Rafale - Development
Rafale emerged in 1985 following the French withdrawal from the European effort to launch a collaborative fighter program, which eventually produced the Eurofighter Typhoon. The French preferred a considerably lighter aircraft than envisioned by the other partners, in order to keep costs down, satisfy French navy requirements for a carrier-based fighter, and facilitate export sales. The French preferred a much lighter aircraft than the heavy long-range interceptor envisioned by the RAF.
The origins of the RAFALE can be traced to joint discussions between European nations taking place in the early eighties. But in the wake of the tri-national Tornado program which had put the most emphasis on air-to-surface functions, it soon appeared that the prime requirement of participating nations other than France was predominantly on the air-to-air side.
The French Forces wanted a balanced multi-role aircraft that would be able to replace 7 types of aircraft around 2000-2010 :
Two of the types to be replaced had to be carrier-based with all the resulting implications in terms of force projection capability: fast-deployed, self-supporting and lethal with limited size. This was the rational that eventually led to the decision by the French industry and Government to go it alone on RAFALE and provide it with distinctive features tuned to world-wide - opposed to strictly West European - market expectations.
The development of an aircraft under the theoretical designation of ACT (Avion de Combat Tactique—Tactical Combat Aircraft), and for the navy, ACM (Avion de Combat Marine—Naval Combat Aircraft), was planned for the 1990s. France's military had a problem with the decision to continue development of the naval version of the Rafale fighter, despite the French navy's preference for the US F/A-18 and soaring development costs. Rafale was developed in a stretched time-scale, and at a low rate of production, after a delayed entry into service, all dictated by financial constraints; technically, the program could have evolved much faster.
Dassault began an all-French program based on a scaled-down version of the Rafale A technology demonstrator, which first flew in July 1986. The Rafale technology demonstration prototype received its "A" designation only after the definition of the considerably smaller production version, which Dassault labelled Rafale D. The Rafale A [and BAE's EAP] reflect a philosophy of building and flight testing basic unequipped airframe prototypes before FSD. Although formally labeled technology demonstrators, both the Rafale A and EAP closely resemble traditional pre-full-scale development (FSD) austere airframe prototypes.
Mark A. Lorell at RAND noted in 1989 that "The sponsoring governments provided no guaranteed financial support for flight testing (in the case of the EAP) and absolutely no commitment to FSD, much less production. Both aircraft were financed on a shoestring and were bereft of virtually all major subsystems, avionics, and weapon systems. Furthermore, both prototypes benefited from incremental development of key technologies on earlier test-beds or prototypes. Small design teams with little government oversight or interference were permitted wide latitude to experiment with creative technical solutions, without the restrictions of detailed government specifications."
Prime Minister Jacques Chirac announced formal "approval of the development of a new fighter to be derived from the Rafale demonstrator" in February 1987. Throughout its history, Rafale generated far less political controversy than EF-2000 or Gripen. No highly publicized major technical snags arose to mar the development effort and fuel criticism of the program. Rafale has experienced some technical difficulties and schedule slippage, and its high costs have caused concern, but the R&D program was politically secure.
The French Air Force required a multi-role aircraft able to carry out ground strike missions as well as air superiority missions and even air defence missions. It must cover an extensive flight envelope, have a manewver capability with a flyinq comfort significantly higher than that of previous aircraft, be capable of operating from short runways. Its carrying capacity and its weapons system were to ensure a large operational efficiency, which will also be obtained from it. The French Navy required defence and air superiority aircraft to ensure the protection of its aircraft carriers and to carry out strike and rconnaissance missons. The maneuverability characteristics requested were very close to those of the French Air Force.
The design of the new family of combat aircraft results from an optimization process, which takes into account, at the utmost, the interaction between the various disciplines involved, such as aerodynamics, structure, propulsion, systems. The more and more ambitious targets, involved by the reqiirements, as well as the essential target of the best cost/efficiency ratio, have moreover required extensive progress in the new technologies which have tbeen included in the optimization process.
For more than 30 years Dassault Aviation had invested large efforts in the field of product modelling and simulation, as it has always been considered as an essential asset in the sustained competitiveness of the company. The best known offspring of this policy is the CATIA software initially developed by Dassault Aviation for its own needs, and now a world standard marketed by Dassault Systems.
A significant example of systematic resorting to simulation is given by the RAFALE program : the number of prototypes was drastically reduced to only 4, for an airplane in 3 different versions and due to replace 7 existing different aircraft of French Forces. The Rafale N version of Rafale twin seater for the French Navy was directly developed as a production aircraft. This is only possible by virtue of the quality of the modelisation, particularly the multidisciplinary modelisation of catapult launching and arrested landing.
