Translated by BabelFish
The US Air Force is not sulky its pleasure. "If we go in war tomorrow, Raptor will be ours", declared the General Ronald Keys, owner of the Air Fights Command (ACC), at the time of the ceremony which marked on December 15 on the basis of Langley (Virginia) the official startup of the first fighter of fifth generation, the F-22A of Lockheed Martin. Apparently, USAF takes place any to be satisfied. This 15 December marks a major stage of its evolution. With Raptor, it ensures, for the years to come, its supremacy vis-a-vis with the other military powers of planet. After P-51 Mustang of the Second World war, F-84 Sabres cold war, F-4 Phantom and the F-15 Eagle, the F-22A Raptor constitutes the most advanced system of weapon of its time. The tool of a marked political good-will: "all over the world To maintain the superiority air American."
Admittedly, the first twelve F-22A given to the pilots of the 27' Fighter Squadron (FS) of Fighter Wing de Langley AFB are titular only of one initial operational capacity (FAKE) which confines them, for the hour, with the missions of interception and air superiority. With a special mention qualifying them for missions of interior defense of the American territory. But it is only next June that the twelve deployed F-22A with Elmendorf AFB (Alaska) will prove reliable first operational in times of peace for the exercise "Northern Edge".
Then? Logically, a second operational squadron should be detached on this same basis of Elmendorf to take part, at the sides of the F-15C, the defense of the Northern airspace. And, already, the Air Force studies a first deployment of F-22A "some share in the Pacific" in protection of the Korean peninsula. To date, a little less than one about sixty Raptor were delivered by the American Air Force. In addition to those of Langley AFB, the other apparatuses are distributed between the establishments of Tyndall (Florida) and Nellis (Virginia) for the drive and the formation with the techniques of combat.
All that constitutes only one first stage. Because current Raptor 1 (official designation of USAF) has to evolve/move in its initial version, but also worms of the offensive alternatives of penetration which, in the long term, could lead to the "hunter with to do everything USAF".
For that, the apparatus of Lockheed Martin incorporates right now considerable new concepts related to very high technologies. Conceived to succeed the F-15C Eagle, Raptor has for principal characteristic to be the most furtive fighter produces to date. A "passive" furtivity due to its forms external and the generalized use of a material coating absorbing the waves radars (cf p. 20-21). And, in the future, it is even envisaged a furtivity known as "active" with the recourse to liquid crystal coatings. In the same way, Raptor is the first hunter - since the years 1950 - to place out of compartment the integrality of its armament. A provision which increases the furtivity but also takes part in the reduction of the trail by supporting the possibility of flight as a supercroisière, in other words into supersonic until Mach 1,4 without using afterburning. This architecture dedicated to discretion does not make of it less of Raptor a true hunter, suited to the whirling combat and even "hypermanoeuvrant" thanks to mobile surfaces of adapted forms and to its two engines P&W F119-PW100 (160 kN unit) equipped with directional conduits. The shape of the apparatus enables him to contain a volume of important fuel. Characteristic being able to be reinforced by the addition of two ejector external tanks for the transits at long distance.
Lastly, with an envelope of flight entirely controlled by computer, the integrated avionics forms part of the essential elements of the F-22A, as well as its furtivity, its maneuverability and its propulsion in mode of supercroisière. The software of Block 3.0 of Raptor 4005, under tests since the beginning 2001, made it possible to obtain a quasi-fusion of the data of transmissions and sensors. The pilot is thus released from the tasks of management of the sensors to allow him to concentrate on his operational missions. The radar with electronic sweeping with active modules APG-77 of Northrop Grumman and the system of countermeasures integrated of Lockheed Martin constitute determining elements of the furtive hunter whose programming of the software of integration required nearly two million lines of code in language Ada.
The armament of the F-22A, laid out out of principal compartment, is composed of six air-to-air missiles with average carried AIM-120C Amraam, guided by radar. In two side compartments two other short-range missiles Sidewinder AIM-9M are placed, are guided by infra-red. But the armament of the furtive hunter includes/understands also a advanced version of the traditional M61 gun of the type Gatling, the M61A2.
Conceived at the origin for missions of aerial combat, F-22 gradually adapted to the carrying of air-to-ground armaments. From where its provisional designation of F/A-22 ("F" for Fighter, "A" for Attack) data by the Air Force in 2002. For that it will be able to carry out of principal compartment two bombs of precision of almost 500 kg of class GBU-32 of Jdam (Joined Direct Attack Munition) or, in the future, of the future bombs 110 kg in low diameter SDB (Small Diameter Bomb) guided by GPS.
