan war, and like its ancestor, the Ouragan, proved robust and able to absorb punishment.
The Mystere series continued to evolve, with an improved "Mystere IVB" developed to take advantage of the new afterburning engines. The Mystere IVB was almost a new aircraft, with a new fuselage and redesigned vertical stabilizer, and also featured a radar gunsight similar to that used on the F-86 in the upper lip of the intake.
The first prototype flew in December 1953, and was powered by an afterburning Rolls-Royce Avon RA.7R axial-flow turbojet, with a maximum afterburning thrust of 42.5 kN (4,330 kgp / 9,550 lbf). Another Avon-powered prototype flew in June 1954, while a third prototype, powered by the Atar 101F (which, as mentioned, was fitted experimentally to two pre-production Mystere IICs), flew in March 1955.
Seven pre-production Mirage IVB aircraft were also completed. The first two were fitted with a SEPR 66 bi-fuel rocket motor to provide boost thrust, and the last two were powered by the afterburning Atar 101G-2 turbojet with 44.1 kN (4,500 kg / 9,920 lbf) afterburning thrust.
The Mystere IVB was promising, but Dassault was already working on an even better aircraft, the Super Mystere, and so the Mystere IVB did not enter production.
As mentioned previously, a single night-fighter version of the Mystere IVB, the "Mystere IVN", was completed and flew in 1954. The prototype was powered by an Avon RA.7R, and was stretched 1.4 meters (4 feet 7 inches) to accommodate two tandem seats and additional fuel. It was to be fitted with US-built AN/APG-33 air-intercept radar in a nose radome above the intake, giving it a certain resemblance to the US F-86D "Sabre Dog" interceptor.
It had two 30-millimeter DEFA cannon, and like the F-86D had a retractable tray for unguided air-to-air rockets, in this case accommodating 55 68-millimeter rockets. Some sources claim that this tray was optionally fitted to the standard Mystere IVA, but if so it appears to have been little used.
The project went nowhere because of problems with the radar and the limited endurance of the aircraft. The French were also developing another night fighter that seemed more promising, the "Sud-Ouest Vautour IIN", and the Mystere IVN was cancelled.