Many preliminary studies were carried out, completed by wind tunnel tests. Several configurations adapted to the low speed targets were studied. For cost and simplicity reasons, the compromise his been orientated towards a delta-canard configuration. Performance in combat was studied for various aircraft configurations so as to determine the influence of the wing area, the aspect ratio, the thrust-to-weight ratio and thrust deflection devices or moving wing control surfaces. The delta-canard configuration proved to be superior. On the basis of this configuration, several other possible solutions could be studied concerning the position of the wings (high, medium, low), the position and number of fins (single fin, fuselage or wing double fin), the position of the air intakes and the type of protection.
It had become traditional within Dassault to manufacture at the beginning of the design process an entire full-scale layout mock-up. This mock-up becomes essential to fit out an aircraft of reduced size, using for the airframe a large part of new materials where retrofit is difficult and receiving a large number of equipment (operational or ancillary equipment), which are not on the shelf and thp overall size of which has not beer entirely defined. This mock-up facilitates study and solving more easily and sufficiently soon the problems of location of equipment and the problems of runninq the numerous related wiring and piping. But it also enables every one, and in particular the future operational users, to help along the design, so to consider the correct accessibility to the circuits and equipment.
In the RAFALE demonstration aircraft composite materials were used not only for the control surfaces (elevons, rudder, canard), and the wings - for which a new high modulus fibre was used for the very first time - but also for the fuselage front section (cockpit structure, equipment bay), central section (complete fuel tank) and rear section (below engine area). All landing gear doors as well as numerous access panels were made from composite material. The RAFALE demonstration aircraft also incorporated Aramid fibre for numerous elements such as wing-to-fuselage fillets, fairings and the nose radome. Altogether, composite materials accounted for over a fourth of the structure weight in the RAFALE demonstration aircraft.
The Rafale A first flew on 04 July 1986. This larger Rafale, designated "A," was sized to meet the EFA requirement. The Rafale A was a technology demonstrator with the additional task of optimizing the aerodynamic configuration for the full Rafale development program. It was the first French aircraft with full authority digital flight control system (FCS). Rafale A was powered by a completely different engine - the GE F404 - than the SNECMA M88 in development for the production version. It had no major subsystems, avionics, and weapon systems - other than the flight control system and man-machine cockpit interfaces-intended for use on the fully missionized and developed weapon system.
The scaled-down production version intended for the French Air Force, called Rafale D, was slightly smaller and about 2000 lb lighter empty but of identical shape and configuration. The main Rafale flight test program commenced in 1991 with the first flight of the Rafale C. This was followed by the Rafale M and B variants. The navalized Rafale first flew in December 1991. As of February 1994, Rafale prototypes had logged 1712 test flights. An additional 62 flights of the naval version were carried out in May 1994 during sea trials on the carrier Foch. The first flight of a production Rafale M took place in July 1999.
The Rafale and Eurofighter are comparable, at least in the general configuration (delta canard) and control technology (quadruplex fly-by-wire). The Rafale exceeded Mach 1 on the first flight, and attained Mach 1.8 on the third flight. The first flight of Eurofighter was delayed two years because of flight control system software concerns, and in the first flight the aircraft did not retract the undercarriage. Was Dassault cavalier in the first flights of Rafale, or were the Eurofighter partners too cautious?
The basic objective of the flight test development program was to gather data that enable the various models used in the design process to be adjusted where necessary and thus validated. A step by step approach was used such that functions were progressively added to the FCS at each software upgrade and assessed/validated in flight before the next major upgrade. The final proof of design of any control system is the demonstration of successful integration of the control system into the total vehicle of which it is a part.
By the year 2000 the development aircraft had been joined by instrumented production aircraft to cope with the aggressive schedule of flight testing (at the Istres Flight Test Center) and demos. Test highlights included the firing of active seeker Mica against twin targets in electronic warfare environment, and live GBU-12 firing at the Cazaux test range in southwestern France. The airframe (which has 80% commonality between all versions) has been certified to 9g with a demonstrated margin of 90% on top of that, after 10,000 hours of testing on the fatigue test rig - the cycles were typical of carrier-based operations with stress loads simulating catapult launches and arrested deck landings, more than will be endured by any land-based fighter. Separation trials of the Scalp missile were also been carried out as a risk reduction measure in anticipation of the final Scalp integration tests.
In a ceremony held in December 2000 at Landivisiau Naval Air Station, the French Navy accepted into service its first two Rafale M combat aircraft. This crucial event marks the beginning of an extensive fleet renewal programme encompassing the successive replacement of F-8E Crusader fighters, Etendard IVPM reconnaissance aircraft and Super Etendard strike fighters.
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