Rafale --- Files of ATFX Aerodynamic and FighterJets - http://atfx.org

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Rafale

Why the RAFALE?

A modern Air Force must have a lead over the moment. To appreciate the future evolution of the strategic situations, to imagine the systems of weapons likely to provide the capacities required by this evolution, to aim at the technical quality adapted so that will be able to make aviations of allied or the adversaries, such are the constant duties of a staff charged to get in permanence with the country the military tool of a policy of defense. The staff thus has always, in theory, a project of future fighter. But there are soft evolutions and sometimes ruptures. There are technical jumps which it should be crossed if one wants to remain in the race. There are also discontinuities in the adequacy of the costs to the possible budgets. Sometimes the jump technical, necessary to the effectiveness, generates a too brutal raising of prices so that the public opinion can adhere: the citizen is always persuaded to pay dimpôts too much and, in the absence of a pressing threat, finds always excessive the price of Defense.

Dassault Aviation, obviously, thanks to the experience gained within a number of military aviations with Mirage III, IV and 5, answered quasi instantaneously this challenge with the Mirage 2000, while developing on its capital stocks own a twin-jet aircraft Mirage 4000, completely able to enter the skin of a modern and exportable fighter. The Mirage 2000 became operational on July 2, 1984. The Air Force which has not been able to also integrate Mirage 4000 in its park, the career of this marvellous apparatus was stopped because a plane of war is exported only if the Air Force of its country of origin uses it and shows its capacities.

But, since 1983, there was another idea for a "future" fighter, of which it had initially to be made sure that it would enter the French budgetary groundwork. For that, it was advisable to widen this groundwork with a European diagram, as well on the budgetary level as operational and industrial. In harmony with Charles Hernu, Minister for Defense, the General Bernard Capillon, chief of staff of the Air Force got busy to make succeed this principle. Obvious operational needs claimed, for the Air Force French and naval aeronautics, a successor with all the Mirage, Jaguar, Crusader and other Standard. The military aviations German, British, Italian, Spanish, etc were they to also find successors with Tornado, F16 and other apparatuses belonging already to an exceeded technology. But in Europe which seems to want to seek itself still a long time, it proved to be impossible to find an agreement reasonable on a definition of specification of operational need single. One had to resign oneself to see developing in competition a project inspired by the British, to which hung up again themselves other Europeans, Eurofighter, and a project meeting the standards identified by the Air Force, the A.C.X. (for experimental Fighter). One knows the serious difficulties of development of the E.A.P. preceding Eurofighter, too large machine and too new for a group of industrialists who had, of the concept chosen, an insufficient experiment. One also knows, like a demonstration opposite and parallel, the fantastic technical success of the A.C.X. become RAFALE A, whose development posts, since practically ten years, a facility which would be almost worrying if the capacities of the system of weapons as a whole were not, with each stage, rigorously present at go fixed. The political good-will had, despite everything, to weigh to overcome the reserves of the national Navy, of access anxious to replace with earliest of Crusader in quite old truth and of which it had not been able to plan the more early changing in reason of these other loads. It is that an aircraft carrier is well expensive! But an aircraft carrier is not a useful investment that if it carries planes... And an aircraft carrier as modern as will be to it "Charles-of-Gaulle" could not be satisfied with aircraft of yesterday... It is thus happy that this ship of tomorrow can, finally, to profit from this very modern plane which is the RAFALE.

