167-599: The Advanced Tactical Fighter ( ATF ) was a program undertaken by the United States Air Force to develop a next-generation air superiority fighter to replace the F-15 Eagle in order to counter emerging worldwide threats in the 1980s, including Soviet Sukhoi Su-27 and Mikoyan MiG-29 fighters under development, Beriev A-50 airborne warning and control systems (AWACS), and increasingly sophisticated surface-to-air missile systems. The ATF would make
334-470: A corner reflector consisting of either a dihedral (two plates) or a trihedral (three orthogonal plates). This configuration occurs in the tail of a conventional aircraft, where the vertical and horizontal components of the tail are set at right angles. Stealth aircraft such as the F-117 use a different arrangement, tilting the tail surfaces to reduce corner reflections formed between them. A more radical method
501-617: A radial velocity component relative to the radar. Mission planners use their knowledge of enemy radar locations and the RCS pattern of the aircraft to design a flight path that minimizes radial speed while presenting the lowest-RCS aspects of the aircraft to the threat radar. To be able to fly these "safe" routes, it is necessary to understand an enemy's radar coverage (see electronic intelligence ). Airborne or mobile radar systems such as airborne early warning and control (AEW&C, AWACS) can complicate tactical strategy for stealth operation. After
668-628: A "systemic problem" in the USAF's management of the nuclear mission. Stealth technology Stealth technology , also termed low observable technology ( LO technology ), is a sub-discipline of military tactics and passive and active electronic countermeasures . The term covers a range of methods used to make personnel, aircraft , ships , submarines , missiles , satellites , and ground vehicles less visible (ideally invisible ) to radar , infrared , sonar and other detection methods. It corresponds to military camouflage for these parts of
835-588: A 50-month Dem/Val phase, culminating in the flight test of two technology demonstrator prototypes, the YF-22 and the YF-23 ; Pratt & Whitney and General Electric would also receive $ 341 million (~$ 820 million in 2023) each for the development and prototyping of the competing engines (designated YF119 and YF120 respectively), and the JAFE propulsion effort would later be renamed ATF Engine (ATFE) and directly managed by
1002-451: A British bomber of the 1960s, had a remarkably small appearance on radar despite its large size, and occasionally disappeared from radar screens entirely. It is now known that it had a fortuitously stealthy shape apart from the vertical element of the tail. Despite being designed before a low radar cross-section (RCS) and other stealth factors were ever a consideration, a Royal Aircraft Establishment technical note of 1957 stated that of all
1169-426: A broader dimension of time or space than do tactics; they provide the means by which tactical successes are exploited to achieve strategic and operational objectives. Tactical Level Command and Control is where individual battles and engagements are fought. The tactical level of war deals with how forces are employed, and the specifics of how engagements are conducted and targets attacked. The goal of tactical level C2
1336-438: A cleanup plan for drinking water around Tucson, Arizona after the region's groundwater was contaminated by PFAS runoff from nearby Air Force bases. The United States Air Force has been involved in many wars, conflicts and operations using military air operations. The USAF possesses the lineage and heritage of its predecessor organizations, which played a pivotal role in U.S. military operations since 1907: In addition since
1503-458: A commander in planning, directing, coordinating, and controlling forces and operations in the accomplishment of the mission" (JP 1-02). This core function includes all of the C2-related capabilities and activities associated with air, cyberspace, nuclear, and agile combat support operations to achieve strategic, operational, and tactical objectives. At the strategic level command and control,
1670-479: A competitive flyoff or represent a production aircraft that meets every requirement, but to demonstrate the viability of its concept and mitigate risk. In July 1986, proposals were provided by Boeing , General Dynamics , Grumman , Lockheed , Northrop , McDonnell Douglas , and North American Rockwell ; Grumman and North American Rockwell would drop out shortly afterwards. Because contractors were expected to make immense investments of their own — likely approaching
1837-402: A digital glitch in the processing system. Stealth airframes sometimes display distinctive serrations on some exposed edges, such as the engine ports. The YF-23 has such serrations on the exhaust ports. This is another example in the parallel alignment of features, this time on the external airframe. The shaping requirements detracted greatly from the F-117 's aerodynamic properties. It
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#17327798149692004-482: A door or hatch opens. Parallel alignment of edges or even surfaces is also often used in stealth designs. The technique involves using a small number of edge orientations in the shape of the structure. For example, on the F-22A Raptor , the leading edges of the wing and the tail planes are set at the same angle. Other smaller structures, such as the air intake bypass doors and the air refueling aperture, also use
2171-894: A force multiplier. It allows air assets to more rapidly reach any trouble spot around the world with less dependence on forward staging bases or overflight/landing clearances. Air refueling significantly expands the options available to a commander by increasing the range, payload, persistence, and flexibility of receiver aircraft. Aeromedical evacuation is "the movement of patients under medical supervision to and between medical treatment facilities by air transportation" (JP 1-02). JP 4-02, Health Service Support, further defines it as "the fixed wing movement of regulated casualties to and between medical treatment facilities, using organic and/or contracted mobility airframes, with aircrew trained explicitly for this mission." Aeromedical evacuation forces can operate as far forward as fixed-wing aircraft are able to conduct airland operations. Global precision attack
2338-498: A leap in performance and capability by taking advantage of emerging technologies, including advanced avionics and flight control systems, more powerful propulsion systems, and stealth technology. Lockheed and Northrop were selected in 1986 to respectively develop the YF-22 and the YF-23 technology demonstrator prototype aircraft and associated avionics prototypes for the program's Demonstration and Validation (Dem/Val) phase. These aircraft were flight tested in 1990; after evaluations,
2505-523: A nation state, or non-state/transnational actor. The Air Force maintains and presents credible deterrent capabilities through successful visible demonstrations and exercises that assure allies, dissuade proliferation, deter potential adversaries from actions that threaten US national security or the populations, and deploy military forces of the US, its allies, and friends. Nuclear strike is the ability of nuclear forces to rapidly and accurately strike targets which
2672-422: A number of stealthy features including special fuel to reduce the signature of the exhaust plume, canted vertical stabilizers, the use of composite materials in key locations, and the overall finish in radar-absorbent paint. In 1960, the USAF reduced the radar cross-section of a Ryan Q-2C Firebee drone. This was achieved through specially designed screens over the air intake, and radiation-absorbent material on
2839-697: A part in the development of composite material and curvilinear surfaces, low observables, fly-by-wire, and other stealth technology innovations. The success of Have Blue led the Air Force to create the Senior Trend program which developed the F-117. In the early 21st century, the proliferation of stealth technology began outside of the United States. Both Russia and China tested their stealth aircraft in 2010. Russia manufactured 10 flyable prototypes of
3006-557: A person or vehicle can be detected; more so radar cross-section reductions , but also acoustic , thermal , and other aspects. Almost since the invention of radar , various methods have been tried to minimize detection. Rapid development of radar during World War II led to equally rapid development of numerous counter radar measures during the period; a notable example of this was the use of chaff . Modern methods include radar jamming and deception . The term stealth in reference to reduced radar signature aircraft became popular during
3173-405: A precondition" (Annex 3–70, Strategic Attack). Air Interdiction is defined as "air operations conducted to divert, disrupt, delay, or destroy the enemy's military potential before it can be brought to bear effectively against friendly forces, or to otherwise achieve JFC objectives. Air Interdiction is conducted at such distance from friendly forces that detailed integration of each air mission with
3340-465: A primary role for submarines and ground vehicles. Submarines use extensive rubber mountings to isolate, damp, and avoid mechanical noises that can reveal locations to underwater passive sonar arrays. Early stealth observation aircraft used slow-turning propellers to avoid being heard by enemy troops below. Stealth aircraft that stay subsonic can avoid being tracked by sonic boom . The presence of supersonic and jet-powered stealth aircraft such as
