109-539: The Lockheed YF-12 is an American Mach 3+ capable, high-altitude interceptor prototype , developed and manufactured by American aerospace company Lockheed Corporation . The interceptor was developed during the late 1950s and early 1960s as a potential replacement for the F-106 Delta Dart interceptor for the United States Air Force (USAF). The YF-12 was a twin-seat version of
218-425: A channel becomes supersonic, one significant change takes place. The conservation of mass flow rate leads one to expect that contracting the flow channel would increase the flow speed (i.e. making the channel narrower results in faster air flow) and at subsonic speeds this holds true. However, once the flow becomes supersonic, the relationship of flow area and speed is reversed: expanding the channel actually increases
327-546: A coordinated jamming attack to complicate the testing. When inside the range of the GCI radar, and in anticipation of interception, chaff was dispensed to confuse the defense force and electronic pulses to jam radar signals were turned on. It was up to the defending interceptors and GCI stations to sort out the correct interception. Units operating these specially equipped aircraft were designated Defense Systems Evaluation Squadrons (DSES). The 4713th Defense Systems Evaluation Squadron
436-439: A corresponding speed of sound (Mach 1) of 295.0 meters per second (967.8 ft/s; 659.9 mph; 1,062 km/h; 573.4 kn), 86.7% of the sea level value. The terms subsonic and supersonic are used to refer to speeds below and above the local speed of sound, and to particular ranges of Mach values. This occurs because of the presence of a transonic regime around flight (free stream) M = 1 where approximations of
545-703: A former hallway/latrine area. The headquarters was moved to Ent Air Force Base in Colorado Springs on 8 January 1951. It received 21 former ConAC active-duty fighter squadrons (37 additional Air National Guard fighter squadrons if called to active duty). ADC was also assigned the 25th, 26th 27th and 28th Air Divisions (Defense) ADC completed the Priority Permanent System network for Aircraft Warning and Control ( ground-controlled interception ) in 1952. Gaps were filled by additional Federal Aviation Administration (FAA) radar stations and
654-506: A gain of at least 30 extra minutes warning time of an oncoming bomber attack. ADC's Operation Tail Wind on 11–12 July tested its augmentation plan that required Air Training Command interceptors participate in an air defense emergency. A total of seven ATC bases actively participated in the exercise, deploying aircraft and aircrews and supporting the ADC radar net. As the USAF prepared to deploy
763-407: A gas or a liquid. The boundary can be travelling in the medium, or it can be stationary while the medium flows along it, or they can both be moving, with different velocities : what matters is their relative velocity with respect to each other. The boundary can be the boundary of an object immersed in the medium, or of a channel such as a nozzle , diffuser or wind tunnel channelling the medium. As
872-652: A joint USAF/NASA investigation of supersonic cruise technology, and then flown to the National Museum of the United States Air Force at Wright-Patterson Air Force Base near Dayton, Ohio on 17 November 1979. A fourth YF-12 aircraft, the "YF-12C", was actually the second SR-71A (AF Ser. No. 61–7951). This SR-71A was re-designated as a YF-12C and given the fictitious Air Force Serial Number 60-6937 from an A-12 to maintain SR-71 secrecy. The aircraft
981-422: A landing mishap on 14 August 1966; its rear half was salvaged and combined with the front half of a Lockheed static test airframe to create the only SR-71C . YF-12A, AF Ser. No. 60-6936 was lost on 24 June 1971 due to an in-flight fire caused by a failed fuel line; both pilots ejected safely just north of Edwards AFB. YF-12A, AF Ser. No. 60-6935 is the only surviving YF-12A; it was recalled from storage in 1969 for
1090-589: A lower priority on defense of the continental US, so the F-12B was deemed no longer needed. Then in January 1968, the F-12B program was officially ended. During flight tests the YF-12As set a speed record of 2,070.101 miles per hour (3,331.505 km/h) and altitude record of 80,257.86 feet (24,462.60 m), both on 1 May 1965, and demonstrated promising results with its unique weapon system. Six successful firings of
