Radar cross-section ( RCS ), denoted σ, also called radar signature , is a measure of how detectable an object is by radar . A larger RCS indicates that an object is more easily detected.
90-821: The Boeing X-32 is a concept demonstrator aircraft that was designed for the Joint Strike Fighter competition . It lost to the Lockheed Martin X-35 demonstrator, which was further developed into the Lockheed Martin F-35 Lightning II . In 1993, the Defense Advanced Research Projects Agency (DARPA) launched the Common Affordable Lightweight Fighter project (CALF). The project's purpose
180-427: A Leontovich impedance boundary condition (see also Electrical impedance ). This is the ratio of the tangential electric field to the tangential magnetic field on the surface, and ignores fields propagating along the surface within the coating. This is particularly convenient when using boundary element method calculations. The surface impedance can be calculated and tested separately. For an isotropic surface
270-419: A competitive advantage was to offer substantially lower manufacturing and life-cycle costs by minimizing variations between the different JSF versions. The X-32 therefore was designed around a large one piece carbon fiber composite delta wing . The wing had a span of 9.15 meters, with a 55-degree leading edge sweep, and could hold up to 20,000 pounds (9,000 kg) of fuel. The purpose of the high sweep angle
360-719: A complement to the F-22 Raptor . The Joint Advanced Strike Technology (JAST) program was created in 1993, implementing one of the recommendations of a United States Department of Defense (DoD) "Bottom-Up Review to include the United States Navy in the Common Strike Fighter program." The review also led the Pentagon to continue the F-22 Raptor and F/A-18E/F Super Hornet programs, cancel
450-571: A constant engine match, facilitated by the control system algorithm maintaining a fixed total nozzle effective area. Thus the engine was unaware of various nozzles being opened up and closed off to complete the transition. The F119-PW-614S was a direct lift engine, whereas the Lockheed Martin STOVL team used a more complex and riskier alternative, known as the F119-PW-611, which comprised a remote shaft-driven lift fan powered by
540-520: A minor hydraulic leak was discovered and the flight was shortened to 20 minutes from the expected 30–40 minutes. According to Knox, the F/A-18 chase plane required "a lot of afterburner" to keep up with the X-32 during the initial stages. During the flight, the aircraft reached 10,000 feet (3,000 m), attained a speed of 200 knots (370 km/h; 230 mph), and attained an angle of attack of 13°. Despite
630-406: A radar system with a given target to be analysed independent of the radar and engagement parameters. In general, RCS is a function of the orientation of the radar and target. A target's RCS depends on its size, reflectivity of its surface, and the directivity of the radar return caused by the target's geometric shape. As a rule, the larger an object, the stronger its radar reflection and thus
720-436: A range eliminates the need for placing radar absorbers behind the target, however multi-path interactions with the ground must be mitigated. An anechoic chamber is also commonly used. In such a room, the target is placed on a rotating pillar in the center, and the walls, floors and ceiling are covered by stacks of radar absorbing material. These absorbers prevent corruption of the measurement due to reflections. A compact range
810-514: A related quantity called the normalized radar cross-section ( NRCS ), also known as differential scattering coefficient or radar backscatter coefficient , denoted σ or σ 0 ("sigma nought"), which is the average radar cross-section of a set of objects per unit area: where: The NRCS has units of area per area, or m / m in MKS units. Informally, the RCS of an object
900-573: A result of these media reports, then Australian defence minister Joel Fitzgibbon requested a formal briefing from the Australian Department of Defence on the simulation. This briefing stated that the reports of the simulation were inaccurate and that it did not compare the F-35's performance against that of other aircraft. Andrew Hoehn, Director of RAND Project Air Force, made the following statement: "Recently, articles have appeared in
990-412: A spherical target), and the RCS is a hypothetical area. In this light, RCS can be viewed as a correction factor that makes the radar equation "work out right" for the experimentally observed ratio of P r / P t {\textstyle P_{r}/P_{t}} . However, RCS is a property of the target alone and may be measured or calculated. Thus, RCS allows the performance of
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#17327798872331080-425: A surface could contain indentations that act as corner reflectors which would increase RCS from many orientations. This could arise from open bomb-bays , engine intakes, ordnance pylons, joints between constructed sections, etc. Also, it can be impractical to coat these surfaces with radar-absorbent materials . The size of a target's image on radar is measured by the radar cross section or RCS, often represented by
