151-516: The Boeing–Sikorsky RAH-66 Comanche is an American stealth armed reconnaissance and attack helicopter designed for the United States Army . Following decades of study and development, the RAH-66 program was cancelled in 2004 before mass production began, by which point nearly US$ 7 billion had been spent on the program. During the early 1980s, the U.S. Army started to formulate requirements for
302-639: A Unified Command Plan —a frequently updated document (produced by the DoD), which lays out the Command's mission, geographical/functional responsibilities, and force structure. During military operations, the chain of command runs from the president to the secretary of defense to the combatant commanders of the Combatant Commands. As of 2019 , the United States has eleven Combatant Commands, organized either on
453-466: 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
604-614: 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
755-453: A stealth helicopter , incorporating a number of different techniques and technologies in order to reduce its radar cross-section (RCS) along with other areas of visibility and detectability. The exterior surfaces of the RAH-66 were faceted and covered with both radar-absorbent material (RAM) coatings and infrared -suppressant paint; as a result of these combined measures, the Comanche's RCS
906-427: A $ 106 billion subtotal (the so-called "fourth estate" agencies such as missile defense, and defense intelligence, amounting to 16% of the defense budget), He will re-deploy to the modernization of hypersonics, artificial intelligence, and missile defense. Beyond 2021 the 27th secretary of defense is projecting the need for yearly budget increases of 3 to 5 percent to modernize. The Department of Defense accounts for
1057-501: A Block I configuration that included the majority of the rotorcraft's planned weapons and sensors. From the 16th Comanche onwards, deliveries would have been made to the Block II standard with all of the planned capabilities. On 23 February 2004, the U.S. Army announced that they had decided to terminate all work on the Comanche program. At the time, it was stated that the Army had determined that
1208-451: 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
1359-665: A centralized research authority, the Advanced Research Projects Agency , eventually known as DARPA . The act was written and promoted by the Eisenhower administration and was signed into law on August 6, 1958. The Secretary of Defense , appointed by the president with the advice and consent of the Senate , is by federal law ( 10 U.S.C. § 113 ) the head of the Department of Defense, "the principal assistant to
1510-486: A choice between which defense development programs were to be scrapped. During mid-1999, the Comanche was subject to substantial governmental scrutiny; the Government Accountability Office (GAO) reported that it had "serious doubts" about the program and noted that the Comanche would "consume almost two thirds of the whole Aviation budget by Fiscal Year 2008". In addition, wartime experiences, such as from
1661-660: A contract for construction of prototypes was awarded. The Comanche was to incorporate several advanced elements, such as stealth technologies, and a number of previously untried design features. Operationally, it was to employ advanced sensors in its reconnaissance role, in which it was intended to designate targets for the AH-64 Apache . It was also armed with one rotary cannon and could carry missiles and rockets in internal bays and optionally on stub wings for light attack duties. Two RAH-66 prototypes were constructed and underwent flight testing between 1996 and 2004. On 1 June 2000,
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#17328528449621812-402: 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
1963-476: 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
2114-447: A geographical basis (known as " area of responsibility ", AOR) or on a global, functional basis: Department of Defense spending in 2017 was 3.15% of GDP and accounted for about 38% of the budgeted global military spending – more than the next 7 largest militaries combined. By 2019, the 27th secretary of defense had begun a line-by-line review of the defense budget; in 2020 the secretary identified items amounting to $ 5.7 billion, out of
2265-531: A negative cycle that functioned to greatly extend the rotorcraft's development schedule. Over the course of the Comanche's development, multiple government agencies had acted to cut the number of helicopters that were intended to be ordered; one particularly common basis for such curtailments was that the Cold War had ended and thus such quantities were unnecessary (a phenomenon known as the " peace dividend "). However, significant reductions in volume directly resulted in
2416-469: 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
2567-443: A number of structural and software problems that had been encountered. On 30 March 1999, the second prototype conducted its first flight, before joining the flight test program shortly thereafter. The flight test program was conducted using the pair of prototypes produced, which had been assigned the serial numbers 94-0327 and 95-0001 . Following a demonstration of its ability to meet certain key criteria, on 1 June 2000,
2718-406: A number of upgrades would be necessary in order for the RAH-66 to be capable of surviving on the battlefield in the face of current anti-aircraft threats; however, the Army had instead decided to re-direct the bulk of its funding for rotary development toward the renovation of its existing helicopter fleet of attack, utility, and reconnaissance aircraft. Specifically, the Army also had plans to reuse