3507-494: A rapid cessation of hostilities. Post-conflict, regeneration of a credible nuclear deterrent capability will deter further aggression. The Air Force may present a credible force posture in either the Continental United States , within a theater of operations, or both to effectively deter the range of potential adversaries envisioned in the 21st century. This requires the ability to engage targets globally using
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#17327798149693674-535: A review of the flight test results and proposals, the USAF announced the Lockheed team and Pratt & Whitney as the competition winner for full-scale development, or Engineering and Manufacturing Development (EMD), on 23 April 1991; by this time, the 1990 Major Aircraft Review by Defense Secretary Dick Cheney had reduced the planned total ATF buy to 650 aircraft and peak production rate to 48 per year. Both air vehicle designs met or exceeded all performance requirements;
3841-710: A sharp reduction in flight hours for crew training since 2005 and the Deputy Chief of Staff for Manpower and Personnel directing Airmen's Time Assessments. On 5 June 2008, Secretary of Defense Robert Gates accepted the resignations of both the Secretary of the Air Force , Michael Wynne , and the Chief of Staff of the Air Force , General T. Michael Moseley . In his decision to fire both men Gates cited "systemic issues associated with... declining Air Force nuclear mission focus and performance". Left unmentioned by Gates
4008-497: A sizeable return), and possibly return to the radar, but the conductive coating creates a controlled shape that deflects the incoming radar waves away from the radar. The coating is thin enough that it has no adverse effect on pilot vision. Ships have also adopted similar methods. Though the earlier Arleigh Burke-class destroyer incorporated some signature-reduction features. the Norwegian Skjold-class corvette
4175-439: A square flat plate of area 1 m will have an RCS of σ=4π A / λ (where A =area, λ =wavelength), or 13,982 m at 10 GHz if 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
4342-483: A stealth vehicle must avoid radiating any other detectable energy, such as from onboard radars, communications systems, or RF leakage from electronics enclosures. The F-117 uses passive infrared and low light level television sensor systems to aim its weapons and the F-22 Raptor has an advanced LPI radar which can illuminate enemy aircraft without triggering a radar warning receiver response. The size of
4509-452: A strong focus on the improvement of Basic Military Training (BMT) for enlisted personnel. While the intense training has become longer, it also has shifted to include a deployment phase. This deployment phase, now called the BEAST, places the trainees in a simulated combat environment that they may experience once they deploy. While the trainees do tackle the massive obstacle courses along with
4676-421: A takeoff gross weight of 50,000 pounds (23,000 kg), a mission radius of 500 nautical miles (930 km) mixed subsonic/supersonic or 700–800 nautical miles (1,300–1,480 km) subsonic, supercruise speed of Mach 1.4–1.5, the ability to use a 2,000-foot (600 m) runway, and signature reduction particularly in the frontal sector. A request for proposals (RFP) for demonstration and validation (Dem/Val)
4843-420: A target's image on radar is measured by the radar cross section (RCS), often represented by 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 . Note that for radar wavelengths much less than the diameter of the sphere, RCS is independent of frequency. Conversely,
5010-417: A team with a similar agreement. On 31 October 1986, Lockheed and Northrop, the two industry leaders in stealth aircraft , were selected as first and second place respectively and would proceed as the finalists. Noteworthy is the divergent approach of the two finalists' proposals. Northrop's proposal leveraged its considerable experience with stealth to produce a refined and well-understood aircraft design that
5177-510: A variety of methods; therefore, the Air Force should possess the ability to induct, train, assign, educate and exercise individuals and units to rapidly and effectively execute missions that support US NDO objectives. Finally, the Air Force regularly exercises and evaluates all aspects of nuclear operations to ensure high levels of performance. Nuclear surety ensures the safety, security and effectiveness of nuclear operations. Because of their political and military importance, destructive power, and
Advanced Tactical Fighter - Misplaced Pages Continue
5344-417: Is inherently unstable , and cannot be flown without a fly-by-wire control system . Similarly, coating the cockpit canopy with a thin film transparent conductor ( vapor-deposited gold or indium tin oxide ) helps to reduce the aircraft's radar profile, because radar waves would normally enter the cockpit, reflect off objects (the inside of a cockpit has a complex shape, with a pilot helmet alone forming
5511-459: Is "the acquisition of information and the provision of this information to processing elements" (JP 2-01). It provides the ability to obtain required information to satisfy intelligence needs (via use of sources and methods in all domains). Collection activities span the Range of Military Operations (ROMO). Processing and exploitation is "the conversion of collected information into forms suitable to
5678-417: Is "the employment of limited offensive action and counterattacks to deny a contested area or position to the enemy" (JP 1-02). It includes both ballistic missile defense and airborne threat defense and encompasses point defense, area defense, and high-value airborne asset defense. Passive defense is "measures taken to reduce the probability of and to minimize the effects of damage caused by hostile action without
5845-543: Is a phenomenon proposed to use ionized gas, termed a plasma , to reduce RCS of vehicles. Interactions between electromagnetic radiation and ionized gas have been studied extensively for many purposes, including concealing vehicles from radar. Various methods might form a layer or cloud of plasma around a vehicle to deflect or absorb radar, from simpler electrostatic to radio frequency (RF) more complex laser discharges, but these may be difficult in practice. Several technology research and development efforts exist to integrate
6012-414: Is assumed that Yehudi lights could be used in the future to hide the airframe (against the background of the sky, including at night, aircraft of any colour appear dark ) or as a sort of active camouflage. The original B-2 design had wing tanks for a contrail -inhibiting chemical, alleged by some to be chlorofluorosulfonic acid, but this was replaced in the final design with a contrail sensor that alerts
6179-425: Is defined as "all the defensive measures designed to detect, identify, intercept, and destroy or negate enemy forces attempting to penetrate or attack through friendly airspace" (JP 1-02). In concert with OCA operations, a major goal of DCA operations is to provide an area from which forces can operate, secure from air and missile threats. The DCA mission comprises both active and passive defense measures. Active defense
6346-534: Is defined as "offensive operations to destroy, disrupt, or neutralize enemy aircraft, missiles, launch platforms, and their supporting structures and systems both before and after launch, but as close to their source as possible" (JP 1-02). OCA is the preferred method of countering air and missile threats since it attempts to defeat the enemy closer to its source and typically enjoys the initiative. OCA comprises attack operations, sweep, escort, and suppression/destruction of enemy air defense. Defensive Counter-Air (DCA)
6513-518: Is designed from the outset to have a chosen spectral signature . The degree of stealth embodied in a given design is chosen according to the projected threats of detection. Camouflage to aid or avoid predation predates humanity, and hunters have been using vegetation to conceal themselves, perhaps as long as people have been hunting. The earliest application of camouflage in warfare is impossible to ascertain. Methods for visual concealment in war were documented by Sun Tzu in his book The Art of War in
6680-414: Is essential, and mistakes can lead to detectability enhancement rather than the desired reduction. An exhaust plume contributes a significant infrared signature. One means to reduce IR signature is to have a non-circular tail pipe (a slit shape) to minimize the exhaust cross sectional area and maximize the mixing of hot exhaust with cool ambient air (see Lockheed F-117 Nighthawk , rectangular nozzles on
6847-460: Is proportional to the fourth root of RCS; thus, reducing detection range by a factor of 10 requires a reduction of RCS by a factor of 10,000. The possibility of designing aircraft in such a manner as to reduce their radar cross-section was recognized in the late 1930s, when the first radar tracking systems were employed, and it has been known since at least the 1960s that aircraft shape makes a significant difference in detectability. The Avro Vulcan ,
Advanced Tactical Fighter - Misplaced Pages Continue
7014-482: Is radar transparent or absorbing, behind which are structures termed reentrant triangles . Radar waves penetrating the skin get trapped in these structures, reflecting off the internal faces and losing energy. This method was first used on the Blackbird series: A-12 , YF-12A , Lockheed SR-71 Blackbird . The most efficient way to reflect radar waves back to the emitting radar is with orthogonal metal plates, forming