The RAFALE, plane of tomorrow, plane of XXIe century, have already a history. The A.C.X., governmental project of 1983, whose initial development was financed at the same time by the State (65%) and the industrialists (35%). The objective was to conceive and build an apparatus which was to gather, for the benefit of Defense, all new technologies and to be ready to integrate, progressively with their appearance, the innovations which would reveal such or such warlike circumstance (the war of the Gulf, for example, put, in particular the accent on the "furtivity"). Such an objective carried obviously germinates of it léclatante demonstration of the high technicality of the French industrialists. Conceived from this point of view of constant optimization of the evolutionary last word, RAFALE A was initially a demonstrator and, a priori, the precursor of the single future fighter. Single and adapted to all the needs for the Air Force. Single and commun run with the Air Force and the Navy. Multi-missions and able to replace six types of different planes in France, the project will be, by its design, the image even of the versatility. It is an innovation. At one time, the versatility was only one compromise giving to the poor the illusion of a certain opulence. From a technical or operational point of view, it was always, in the past, a badly cut dimension and the good apparatuses with all were very often not good with large-thing. Progress is significant today: well controlled data processing, electronics and the modularity authorize today what were prohibited yesterday. Moreover, evolution of the missions - because of the evolution of the strategic situations - conduit to put forward the offensive capacity of the vectors, including in their defensive roles.

Project whose Dassault Aviation was, right from the start, the technical originator, the RAFALE had, the such most famous products of the house, to bear a Christian name starting with M (like Marcel! ). But, by reference to the first French jet built by the firm, the Hurricane, this future plane received the name of "RAFALE", evoking thus at the same time the breath, the dynamism and the spirit of the company. The RAFALE is, finally, the future fighter that the Air Force waits since until it registered of it the concept in its long-term plan of 1972.

Wings of technology: RAFALE A

A manufacturer of fighters draws and manufactures fighters, designed to meet the needs expressed by military users, for lexécution of precise missions. But, as Léonard de Vinci made initially outlines, which sometimes were chiefs of work, an airframe manufacturer inspired designs sometimes a preliminary draft close to the technical perfection.

The demonstrator "RAFALE A" is one of these completed preliminary drafts. As of its design and by assumption, it is placed in the universe of the most advanced technologies: it belongs to the generation of the technical combinations which are based in a system of weapons. Precursor of a plane of weapons limited in mass for requirements of control of the costs, it is however slightly bulkier and heavier than will be to it the final elaborate product. Defined to be a "demonstrator essentially", it must make it possible, initially, with the industrialists to leave free court with their imagination, while remaining with the mounting of the most daring technical innovation, without the constraint of a card-program whose detail could restrict boldness. The synthesis of desirable and necessary, fascinating of the account the need and the resources, will intervene at the time only where the series will be defined, always perfectible.

The aerodynamic design is characterized by a Delta aerofoil with double arrow and relatively great lengthening. Such a formula, by getting a greater airfoil, authorizes wing loads which supports the supersonic flight and give good performances into subsonic, in particular at the low speeds. In comparison with a traditional Delta, this wing offers a better handiness and a greater effectiveness to the strong incidences. Its volume authorizes a large quantity of fuel. The effectiveness of this wing is improved thanks to an empennage active duck. The two mobile, elevated ducks compared to the principal aerofoil - and slightly behind of the cockpit in order not to obstruct the visibility of the pilot - contribute to the direct control of the bearing pressure, in complement of the elevons out of trailing edge, and allow an instantaneous displacement of the aerodynamic center of the plane. The optimization of the aerodynamic forms resulted in placing the air intake in semi-ventral position and the experiment to show that one could do without the systems of mobile cones (called "mouse") and without the at one time essential systems of aspiration on certain apparatuses, in order to adapt them to other engines. The adopted provision constitutes a very effective compromise in all the speed, flight envelope low at Mach 2, strong incidence and even skid.

To answer the joint and complementary requests of the Navy and the Air Force, the design of general aerodynamics must give to the RAFALE operational a great maneuverability in very vast flight envelopes, and excellent qualities of flight at the very low speed wished for an embarked aircraft, while getting the capacities of carrying of external loads of a general-purpose plane.