1199-659: A satellite in 1984. ADC's Consolidated Command. Control and Communications Program, FY 1965–1972 was an outgrowth of a 196x "ADC-NORAD PAGE Study" for replacing SAGE/BUIC with a Primary Automated Ground Environment (PAGE) . The program with a Joint DOD/FAA National Airspace System (NAS) resulted with DOD/FAA agreements for a common aircraft surveillance system, with the FAA "to automate its new National Airspace System (NAS) centers". ADC estimated its portion "would cost about $ 6 million, with annual operating, maintenance, and communication costs about $ 3.5 million" ("the first BUIC III
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#17327722703301308-764: A separate Air Defense Command [from CONAC ] with headquarters on Ent ." The new command's mission was to be to stop a handful of conventionally armed piston engine-powered bombers on a one-way mission. The command was formally reactivated on 1 January 1951. With advances in Soviet bombers, ADC completed improved radar networks and manned interceptors in the 1950s. At the end of the decade it computerized Air Defense Direction Centers to allow air defense controllers to more quickly review integrated military air defense warning (MADW) data and dispatch defenses (e.g., surface-to-air missiles in 1959). ADC began missile warning and space surveillance missions in 1960 and 1961, and established
1417-587: A separate multi-service CONAD headquarters staff (with an Air Force Element), separated command of ADC from CINCONAD, and in 1957 added Alaskan Air Command and Northeast Air Command components to ADC Former NEAC installations in the smaller "Canadian Northeast Area" were transferred to the Canadian Air Defence Command . (e.g., the Hall Beach DEW Line station constructed 1955–1957 -- cf. Canada's Hopedale stations of
1526-466: A sharp object, there is no air between the nose and the shock wave: the shock wave starts from the nose.) As the Mach number increases, so does the strength of the shock wave and the Mach cone becomes increasingly narrow. As the fluid flow crosses the shock wave, its speed is reduced and temperature, pressure, and density increase. The stronger the shock, the greater the changes. At high enough Mach numbers
1635-533: A success and ordered 96 aircraft and had an initial budget of $ 90 million to further testing, but this was withheld by Secretary of Defense McNamara, who on 23 November 1967 put it towards the much less successful F-106X program that nearly failed. The successful AIM-47 Falcon missile was increased in size and performance and became the AIM-54 Phoenix missile for the F-14 Tomcat . The AN/ASG 18 radar
1744-599: A supersonic compressible flow can be found from the Rayleigh supersonic pitot equation (above) using parameters for air: M ≈ 0.88128485 ( q c p + 1 ) ( 1 − 1 7 M 2 ) 2.5 {\displaystyle \mathrm {M} \approx 0.88128485{\sqrt {\left({\frac {q_{c}}{p}}+1\right)\left(1-{\frac {1}{7\,\mathrm {M} ^{2}}}\right)^{2.5}}}} where: As can be seen, M appears on both sides of
1853-769: A supersonic compressible flow is derived from the Rayleigh supersonic pitot equation: p t p = [ γ + 1 2 M 2 ] γ γ − 1 ⋅ [ γ + 1 1 − γ + 2 γ M 2 ] 1 γ − 1 {\displaystyle {\frac {p_{t}}{p}}=\left[{\frac {\gamma +1}{2}}\mathrm {M} ^{2}\right]^{\frac {\gamma }{\gamma -1}}\cdot \left[{\frac {\gamma +1}{1-\gamma +2\gamma \,\mathrm {M} ^{2}}}\right]^{\frac {1}{\gamma -1}}} Mach number
1962-1008: A temporary missile warning network for the 1962 Cuban Missile Crisis . In 1968 it was redesignated Aerospace Defense Command (ADCOM). In 1975, ADCOM became a specified command and the United States' executive agent in the North American Air Defense Command —the single CINCNORAD/CINCAD commanded both. ADCOM's last surface-to-air missiles were taken off alert in 1972, and the Federal Aviation Administration took over many of ADCOM's SAGE radar stations . On 1 October 1979 ADCOM interceptors/bases and remaining air warning radar stations transferred to Tactical Air Command (TAC), with these "atmospheric" units assigned to Air Defense, Tactical Air Command (ADTAC). ADCOM's missile warning and space surveillance installations transferred in 1979 to