7181-451: Is the Lockheed team's complete redesign of the entire YF-22's shape and configuration in summer of 1987 due to weight concerns, while the YF-23 was a continual refinement of Northrop's concept prior to Dem/Val proposal submission. Accurate artwork of the prototypes, which had been highly classified due to the stealth shaping, was first officially released in 1990 ahead of their public unveiling;
7348-486: Is the ability to hold at risk or strike rapidly and persistently, with a wide range of munitions, any target and to create swift, decisive, and precise effects across multiple domains. Strategic attack is defined as "offensive action specifically selected to achieve national strategic objectives. These attacks seek to weaken the adversary's ability or will to engage in conflict, and may achieve strategic objectives without necessarily having to achieve operational objectives as
7515-583: Is the cornerstone of the credibility of the NDO mission. Positive nuclear command, control, communications; effective nuclear weapons security; and robust combat support are essential to the overall NDO function. Command and control is "the exercise of authority and direction by a properly designated commander over assigned and attached forces in the accomplishment of the mission. Command and control functions are performed through an arrangement of personnel, equipment, communications, facilities, and procedures employed by
7682-684: Is to achieve commander's intent and desired effects by gaining and keeping offensive initiative. The origins of the United States Air Force can be traced back to the Union Army Balloon Corps of the American Civil War . The Union Balloon Corps, established by aeronaut Thaddeus S. C. Lowe , provided aerial reconnaissance for the Union Army . This early use of balloons for military purposes marked
7849-462: Is to omit the tail, as in the B-2 Spirit . The B-2's clean, low-drag flying wing configuration gives it exceptional range and reduces its radar profile. The flying wing design most closely resembles a so-called infinite flat plate (as vertical control surfaces dramatically increase RCS), the perfect stealth shape, as it would have no angles to reflect back radar waves. In addition to altering
8016-429: Is to provide what the Air Force states as global vigilance, global reach, and global power. Air superiority is "that degree of dominance in the air battle of one force over another which permits the conduct of operations by the former and its related land, sea, air, and special operations forces at a given time and place without prohibitive interference by the opposing force" (JP 1-02). Offensive Counter-Air (OCA)
8183-571: Is to use metasurfaces which can redirect scattered waves without altering the geometry of a target. Such metasurfaces can primarily be classified in two categories: (i) checkerboard metasurfaces, (ii) gradient index metasurfaces. Similarly, negative index metamaterials are artificial structures for which refractive index has a negative value for some frequency range, such as in microwave, infrared, or possibly optical. These offer another way to reduce detectability, and may provide electromagnetic near-invisibility in designed wavelengths. Plasma stealth
8350-591: The Have Blue / F-117 , Tacit Blue , and the Advanced Technology Bomber (ATB) program (which would result in the B-2 Spirit , or " Senior Ice ") promised greatly reduced radar cross sections (RCS) that were orders of magnitude smaller than existing aircraft. The ATF requirements would place increasing emphasis on stealth to improve survivability over the course of concept exploration, while still demanding fighter-like speed and maneuverability;
8517-689: The Bomber Mafia ), followed by fighters ( Fighter Mafia ). In response to a 2007 United States Air Force nuclear weapons incident , Secretary of Defense Robert Gates accepted in June 2009 the resignations of Secretary of the Air Force Michael Wynne and the Chief of Staff of the Air Force General T. Michael Moseley . Moseley's successor, General Norton A. Schwartz , a former airlift and special operations pilot,
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#17327798149698684-582: The Department of Defense . The Air Force through the Department of the Air Force is headed by the civilian Secretary of the Air Force , who reports to the Secretary of Defense and is appointed by the President with Senate confirmation . The highest-ranking military officer in the Air Force is the Chief of Staff of the Air Force , who exercises supervision over Air Force units and serves as one of
8851-628: The F-15E Strike Eagle ) as well as the then-classified F-117 Nighthawk (" Senior Trend "), while the air-to-air threat from the new Soviet fighters and AWACS remained. Additionally, as with ASD and industry responses, TAC did not want the ATF to be at either extremes of the quality-versus-quantity spectrum. Thus, the ATF would be a new air superiority fighter in the vein of the SCM concept with outstanding aerodynamic performance, and intended to replace
9018-606: The Gulf War . While the YF-23 air vehicle was in a higher state of maturity and refinement compared to the YF-22 due to the latter's late redesign and partly as a result had better flight performance, the Lockheed team executed a more aggressive flight test plan with considerably higher number of sorties and hours flown; furthermore, Lockheed chose to execute high-visibility tests such as firing missiles and high angle-of-attack maneuvers that, while not required, improved its perception by
9185-614: The Joint Chiefs of Staff . As directed by the Secretary of Defense and Secretary of the Air Force, certain Air Force components are assigned to unified combatant commands . Combatant commanders are delegated operational authority of the forces assigned to them, while the Secretary of the Air Force and the Chief of Staff of the Air Force retain administrative authority over their members. Along with conducting independent air operations,
9352-545: The Lockheed Martin F-22 , and serrated nozzle flaps on the Lockheed Martin F-35 ). Often, cool air is deliberately injected into the exhaust flow to boost this process (see Ryan AQM-91 Firefly and Northrop B-2 Spirit ). The Stefan–Boltzmann law shows how this results in less energy ( Thermal radiation in infrared spectrum) being released and thus reduces the heat signature. In some aircraft,
9519-678: The MiG-31 "Foxhound" , as well as the appearance of an Il-76 -based airborne warning and control system (AWACS) aircraft called the A-50 "Mainstay" ; these systems, revealed in 1978, greatly reduced the effectiveness and survivability of low-altitude penetration . Furthermore, experience and data from the Vietnam War and the more recent 1973 Arab-Israeli war demonstrated the increasing lethality and sophistication of Soviet surface-to-air missile systems. In 1981, USAF began forming requirements for
9686-646: The National Security Act of 1947 (61 Stat . 502), which created the USAF: Section 9062 of Title 10 US Code defines the purpose of the USAF as: The five core missions of the Air Force have not changed dramatically since the Air Force became independent in 1947, but they have evolved and are now articulated as air superiority, global integrated ISR (intelligence, surveillance and reconnaissance), rapid global mobility, global strike, and command and control. The purpose of all of these core missions
9853-470: The SR-71 Blackbird indicates that acoustic signature is not always a major driver in aircraft design, as the Blackbird relied more on its very high speed and altitude. One method to reduce helicopter rotor noise is modulated blade spacing . Standard rotor blades are evenly spaced, and produce greater noise at a given frequency and its harmonics . Using varied spacing between the blades spreads
10020-776: The Soviet Union . Between 1977 and 1979, American satellite photographs of the " Ram-K " and " Ram-L " fighter prototypes at Ramenskoye air base in Zhukovsky—later identified as the Su-27 "Flanker" and the MiG-29 "Fulcrum" respectively—indicated that a new generation of Soviet fighter aircraft comparable to the recently introduced F-15 Eagle and F-16 Fighting Falcon would soon enter service. Also concerning were Soviet reports of " look-down/shoot-down " capability being introduced on an advanced MiG-25 derivative, later revealed to be
10187-656: The United States Armed Forces , and is one of the eight uniformed services of the United States . Originally created on 1 August 1907, as a part of the United States Army Signal Corps , the USAF was established as a separate branch of the United States Armed Forces in 1947 with the enactment of the National Security Act of 1947 . It is the second youngest branch of the United States Armed Forces and
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#173277981496910354-533: The Very High Speed Integrated Circuit program. The Dem/Val phase for avionics development was marked by demonstrations of the hardware and software with Avionics Ground Prototypes (AGP) to evaluate performance and reliability. The SPO gave the teams flexibility to pick their own vendors for some subsystems; for instance, the Lockheed team's infrared search and track (IRST) sensor was supplied by General Electric, while Northrop team's