2869-418: A pair of retractable weapons pylons . Beyond storing munitions internally, the Comanche could also mount external stub wings to carry up to eight Hellfire missiles or sixteen Stinger missiles. However, operations performing with armaments mounted externally would reduce the effectiveness of the Comanche's stealth technologies. In 2001, the Army sought to procure a "heavy attack" variant of the Comanche, which
3020-619: 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
3171-557: 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
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#17328528449623322-465: 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
3473-487: 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
3624-439: 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
3775-477: 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
3926-420: 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,
4077-417: 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
4228-513: Is a military command composed of personnel/equipment from at least two Military Departments, which has a broad/continuing mission. These military departments are responsible for equipping and training troops to fight, while the Unified Combatant Commands are responsible for military forces' actual operational command. Almost all operational U.S. forces are under the authority of a Unified Command. The Unified Commands are governed by
4379-746: Is a parent agency of the following defense agencies: Several defense agencies are members of the United States Intelligence Community . These are national-level intelligence services that operate under the Department of Defense jurisdiction but simultaneously fall under the authorities of the Office of the Director of National Intelligence . They fulfill the requirements of national policymakers and war planners, serve as Combat Support Agencies , and also assist and deploy alongside non-Department of Defense intelligence or law enforcement services such as
4530-543: 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
4681-507: 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 the electromagnetic spectrum (i.e., multi-spectral camouflage ). Development of modern stealth technologies in
Boeing–Sikorsky RAH-66 Comanche - Misplaced Pages Continue
4832-607: Is alleged to be due to the Establishment's abbreviation, NME, being pronounced "enemy". Under the Department of Defense Reorganization Act of 1958 ( Pub. L. 85–599 ), channels of authority within the department were streamlined while still maintaining the ordinary jurisdiction of the Military Departments to organize, train, and equip their associated forces. The Act clarified the overall decision-making authority of
4983-467: Is an executive branch department of the federal government of the United States charged with coordinating and supervising all agencies and functions of the U.S. government directly related to national security and the United States Armed Forces . As of November 2022, the U.S. Department of Defense is the second largest employer in the world after India (and potentially China, if including
5134-414: 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
5285-414: 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
5436-494: Is in the Department of Energy budget, Veterans Affairs, the Treasury Department's payments in pensions to military retirees and widows and their families, interest on debt incurred in past wars, or State Department financing of foreign arms sales and militarily-related development assistance. Neither does it include defense spending that is not military, such as the Department of Homeland Security, counter-terrorism spending by
5587-460: 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 ,
5738-477: 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
5889-456: 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
6040-571: 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
6191-613: The Central Intelligence Agency and the Federal Bureau of Investigation . The military services each have their intelligence elements that are distinct from but subject to coordination by national intelligence agencies under the Department of Defense. Department of Defense manages the nation's coordinating authorities and assets in disciplines of signals intelligence , geospatial intelligence , and measurement and signature intelligence , and also builds, launches, and operates
Boeing–Sikorsky RAH-66 Comanche - Misplaced Pages Continue
6342-747: The Department of the Army , the Department of the Navy , and the Department of the Air Force . In addition, four national intelligence services are subordinate to the Department of Defense: the Defense Intelligence Agency ( DIA ), the National Security Agency ( NSA ), the National Geospatial-Intelligence Agency ( NGA ), and the National Reconnaissance Office ( NRO ). Other Defense agencies include
6493-491: The Kosovo War , had led to some senior figures within the Army to place a greater emphasis on the use of unmanned platforms for conducting many of the same roles for which the Comanche was being developed to perform. By 2000, Williams postulates that the primary reason for retaining the program was out of concern for the state of the helicopter industry—Sikorsky's production and employment figures were at their lowest for decades and
6644-527: 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,
6795-463: 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