2071-461: Is a dimensionless quantity in fluid dynamics representing the ratio of flow velocity past a boundary to the local speed of sound . It is named after the Austrian physicist and philosopher Ernst Mach . M = u c , {\displaystyle \mathrm {M} ={\frac {u}{c}},} where: By definition, at Mach 1, the local flow velocity u is equal to
2180-642: Is a function of temperature and true airspeed. Aircraft flight instruments , however, operate using pressure differential to compute Mach number, not temperature. Assuming air to be an ideal gas , the formula to compute Mach number in a subsonic compressible flow is found from Bernoulli's equation for M < 1 (above): M = 5 [ ( q c p + 1 ) 2 7 − 1 ] {\displaystyle \mathrm {M} ={\sqrt {5\left[\left({\frac {q_{c}}{p}}+1\right)^{\frac {2}{7}}-1\right]}}\,} The formula to compute Mach number in
2289-453: Is greater than 1.0 at that point, then the value of M from the subsonic equation is used as the initial condition for fixed point iteration of the supersonic equation, which usually converges very rapidly. Alternatively, Newton's method can also be used. Aerospace Defense Command 1951 January 8: Ent AFB , Colorado Aerospace Defense Command was a major command of the United States Air Force , responsible for air defense of
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#17327722703302398-418: Is not a constant; in a gas, it increases proportionally to the square root of the absolute temperature , and since atmospheric temperature generally decreases with increasing altitude between sea level and 11,000 meters (36,089 ft), the speed of sound also decreases. For example, the standard atmosphere model lapses temperature to −56.5 °C (−69.7 °F) at 11,000 meters (36,089 ft) altitude, with
2507-621: Is that range of speeds within which the airflow over different parts of an aircraft is between subsonic and supersonic. So the regime of flight from Mcrit up to Mach 1.3 is called the transonic range. Aircraft designed to fly at supersonic speeds show large differences in their aerodynamic design because of the radical differences in the behavior of flows above Mach 1. Sharp edges, thin aerofoil sections, and all-moving tailplane / canards are common. Modern combat aircraft must compromise in order to maintain low-speed handling. Flight can be roughly classified in six categories: At transonic speeds,
2616-418: The 551st Airborne Early Warning and Control Wing , based at Otis Air Force Base , Massachusetts , and the 552nd AEWCW , based at McClellan Air Force Base , California , one wing stationed on each coast. The RC-121s, EC-121s and Texas Towers, it was believed, would contribute to extending contiguous east-coast radar coverage some 300 to 500 miles seaward. In terms of the air threat of the 1950s, this meant
2725-873: The 556th Reconnaissance Squadron and moved to Kadena AB , Okinawa. EB-57s were also deployed to Alaskan Air Command , Elmendorf AFB , Alaska, frequently. The 134th Defense Systems Evaluation Squadron , Vermont Air National Guard, retired its last EB-57 in 1983, and the operational use of the B-57 Canberra ended. ADC supported 4-story SAGE blockhouses were hardened for overpressures of 5 psi (34 kPa). NORAD sector direction center (NSDCs) also had air defense artillery director (ADAD) consoles [and an Army] ADA battle staff officer." The sector direction centers automatically communicated crosstelling of "SAGE reference track data" to/from adjacent sectors' DCs and to 10 Project Nike Missile Master Army Air Defense Command Posts . From 1 September 1954 until 1975, ADC
2834-589: The AIM-47 missiles were completed, and a seventh failed due to a gyro failure on one of the missiles. The last one was launched from the YF-12 at Mach 3.2 at an altitude of 74,000 feet (23,000 m) to a JQB-47E target drone 500 feet (150 m) off the ground. The missile did not have a warhead but still managed to hit the B-47 directly and take a 4 feet (120 cm) section off its tail. The Air Force considered it
2943-834: The Eglin AFB Site C-6 Project Space Track radar (the Eglin phased array's IOC was in 1969, and the North Dakota CMEWS "began passing" PARCS phased array data to NORAD in 1977 after being "modified for the ADCOM mission". After claiming in March 1958 that "the Army's ZEUS did not have the growth potential to handle possible enemy evasion decoy and countermeasure tactics", the USAF similarly identified by early 1959 that its planned Wizard missile