10521-425: The diffraction-limited systems given their long wavelengths, and by the radar's size, making it difficult to transport. A long-wave radar may detect a target and roughly locate it, but not provide enough information to identify it, target it with weapons, or even to guide a fighter to it. Stealth aircraft attempt to minimize all radar reflections, but are specifically designed to avoid reflecting radar waves back in
10688-557: The dissolution of the Soviet Union in 1991 and the subsequent reductions in defense spending, the F-22's development would be "re-phased", or drawn out and extended multiple times. The program was scrutinized for its costs and less expensive alternatives such as modernized F-15 or F-16 variants were continually being proposed, even though the USAF considered the F-22 to provide the greatest capability increase against peer adversaries for
10855-505: The 5th century BC, and by Frontinus in his work Strategemata in the 1st century AD. In England, irregular units of gamekeepers in the 17th century were the first to adopt drab colours (common in 16th century Irish units) as a form of camouflage , following examples from the continent. During World War I , the Germans experimented with the use of Cellon ( Cellulose acetate ), a transparent covering material, in an attempt to reduce
11022-618: The ATF Concept Development Team had become the System Program Office (SPO) led by Colonel Albert C. Piccirillo at Wright-Patterson Air Force Base . After discussions with Tactical Air Command (TAC), the CDT/SPO determined that the ATF should focus on air-to-air missions; the air-to-surface missions would be handled by the upgraded F-111 , the upcoming Dual-Role Fighter (DRF) (which would result in
11189-469: The ATF SPO. The Dem/Val phase was intended to develop and mature ATF technologies that would facilitate the fighter's eventual full-scale development and production, and focused on three main activities: requirements and system specification development, avionics ground prototypes and flying laboratories, and prototype air vehicles. During Dem/Val, the ATF SPO program manager was Colonel James A. Fain, while
11356-537: The ATF was still early in its requirements definition, including whether the aircraft should be focused on air-to-air or air-to-surface, there was great variety in the RFI responses; the submitted designs generally fell into four concepts. Further analysis by ASD would indicate that the best air-to-surface concept was SLO, while the best air-to-air concept was SCM; neither N nor HI were rated highly, and responses from contractors also broadly agreed on avoiding either extremes of
11523-469: The ATF would make a leap in avionics performance with a fully integrated avionics suite that fuses sensor information together into a common tactical picture, thus improving the pilot's situational awareness and reducing workload; the avionics were expected to make up about 40% of the ATF's flyaway cost. The avionics system was to employ the PAVE PILLAR system architecture and leverage technology from
11690-741: The ATF, eventually codenamed " Senior Sky ". In May, a request for information (RFI) was published by the USAF Aeronautical Systems Division (ASD), followed by another RFI for the ATF propulsion systems in June. Design concepts were provided by defense contractors and analyzed by the ASD, which released their final report in December 1982. During this time, the ASD also established an internal ATF Concept Development Team in October 1982 to manage concept development studies. As
11857-671: The Advanced Tactical Fighter in August 1991, initially worth $ 9.55 billion and $ 1.375 billion respectively for a total of approximately $ 11 billion (~$ 21.9 billion in 2023) as cost-plus contracts (which did eventually grow considerably). The YF-22 design was evolved and significantly refined to become the EMD/production F-22 Raptor version, which first flew in September 1997. However, with
12024-422: The Air Force's readiness to carry out the nuclear strike operations mission as well as from specific actions taken to assure allies as a part of extended deterrence. Dissuading others from acquiring or proliferating WMD and delivering them contributes to promoting security and is also an integral part of this mission. Moreover, different deterrence strategies are required to deter various adversaries, whether they are
12191-547: The BEAST, the other portions include defending and protecting their base of operations, forming a structure of leadership, directing search and recovery, and basic self aid buddy care. During this event, the Military Training Instructors (MTI) act as mentors and opposing forces in a deployment exercise. In November 2022, the USAF announced that it will discontinue BEAST and replace it with another deployment training program called PACER FORGE. In 2007,
12358-707: The Kriegsmarine on submarines in World War II. Tests showed they were effective in reducing radar signatures at both short (centimetres) and long (1.5 metre) wavelengths. In 1956, the CIA began attempts to reduce the radar cross-section (RCS) of the U-2 spyplane. Three systems were developed, Trapeze, a series of wires and ferrite beads around the planform of the aircraft, a covering material with PCB circuitry embedded in it, and radar-absorbent paint. These were deployed in
12525-462: The Lockheed and Northrop teams respectively, not counting additional investments during prior phases or by subcontractors; Pratt & Whitney and General Electric would each invest $ 100 million as well (~$ 222 million in 2023). With the ATF system specification, the SPO had set the technical requirements without specifying the "how"; this was meant to give the contractor teams flexibility in developing
12692-474: The Lockheed team was selected in 1991 for ATF full-scale development, or Engineering and Manufacturing Development (EMD). The Lockheed team then developed the F-22 Raptor , which first flew in 1997, for production and operational service. The U.S. Navy considered using a naval version of the ATF (called NATF) as a replacement for the F-14 Tomcat , but these plans were later canceled due to costs. Although
12859-797: The Navy , and the newly created Department of the Air Force. Prior to 1947, the responsibility for military aviation was shared between the Army Air Forces and its predecessor organizations (for land-based operations), the Navy (for sea-based operations from aircraft carriers and amphibious aircraft), and the Marine Corps (for close air support of Marine Corps operations). The 1940s proved to be important for military aviation in other ways as well. In 1947, Air Force Captain Chuck Yeager broke
13026-568: The Navy under Congressional pressure joined the ATF program initially as an observer to examine the possibility using a navalised derivative, named the Navy Advanced Tactical Fighter (NATF), to replace the F-14 Tomcat ; the Navy would eventually announced that they would procure 546 aircraft under the NATF program at a peak rate of 48 per year. The Dem/Val RFP would indeed see some changes after its first release that pushed
13193-566: The Northrop team using a modified BAC One-Eleven . The avionics requirements were also the subject of SRRs and adjustments; as avionics was a significant cost driver, side-looking radars were deleted, and the dedicated IRST system was downgraded from multicolor to single color before changing from requirement to goal and provision for future addition. In 1989, a $ 9 million per aircraft cost cap on avionics in FY 1985 dollars (~$ 21.7 million in 2023)
13360-564: The RCS was directly related to the target's cross-sectional area, the only way to reduce it would be to make the physical profile smaller. Rather, by reflecting much of the radiation away or by absorbing it, the target achieves a smaller radar cross section. Stealthy strike aircraft such as the Lockheed F-117 Nighthawk , are usually used against heavily defended enemy sites such as command and control centers or surface-to-air missile (SAM) batteries. Enemy radar will cover
13527-461: The ROMO. The purpose of nuclear deterrence operations (NDO) is to operate, maintain, and secure nuclear forces to achieve an assured capability to deter an adversary from taking action against vital US interests. In the event deterrence fails, the US should be able to appropriately respond with nuclear options. The sub-elements of this function are: Assure/Dissuade/Deter is a mission set derived from
13694-451: The SPO had anticipated procuring 750 ATFs at a unit cost of $ 35 million in fiscal year (FY) 1985 dollars (~$ 84.2 million in 2023) with final design selection in 1989 and service entry in 1995 with a peak production rate of 72 aircraft per year, although even at this point the peak rate was being questioned and the entry date was at risk of slipping to the late 1990s due to potential RFP adjustments and budget constraints. Shortly afterwards,
13861-453: The SPO's willingness to give contractor teams the flexibility in determining how to achieve the ATF requirements, the flight test plans were created and executed by the teams themselves and the prototype air vehicles were not flown against each other for direct comparisons; neither the YF-22 nor YF-23 would share the same test points, which were set by their own teams to demonstrate concept viability and validate engineering predictions. Noteworthy
14028-467: The Su-57, while China produced two stealth aircraft, Chengdu J-20 and Shenyang FC-31 . In 2017, China became the second country in the world to field an operational stealth aircraft, challenging the United States and its Asian allies. Stealth technology (or LO for low observability ) is not one technology. It is a set of technologies, used in combinations, that can greatly reduce the distances at which