In addition, the furtive hunter has four external points of carrying being able to support 2.500 kg each one. The tests of Jdam were carried out from September to November 2005 during the ultimate phase of its operational evaluation (FOT&E) in the center of shooting of Utah. A score of Jdam were drawn, of which some in supersonic limit of flight. A capacity of shooting at high speed (Mach 1,5) that F-22 could integrate since 2007 within the framework of the program "Spiral". Because it is clear that, parallel to its startup, the F-22A reserves a strong potential of development towards its general-purpose version (air-air-to-air-ground).
A financial pit.
All is from now on question of cost, of quantity of production and budget. By reducing by 40 % the component count of the F-22A compared to the F-15, Lockheed Martin intends to decrease in a substantial way the prices of maintenance of the furtive hunter. The posted objective is to reduce the total cost of the "cycle of life" of the F-22A of 40 % compared to that of the F-15, while bringing 100 % of improvement of performances. This economy will not be able however to justify with it only the enormous sums already absorbed in this always discussed program. In gestation since the end of 1970, the F-22A was conceived at the time of the cold war to lead missions of combat to deepest of the Soviet empire. But nowadays "Al-Qaida does not form nor does not use pilots of combat", observes the colonel (CR) Everest Riccioni, by explicitly criticizing the F-22A on behalf of the organization of monitoring of the governmental programs Pogo. Who more is, the restricted number of apparatuses envisaged risk to decrease by as much the capacities of intervention of the Air Force on several faces and in the durationBecause the forecasts and the orders of F22 did not cease being re-examined with the fall throughout these last years and even of these last months (cf framed). Taking into account budgetary uncertainties, the Air Force is likely to have to be satisfied with 179 F-22A from here at at the end of 2012. In other words, to draw a feature on 202 planes registered under a posted need, a few months ago still, of 381 apparatuses. A clear cut which involves a serious increase in the invoice. The unit price of Raptor, envisaged at the origin of the program in the neighbourhoods of 35 M$, is estimated today between 133 M$ and 153 M$ (fly-away) according to the orders and of the rates of output. What comes down to saying that, very included/understood (studies, developments, replacements and tests), the unit price of F-22 reached or exceeds 260 M$ with 270 M$.
USAF is not unaware of that its room for manoeuvre is narrow. So much so that, at the time of a recent press conference, its new chief of staff, the General Michael Moseley, came from there to wish "four additional apparatuses (sic)" and a prolongation of the chain of production until 2013 allowing a welding with the arrival of F-35 (JSF) and to be able at least "to constitute a seven total will squadrons equipped". But, even carried with 183 production aircraft, the program will absorb between 60 M$ and 70 Md$.
In spite of the optimism of circumstance posted by the Moseley General, much wonder about the operational capacity of F-22 reduced to such a small size. For colonel Riccioni, a fleet of F-22A brought back to less than 200 apparatuses "cannot allow the multiple and simultaneous missions carried out by thousands of F-15, F-16 and F18 currently in service". And the former person in charge for USAF to recommend the assignment from the some 5 Md$ of the annual budget of F-22 to the modernization of the existing park of the F-15C and F-16C/D and to the fight against terrorism. An extreme measurement that divide neither Lockheed Martin nor the US Air Force which estimates, for its part, which even in a number limited the need for F-22 is real vis-a-vis with the potential threat that make weigh the new systems of detection and the fighters of fourth generation like Known-35 Russian, European Eurofighter or the French Rafale.
The American Air Force seeks a solution with the financial equation by suggesting a limitation of the improvements envisaged with the title of the program of "Spiral" valorization. What would amount cutting down, or at least delaying, a really general-purpose version of Raptor and, consequently, would condition in the long term the development of alternative FB-22.
As many arguments which let plane many uncertainties and feed the controversy on an apparatus which, hardly entered in service, expensive deserves already the qualifier of fighter "in the world ever built".
Fusion of sensors and evolutionarity
What will receive the pilot of the US Air Force in 2006 per 150 M$? Answer: the only fighter to reaction of the fifth generation and, consequently, most modern of all. A privilege which treats to two to three times nevertheless the price of the most modern fighters (Rafale, Super Hornet, Typhoon and JSF) and that it is sometimes difficult to measure with its right value.
Put aside the horse-power and the furtivity, largely detailed in the pages which follow, the F-22A does not widen the gap in an obvious way. Radar APG-77 with active modules is certainly very modern with its 2.000 modules transmitter-receivers and its angle of sweeping of 120° on both sides of the axis plane. But this technology is already produced in series on the F/A-18E/F and will be available in Europe on Rafale and Eurofighter towards 2012.
The engines with directed push are undeniable. But this choice seems to be dictated by impossibility of establishing ducks plans with which all its modern European competitors are equipped, but which would have compromised the performances in term of furtivity forwards. The armament
does not differ radically from what propose the competitor planes. American Amraam and French Mica are worth overall and Europe develops for 2011 Meteor which, with its ramjet, on will classify largely in range the American missile of interception.