1170-409: A target can be detected for a given radar configuration varies with the fourth root of its RCS. Therefore, in order to cut the detection distance to one tenth, the RCS should be reduced by a factor of 10,000. While this degree of improvement is challenging, it is often possible when influencing platforms during the concept/design stage and using experts and advanced computer code simulations to implement
1260-569: A variety of analytic and numerical methods, but changing levels of military interest and the need for secrecy have made the field challenging, nonetheless. The field of solving Maxwell's equations through numerical algorithms is called computational electromagnetics , and many effective analysis methods have been applied to the RCS prediction problem. RCS prediction software are often run on large supercomputers and employ high-resolution CAD models of real radar targets. High frequency approximations such as geometric optics , physical optics ,
1350-492: A very thin layer of metal can make an object strongly radar reflective. Chaff is often made from metallised plastic or glass (in a similar manner to metallised foils on food stuffs) with microscopically thin layers of metal. Also, some devices are designed to be Radar active, such as radar antennas and this will increase RCS. The SR-71 Blackbird and other aircraft were painted with a special " iron ball paint " that consisted of small metallic-coated balls. Radar energy received
1440-657: Is a development and acquisition program intended to replace a wide range of existing fighter , strike , and ground attack aircraft for the United States, the United Kingdom, Italy, Canada, Australia, the Netherlands, Denmark, Norway, and formerly Turkey. After a competition between the Boeing X-32 and the Lockheed Martin X-35 , the latter aircraft was selected for a contract award and developed into
1530-443: Is an anechoic chamber with a reflector to simulate far field conditions. Typical values for a centimeter wave radar are: Quantitatively, RCS is calculated in three-dimensions as Where σ {\displaystyle \sigma } is the RCS, S i {\displaystyle S_{i}} is the incident power density measured at the target, and S s {\displaystyle S_{s}}
1620-428: Is chiefly important in stealth technology for aircraft, missiles, ships, and other military vehicles. With smaller RCS, vehicles can better evade radar detection, whether it be from land-based installations, guided weapons or other vehicles. Reduced signature design also improves platforms' overall survivability through the improved effectiveness of its radar counter-measures. Several methods exist. The distance at which
1710-474: Is converted to heat rather than being reflected. The surfaces of the F-117A are designed to be flat and very angled. This has the effect that radar will be incident at a large angle (to the normal ray ) that will then bounce off at a similarly high reflected angle; it is forward-scattered. The edges are sharp to prevent rounded surfaces which are normal at some point to the radar source. As any ray incident along
1800-704: Is extremely difficult due to the complex processing requirements and the difficulty of predicting the exact nature of the reflected radar signal over a broad aspect of an aircraft, missile or other target. Radar absorbent material (RAM) can be used in the original construction, or as an addition to highly reflective surfaces. There are at least three types of RAM: resonant, non-resonant magnetic and non-resonant large volume. Thin coatings made of only dielectrics and conductors have very limited absorbing bandwidth, so magnetic materials are used when weight and cost permit, either in resonant RAM or as non-resonant RAM. Thin non-resonant or broad resonance coatings can be modeled with
1890-453: Is the cross-sectional area of a perfectly reflecting sphere that would produce the same strength reflection as would the object in question. (Bigger sizes of this imaginary sphere would produce stronger reflections.) Thus, RCS is an abstraction: the radar cross-sectional area of an object does not necessarily bear a direct relationship with the physical cross-sectional area of that object but depends upon other factors. Somewhat less informally,
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#17327798872331980-409: Is the scattered power density seen at a distance r {\displaystyle r} away from the target. In electromagnetic analysis this is also commonly written as where E s {\displaystyle E_{s}} and E i {\displaystyle E_{i}} are the far field scattered and incident electric field intensities, respectively. In