14195-647: The U.S. Central Intelligence Agency requested funding for a reconnaissance aircraft to replace the existing U-2 spy planes, and Lockheed secured contractual rights to produce it. "Kelly" Johnson and his team at Lockheed's Skunk Works were assigned to produce the A-12 (or OXCART), which operated at high altitude of 70,000 to 80,000 ft (21,000 to 24,000 m) and speed of Mach 3.2 (2,400 mph; 3,800 km/h) to avoid radar detection. Various plane shapes designed to reduce radar detection were developed in earlier prototypes, named A-1 to A-11. The A-12 included
14362-571: The U.S. Department of Defense launched project Lockheed Have Blue , with the aim of developing a stealth fighter. There was fierce bidding between Lockheed and Northrop to secure the multibillion-dollar contract. Lockheed incorporated into its bid a text written by the Soviet-Russian physicist Pyotr Ufimtsev from 1962, titled Method of Edge Waves in the Physical Theory of Diffraction , Soviet Radio, Moscow, 1962. In 1971, this book
14529-543: The US determines national or multinational security objectives and guidance, and develops and uses national resources to accomplish these objectives. These national objectives in turn provide the direction for developing overall military objectives, which are used to develop the objectives and strategy for each theater. At the operational level command and control, campaigns and major operations are planned, conducted, sustained, and assessed to accomplish strategic goals within theaters or areas of operations. These activities imply
14696-514: The USAF dwarfs all other U.S. and allied air components, it often provides support for allied forces in conflicts to which the United States is otherwise not involved, such as the 2013 French campaign in Mali . The USAF has also taken part in numerous humanitarian operations. Some of the more major ones include the following: The culture of the United States Air Force is primarily driven by pilots, at first those piloting bombers (driven originally by
14863-464: The USAF established the nuclear-focused Air Force Global Strike Command on 24 October 2008, which later assumed control of all USAF bomber aircraft. On 26 June 2009, the USAF released a force structure plan that cut fighter aircraft and shifted resources to better support nuclear, irregular and information warfare. On 23 July 2009, The USAF released their Unmanned Aerial System (UAS) Flight Plan, detailing Air Force UAS plans through 2047. One third of
15030-460: The USAF in managing weapons systems risk. With the overall final F-22 and F-23 designs competitive with each other in technical performance and meeting all requirements, the USAF decision then took into consideration non-technical aspects such as confidence in program management when determining the winner. The Lockheed team and Pratt & Whitney were awarded the EMD contracts to fully develop and build
15197-509: The USAF undertook a Reduction-in-Force (RIF). Because of budget constraints, the USAF planned to reduce the service's size from 360,000 active duty personnel to 316,000. The size of the active duty force in 2007 was roughly 64% of that of what the USAF was at the end of the first Gulf War in 1991. However, the reduction was ended at approximately 330,000 personnel in 2008 in order to meet the demand signal of combatant commanders and associated mission requirements. These same constraints have seen
15364-577: The United States Air Force provides air support for land and naval forces and aids in the recovery of troops in the field. As of 2020 , the service operates approximately 5,500 military aircraft and approximately 400 ICBMs . The world's largest air force, it has a $ 179.7 billion budget and is the second largest service branch of the U.S. Armed Forces, with 321,848 active duty airmen , 147,879 civilian personnel, 68,927 reserve airmen, 105,104 Air National Guard airmen, and approximately 65,000 Civil Air Patrol auxiliarists . According to
15531-590: The Vulcan's shape as acting to reduce the RCS. In contrast, the Tupolev 95 Russian long-range bomber ( NATO reporting name 'Bear') was conspicuous on radar. It is now known that propellers and jet turbine blades produce a bright radar image; the Bear has four pairs of large 18-foot (5.6 m) diameter contra-rotating propellers . Another important factor is internal construction. Some stealth aircraft have skin that
15698-580: The YF-23 was stealthier and faster, but the YF-22 was more agile. The U.S. Navy had begun considering a version of the ATF called Navy Advanced Tactical Fighter (NATF) in 1986. It has been speculated in the aviation press that the YF-22 was also seen as more adaptable to the NATF. However, by late 1990 to early 1991, the Navy was beginning to back out of NATF due to escalating costs, and abandoned NATF completely by FY 1992. The selection decision has been speculated by aviation observers to have involved industrial factors and perception of program management as much as
15865-586: The YF-23s flew 65.2 hours in 50 sorties. While the prototype air vehicle designs were frozen in 1988 in order to build them and begin flight tests in 1990, both teams continued to refine their F-22 and F-23 designs, or Preferred System Concepts, for ATF full-scale development; following flight testing, the contractor teams submitted proposals on 31 December 1990. The teams' NATF designs, often referred to as " NATF-22 " and " NATF-23 " (they were never formally designated), were included in their proposals as well. Following
16032-526: The ability to fulfill their primary mission. Rapid Global Mobility is essential to virtually every military operation, allowing forces to reach foreign or domestic destinations quickly, thus seizing the initiative through speed and surprise. Airlift is "operations to transport and deliver forces and materiel through the air in support of strategic, operational, or tactical objectives" (Annex 3–17, Air Mobility Operations). The rapid and flexible options afforded by airlift allow military forces and national leaders
16199-407: The ability to integrate, evaluate, and interpret information from available sources to create a finished intelligence product for presentation or dissemination to enable increased situational awareness. Dissemination and integration is "the delivery of intelligence to users in a suitable form and the application of the intelligence to appropriate missions, tasks, and functions" (JP 2-01). It provides
16366-425: The ability to present information and intelligence products across the ROMO enabling understanding of the operational environment to military and national decision-makers. Rapid global mobility is the timely deployment, employment, sustainment, augmentation, and redeployment of military forces and capabilities across the ROMO. It provides joint military forces the capability to move from place to place while retaining
16533-455: The ability to respond and operate in a variety of situations and time frames. The global reach capability of airlift provides the ability to apply US power worldwide by delivering forces to crisis locations. It serves as a US presence that demonstrates resolve and compassion in humanitarian crisis. Air refueling is "the refueling of an aircraft in flight by another aircraft" (JP 1-02). Air refueling extends presence, increases range, and serves as
16700-417: The aforementioned Dem/Val extensions also pushed flight testing from 1989 to 1990. The first YF-23 made its maiden flight on 27 August 1990 and the first YF-22 first flew on 29 September 1990. Flight testing began afterwards at Edwards Air Force Base and added the second aircraft for each competitor in late October 1990. The first YF-23 with P&W engines supercruised at Mach 1.43 on 18 September 1990 and
16867-488: The aircraft designs themselves as contractors would later discover in their debriefs after Dem/Val selection. This was because the SPO anticipated that the ATF would need to employ emerging technologies beyond even the contemporary state-of-the-art and did not want a point aircraft design frozen at then-mature technology readiness levels; as such, the SPO needed to evaluate its confidence in a contractor's ability to effectively and affordably develop new technology. At this time,
17034-423: The aircraft so far studied, the Vulcan appeared by far the simplest radar echoing object, due to its shape: only one or two components contributing significantly to the echo at any aspect (one of them being the vertical stabilizer , which is especially relevant for side aspect RCS), compared with three or more on most other types. While writing about radar systems, authors Simon Kingsley and Shaun Quegan singled out
17201-652: The airspace around these sites with overlapping coverage, making undetected entry by conventional aircraft nearly impossible. Stealthy aircraft can also be detected, but only at short ranges around the radars; for a stealthy aircraft there are substantial gaps in the radar coverage. Thus a stealthy aircraft flying an appropriate route can remain undetected by radar. Even if a stealth aircraft is detected, fire-control radars operating in C , X and Ku bands cannot paint (for missile guidance) low observable (LO) jets except at very close ranges. Many ground-based radars exploit Doppler filter to improve sensitivity to objects having
17368-407: The amount awarded by the contracts themselves when combined — in order to develop the necessary technology to meet the ambitious requirements, teaming was encouraged by the SPO. Following proposal submissions, Lockheed (through its Skunk Works division), Boeing, and General Dynamics formed a team to develop whichever of their proposed designs was selected, if any. Northrop and McDonnell Douglas formed