Remain aspects much less tangible, like the fusion of sensors. Any modern fighter asserts it. But quality of this one is impossible to apprehend on paper, if it is not while referring to the computing power embarked which is the only evidence of the smoothness of the algorithms and their capacity to correlate heterogeneous information, so much from the point of view of their origin than of their format. However this point of view, the F-22A crushes completely competition.
The power of calculator CIP (Common Integrated Processor) is 700 Mips (million instructions a second) and it can be tripled by simple addition of additional electronic charts. Figures to be brought closer 14 Mips of the first generation of the Rafale and the 65 Mips of the Emti calculator (Together modular of data processing) of the F2 standard. All this reserve of power is available to lodge evolutions towards the NCW (Network CentricWarfare), i.e. the war in network, which one knows that it will be large consumer of computing power.
And of the evolutions, the Raptor program in planned a good quantity. Six months after its operational service entrance, the plane will evolve to a standard which is already indicated Block 20. The envelope of shooting of Jdam will then be widened at the supersonic speeds. Jdam Mk-83, released in the optimal area of the flight envelope of F-22 (that is to say to 15.000 m of altitude and at the cruising speed of Mach 1,5), can plane on 40 km, which will then give a distance of already comfortable safety for the plane.
(or both the) standard one according to corresponds to Block 30 (and perhaps with a Block 32, if the US Air Force preserves the principle of designation in force for F-16). A new antenna radar with active modules of fourth generation, directly resulting from program JSF, and refitted with dimensions of the point before of F-22 will make it possible to insert modes of imagery high resolution as well as anti-ship modes. Calculators CIP of F-22, of which microprocessors INTEL i960MX any more are not produced today, will be also replaced by calculators ICP (Integrated Common Processor) also coming from the JSF. Also appears with Block 30 an emission mode for connection 16, not provided on the initial standard since any emission compromises the furtivity and that connection 16 must function permanently to be useful. In fact, the pilot of F-22 can order five levels of discretion for his system of weapon: level 1 where no emission is authorized, on the level 5 where all the equipment likely to radiate is activated. The emission mode of connection 16 will thus make it possible F-22 to repatriate towards Awacs the tracks of their radar.
The two generations of future bomb SDB (decametric, then metric) will be also integrated in this standard. Smaller (113 kg) that Jdam, the SDB will be able to take seat 8 (instead of two) in the internal compartments of F-22. Their aerofoil dépliable will give them more lengthening-piece and also more maneuverability, then making it possible a raid of F-22 to treat objectives located up to 50 km on both sides of their corridor of penetration.
From Block 40, the future becomes frankly dubious because the financing of the evolutions is not planned yet. Lockheed Martin plans to add two side active antennas to the back of the current radar. Those will make it possible the plane to see in a broad back sector like under him. Their site and their cooling were already envisaged on the current aircraft. Lastly, with the standard Block 50 should arrive a satellite connection at high flow and possibly of the tanks in conformity making it possible the plane to operate far in hostile territory and under control in real time of the network of command. Contrary to connection 16, a satellite connection would not compromise the total furtivity of the apparatus, since the beam of emission very fine and is directed towards the sky.
All these projects will be expensive. The development of the successive standards was quantified to the US Air Force with 11,7 Md$. An amount to be paid to the development cost of the plane until today (28,7 Md$). Moreover, the advertisement on 15 last December of a two years spreading out of the series and purchase of four additional apparatuses will be able to be made only with the detriment future evolutions. Because the American Congress already put a ceiling to to 36,8 Md$ the total budget of the program. Moreover, the General Michael Moseley, chief of staff of USAF, already admitted that these decisions would involve a deceleration of the future evolutions of F-22.
How F-22 became furtive
Twenty-three years separate first startup from the first furtive plane of the US Air Force, the F-117A Night Hawk, of that of the F-22A Raptor. Two tactical planes which have the characteristic to carry their armaments in compartments intern, because the missiles, the bombs, and especially the pylons and their mechanisms of ejection are as many sources of reflexions very strong radars.
But F-117, with its form characteristic of domestic iron, was all in arrises and its dorsal air intake was far from having an ideal establishment, whereas the F-22A has from now on all the appearance of a nimble and handy hunter, and would be quite as furtive.
Explanation of this difference: power of the computers and precision of the codes of simulation, which exploded during two decades separating the two generations from planes. Henceforth, these data-processing models make it possible to predict with a great exactitude, before is not cut the first chip of the structure, the signature radar of the apparatus and thus to obtain complex furtive forms which do not compromise any more aerodynamic qualities.