6946-759: The Thirteen Colonies and the British government , one of the first actions taken by the First Continental Congress in September 1774 was to recommend that the colonies begin defensive military preparations. In mid-June 1775, after the outbreak of the Revolutionary War , the Second Continental Congress , recognizing the necessity of having a national army that could move about and fight beyond
7097-595: The commanders of the Combatant Commands . Goldwater–Nichols also created the office of vice-chairman, and the chairman is now designated as the principal military adviser to the secretary of defense, the Homeland Security Council, the National Security Council and to the president. The Joint Staff (JS) is a headquarters staff at the Pentagon made up of personnel from all five services that assist
7248-425: 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
7399-511: The fiscal year 2024 (FY2024) presidential budget request was $ 842 billion. In January 2023 Treasury Secretary Janet Yellen announced the US government would hit its $ 31.4 trillion debt ceiling on 19 January 2023; the date on which the US government would no longer be able to use extraordinary measures such as issuance of Treasury securities is estimated to be in June 2023. On 3 June 2023,
7550-500: 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
7701-676: The Army , Commandant of the Marine Corps , Chief of Naval Operations , Chief of Staff of the Air Force , and Chief of Space Operations ) over forces not assigned to a Combatant Command . Secretaries of Military Departments and service chiefs do not possess operational command authority over U.S. troops (this power was stripped from them in the Defense Reorganization Act of 1958 ), and instead, Military Departments are tasked solely with "the training, provision of equipment, and administration of troops." A unified combatant command
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#17328528449627852-693: The Army , Secretary of the Navy , and Secretary of the Air Force . Following the Goldwater–Nichols Act in 1986, the Joint Chiefs of Staff no longer maintained operational command authority individually or collectively. The act designated the Chairman of the Joint Chiefs of Staff (CJCS) as the "principal military adviser to the President, the National Security Council, the Homeland Security Council, and
8003-520: The Army announced two teams, these being Boeing – Sikorsky and Bell – McDonnell Douglas , received contracts to further develop their concepts. During the 1990s, the program's name was changed from LHX to simply Light Helicopter (LH). In April 1991, the Army awarded the Boeing–Sikorsky team a $ 2.8 billion contract to complete six prototypes. Later that month the helicopter was officially named RAH-66 Comanche . During November 1993, assembly of
8154-576: The Army decided to pursue development of another battlefield scout helicopter under the Armed Reconnaissance Helicopter program; this resulted in another rotorcraft, designated as the Bell ARH-70 , being selected and developed with the intention to replace the OH-58D in place of the Comanche. However, on 16 October 2008, the Department of Defense notified Congress and Bell that it was canceling
8305-604: The Central Military Commission), with over 1.4 million active-duty service personnel, including soldiers, marines, sailors, airmen, and guardians. The Department of Defense also maintains over 778,000 National Guard and reservists, and over 747,000 civilians, bringing the total to over 2.91 million employees. Headquartered at the Pentagon in Arlington County, Virginia , just outside Washington, D.C. ,
8456-418: The Comanche occupies is unnecessary in the near term and probably not viable in the longer term. Secondly, as with all rotary-wing aircraft, the Comanche is a voracious consumer of strategic airlift." The manufacturing team, Sikorsky and Boeing, have attributed factors that were outside of their control, such as budget cuts, " requirement creep ", and a protracted development period, to have caused problems with
8607-429: The Comanche was recorded as having attained a cruise speed of 162 knots (186 mph; 300 km/h), as well as having achieved a "dash speed" of 172 knots (198 mph; 319 km/h). It also demonstrated ability to perform a 180° turn in under five seconds. During 2002, the Comanche program underwent heavy restructuring; consequently, the planned number of Comanches to be purchased was decreased to 650 rotorcraft. At
8758-921: The Defense Advanced Research Projects Agency ( DARPA ), the Defense Logistics Agency ( DLA ), the Missile Defense Agency ( MDA ), the Defense Health Agency ( DHA ), Defense Threat Reduction Agency ( DTRA ), the Defense Counterintelligence and Security Agency ( DCSA ), the Space Development Agency ( SDA ) and the Pentagon Force Protection Agency ( PFPA ), all of which are subordinate to the secretary of defense. Additionally,
8909-600: The Defense Contract Management Agency ( DCMA ) is responsible for administering contracts for the Department of Defense. Military operations are managed by eleven regional or functional unified combatant commands . The Department of Defense also operates several joint services schools, including the Eisenhower School (ES) and the National War College (NWC). Faced with rising tensions between
9060-483: The Department of Defense is approximately $ 686,074,048,000 (Including Base + Overseas Contingency Operations + Emergency Funds) in discretionary spending and $ 8,992,000,000 in mandatory spending totaling $ 695,066,000,000 Undersecretary of Defense (Comptroller) David L. Norquist said in a hearing regarding the FY 2019 budget: "The overall number you often hear is $ 716 billion. That is the amount of funding for national defense,