2070-490: Is to utilize metasurfaces which can redirect scattered waves without altering the geometry of the target. Such metasurfaces can primarily be classified in two categories: (i) Checkerboard metasurfaces, (ii) Gradient index metasurfaces. With active cancellation, the target generates a radar signal equal in intensity but opposite in phase to the predicted reflection of an incident radar signal (similarly to noise canceling ear phones). This creates destructive interference between
2160-474: Is used to detect airplanes in a wide variation of ranges. For example, a stealth aircraft (which is designed to have low detectability) will have design features that give it a low RCS (such as absorbent paint, flat surfaces, surfaces specifically angled to reflect the signal somewhere other than towards the source), as opposed to a passenger airliner that will have a high RCS (bare metal, rounded surfaces effectively guaranteed to reflect some signal back to
2250-589: The F-117A Nighthawk stealth attack aircraft. This aircraft, designed in the late 1970s though only revealed to the public in 1988, uses a multitude of flat surfaces to reflect incident radar energy away from the source. Yue suggests that limited available computing power for the design phase kept the number of surfaces to a minimum. The B-2 Spirit stealth bomber benefited from increased computing power, enabling its contoured shapes and further reduction in RCS. The F-22 Raptor and F-35 Lightning II continue
2340-695: The F-16 Agile Falcon in the late 1980s, essentially an enlarged F-16, and continued to mull other designs. In 1992, the Marine Corps and Air Force agreed to jointly develop the Common Affordable Lightweight Fighter, which continued development efforts under ASTOVL. CALF project was chosen after Paul Bevilaqua persuaded the Air Force that his team's concept (if stripped of its lift system ) had potential as
2430-639: The F-35 Lightning II , which will replace various tactical aircraft, including the US F-16 , A-10 , F/A-18A-D , AV-8B , EA-6B and British Harrier GR7, GR9s and Tornado GR4 . The projected average annual cost of the program is $ 12.5 billion in 2012 with an estimated cost in 2024 of $ 2 trillion over its lifespan. The JSF program was the result of the merger of the Common Affordable Lightweight Fighter (CALF) and Joint Advanced Strike Technology (JAST) projects. The merged project continued under
2520-901: The Future Carrier Borne Aircraft project. This program sought a replacement for the Sea Harrier (and later the Harrier GR7 ); the Joint Strike Fighter was selected in January 2001. During concept definition, two Lockheed Martin airplanes were flight-tested: the X-35A (which was later converted into the X-35B), and the larger-winged X-35C. Arguably the most persuasive demonstration of the X-35's capability
2610-437: The boundary element method ( method of moments ), finite difference time domain method ( FDTD ) and finite element methods are limited by computer performance to longer wavelengths or smaller features. Though, for simple cases, the wavelength ranges of these two types of method overlap considerably, for difficult shapes and materials or very high accuracy they are combined in various sorts of hybrid method . RCS reduction
2700-477: The data into China's Chengdu J-20 and Shenyang FC-31 fighters. On February 1, 2010, Secretary of Defense Robert M. Gates announced that, due to delays and other problems with the JSF development program, he was removing Major General David R. Heinz from command of the program and would withhold $ 614 million in bonuses from Lockheed Martin. On February 16, 2010, Deputy Defense Secretary Bill Lynn announced that
2790-457: The geometric theory of diffraction , the uniform theory of diffraction and the physical theory of diffraction are used when the wavelength is much shorter than the target feature size. Statistical models include chi-square , Rice , and the log-normal target models. These models are used to predict likely values of the RCS given an average value, and are useful when running radar Monte Carlo simulations. Purely numerical methods such as
Boeing X-32 - Misplaced Pages Continue
2880-565: The -614C engine, known as the F119-PW-614S, powered the STOVL aircraft. In normal flight, the -614S was configured as a conventional afterburning turbofan. However, in the STOVL mode a butterfly valve diverted the core stream exhaust gases to a pair of thrust vectoring nozzles located close to the aircraft's center-of-gravity. Forward of these nozzles, a jet screen nozzle provided a sheet of cool bypass air to minimise hot gas recirculation. There
2970-504: The Air Force's Multi-Role Fighter (MRF) and the Navy's Advanced Attack/Fighter (A/F-X) programs, and curtail F-16 and F/A-18C/D procurement. The JAST program office was established on 27 January 1994 to develop aircraft , weapons , and sensor technology with the aim of replacing several disparate US and UK aircraft with a single family of aircraft; the majority of those produced would replace F-16s. Merrill McPeak , former Chief of Staff of