17535-430: The beginning of modern aerial warfare and set the stage for the development of the United States Air Force. The U.S. War Department created the first antecedent of the U.S. Air Force, as a part of the U.S. Army, on 1 August 1907, which through a succession of changes of organization, titles, and missions advanced toward eventual independence 40 years later. In World War II , almost 68,000 U.S. airmen died helping to win
17702-641: The capability of the F-15 Eagle ; in the potential scenario of a Soviet and Warsaw Pact invasion in Central Europe , the ATF was envisaged to support the air-land battle by performing offensive and defensive counter-air missions against the Soviet air-to-air threats that would then allow the DRF and other strike aircraft to perform air interdiction against ground targets. With the ATF's mission now focused on air-to-air, another round of requests were sent to
17869-407: The coating and convert it to heat rather than reflect it back. Current technologies include dielectric composites and metal fibers containing ferrite isotopes. Ceramic composite coating is a new type of material systems which can sustain at higher temperatures with better sand erosion resistance and thermal resistance. Paint comprises depositing pyramid-like colonies on the reflecting superficies with
18036-465: The combination of low observables with the SCM concept was expected to greatly reduce the lethal zone of hostile surface-to-air missiles. As a result of stealth technology, the design details became "black" even though the ATF was a publicly acknowledged program. By late 1984, the SPO had settled on the ATF requirements and released the Statement of Operational Need (SON), which called for a fighter with
18203-438: The development and production of prototype engines in September 1983. Avionics were also expected to be a major component of the ATF in light of rapidly advancing semiconductor technology; requests for advanced avionics components such as the integrated electronic warfare system were sent out that November. During this time, the SPO took an increasing interest in stealth as results from classified " black world " programs such as
18370-577: The direction they came from (since in most cases a radar emitter and receiver are in the same location). They are less able to minimize radar reflections in other directions. Thus, detection can be better achieved if emitters are in different locations from receivers. One emitter separate from one receiver is termed bistatic radar ; one or more emitters separate from more than one receiver is termed multistatic radar . Proposals exist to use reflections from emitters such as civilian radio transmitters , including cellular telephone radio towers . By Moore's law
18537-659: The due date to July 1986; in December 1985, following discussions with Lockheed and Northrop, the two contractor teams with prior stealth experience from the Have Blue /F-117 and ATB/B-2 respectively, all-aspect stealth requirements were drastically increased. Furthermore, the Packard Commission , a federal commission by President Ronald Reagan to study Department of Defense procurement practices, had released its report in February 1986 and one of its recommendations
18704-519: The effort to make transparent aircraft ceased. In 1916, the British modified a small SS class airship for the purpose of night-time reconnaissance over German lines on the Western Front . Fitted with a silenced engine and a black gas bag, the craft was both invisible and inaudible from the ground but several night-time flights over German-held territory produced little useful intelligence and
18871-528: The electromagnetic spectrum (i.e., multi-spectral camouflage ). Development of modern stealth technologies in the United States began in 1958, where earlier attempts to prevent radar tracking of its U-2 spy planes during the Cold War by the Soviet Union had been unsuccessful. Designers turned to developing a specific shape for planes that tended to reduce detection by redirecting electromagnetic radiation waves from radars. Radiation-absorbent material
19038-422: The enemy holds dear in a devastating manner. If a crisis occurs, rapid generation and, if necessary, deployment of nuclear strike capabilities will demonstrate US resolve and may prompt an adversary to alter the course of action deemed threatening to our national interest. Should deterrence fail, the President may authorize a precise, tailored response to terminate the conflict at the lowest possible level and lead to
19205-579: The exhaust plume. Another way to reduce the exhaust temperature is to circulate coolant fluids such as fuel inside the exhaust pipe, where the fuel tanks serve as heat sinks cooled by the flow of air along the wings. Ground combat includes the use of both active and passive infrared sensors. Thus, the United States Marine Corps (USMC) ground combat uniform requirements document specifies infrared reflective quality standards. In addition to reducing infrared and acoustic emissions,
19372-426: The ferrite layer. FSS are used for filtration and microwave absorption. Shaping offers far fewer stealth advantages against low-frequency radar . If the radar wavelength is roughly twice the size of the target, a half-wave resonance effect can still generate a significant return. However, low-frequency radar is limited by lack of available frequencies (many are heavily used by other systems), by lack of accuracy of
19539-403: The field on the so-called dirty birds but results were disappointing, the weight and drag increases were not worth any reduction in detection rates. More successful was applying camouflage paint to the originally bare metal aircraft; a deep blue was found to be most effective. The weight of this cost 250 ft in maximum altitude, but made the aircraft harder for interceptors to see. In 1958,
19706-483: The fire and movement of friendly forces is not required" (Annex 3-03, Counterland Operations). Close Air Support is defined as "air action by fixed- and rotary-winged aircraft against hostile targets that are in close proximity to friendly forces and which require detailed integration of each air mission with the fire and movement of those forces" (JP 1-02). This can be as a pre-planned event or on demand from an alert posture (ground or airborne). It can be conducted across
19873-402: The fourth in order of precedence . The United States Air Force articulates its core missions as air supremacy , global integrated intelligence, surveillance and reconnaissance , rapid global mobility , global strike , and command and control . The United States Air Force is a military service branch organized within the Department of the Air Force , one of the three military departments of
20040-548: The fuselage, and radar-absorbent paint. The United States Army issued a specification in 1968 which called for an observation aircraft that would be acoustically undetectable from the ground when flying at an altitude of 1,500 ft (460 m) at night. This resulted in the Lockheed YO-3A Quiet Star , which operated in South Vietnam from late June 1970 to September 1971. During the 1970s,
20207-532: The gaps filled with ferrite-based RAM. The pyramidal structure deflects the incident radar energy in the maze of RAM. One commonly used material is called iron ball paint . It contains microscopic iron spheres that resonate in tune with incoming radio waves and dissipate most of their energy as heat, leaving little to reflect back to detectors. FSS are planar periodic structures that behave like filters to electromagnetic energy. The considered frequency-selective surfaces are composed of conducting patch elements pasted on
20374-603: The globe to conduct current and future operations. Planning and directing is "the determination of intelligence requirements, development of appropriate intelligence architecture, preparation of a collection plan, and issuance of orders and requests to information collection agencies" (JP 2-01, Joint and National Intelligence Support to Military Operations). These activities enable the synchronization and integration of collection, processing, exploitation, analysis, and dissemination activities/resources to meet information requirements of national and military decision-makers. Collection
20541-605: The idea was dropped. Diffused lighting camouflage , a shipborne form of counter-illumination camouflage, was trialled by the Royal Canadian Navy from 1941 to 1943. The concept was followed up for aircraft by the Americans and the British: in 1945, a Grumman Avenger with Yehudi lights reached 3,000 yards (2,700 m) from a ship before being sighted. This ability was rendered obsolete by radar . Chaff
20708-629: The industry for concept exploration and study contracts were awarded to seven airframe manufacturers for further definition of their designs. A request for proposals (RFP) for the fighter's engine, called the Joint Advanced Fighter Engine (JAFE) due to its potential joint application with the U.S. Navy's Advanced Carrier-Based Multirole Fighter (VFMX), was released in May 1983. Pratt & Whitney and General Electric each received $ 202 million contracts (~$ 519 million in 2023) for
20875-442: The intention of taking the initiative" (JP 1-02). It includes detection and warning; chemical, biological, radiological, and nuclear defense; camouflage, concealment, and deception; hardening; reconstitution; dispersion; redundancy; and mobility, counter-measures, and stealth. Airspace control is "a process used to increase operational effectiveness by promoting the safe, efficient, and flexible use of airspace" (JP 1-02). It promotes