9211-537: The Department of Defense who advise the secretary of defense, the Homeland Security Council , the National Security Council and the president on military matters. The composition of the Joint Chiefs of Staff is defined by statute and consists of the chairman of the Joint Chiefs of Staff (CJCS), vice chairman of the Joint Chiefs of Staff (VCJCS), senior enlisted advisor to the chairman (SEAC),
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#17328528449629362-521: The Department of Defense's stated mission is "to provide the military forces needed to deter war and ensure our nation's security". The Department of Defense is headed by the secretary of defense , a cabinet-level head who reports directly to the president of the United States , the latter of which is also the commander-in-chief of the United States Armed Forces . Beneath the Department of Defense are three subordinate military departments:
9513-629: The FBI, and intelligence-gathering spending by the NSA. In the 2010 United States federal budget , the Department of Defense was allocated a base budget of $ 533.7 billion, with a further $ 75.5 billion adjustment in respect of 2009, and $ 130 billion for overseas contingencies. The subsequent 2010 Department of Defense Financial Report shows the total budgetary resources for fiscal year 2010 were $ 1.2 trillion. Of these resources, $ 1.1 trillion were obligated and $ 994 billion were disbursed, with
9664-587: The Intelligence Community's satellite assets. Department of Defense also has its own human intelligence service , which contributes to the CIA's human intelligence efforts while also focusing on military human intelligence priorities. These agencies are directly overseen by the Under Secretary of Defense for Intelligence and Security . The Joint Chiefs of Staff (JCS) is a body of senior uniformed leaders in
9815-643: 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
9966-565: The Military Service chiefs from the Army , Marine Corps , Navy , Air Force , and Space Force , in addition to the chief of National Guard Bureau , all appointed by the president following U.S. Senate confirmation. Each of the individual Military Service Chiefs, outside their Joint Chiefs of Staff obligations, works directly for the secretary of the military department concerned: the Secretary of
10117-584: The NDAA on 14 December 2023. The Senate will next undertake negotiations on supplemental spending for 2024. A government shutdown was averted on 23 March 2024 with the signing of a $ 1.2 trillion bill to cover FY2024. A 2013 Reuters investigation concluded that Defense Finance & Accounting Service , the Department of Defense's primary financial management arm, implements monthly "unsubstantiated change actions"—illegal, inaccurate "plugs"—that forcibly make DoD's books match Treasury's books. Reuters reported that
10268-532: The Navy (DON) & Department of the Air Force (DAF)), the Defense Agencies and Department of Defense Field Activities , the National Guard Bureau (NGB), and such other offices, agencies, activities, organizations, and commands established or designated by law, or by the president or by the secretary of defense. Department of Defense Directive 5100.01 describes the organizational relationships within
10419-416: The Pentagon was the only federal agency that had not released annual audits as required by a 1992 law. According to Reuters, the Pentagon "annually reports to Congress that its books are in such disarray that an audit is impossible". In 2015, a Pentagon consulting firm performed an audit on the Department of Defense's budget. It found that there was $ 125 billion in wasteful spending that could be saved over
10570-454: The President in all matters relating to Department of Defense", and has "authority, direction, and control over the Department of Defense". Because the Constitution vests all military authority in Congress and the president, the statutory authority of the secretary of defense is derived from their constitutional authority. Since it is impractical for either Congress or the president to participate in every piece of Department of Defense affairs,
10721-435: The RAH-66 entered the $ 3.1 billion engineering and manufacturing development (EMD) phase of the program. Through the early 2000s, the U.S. Army maintained its plans for the intended purchase of over 1,200 Comanches, which were to fill both the scout helicopter and light attack roles; as late as 2003, it was being anticipated that deliveries of operational RAH-66s would commence as scheduled during 2006. During late 2000, it
10872-487: The RAH-66 was to be furnished with various armaments. It was equipped with a single chin-mounted 20 mm three-barrel XM301 rotary cannon, which could be pointed rearwards and retracted under a fairing when not in use to decrease the helicopter's radar cross-section. In addition, the RAH-66 was capable of internally carrying a maximum of six AGM-114 Hellfire air-to-ground missiles or up to twelve AIM-92 Stinger air-to-air missiles , which would be evenly divided between
11023-457: The RAH-66 would require numerous upgrades to be viable on the battlefield and that the service would instead direct the bulk of its rotary systems funds to renovating its existing attack, utility, and reconnaissance helicopters. The Army also announced new plans to accelerate the development of unmanned aerial vehicles (UAVs), which could also perform the scouting role intended for the Comanche, but with less risk. Since program cancellation, both of