3060-630: The Australian press with assertions regarding a war game in which analysts from the RAND Corporation were involved. Those reports are not accurate. RAND did not present any analysis at the war game relating to the performance of the F-35 Joint Strike Fighter, nor did the game attempt detailed adjudication of air-to-air combat. Neither the game nor the assessments by RAND in support of the game undertook any comparison of
3150-854: The Concept Demonstration phase with an investment of US$ 10 million. This investment allowed Canada to participate in the extensive and rigorous competitive process where Boeing and Lockheed Martin developed and competed their prototype aircraft. Studies supporting JAST/JSF started in 1993 and led to STOVL submissions to the DOD by McDonnell Douglas , Northrop , Lockheed and Boeing : Two contracts to develop prototypes were awarded on November 16, 1996, one each to Lockheed Martin and Boeing . Each firm would produce two aircraft to demonstrate conventional takeoff and landing (CTOL), carrier takeoff and landing (CV version), and short takeoff and vertical landing ( STOVL ). McDonnell Douglas ' bid
3240-730: The Conservatives declared that the total cost over 20 years would be $ 16 billion. On 19 October 2015 the Liberal Party of Canada under Justin Trudeau won a majority in part on a campaign promise to not purchase the F-35, but instead "one of the many, lower-priced options that better match Canada's defence needs". Concerns about the F-35's performance have resulted partially from reports of simulations by RAND Corporation in which three regiments of Chinese Sukhoi Su-27 fighters defeat six F-22s by denying tanker refueling. As
3330-702: The JAST name until the engineering, manufacturing and development (EMD) phase, during which the project became the Joint Strike Fighter. The CALF was a DARPA program to develop a STOVL strike fighter (SSF), originally under the Advanced Short Takeoff and Vertical Landing (ASTOVL) project, for the United States Marine Corps and replacement for the F-16 Fighting Falcon . The United States Air Force passed over
3420-444: The JSF program has led to a more conservative and open-ended Future Vertical Lift program. Radar cross-section An object reflects a limited amount of radar energy back to the source. The factors that influence this include: While important in detecting targets, strength of emitter and distance are not factors that affect the calculation of an RCS because RCS is a property of the target's reflectivity. Radar cross-section
3510-640: The Lockheed Martin X-35 concept demonstrator aircraft were capable of transitioning between their STOVL and supersonic configurations in mid-flight. The first flight of the X-32A (designed for CTOL and carrier trials) took place on 18 September 2000, from Boeing's Palmdale plant to Edwards Air Force Base . The aircraft, piloted by Boeing test pilot Fred Knox, took 2,200 feet (670 m) of runway before becoming airborne at 150 knots (280 km/h; 170 mph) at around 8:00 am. Shortly after takeoff,
3600-486: The Lockheed entry looked like, if anything, a smaller version of the F-22 Raptor stealth fighter. Yet another effect of the selection of the direct-lift system was the large chin-mounted air intake. This was required to feed sufficient air to the main engine (to provide the thrust necessary to hover) during the zero horizontal velocity phase, when it could not exploit ram-air pressure. A knock-on effect of this large intake
3690-410: The RCS of a radar target is an effective area that intercepts the transmitted radar power and then scatters that power isotropically back to the radar receiver. More precisely, the RCS of a radar target is the hypothetical area required to intercept the transmitted power density at the target such that if the total intercepted power were re-radiated isotropically, the power density actually observed at
Boeing X-32 - Misplaced Pages Continue
3780-406: The RCS relates to the two scattering phenomena that takes place at the antenna. When an electromagnetic signal falls on an antenna surface, some part of the electromagnetic energy is scattered back to the space. This is called structural mode scattering. The remaining part of the energy is absorbed due to the antenna effect. Some part of the absorbed energy is again scattered back into the space due to
3870-583: The UK Minister of Defence Procurement, said the X-35 consistently outperformed the X-32, although both met or exceeded requirements. The development of the JSF was jointly funded by the United States , United Kingdom , Italy , the Netherlands , Canada , Turkey , Australia , Norway and Denmark . In July 2019 United States removed Turkey from the Joint Strike Fighter program, following
3960-535: The US would buy a total of 2,443 JSFs. In April 2009, the Wall Street Journal reported that computer spies, allegedly Chinese but acknowledged to be from uncertain sources, had penetrated the database and acquired terabytes of secret information about the fighter, possibly compromising its future effectiveness. The state-run Aviation Industry Corporation of China (AVIC) has been alleged to incorporate
