Dassault Mirage IV - Development - Proposed Export Variants

Proposed Export Variants

In 1963, the Australian government sought a replacement for the Royal Australian Air Force fleet of English Electric Canberra bombers, largely in response to the Indonesian Air Force's purchase of missile-armed Tupolev Tu-16 bombers. Dassault proposed a version of the Mirage IVA with Rolls-Royce Avon engines. Australian Air Marshall Frederick Scherger seriously considered purchase of the IVA in 1961 because it was considered proven hardware already in service (in contrast to the BAC TSR-2 still in development), before settling on the General Dynamics F-111C. The IVA was one of five aircraft types short listed but the General Dynamics F-111C was eventually selected.

In April 1965, the British Government cancelled the BAC TSR-2 reconnaissance-strike aircraft. In response, Dassault and the British Aircraft Corporation (BAC) proposed a modified Mirage IV variant as a replacement in July 1965. The aircraft, known as the Mirage IV* or Mirage IVS (S for Spey) was to use 2 of the more powerful Rolls-Royce Spey turbofan engines with a total of 41,700 lbs of thrust, was larger (fuselage depth increased by 3 inches, had an approximately 2 foot forward fuselage extension, and was to weigh 80,000 lb), and was to use avionics planned for the TSR-2, although British Aircraft Corporation preferred the French Antilope radar. Although it was to be designed by Dassault, the production was to carried out jointly between Dassault and its subcontractors (wing, mid-fuselage, and tail) and British Aircraft Corporation or BAC (front and rear fuselage); the final assembly location was not determined before this proposal was rejected. The Mirage IV* was to carry a bombload of up to 20,000 lb. While the IV* was claimed to meet most of the RAFs requirements, and to be £1 million cheaper than the American F-111, the F-111 was preferred (only to be cancelled in turn) and the Spey-engined Mirage abandoned.

The Mirage IV* met nearly every RAF requirement except for field length, and some claim it exceeded the F-111 slightly in speed and had at least equal range. The estimated cost was 2.321 million pounds per aircraft (for 50) or 2.067 million (for 110), less than the price of the F-111K. British Aircraft Corporation claimed that the British government evaluation into the Mirage IV* was "relatively superficial". However, some British government officials, including Parliament members Julian Risdale and Roy Jenkins, questioned the Mirage IV*'s capacity to operate from unprepared airstrips or to operate at low level, or claimed that the F-111 was a superior aircraft "in a class of its own". However, Gunston notes that low-level Mirage IV missions had been planned since 1963 and Mirage IVs operated regularly at low level since 1965, and argues that the ability of a strategic bomber to operate from unprepared airstrips is historically unimportant. Royal Air Force pilots who test-flew the Mirage IV were "favourably impressed" with its low level performance.

BAC and Dassault had also hoped to sell the Mirage IV* to France and to export the Mirage IV* to various nations, such as India, possibly Israel, and others; the lack of a British sale put an end to such possibilities. Some aviation journalists claim that the rejection of the Mirage IV* may have dampened French interest in joint Anglo-French cooperation.