11174-554: 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
11325-589: The Secretary of Defense in the exercise of policy development, planning, resource management, fiscal and program evaluation and oversight, and interface and exchange with other U.S. federal government departments and agencies, foreign governments, and international organizations, through formal and informal processes. OSD also performs oversight and management of the Defense Agencies, Department of Defense Field Activities, and specialized Cross Functional Teams . OSD
11476-450: The Secretary of Defense". The remaining Joint Chiefs of Staff may only have their advice relayed to the President, National Security Council, the Homeland Security Council , or the Secretary of Defense after submitting it to the CJCS. By law, the chairman has to present that advice whenever he is presenting his own. The chain of command goes from the president to the secretary of defense to
11627-549: The Secretary of Defense. After the end of World War II , President Harry Truman proposed the creation of a unified department of national defense. In a special message to the Congress on December 19, 1945, the president cited wasteful military spending and interdepartmental conflicts. Deliberations in Congress went on for months focusing heavily on the role of the military in society and the threat of granting too much military power to
11778-463: 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
11929-643: 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
12080-557: 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
12231-489: 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 was also tested and made to reduce or block radar signals that reflect off
12382-577: 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
12533-428: The accounting code is 050 and includes more than simply the Department of Defense. It includes, for example, the Department of Energy and others. That large a number, if you back out the $ 30 billion for non-defense agencies, you get to $ 686 billion. That is the funding for the Department of Defense, split between $ 617 billion in base and $ 69 billion in overseas contingency ". The Department of Defense budget encompasses
12684-423: 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
12835-652: 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
12986-533: The annual federal expenditures in the United States federal budget discretionary budget . On September 28, 2018, President Donald Trump signed the Department of Defense and Labor, Health and Human Services, and Education Appropriations Act, 2019, and Continuing Appropriations Act, 2019 (H.R.6157) into law. On September 30, 2018, the FY2018 Budget expired and the FY2019 budget came into effect. The FY2019 Budget for
13137-646: The boundaries of any particular colony, organized the Continental Army on June 14, 1775. This momentous event is commemorated in the U.S. annually as Flag Day . Later that year, Congress would charter the Continental Navy on October 13, and the Continental Marines on November 10. Upon the seating of the 1st U.S. Congress on March 4, 1789, legislation to create a military defense force stagnated as they focused on other concerns relevant to setting up
13288-510: The chairman and vice chairman in discharging their duties. It is managed by the Director of the Joint Staff (DJS) who is a lieutenant general or vice admiral . There are three military departments within the Department of Defense: The Military Departments are each headed by their secretary (i.e., Secretary of the Army , Secretary of the Navy and Secretary of the Air Force ), appointed by
13439-407: 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
13590-481: The contract was considered critical. Author Fred Brooks criticized the program's requirement for the Comanche to be capable of ferrying itself across the Atlantic as an example of excessive requirements being present in a project's design phase and of their costly repercussions. Williams observes that the Comanche's weight requirements were unachievable, and claimed that this was due to poor management, in which no party
13741-434: The control of a single secretary of defense . The National Military Establishment formally began operations on September 18, the day after the Senate confirmed James V. Forrestal as the first secretary of defense. The National Military Establishment was renamed the "Department of Defense" on August 10, 1949, and absorbed the three cabinet-level military departments, in an amendment to the original 1947 law. The renaming
13892-487: The debt ceiling was suspended until 2025. The $ 886 billion National Defense Authorization Act is facing reconciliation of the House and Senate bills after passing both houses 27 July 2023; the conferees have to be chosen, next. As of September 2023, a Continuing resolution is needed to prevent a Government shutdown . A shutdown was avoided on 30 September for 45 days (until 17 November 2023), with passage of
14043-452: The department and is the foundational issuance for delineating the major functions of the department. The latest version, signed by former Secretary of Defense Robert Gates in December 2010, is the first major re-write since 1987. The Office of the Secretary of Defense ( OSD ) is the secretary and their deputies, including predominantly civilian staff. OSD is the principal staff element of
14194-577: 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
14345-507: 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