A Delta approaches, by its form, of a domestic iron, and its unstable nature is demanding in modes of piloting. The solutions imagined by the engineering and design department of Dassault Aviation comprise, in more of the broad mobile and controlled ducks, placed very close to the aerofoil - which contribute in an interactive way to general stability while making it possible to largely increase the bearing pressure at the low speeds - electric orders of flight on three numerical chains and an analogical double chain. A series of sensors permanently compare the behavior of the plane and the orders of the pilot, transmit the analysis to a calculator which makes the synthesis and processes of it all the data before acting on the various ones surfaces of control which are the elevons, the nozzles of leading edge, the control surface of lace (called flag) and the ducks. Such orders of flight are integrated in a complex system and, in addition to the traditional functions of pitching, lace and rolling, they are able to ensure an anti-turbulence role (thanks to the detection instantaneous of accelerations), the control of the high incidences and, through orders transmitted to the engines, the control of the push-trainée ratio which supports at the same time short and precise landings. All these innovations in the field of aerodynamics could be checked, tested, appreciated thanks to the system CATIA (Interactive Design Assisted Three-dimensional) which, by a tetrahedral process of grid, allowed to solve the equations of the air flow like establishing the cartography of the pressures on aerodynamic surfaces, in correlation with the action of the orders of flight.

With a new aerodynamic formula, this aircraft is also a revolutionist by his structure. Indeed, the severe limitation masses some which forms part of the primary requirements of the Navy and of the Air Force led, to remain under the bar of the nine tons and half of empty weight equipped, to use in an intensive way the composite materials, which count for 25% of the mass of the cell. Resulting from an experience gradually gained in the past, these materials are made many carbon fibres woven and maintained in place in a resin matrix. Passed at the furnace at high temperatures, the parts thus realized have finally a resistance equal to that of steel, for an incomparably less weight. The bucket of the pilot, skins of the aerofoils, under-surface and suction face, the ducks, control surfaces, as well as the drift are out of epoxy carbon. This material, very resistant and sufficiently rubber band to endure very important load factors, also result from the intersection and the cooking of made carbon fibre sheets. Ultimately, the cell of RAFALE A comprises the proportion of new materials ever highest reached in a fighter.

But to design a plane presupposing the extreme maneuverability which the association of a thrust/weight ratio higher than 1 allows and of an aerodynamic instability controlled by electric orders of ultra flight fast poses the serious following problem: the pilot can-you it to survive the efforts imposed by the performances of the machine? There truly the change of generation appears, which makes reach a thrust difficult to pass. Calculation shows indeed that the accelerations induced by the operation and especially their speed of installation are likely to largely exceed the tolerances physical. One optimizes these limits by giving to the pilot the means of a greater resistance to the load factors: inclined seat with 32° compared to the normal, position of the legs and the arms, and entirely re-examined plan of lappui-head compared to what was done until there. This new provision also results in refitting the cabin in order to increase the ease of piloting: disappearance of the traditional handle, replaced by a side mini-handle, new presentation of information necessary to the control of the mission. The position of the orders answers the concept "3M" (Hands on Handle and Lever). The mini-handle is on the right, the single throttle lever for the two engines, on the left; the arms of the pilot rest in permanences on the balustrades: the high load factors are supported thus better. Thanks to the use of selective processes of visualization, it is today possible to the engineers to locate a new definition of the "dashboard" in the very reduced place available in the field of vision of the pilot. The cockpit has thus of holographic sight high head a "with great angle", of a sight average head and two side screens. Such a limitation of the number of the consoles is made possible by a maximum integration of the system; it as well as possible facilitates the piloting and the management of the various functions available by giving only information necessary. These mini-televisions with drop-down menu reflect totality of information which the pilot, who can consult them constantly, with the request needs.

The environment of the cockpit is animated by a vocal warning device which supplements visualized information and, in this case of anomaly or emergency (limit of the flight envelope, minima of safety...), invites the pilot to consult the corresponding page of the televised menu. Initially, these messages were delivered with the crew by a synthetic voice in English language. Enough early, the voice more suave of Yolaine of Bigne took the changing, with general satisfaction. The dialogue "pilot-system" is carried out by impulses on the orders placed as well on the mini-handle as on the lever of the engines. While waiting for the vocal order, the pilot will continue to behave as a clarinettist like it has the practice of it.