4050-591: The United States Air Force, has complained that Defense Secretary Les Aspin 's decision to force all three services to use a single airframe greatly increased the costs and difficulty of the project. In November 1995, the United Kingdom signed a memorandum of understanding to become a formal partner, and agreed to pay $ 200 million, or 10% of the concept demonstration phase. In 1997, Canada 's Department of National Defence signed on to
4140-436: The X-32A commenced low- and medium-speed taxi tests, which had been completed by late May. Due to the heavy delta wing design of the X-32, Boeing demonstrated STOVL and supersonic flight in separate configurations, with the STOVL configuration requiring that some parts be removed from the fighter. The company promised that their conventional tail design for production models would not require separate configurations. By contrast,
4230-561: The X-32A was expected to make an appearance, the roll out of the X-32B was a surprise, as construction of the latter aircraft had started some three months after the former and was completed six weeks after the X-32A. Boeing attributed the rapid construction of the STOVL version to the use of digital design and assembly methods. After having the Pratt & Whitney F119 engine installed in April 2000,
4320-589: The addition of a thrust vectoring module around the main engine. However, this choice required the engine to be mounted directly behind the cockpit, and moved the center of gravity forward from its usual position in jet fighters (towards the rear of the airplane) to enable a neutral-attitude hover. Boeing had proposed, in the 1960s, a similar supersonic fighter with a mid-center-of-gravity mounted engine with vectored thrust nozzles, but this never proceeded beyond pictures published in Aviation Week . By comparison,
4410-415: The anisotropic surface impedance, aligned with edges and/or the radar direction. A perfect electric conductor has more back scatter from a leading edge for the linear polarization with the electric field parallel to the edge and more from a trailing edge with the electric field perpendicular to the edge, so the high surface impedance should be parallel to leading edges and perpendicular to trailing edges, for
4500-543: The awarding of the contract, many lawmakers pushed the idea of retaining the losing competitor as a sub-contractor; however, the "winner takes all" principle was not changed. Nonetheless, Boeing views its work on the X-32 as a strategic investment, yielding important technologies which it has been able to adopt in the Boeing F/A-18E/F Super Hornet and other studies. In 2005, the Boeing X-32A
4590-487: The contract, these fighters were required to demonstrate conventional take-off and landing (CTOL), carrier take-off and landing (CV version), and short take-off and vertical landing (STOVL). They were also expected to include ground demonstrations of a production representative aircraft's systems, such as the Preferred Weapon System Concept (PWSC). One major departure from previous projects was
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#17327798872334680-421: The control options described below. With purpose shaping, the shape of the target's reflecting surfaces is designed such that they reflect energy away from the source. The aim is usually to create a “cone-of-silence” about the target's direction of motion. Due to the energy reflection, this method is defeated by using passive (multistatic) radars . Purpose-shaping can be seen in the design of surface faceting on
4770-527: The country's acquisition of the Russian S-400 missile system . Turkey had planned to buy 100 F-35 Lightning II jets. Lockheed Martin 's X-35 would become the basis of the F-35 Lightning II , currently in production and service; Pratt & Whitney 's YF119-PW-611 would be the basis for the F135 -PW-600 on the production F-35B. On April 6, 2009, US Secretary of Defense Robert Gates announced that
4860-410: The design phase, it is often desirable to employ a computer to predict what the RCS will look like before fabricating an actual object. Many iterations of this prediction process can be performed in a short time at low cost, whereas use of a measurement range is often time-consuming, expensive and error-prone. The linearity of Maxwell's equations makes RCS relatively straightforward to calculate with
4950-407: The diffraction coefficients, with the physical theory of diffraction or other high frequency method, combined with physical optics to include the contributions from illuminated smooth surfaces and Fock calculations to calculate creeping waves circling around any smooth shadowed parts. Optimization is in the reverse order. First one does high frequency calculations to optimize the shape and find
5040-630: The dimensions of power (watts), and represents a hypothetical total power intercepted by the radar target. The second 1 4 π r 2 {\textstyle {{1} \over {4\pi r^{2}}}} term represents isotropic spreading of this intercepted power from the target back to the radar receiver. Thus, the product P t G t 4 π r 2 σ 1 4 π r 2 {\textstyle {{P_{t}G_{t}} \over {4\pi r^{2}}}\sigma {{1} \over {4\pi r^{2}}}} represents