14496-540: The executive. On July 26, 1947, Truman signed the National Security Act of 1947 , which set up a unified military command known as the National Military Establishment and created the Central Intelligence Agency , the National Security Council , National Security Resources Board , United States Air Force , and the Joint Chiefs of Staff . The act placed the National Military Establishment under
14647-568: 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,
14798-436: The existence of insurmountable technical problems. Prized elements of the program, such as certain software capabilities and its integration, failed to foster confidence with Army overseers; several capabilities were viewed as having been unproven and risky, while the anticipated consumption of up to 40 percent of the aviation budget by the Comanche alone for a number of years was considered to be extreme. According to Williams, it
14949-426: 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
15100-403: 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,
15251-432: The first Comanche prototype was formally rolled out at Sikorsky's production facility, after which it was transferred to West Palm Beach, Florida to commence flight testing activities. On 4 January 1996, the prototype Comanche, flown by test pilots Bob Gradle and Rus Stiles, performed its 39-minute maiden flight . The first flight had been originally planned to take place during August 1995, but had been delayed by
15402-561: The first prototype commenced at Sikorsky's facility in Stratford, Connecticut and at Boeing's manufacturing plant in Philadelphia , Pennsylvania . Later all of the rotorcraft's sub-assemblies were transferred to the former location where final assembly occurred. In December 1994, the Department of Defense reduced the number of planned prototypes to two as the services shifted budgets to pay for increased troop salaries. On 25 May 1995,
15553-689: The functions of aircraft flight control systems such as ailerons , elevators , elevons , flaps , and flaperons into wings to perform the aerodynamic purpose with the advantages of lower RCS for stealth, via simpler geometries and lower complexity (mechanically simpler, fewer or no moving parts or surfaces, less maintenance), and lower mass, cost (up to 50% less), drag (up to 15% less during use), and inertia (for faster, stronger control response to change vehicle orientation to reduce detection). Two promising approaches are flexible wings, and fluidics. United States Department of Defense The United States Department of Defense ( DoD , USDOD , or DOD )
15704-427: The funds allocated to the Comanche program to speed up development of unmanned aerial vehicles (UAVs), which could also perform the scouting role intended for the vehicle. At the time of its termination, the Comanche program had reportedly spent US$ 6.9 billion. The contract termination fees involved were estimated to total US$ 450–680 million for the main program partners Sikorsky and Boeing . Subsequently,
15855-530: 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,
16006-532: 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
16157-586: 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
16308-418: 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,
16459-476: 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
16610-404: The jurisdiction of other congressional committees. The Department of Defense is unique because it is one of the few federal entities where the majority of its funding falls into the discretionary category. The majority of the entire federal budget is mandatory, and much of the discretionary funding in the budget consists of DoD dollars. * Numbers may not add due to rounding As of 10 March 2023
16761-701: 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
16912-493: The latest Center for Effective Government analysis of 15 federal agencies which receive the most Freedom of Information Act requests, published in 2015 (using 2012 and 2013 data, the most recent years available), the DoD earned 61 out of a possible 100 points, a D− grade. While it had improved from a failing grade in 2013, it still had low scores in processing requests (55%) and disclosure rules (42%). The organization and functions of
17063-452: The majority of federal discretionary spending. In FY 2017, the Department of Defense budgeted spending accounted for 15% of the U.S. federal budget, and 49% of federal discretionary spending , which represents funds not accounted for by pre-existing obligations. However, this does not include many military-related items that are outside the Department of Defense budget, such as nuclear weapons research, maintenance, cleanup, and production, which
17214-561: The majority of the National Defense Budget of approximately $ 716.0 billion in discretionary spending and $ 10.8 billion in mandatory spending for a $ 726.8 billion total. Of the total, $ 708.1 billion falls under the jurisdiction of the House Committee on Armed Services and Senate Armed Services Committee and is subject to authorization by the annual National Defense Authorization Act (NDAA). The remaining $ 7.9 billion falls under
17365-415: 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
17516-613: The new government. President George Washington went to Congress to remind them of their duty to establish a military twice during this time. Finally, on the last day of the session, September 29, 1789, Congress created the War Department . The War Department handled naval affairs until Congress created the Navy Department in 1798. The secretaries of each department reported directly to the president as cabinet-level advisors until 1949, when all military departments became subordinate to