But RAFALE A could not have taken the air nor to answer the expected performances if it had been provided with engines also elaborate only the remainder. To animate a modern plane, it is not enough to push and howl: it is necessary still that the technology of the turbo machine is in harmony with the perfection of the cell. But if, experiment helping, the construction of a prototype of plane could be carried out within extremely short times, it should be noted that the design and the development of a new engine, even envisaged and for a long time described, request a little more time, even much more. To hold account of this data, the airframe manufacturer used, while waiting for famous M-88 of the SNECMA, F-404 of General-Electric, perfectly adapted by its size, its mass and its push with this temporary role. They were thus two F-404 which propelled the demonstrator RAFALE A during 460 exits of tests and presentation.

RAFALE A, controlled by Guy Mitaux-Maurouard, flew for the first time on July 4, 1986, since the base of Istres, which saw taking off so much of prototypes. During this first one hour flight, the plane reached Mach 1.3, with the altitude of 35000 feet and open the field of evolution until 5G. This manner of entering straightforwardly the sharp one of the subject shows the excellence of preliminary work of the engineers of studies and the considerable contribution provided by the "computer-aided design". But a plane always shows its title by an effective takeoff. The many assembly of specialists come to attend with this this historical take-off had only one exclamation when the wheels separated from the track: "It flies!" Reaction undoubtedly unexpected on behalf of manufacturers of aircraft ", but which testified the height of the technological bet which had been just controlled.

During almost 500 flights without stories, RAFALE A was the bench of very many tests which gradually made it possible to open the flight envelope in all its extent and multiple configurations. Also, and almost especially, that made it possible to show, by precise approaches and without any difficulty carried out on the "Foch" and the "Clémenceau", that this plane had all faculties necessary for the landing, at one time when Navy, pressed by time, seemed to direct its choice towards the American F-18, in spite of its somewhat exceeded technology.

During the time of these tests, M-88 turned to the bench and developed rather harmoniously so that it was possible to make it fly, in left place, on RAFALE A, while keeping F-404 on the right. Favour twin-engine and facility of the strong pushes, such circumstances authorized, thanks also to the data-processing management of the data of flight, which at one time had passed for pure acrobatics. Because this hybrid provision, in addition to that it did not modify appreciably the appearance of the plane, was not used like a simple relatively quiet bench flying. On the contrary, all the tests were continued until in the corners of the field and without any restriction. One can draw from this observation many conclusions, in particular on the know-how of engineers Dassault Aviation and SNECMA. It was indeed necessary to adopt a new engine with a cell which preserved the other, this engine not having neither same dimensions nor the same operating features as its neighbor, with regard to the masses of air digested, in particular, and the pressures of ingestion... The observer could notice that the left conduit was a little shorter and that the right tail opened more. The pilot noted that it was necessary for him from now on to operate two throttle levers, as on an ordinary twin-jet aircraft and to divide his glance on instruments specific to each engine.

RAFALE A, since its first flight with two dissimilar engines on February 27, 1990 and until its last service on January 24, 1994, had for principal function to carry out the flight tests of M-88, with the advantage, for the French motor mechanic, to carry out these tests in the presence of the known and tested elements American engine.

Since his inaugural takeoff of July 4, 1986, which was a complete trial flight in an already wide flight envelope, the "demonstrator" RAFALE will have carried out 867 exits in seven years and half, 455 hours having been used to develop the operational engine. This procedure made it possible to await in all serenity the arrival of the C01 single-seater defined for the Air Force. This new prototype saw the way traced by its predecessor, in spite of slightly reduced size and new requirements, in particular of furtivity. The operational qualification was still going to ask for work of adaptation, which would be concluded on four new prototypes: C01, single-seat Air Force; M01 and M02, single-seaters Naval Aviation; and B01, two-seater of combat Air Force. Before returning to the hangar, RAFALE A had shown exceptional qualities of the formula active Delta-Ducks, as well as the resistance of new materials used and the capacity of carrying of load of a general-purpose apparatus. It had also allowed, under the best conditions, to develop the definition of the prototypes which soon was going to precede the series.

In illustrations of these achievements, one could admire the "steel Patrol" of the five RAFALE which stole on January 24, 1994, proving at the same time the harmony of its diversity and the coherence of the family around old ancestor an "of less than eight years".