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Aviation History
1967
1967 - 0114.PDF
112 FLIGHT International, 26 January (957 ANGLO-FRENCH PROJECTS GO AHEAD . .. 2-THE AFVG AND ITS DUAL ROLE The Anglo-French variable-geometry aircraft, described in last year's Defence White Paper as "operationally and industrially the core of our long-term aircraft programme," has a dual role to fulfil in which the British requirement is for strike per- formance with interception as a secondary task. The V-bomber force, comprising about 180 Victors and Vulcans (including tankers) at present, will remain in service until at least 1975 (replacing, to some extent, the Canberra). By that time their role will have been taken over by the 50 F-lllKs which will start to enter service in 1969-70, under- taking the very-long-range strike and reconnaissance tasks. But 50 aircraft will be very thinly spread even in this limited (and mainly east of Suez) role, and the hope is that the AFVG will be capable of undertaking about 80 per cent of the F-lllK's missions. It will be very much smaller—less than 50,0001b— but, being a second-generation-technology aircraft, and having in particular what will probably be the most advanced turbo- fan engine in the world, its much greater efficiency will com- pensate for its smaller size. The current sitrike fighter in the RAF is the Hunter FGA.9. This will be replaced entirely, from 1969-1970 onwards, by a mixture of F-4K Phantoms and P.I 127s, with the latter oper- ating under the "air-superiority" umbrella of the former in the close-support role. From about 1975 the Jaguar "S" will have completely taken over the close-support role from the Phantom, leaving the latter increasingly to supplement and eventually replace the Lightning as the standard intercepted. The Jaguar will also replace the Gnat in the (training role, and a large percentage of Britain's "B"-version Jaguars will be so employed. The AFVG aircraft, of which about 175 will be acquired by Great Britain, will be introduced into RAF service in about 1974. At that time they will complement the F-111K in strike and reconnaissance missions not requiring such long range (up to about 1,000-mile radius). The striking force of the RAF will subsequently comprise four squadrons of F-lllKs, ten squadrons of AFVGs and ten Phantom squad- rons, together with about five Jaguar squadrons. Eventually, the AFVG is expected to replace the Phantom in the inter- cepter role, thus duplicating the Phantom's change of role from strike to Antercepter. It is probable that the British Government will keep the level of F-lllKs constant at about 50 by the purchase from time to time of additional aircraft to balance wastage. With the demise of the carrier force in about 1975, there are no plans to procure any AFVGs for the Royal Navy. The role of the v-g aircraft in the French armed Services has been defined as that of an initercepter fighter for the Air Force. Because of French financial difficulties, it will be taken later than was originally planned, with first deliveries prob- ably in 1976. The idea of an interim aircraft type to replace the Mirage HIE intercepter has found favour with the French Air Force; this would almost certainly be the Mirage F.I or F.2. A number of AFVGs will also be supplied to the French Navy, probably for carrier air-patrol work. The operational similarity between the F-lll and the AFVG is striking; the F-111A strike fighter forthe USAF, and the carrier air-patrol F-I11B for the USN, have their counterparts in the RAF and French Navy versions of the AFVG, bearing witness to the flexibility of the variable-geometry wing, and perhaps, too, of lessons to be learned from the F-lll's weight growth. The French Navy aircraft will be operated from the two strike carriers Foch and Clemenceau, and will probably replace the Crusaders now in service (it is probable also that an "M" version of Jaguar will be used for French Navy carrier-borne strike operations). The AFVG gross weight of 40,0001b which has been mentioned clearly depends on the deck strength, lift and catapults (British) of these carriers; with a lot of develop- ment ahead of the aircraft, it would be surprising if the French Navy did not have plans for taking advantage of weight and performance growth, which is bound to occur, by suitable carrier modifications. Power for the AFVG will be supplied by two Soecma Bristol Siddeley M45G-10 engines understood to have a by- pass ratio of about 3:1, a pressure-ratio of about 24:1, and a thrust of 7,0001b—or 12,0001b with an infinitely variable reheat system. Datum weight of the aircraft is about 40,0001b. This is applicable to the French carrier-landing version and can no doubt be increased for runway operation—the landing-gear stressing necessary for deck landing at this weight would allow land operation at up to 50,0001b. Operation from semi-pre- pared surfaces is specified. The thrust:weight ratio of the AFVG at 40,0001b will be somewhat greater than that of the F-111B, thus conferring a shorter timento-height in the inter- oepter role. No dimensions have been announced, but the gross weigh: of the aircraft (and the fact that it will use deck lifts measur- ing 52.5ft X 36ft on the two French carriers) gives some idea of its size. If the structure is as "dense" as that of the Phantom (and for the same reason—strength to meet deck- landing and ground^attack/manoeuvre requirements) then a span of about 33ft (fully swept) or 47ft (unswept), and a length of about 45ft, are suggested as the minimum necessary to carry two crew, two engines and a fairly comprehensive nav/attack system over a radius of about 1,000 n.m. in the high-altitude reconnaissance role. Our artist's impression shows how the aeroplane might look in its two forms: as an RAF strike bomber with unswept wings, carrying two Mairtel air-to-surface missiles; and as a French intercepter with fully swept wings and mounting two Matra R.530 air-to-air missiles. All these stores will be mounted on swivelling pylons, a la F-lll. Maximum speed will be about Mach 2.4, limited by kinetic heating at critical places in the conventional aluminium-alloy airframe. The strike and intercepter versions will probably differ only in their equipment and, unlike the F-111A and F-111B variants, will almost certainly have identical airframes, The relatively low unit price of about £1.5 million arises, at least in part, because the British electronics equipment will comprise mainly off-the-shelf items. This is an importanrt factor when avionics costs are much less predictable than airframe costs, and will go some way to retrieve the R&D expenditure on the TSR.2 avionics which, it is to be hoped, will find some place in the new aircraft. The British avionics will. probably include an inertial plat- form, small digital navigation/bombing computer (such as th: Elliott MCS-900M or Ferranti Argus), lightweight terrain- following or terrain-clearance radar and, in the reconnaissance role, the EMI pack developed for the RAF Phantoms. Bui the unusual cost-sensitivity which both Britain and France are showing in this programme will almost certainly mean that no major weapon or avionics project which cannot be spread over other aircraft is likely to be started. Cost control has probably absorbed more time than any- thing else on the Anglo-French agenda to date, and has verv nearly brought the programme to an end as a co-operative venture. Total costs may be very great indeed, and it is doubt- ful whether the two Governments will obtain a fixed- price quotation—as they have for Jaguar—for the design and construction of prototypes. Probably the closest estimate for the cost of development, including the very advanced engine but excluding avionics, would be £110 million per country. If, eventually, interception becomes the main RAF require- ment, then a change of avionics and weapons would be re- quired. The British Government has ordered the America" Sparrow III air-to-air missile for the Phantom, and does no' appear likely to embark alone on the development of advanced air-to-air missile for AFVG. The interception radar will therefore probably remain American (although an alter- native would be to use French radars and missiles).
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