17667-639: The next five years without layoffs or reduction in military personnel. In 2016, The Washington Post uncovered that rather than taking the advice of the auditing firm, senior defense officials suppressed and hid the report from the public to avoid political scrutiny. In June 2016, the Office of the Inspector General released a report stating that the Army made $ 6.5 trillion in wrongful adjustments to its accounting entries in 2015. The Department of Defense failed its fifth audit in 2022, and could not account for more than 60% of its $ 3.5 trillion in assets. In
17818-488: 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
17969-501: 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
18120-399: 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
18271-400: 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 is designed from
18422-641: The president, with the advice and consent of the Senate . They have the legal authority under Title 10 of the United States Code to conduct all the affairs of their respective departments within which the military services are organized. The secretaries of the Military Departments are (by law) subordinate to the secretary of defense and (by SecDef delegation) to the deputy secretary of defense . Secretaries of military departments, in turn, normally exercise authority over their forces by delegation through their respective service chiefs (i.e., Chief of Staff of
18573-418: 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
18724-470: The program entered its $ 3.1 billion engineering and manufacturing development (EMD) phase. However, during 2002, the Comanche program underwent heavy restructuring; the number of Comanches that were to be purchased was cut to 650. At the time, the projected total cost for the full production of the Comanche in such numbers stood at $ 26.9 billion. As early as the late 1990s, the Government Accountability Office (GAO) had reported that it had "serious doubts" about
18875-425: The program, observing that the Comanche would "consume almost two thirds of the whole Aviation budget by Fiscal Year 2008". Multiple government agencies had acted to cut the number of Comanches on order, but, as a consequence of the heavy reductions to the numbers to be procured, the unit costs soared. On 23 February 2004, the U.S. Army announced the termination of the Comanche program, stating they had determined that
19026-529: The program, rather than dysfunctionality on their part. Under the Comanche program, each company was responsible for the construction of different elements of the rotorcraft. Since the termination, both companies have decided to team up again to produce a jointly-developed prototype, designated as the SB-1 Defiant , for the Army's Future Vertical Lift (FVL) program. The Comanche was intended to be an advanced armed reconnaissance and attack helicopter. The Comanche
19177-400: The program, reportedly due to cost overruns on its development. A multitude of reasons contributed to the ultimate cancellation of the RAH-66 program. According to aviation author James Williams, efforts to speed up the program via the elimination of risk-mitigation measures and the stream of continuous adjustments to account for annual budget cuts to the rotorcraft resulted in the formation of
19328-584: The prototypes have been placed on public display. During 1982, the U.S. Army initiated the Light Helicopter Experimental (LHX) program with the aim of producing a replacement for several existing rotorcraft, including the UH-1 , AH-1 , OH-6 , and OH-58 helicopters. Then in 1988 a formal request for proposal (RFP) was issued to various manufacturers; the requirement had evolved into a battlefield reconnaissance helicopter by this time. In October 1988,
19479-489: The rapid climbs in the projections of the Comanche's unit cost; in turn, this stimulated and gave validity to critics of the program, such as the Army Acquisition Executive James Ambrose, who had prominently declared that the Army would not receive any aircraft "costing a dollar over $ 7.5 million". As early as 1995, it is claimed by Williams that the Comanche had been facing complete cancellation as
19630-463: The remaining resources relating to multi-year modernization projects requiring additional time to procure. After over a decade of non-compliance , Congress has established a deadline of Fiscal year 2017 for the Department of Defense to achieve audit readiness . In 2015 the allocation for the Department of Defense was $ 585 billion, the highest level of budgetary resources among all federal agencies, and this amounts to more than one-half of
19781-542: The replacement of its helicopters then in service, which resulted in the launch of the Light Helicopter Experimental (LHX) program. Nearly a decade later, following the refinement of requirements, evaluation of submissions, and the rebranding of the program as the Light Helicopter (LH) program, during April 1991, the Army announced the selection of the Boeing – Sikorsky team's design as the contest winner, shortly after which
19932-405: 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
20083-440: The second RAH-66 was halted while the aircraft underwent extensive modifications, received both mission equipment and more powerful T800-LHT-801 engines. On 23 May 2002, the second prototype re-commenced flight testing with the additional equipment fitted. Accordingly, the expanded test programme involved new aspects such as the testing of the armaments and night vision systems; these test flights continued into 2003. During testing,