Like its elder, F-22 uses and misuses the technique of the facets. The idea is not to leave apparent any surface nor no edge perpendicular to the axis of the plane.
Thus, the sides of the plane, its air intake, its two drifts are all tilted under the same angle. The leading edges of its wings and its horizontal stabilizers, just as their respective trailing edges, also follow parallel lines.
All that the fuselage counts of trap doors, for the landing gears, the compartments of armament, the gun (hidden in the fuselage above the left air intake), the accesses for maintenance, but also the frame of the canopy of cockpit, all is cut in teeth of saw, always following the two same directions, in order to reflect the waves radars towards the side when the plane is presented vis-a-vis at the radar.
Because it is of face that a plane is most vulnerable for a radar. This type of sensor often needs several successive detections "to put in track" and trajectographier a target. With this technique of alignment of its edges, F-22 will be able exceptionally to return a significant echo towards a radar located on the side. But with the turn of antenna according to, the plane will have already moved and will not present itself any more under the same angle at the radar which will have lost it and will arrange this fugitive echo with the row of false alarm.
On the other hand, F-22 is distinguished clearly from Night Hawk by the adoption of a technique of drawing known as of the continuous curve. Thus, front view, the junction wing-fuselage does not form any more one angle Net, source of more intense reflexions radars, but on the contrary, the under-surface is based in the side of the plane following a line to varying radius of curvature uninterrupted. The same technique of continuous curve was obviously applied also to the careenages of the jacks of orders of the ailerons, the spoilers and the horizontal planes.
Before F-22, this technique had already been implemented for B-2 A Spirit which it made it possible to reach an equivalent surface radar of only 0,75 m2, equal to that of a tricycle of child. By comparison, that of smaller planes and former generation, like the F-15, would border 6 m2, affirms official Internet site of the program (www.f-22raptor.com), which is much less eloquent and more allusive on the performances and the solutions implemented on Raptor.
It is the case in particular materials absorbing which are supposed to come to supplement and complete the action of the particular forms of Raptor. Mobile surfaces are carried out in honeycomb, a material which has the property to naturally absorb a great part of the waves radars by trapping them in their cavities.
But the treatments which apply to other surfaces do not differ in the principle. The carbon fibres or the ferrite particles whose these coatings are doped as act they like traps for the incidental waves while returning them towards the interior of the apparatus rather as towards the source of emission, completely with the manner of the carbon foam points of the anechoic rooms where are precisely tested the radars.
Coatings quarter of wave would be also applied by places. These materials are thus called because their thickness is equal to the quarter incidental wavelength, and that their external surface reflects a part of incidental energy, while the remainder is considered on their internal face. The result is that after the crossing return ticket of this layer the wave reflected on the internal face is found in opposition of phase with the wave reflected by the external face, cancelling this one.
The physicists must deploy boundless ingenuity to cover kind of the ranges wavelengths being able to go from the metric waves (territorial radars of monitoring) to the millimetre-length waves (homing heads of missiles). But that is possible by applying several successive layers of absorbents of permittivities carefully selected the ones compared to the others.
If any cavity must be treated carefully, because it is a major source of reflexions, the air intake and the conduits of engines represent enormous cavities at the bottom of which the paddles form mirrors scintillating for the waves radars and are consequently eminently detectable. The more so as the position of the air intake, under the under-surface, was dictated to be able to supply the engines even under strong incidence, whereas it is more visible with the terrestrial radars of air defense.
Engineers de Lockheed Martin thus had to look after the shape of the veins which lead the air to the engines. Those go up gradually to the top of the fuselage where they meet almost, at a place where they are pinches to leave a maximum space with the ventral compartment of missiles. But the result is that no angle of vision to the air intake gives a direct sight on the first stage of the compressors.
As for the conduits, which are airships, the pallets of deviation of jet are they also in teeth of saw and were covered with a supposed ceramics layering also to absorb the residual waves to him. Lastly, to limit the infra-red signature of the engines, Lockheed Martin reduced the heat of combustion gases by diluting them with fresh air taken upstream engines. In addition the two oblique drifts were rejected very behind of the cell in order to mask the exits of the engines for sensors or missiles which would observe them laterally.
The official site of Raptor evokes also materials "chameleons" who were studied on the "Bird of prey" of Boeing and were not used for the moment on F-22. These coatings make it possible the plane more or less to adopt the fill color on which it is seen. Recent technological breakthroughs made it possible to create liquid crystal displays in polymeric materials which can marry the shapes of the plane perfectly. The remainder is a play of child. It is enough to a summary sensor above the plane to detect if the bottom is cloudy or if the sky is blue and to reproduce this environment on the belly of the plane so that this one becomes blow much more difficult to see. But the site does not say if the resistance of these materials to abrasion is compatible with a use on a fighter.