5130-477: The fighting qualities of particular fighter aircraft." Furthermore, Maj. Richard Koch, chief of USAF Air Combat Command's advanced air dominance branch is reported to have said that "I wake up in a cold sweat at the thought of the F-35 going in with only two air-dominance weapons" with an Aviation Week article casting an extremely skeptical eye over the (USAF) source of claims that the F-35 would be "400% more effective" than projected opponents. The experience of
5220-487: The greater its RCS. Also, radar of one band may not even detect certain size objects. For example, 10 cm (S-band radar) can detect rain drops but not clouds whose droplets are too small. Materials such as metal are strongly radar reflective and tend to produce strong signals. Wood and cloth (such as portions of airplanes and balloons used to be commonly made) or plastic and fibreglass are less reflective or indeed transparent to radar making them suitable for radomes . Even
5310-494: The greatest radar threat direction, with some sort of smooth transition between. To calculate the radar cross-section of such a stealth body, one would typically do one-dimensional reflection calculations to calculate the surface impedance, then two dimensional numerical calculations to calculate the diffraction coefficients of edges and small three dimensional calculations to calculate the diffraction coefficients of corners and points. The cross section can then be calculated, using
5400-416: The ideal surface impedance is equal to the 377 ohm impedance of free space . For non-isotropic ( anisotropic ) coatings, the optimal coating depends on the shape of the target and the radar direction, but duality, the symmetry of Maxwell's equations between the electric and magnetic fields, tells one that optimal coatings have η 0 × η 1 = 377 Ω , where η 0 and η 1 are perpendicular components of
5490-435: The impedance mismatches, called antenna mode scattering. For the bistatic radar configuration—transmitter and receiver separated (not co-located) -- the bistatic radar cross-section ( BRCS ) is a function of both the transmitter-target orientation and the receiver-target orientation. A normalized bistatic radar cross-section ( NBRCS ) or bistatic normalized radar cross-section ( BNRCS ) may also be defined, similar to
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#17327798872335580-494: The main engine. However, this generated more lift thrust than possible with only direct exhaust gases. A successful design would have greater payload, and thus longer range than a simple thrust vectored turbofan . Flight testing of both companies' aircraft continued until July 2001. On 26 October 2001, the Department of Defense announced that the Lockheed Martin X-35 had won the JSF competition. The X-35 would be developed into
5670-475: The method of achieving STOVL flight, with the Department of Defense judging that the higher performance lift fan system was worth the extra risk. When near to the ground, the Boeing X-32 suffered from the problem of hot air from the exhaust circulating back to the main engine, which caused the thrust to weaken and the engine to overheat. The United States Department of Defense officials and William Bach ,
5760-478: The most important features, then small calculations to find the best surface impedances in the problem areas, then reflection calculations to design coatings. Large numerical calculations can run too slowly for numerical optimization or can distract workers from the physics, even when massive computing power is available. For the case of an antenna the total RCS can be divided into two separate components as Structural Mode RCS and Antenna Mode RCS. The two components of
5850-417: The normal will reflect back along the normal, rounded surfaces make for a strong reflected signal. From the side, a fighter aircraft will present a much larger area than the same aircraft viewed from the front. All other factors being equal, the aircraft will have a stronger signal from the side than from the front; hence the orientation of the target relative to the radar station is important. The relief of
5940-415: The physical profile smaller. Rather, by reflecting much of the radiation away or by absorbing it, the target achieves a smaller radar cross section. Measurement of a target's RCS is performed at a radar reflectivity range or scattering range . The first type of range is an outdoor range where the target is positioned on a specially shaped low RCS pylon some distance down-range from the transmitters. Such
6030-595: The production Lockheed Martin F-35 Lightning II . The loss of the JSF contract to Lockheed Martin in 2001 was a major blow to Boeing, as it represented the most important international fighter aircraft project since the Lightweight Fighter program competition of the 1960s and 1970s, which had led to the F-16 Fighting Falcon and F/A-18 Hornet . At the time, the production run of the JSF was estimated at anywhere between 3,000 and 5,000. Prior to