20234-508: The secretary of defense and the secretary's subordinate officials generally exercise military authority. The Department of Defense is composed of the Office of the Secretary of Defense ( OSD ), the Joint Chiefs of Staff ( JCS ) and the Joint Staff ( JS ), Office of the Inspector General ( DODIG ), the Combatant Commands , the Military Departments ( Department of the Army (DA), Department of
20385-473: The secretary of defense concerning these subordinate Military Departments. It more clearly defined the operational chain of command over U.S. military forces (created by the military departments) as running from the President to the Secretary of Defense, the service chief of the Unified Combatant Commander(s), and then to the unified combatant commander(s). Also provided in this legislation was
20536-487: 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 the visual background. As
20687-442: 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
20838-525: The time, the projected total cost for the full production of the Comanche in such numbers stood at $ 26.9 billion. Originally, the EMD phase was to last for six years with five Comanches to be constructed for the testing regime. During 2003, production on the third RAH-66, which was to be the first EMD-conformant helicopter, was started. Subsequently, eight RAH-66s were to be constructed for operational testing purposes. The initial production RAH-66s were to be completed in
20989-568: 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
21140-506: Was 43 feet (13 m) long and composed of composite materials ; it was designed to be capable of fitting more readily onto transport ships, enabling the Comanche to be more rapidly deployed to flash points and other rapidly-developing situations. However, in the event of strategic transport assets not being available, the helicopter's ferry range of 1,200 nmi (2,200 km) would have allowed it to fly itself to battlefields overseas on its own. As intended, it would have functioned as
21291-415: Was allegedly aware of or in control of the rotorcraft's final weight; there were concerns that, when outfitted with actual equipment required for operations, the Comanche's engines would be incapable of lifting the total weight of the helicopter. Additionally, it has been claimed that it proved difficult to convince the Army that the program suffered from serious troubles while key individuals failed to realize
21442-597: 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
21593-496: Was concluded that the Army's aviation budget would be better spent on the delivery of less risky and more critical needs. In a report published during 2008, the GAO recorded that an Army spokesperson had stated that "the program's costs could no longer be justified". Author Cindy Williams stated of the Comanche: "The rationale for cutting Comanche... is twofold. First, the doctrinal niche that
21744-669: Was intended to begin replacing Apaches in 2025. Both prototype airframes 94-0327 , 95-0001 , are located at the United States Army Aviation Museum at Fort Novosel , Alabama. Data from Jane's All the World's Aircraft 2005–2006, Frawley, Boeing and Sikorsky, Bonds and Miller General characteristics Performance Armament Avionics Aircraft of comparable role, configuration, and era Stealth technology Stealth technology , also termed low observable technology ( LO technology ),
21895-558: 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
22046-511: Was revealed that an effort to reduce the Comanche's empty weight by approximately 200 lb (91 kg) or 2.1 percent in order to conform with its established target weight had been initiated. The first Comanche prototype, serial 94-0327 , completed 318 flights over 387 hours before reaching the end of its testing career during January 2002. The second prototype, serial 95-0001 , had accumulated 103.5 flight hours and 93 sorties by May 2001. During late 2001 and early 2002, testing with
22197-541: Was scouting using its advanced sensors, in particular locating and designating targets for attack helicopters, such as the AH-64 Apache, to strike. The Comanche was furnished with a digital fly-by-wire flight control system . Each of the two crew members were to be provided with a pair of multi-functional LCDs in addition to the Helmet-Integrated Display and Sight System (HIDSS). For the light attack role,
22348-459: Was specifically tailored to the role of armed scout to replace the U.S. Army's OH-58D Kiowa Warrior , which is an upgraded version of a Vietnam War -era observation helicopter. It was both smaller and lighter than the AH-64 Apache attack helicopter that it had been intended to accompany. The RAH-66 was powered by a pair of LHTEC T800 turboshaft engines, each capable of generating up to 1,563 hp (1,165 kW) of power. The RAH-66's fuselage
22499-550: Was stated to be 360 times smaller than that of the AH-64 Apache. The acoustic signature of the helicopter was also reported to be noticeably lower than that of comparable helicopters; this reduction had been partially achieved through the adoption of an all- composite five- blade main rotor and pioneering canted tail rotor assembly. As intended, the Comanche was to be equipped with sophisticated avionics, including navigation and detection systems, which would have enabled operations at night and in inclement weather. Its primary mission
22650-899: 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
22801-509: 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
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