21042-418: The invention of electromagnetic metasurfaces , the conventional means to reduce RCS have been improved significantly. As mentioned earlier, the main objective in purpose shaping is to redirect scattered waves away from the backscattered direction, which is usually the source. However, this usually compromises aerodynamic performance. One feasible solution, which has extensively been explored in recent time,
21209-468: The investment. While the service adjusted its procurement goal down to 381 aircraft, the funded number in the program of record continued to decline, dropping to 339 at a peak rate of 36 per year by the time the EMD/production aircraft first flew. Both the F-22 and F-23 designs were later considered for modification as a medium-range supersonic regional bomber ( FB-22 and FB-23 respectively), but
21376-486: The jet exhaust is vented above the wing surface to shield it from observers below, as in the Lockheed F-117 Nighthawk, and the unstealthy Fairchild Republic A-10 Thunderbolt II . To achieve infrared stealth , the exhaust gas is cooled to the temperatures where the brightest wavelengths it radiates are absorbed by atmospheric carbon dioxide and water vapor , greatly reducing the infrared visibility of
21543-667: The late eighties when the Lockheed Martin F-117 stealth fighter became widely known. The first large scale (and public) use of the F-117 was during the Gulf War in 1991. However, F-117A stealth fighters were used for the first time in combat during Operation Just Cause , the United States invasion of Panama in 1989. Stealth aircraft are often designed to have radar cross sections that are orders of magnitude smaller than conventional aircraft. The radar range equation meant that all else being equal, detection range
21710-415: The material's surface. Composites may also contain ferrites to optimize the dielectric and magnetic properties of a material for its application. Radiation-absorbent material (RAM), often as paints, are used especially on the edges of metal surfaces. While the material and thickness of RAM coatings can vary, the way they work is the same: absorb radiated energy from a ground- or air-based radar station into
21877-762: The mid-2030s. On 22 October 2023, the USAF conducted its first-ever trilateral exercise with the South Korean and Japanese air forces near the Korean Peninsula. On 29 November 2023, a USAF Bell Boeing V-22 Osprey crashed in the Japan island of Yakushima killing 1 airman. In 2024, citing the Supreme Court 's ruling in Loper Bright Enterprises v. Raimondo , the Air Force refused to comply with an EPA order that they develop
22044-492: The noise or acoustic signature of the rotor over a greater range of frequencies. The simplest technology is visual camouflage ; the use of paint or other materials to color and break up the lines of a vehicle or person. Most stealth aircraft use matte paint and dark colors, and operate only at night. Lately, interest in daylight Stealth (especially by the USAF) has emphasized the use of gray paint in disruptive schemes , and it
22211-522: The number of internal missiles (represented by the AIM-120A ) was reduced from eight to six to reduce weight and cost. Because of the added weight for thrust vectoring/reversing nozzles and related systems on the F-15 S/MTD research aircraft, the SPO changed the runway length requirement to 3,000 feet (900 m) and removed the thrust reverser requirement in late 1987. The ejection seat requirement
22378-399: The pilot when he should change altitude and mission planning also considers altitudes where the probability of their formation is minimized. In space, mirrored surfaces can be employed to reflect views of empty space toward known or suspected observers; this approach is compatible with several radar stealth schemes. Careful control of the orientation of the satellite relative to the observers
22545-415: The planes that the USAF planned to buy in the future were to be unmanned. According to Air Force Chief Scientist, Greg Zacharias , the USAF anticipates having hypersonic weapons by the 2020s, hypersonic unmanned aerial vehicles (also known as remotely-piloted vehicles, or RPAs) by the 2030s and recoverable hypersonic RPAs aircraft by the 2040s. The USAF intends to deploy a Sixth-generation jet fighter by
22712-546: The potential consequences of an accident or unauthorized act, nuclear weapons and nuclear weapon systems require special consideration and protection against risks and threats inherent in their peacetime and wartime environments. In conjunction with other entities within the Departments of Defense or Energy, the Air Force achieves a high standard of protection through a stringent nuclear surety program. This program applies to materiel, personnel, and procedures that contribute to
22879-418: The processing power behind radar systems is rising over time. This will eventually erode the ability of physical stealth to hide vehicles. Synthetic aperture sidescan radars can be used to detect the location and heading of ships from their wake patterns. These are detectable from orbit. When a ship moves through a seaway it throws up a cloud of spray which can be detected by radar. Acoustic stealth plays
23046-483: The production of intelligence" (JP 2-01). It provides the ability to transform, extract, and make available collected information suitable for further analysis or action across the ROMO. Analysis and production is "the conversion of processed information into intelligence through the integration, evaluation, analysis, and interpretation of all source data and the preparation of intelligence products in support of known or anticipated user requirements" (JP 2-01). It provides
23213-416: The proposals have not come to fruition. Following flight and operational testing, the F-22 entered service in December 2005, but with no apparent air-to-air threat present and the Department of Defense focused on counterinsurgency at that time, F-22 production only reached 195 aircraft and ended in 2011. United States Air Force The United States Air Force ( USAF ) is the air service branch of
23380-631: The quality-versus-quantity spectrum. Even with the variety of the submitted designs in the responses, the common areas among some or all the concepts were reduced observability, or stealth (though not to the extent of the final requirements), short takeoff and landing ( STOL ) and sustained supersonic cruise without afterburners, or supercruise . It was envisioned that the ATF would incorporate emerging technologies including advanced alloys and composite material , advanced avionics and fly-by-wire flight control systems, higher power propulsion systems, and low-observable, or stealth technology. By October 1983,
23547-432: The requisite technologies and offer competing methods. Furthermore, the SPO was also open to adjusting requirements if necessary. Both contractor teams conducted performance and cost trade studies and presented them in system requirement reviews (SRRs) with the SPO. This enabled the SPO to adjust ATF requirements and delete ones that were significant weight and cost drivers while having marginal operational value. For instance,
23714-491: The safe, efficient, and flexible use of airspace, mitigates the risk of fratricide, enhances both offensive and defensive operations, and permits greater agility of air operations as a whole. It both deconflicts and facilitates the integration of joint air operations. Global integrated intelligence, surveillance, and reconnaissance (ISR) is the synchronization and integration of the planning and operation of sensors, assets, and processing, exploitation, dissemination systems across
23881-602: The safety, security, and control of nuclear weapons, thus assuring no nuclear accidents, incidents, loss, or unauthorized or accidental use (a Broken Arrow incident ). The Air Force continues to pursue safe, secure and effective nuclear weapons consistent with operational requirements. Adversaries, allies, and the American people must be highly confident of the Air Force's ability to secure nuclear weapons from accidents, theft, loss, and accidental or unauthorized use. This day-to-day commitment to precise and reliable nuclear operations
24048-405: The same angles. The effect of this is to return a narrow radar signal in a very specific direction away from the radar emitter rather than returning a diffuse signal detectable at many angles. The effect is sometimes called "glitter" after the very brief signal seen when the reflected beam passes across a detector. It can be difficult for the radar operator to distinguish between a glitter event and
24215-452: The second YF-23 with GE engines reached Mach 1.72 on 29 November 1990. The first YF-22 with GE engines achieved Mach 1.58 in supercruise and the second YF-22 with P&W engines also achieved Mach 1.43. Maximum speed of both prototype designs in afterburner was in excess of Mach 2.0. Flight testing continued until December 1990 with the YF-22s accumulating 91.6 flight hours in 74 sorties while
24382-558: The sound barrier in his X-1 rocket-powered aircraft, beginning a new era of aeronautics in America. The predecessor organizations in the Army of today's Air Force are: During the early 2000s, two USAF aircraft procurement projects took longer than expected, the KC-X and F-35 programs. As a result, the USAF was setting new records for average aircraft age. Since 2005, the USAF has placed