6120-463: The program will be delayed one year. According to some estimates, overruns could increase the program's total costs to $ 388 billion, a 50% increase from the initial price tag. Many of the program's financial and technical complications result from the Marine version of the JSF, capable of vertical take-offs and landings. On 11 March 2010, United States Senate Committee on Armed Services investigated
6210-542: The progress of the JSF program in a meeting with Pentagon officials, emphasizing cost due to the risk of a Nunn-McCurdy process. According to the Government Accountability Office , F-35A cost has risen from $ 50m in 2002, via $ 69m in 2007 to $ 74m in 2010, all measured in 2002 dollars. Canada reviewed their commitment to the project in December 2012, due to the cost overruns. The decision
6300-430: The prohibition of the companies from using their own money to finance development. Each was awarded $ 750 million to produce their two aircraft – including avionics, software and hardware. This limitation promoted the adoption of low cost manufacturing and assembly techniques, and also prevented either Boeing or Lockheed Martin from bankrupting themselves in an effort to win such an important contest. Boeing's strategy for
6390-412: The radar is perpendicular to the flat surface. At off-normal incident angles , energy is reflected away from the receiver, reducing the RCS. Modern stealth aircraft are said to have an RCS comparable with small birds or large insects, though this varies widely depending on aircraft and radar. If the RCS was directly related to the target's cross-sectional area, the only way to reduce it would be to make
6480-417: The radar transmitter produces at the target. This power density is intercepted by the target with radar cross-section σ {\textstyle \sigma } , which has units of area (meters squared). Thus, the product P t G t 4 π r 2 σ {\textstyle {{P_{t}G_{t}} \over {4\pi r^{2}}}\sigma } has
6570-426: The receiver is produced. This statement can be understood by examining the monostatic (radar transmitter and receiver co-located) radar equation one term at a time: where The P t G t 4 π r 2 {\textstyle {{P_{t}G_{t}} \over {4\pi r^{2}}}} term in the radar equation represents the power density (watts per meter squared) that
6660-405: The reflected and generated signals, resulting in reduced RCS. To incorporate active cancellation techniques, the precise characteristics of the waveform and angle of arrival of the illuminating radar signal must be known, since they define the nature of generated energy required for cancellation. Except against simple or low frequency radar systems, the implementation of active cancellation techniques
6750-419: The reflected power density at the radar receiver (again watts per meter squared). The receiver antenna then collects this power density with effective area A e f f {\textstyle A_{\mathrm {eff} }} , yielding the power received by the radar (watts) as given by the radar equation above. The scattering of incident radar power by a radar target is never isotropic (even for
6840-594: The request of the Navy and Boeing's delta wing design fell short of the new targets. Engineers altered the aircraft's design with a conventional canted twin tail that reduced weight and improved agility, but it was too late to change the demonstrator aircraft. It was judged that they would be sufficient to demonstrate Boeing's technology. On 14 December 1999, Boeing unveiled both its concept demonstrators at its plant in Palmdale, California, in front of 5,500 attendees. While
6930-533: The shortened flight, about 80% of the planned test points were accomplished. It was powered by a conventional derivative of the F-22 afterburning turbofan, designated F119-PW-614C. On 29 March 2001, the X-32B STOVL version made its first flight. The flight lasted 50 minutes as the aircraft flew from Palmdale to Edwards AFB. The flight had originally been scheduled for the third quarter of 2000. A modified version of
7020-412: The source, many protrusions like the engines, antennas, etc.). RCS is integral to the development of radar stealth technology , particularly in applications involving aircraft and ballistic missiles . RCS data for current military aircraft is mostly highly classified. In some cases, it is of interest to look at an area on the ground that includes many objects. In those situations, it is useful to use
7110-453: The symbol σ and expressed in square meters. This does not equal geometric area. A perfectly conducting sphere of projected cross sectional area 1 m (i.e. a diameter of 1.13 m) will have an RCS of 1 m . For radar wavelengths much less than the diameter of the sphere, RCS is independent of frequency. Conversely, a square flat plate of area 1 m will have an RCS of σ = 4π A / λ (where A =area, λ =wavelength), or 139.62 m at 1 GHz if