24549-442: The tail, stealth design must bury the engines within the wing or fuselage , or in some cases where stealth is applied to an extant aircraft, install baffles in the air intakes, so that the compressor blades are not visible to radar. A stealthy shape must be devoid of complex bumps or protrusions of any kind, meaning that weapons, fuel tanks, and other stores must not be carried externally. Any stealthy vehicle becomes un-stealthy when
24716-441: The technical director (or chief engineer) was Eric "Rick" Abell. The director of ATF requirements was Colonel David J. McCloud of TAC, and the draft System Operational Requirements Document (SORD), derived from the 1984 SON, was released in December 1987. In addition to the government contract awards, company investments during Dem/Val would amount to $ 675 million and $ 650 million (~$ 1.5 billion and ~$ 1.45 billion in 2023) for
24883-477: The technical merit of the aircraft designs. At the time, Northrop was viewed as riskier because it was struggling with the B-2 and AGM-137 TSSAM programs in meeting cost, schedule, and predicted stealth performance. In contrast, Lockheed's program management on the F-117 was lauded for meeting performance and delivering on schedule and within budget, with the aircraft achieving operational success over Panama and during
25050-526: The term "Advanced Tactical Fighter" (ATF) appeared in U.S. Air Force (USAF) parlance as far back as 1971 to describe potential future tactical aircraft, the program that would eventually result in the F-22 began in 1981. This was motivated by the shift in U.S. military doctrine towards striking the enemy's rear echelon as eventually outlined in the AirLand Battle concept, as well as intelligence reports of multiple emerging worldwide threats emanating from
25217-584: The visibility of military aircraft. Single examples of the Fokker E.III Eindecker fighter monoplane, the Albatros C.I two-seat observation biplane, and the Linke-Hofmann R.I prototype heavy bomber were covered with Cellon . However, sunlight glinting from the material made the aircraft even more visible. Cellon was also found to degrade quickly from both sunlight and in-flight temperature changes, so
25384-409: The visual background. As the potency of detection and interception technologies ( radar , infrared search and tracking , surface-to-air missiles , etc.) have increased, so too has the extent to which the design and operation of military personnel and vehicles have been affected in response. Some military uniforms are treated with chemicals to reduce their infrared signature . A modern stealth vehicle
25551-467: The war, with only the infantry suffering more casualties. In practice, the U.S. Army Air Forces ( USAAF ) was virtually independent of the Army during World War II, and in virtually every way functioned as an independent service branch, but airmen still pressed for formal independence. The National Security Act of 1947 was signed on 26 July 1947, which established the Department of the Air Force , but it
25718-520: Was a "fly-before-buy" competitive procurement strategy that encouraged prototyping. The ATF SPO was pressured to followed the recommendations of the Packard Commission, and in May 1986, the RFP was changed so that final selection would involve flying prototypes. Because of this late addition due to political pressure, the prototype air vehicles were to be "best-effort" machines not meant to perform
25885-547: Was also tested and made to reduce or block radar signals that reflect off the surfaces of aircraft. Such changes to shape and surface composition comprise stealth technology as currently used on the Northrop Grumman B-2 Spirit "Stealth Bomber". The concept of stealth is to operate or hide while giving enemy forces no indication as to the presence of friendly forces. This concept was first explored through camouflage to make an object's appearance blend into
26052-615: Was applied by Lockheed in computer simulation to design a novel shape they called the "Hopeless Diamond", a wordplay on the Hope Diamond , securing contractual rights to produce the F-117 Nighthawk starting in 1975. In 1977, Lockheed produced two 60% scale models under the Have Blue contract. The Have Blue program was a stealth technology demonstrator that lasted from 1976 to 1979. The Northrop Grumman Tacit Blue also played
26219-564: Was downgraded from a fresh design to the existing McDonnell Douglas ACES II . However, both contractor teams still found the 50,000 lb (22,700 kg) takeoff gross weight goal unachievable, so this was increased to 60,000 lb (27,200 kg), resulting in engine thrust requirement increasing from 30,000 lbf (133 kN) class to 35,000 lbf (156 kN) class. Furthermore, Dem/Val would be extended several times to better mature technologies and reduce near-term budgets. Aside from advances in air vehicle and propulsion technology,
26386-524: Was from Martin Marietta ; both teams chose the Westinghouse / Texas Instruments active electronically scanned array (AESA) radar. The integrated electronics warfare and integrated communication, navigation, and identification avionics were selected by the SPO. Although not required, both teams would employ flying avionics laboratories as well, with the Lockheed team using a modified Boeing 757 and
26553-503: Was imposed by the SPO to contain requirements creep. Finally, two examples of each prototype air vehicles were built and flown for Dem/Val: one with General Electric YF120 engines, the other with Pratt & Whitney YF119 engines. Contractor teams made extensive use of analytical and empirical methods for their air vehicle designs, including wind tunnel testing, RCS pole testing, and software for computational fluid dynamics , RCS calculations, and computer-aided design . Consistent with
26720-563: Was invented in Britain and Germany early in World War II as a means to hide aircraft from radar. In effect, chaff acted upon radio waves much as a smoke screen acted upon visible light. The U-boat U-480 may have been the first stealth submarine. It featured an anechoic tile rubber coating, one layer of which contained circular air pockets to defeat ASDIC sonar. Radar-absorbent paints and materials of rubber and semiconductor composites (codenames: Sumpf , Schornsteinfeger ) were used by
26887-405: Was issued in September 1985, with proposals initially to be due that December. The top four proposals, later reduced to two to reduce program costs, would proceed with Dem/Val. The RFP not only had the ATF's demanding technical requirements, but also placed great importance on systems engineering , technology development plans, and risk mitigation; in fact, these areas were deemed more important than
27054-500: Was not until 18 September 1947, when the first secretary of the Air Force, W. Stuart Symington , was sworn into office that the Air Force was officially formed as an independent service branch. The act created the National Military Establishment (renamed Department of Defense in 1949), which was composed of three subordinate Military Departments, namely the Department of the Army , the Department of
27221-429: Was that he had repeatedly clashed with Wynne and Moseley over other important non-nuclear related issues to the service. This followed an investigation into two incidents involving mishandling of nuclear weapons : specifically a nuclear weapons incident aboard a B-52 flight between Minot AFB and Barksdale AFB , and an accidental shipment of nuclear weapons components to Taiwan. To put more emphasis on nuclear assets,
27388-945: Was the first coastal defence and the French La Fayette-class frigate the first ocean-going stealth ship to enter service. Other examples are the Dutch De Zeven Provinciën class frigates, the Taiwanese Tuo Chiang stealth corvette , German Sachsen-class frigates , the Swedish Visby-class corvette , the USS San Antonio amphibious transport dock , and most modern warship designs. Dielectric composite materials are more transparent to radar, whereas electrically conductive materials such as metals and carbon fibers reflect electromagnetic energy incident on
27555-530: Was the first officer appointed to that position who did not have a background as a fighter or bomber pilot. The Washington Post reported in 2010 that General Schwartz began to dismantle the rigid class system of the USAF, particularly in the officer corps. In 2014, following morale and testing/cheating scandals in the Air Force's missile launch officer community, Secretary of the Air Force Deborah Lee James admitted that there remained
27722-454: Was translated into English with the same title by the U.S. Air Force, Foreign Technology Division. The theory played a critical role in the design of American stealth-aircraft F-117 and B-2. Equations outlined in the paper quantified how a plane's shape would affect its detectability by radar, termed radar cross-section (RCS). At the time, the Soviet Union did not have supercomputer capacity to solve these equations for actual designs. This
27889-549: Was very similar to the eventual flying prototype. While Lockheed also had extensive prior stealth experience, their actual aircraft design was quite immature and only existed as a rough concept; instead, Lockheed primarily focused on systems engineering and trade studies in its proposal, which pulled it ahead of Northrop's to take top rank. The two teams, Lockheed/Boeing/General Dynamics and Northrop/McDonnell Douglas, were awarded $ 691 million firm fixed-price contracts in FY 1985 dollars (~$ 1.66 billion in 2023) and would undertake
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