7200-487: The trend in purpose shaping and promise to have even smaller monostatic RCS. This technique is relatively new compared to other techniques chiefly after the invention of metasurfaces . As mentioned earlier, the primary objective in geometry alteration is to redirect scattered waves away from the backscattered direction (or the source). However, it may compromise performance in terms of aerodynamics. One feasible solution, which has extensively been explored in recent time,
7290-499: The two to be merged into one program under the JAST name, which was renamed the Joint Strike Fighter (JSF) program in 1995. Many companies took part in the first phase of this project, which involved drafting concept aircraft designs for submission to the Department of Defense . On 16 November 1996, Boeing and Lockheed Martin were awarded contracts for them to produce two of their concept demonstrator aircraft (CDA) each. Under
7380-475: Was also a pair of ducts leading to roll nozzles near the wing tips. Two pairs of ducts fed the aft-pitch yaw nozzles and the forward-pitch nozzles. The afterburner was unlit, with no gas flow during lift. The X-32B achieved STOVL flight in much the same way as the AV-8B Harrier II with thrust vectoring of the jet exhaust. A smooth transition (between STOVL and normal modes) was obtained by maintaining
7470-493: Was made following a report by auditing firm KPMG that showed that Canada's purchase would cost C$ 45bn over 42 years. Rona Ambrose , Canada's public works minister said: “We have hit the reset button and are taking the time to do a complete assessment of all available aircraft.” Defence Minister Peter MacKay announced Canada's plan to buy the F-35 in 2010 saying that the purchase price was $ 9 billion, but did not provide operating cost estimates. During an election campaign in 2011,
7560-479: Was rejected in part due to the complexity of its design. Lockheed Martin and Boeing were each given $ 750 million to develop their concept demonstrators and the definition of the Preferred Weapon System Concept (PWSC). The aim of this funding limit was to prevent one or both contractors from bankrupting themselves in an effort to win such an important contract. Also in 1996, the UK Ministry of Defence launched
7650-504: Was the final qualifying Joint Strike Fighter flight trials, in which the X-35B STOVL aircraft took off in less than 500 feet (150 m), went supersonic, and landed vertically – a feat that Boeing 's entry was unable to achieve. The contract for System Development and Demonstration (SDD) was awarded on 26 October 2001 to Lockheed Martin, whose X-35 beat the Boeing X-32 . One of the main reasons for this choice appears to have been
7740-426: Was the potential direct visibility of the compressor blades to radar (see radar cross-section ). Mitigation possibilities included variable baffles designed to block incoming radio waves without adversely affecting airflow. The two X-32 aircraft featured a delta wing design. However, eight months into construction of the concept demonstrator aircraft, the JSF's maneuverability and payload requirements were refined at
7830-493: Was to allow for a thick wing section to be used while still providing limited transonic aerodynamic drag , and to provide a good angle for wing-installed conformal antenna equipment. The wing would prove a challenge to fabricate. The compete-on-cost strategy also led Boeing to pick a direct-lift thrust vectoring system, for the Marines' short take-off and vertical landing (STOVL) requirement, as this would only necessitate
7920-504: Was to develop a stealth-enabled design to replace all of United States Department of Defense lighter weight fighter and attack aircraft, including the F-16 Fighting Falcon , McDonnell Douglas F/A-18 Hornet , and vertical/short takeoff / vertical landing ( V/STOL ) AV-8B Harrier II . Around the same time, the Joint Advanced Strike Technology (JAST) project was started and in 1994, the U.S. Congress ordered
8010-556: Was transferred to the National Museum of the United States Air Force near Dayton, Ohio . Its condition deteriorated due to being outside for several years following the end of the JSF competition. In December 2023, the museum completed a three-month-long restoration of the aircraft. On 31 May 2024, the X-32A was moved into the R&;D gallery as a display, parked close to the similarly ill-fated YF-23 "Black Widow II". The X-32B
8100-743: Was transferred to the Patuxent River Naval Air Museum adjacent to NAS Patuxent River in St. Mary's County, Maryland in 2005. It underwent restoration at the museum's restoration facility in June 2009 and was placed on display outdoors, where it has suffered from severe deterioration due to exposure to the elements. Data from Frawley General characteristics Performance Armament Aircraft of comparable role, configuration, and era Related lists Joint Strike Fighter program Joint Strike Fighter ( JSF )
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