3052-728: The First Air Force , Second Air Force , Third Air Force , and Fourth Air Force . The First and Fourth Air Forces, through their interceptor commands, managed the civilian Aircraft Warning Service on the East and West Coasts , respectively. The USAAF's Aircraft Warning Corps provided air defense warning with information centers that networked an area's " Army Radar Stations " which communicated radar tracks by telephone. The AWC information centers also integrated visual reports processed by Ground Observer Corps filter centers. AWC information centers notified air defense command posts of
3161-533: The Ground Observation Corps (disbanded 1959). In May 1954, ADC moved their initial, rudimentary command center into a "much improved 15,000-square-foot concrete block" building with "main battle control center". During the mid-1950s, planners devised the idea of extending the wall of powerful land-based radar seaward with Airborne early warning and control units. This was done by equipping two wings of Lockheed RC-121 Warning Star aircraft,
3270-539: The Moorestown BMEWS station "to a Spacetrack Analysis Center at Colorado Springs." On 31 December 1965, Forward Scatter Over-the-Horizon network data from the 440L Data Reduction Center was being received by ADC for missile warning, and a NORAD plan for 1 April 1966 was for ADC to "reorganize its remaining 26th , 28th , 29th , and 73d Air Divisions into four air forces." The 1966 20th Surveillance Squadron began ADC's phased array operations with
3379-750: The Navier-Stokes equations used for subsonic design no longer apply; the simplest explanation is that the flow around an airframe locally begins to exceed M = 1 even though the free stream Mach number is below this value. Meanwhile, the supersonic regime is usually used to talk about the set of Mach numbers for which linearised theory may be used, where for example the ( air ) flow is not chemically reacting, and where heat-transfer between air and vehicle may be reasonably neglected in calculations. Generally, NASA defines high hypersonic as any Mach number from 10 to 25, and re-entry speeds as anything greater than Mach 25. Aircraft operating in this regime include
Lockheed YF-12 - Misplaced Pages Continue
3488-683: The P-61 Black Widow , did not have the capabilities to engage the Soviet Tu-4 bomber. Its successor, the F-82 Twin Mustang , was even more disappointing. It took a long time to get into production and did not perform well in inclement weather. The early jet fighters, such as the F-80 Shooting Star and F-84 Thunderjet , lacked all-weather capability and were deemed useless for air defense purposes. Much hope
3597-483: The Space Shuttle and various space planes in development. The subsonic speed range is that range of speeds within which, all of the airflow over an aircraft is less than Mach 1. The critical Mach number (Mcrit) is lowest free stream Mach number at which airflow over any part of the aircraft first reaches Mach 1. So the subsonic speed range includes all speeds that are less than Mcrit. The transonic speed range
3706-911: The Strategic Air Command 's Directorate of Space and Missile Warning Systems (SAC/SX), ) and the North American Aerospace Defense Command 's Air Force Element, NORAD/ADCOM (AFENA) , which was redesignated the Aerospace Defense Center . The command was inactivated on 31 March 1980. With the disestablishment of TAC and SAC in 1992, the Aerospace Defense Center, the ADCOM specified command organizations, along with SAC's missile warning and space surveillance installations. became part of Air Force Space Command (AFSPC). Air Force Space Command activated its headquarters in
3815-690: The Tactical Air Command E-3 Sentry in the later 1970s, active-duty units were phased out EC-121 operations by the end of 1975. All remaining EC-121s were transferred to the Air Force Reserve , which formed the 79th AEWCS at Homestead Air Force Base , Florida in early 1976. The active duty force continued to provide personnel to operate the EC-121s on a 24-hour basis, assigning Detachment 1, 20th Air Defense Squadron to Homestead AFB as associate active duty crews to fly
3924-552: The Vietnam War caused by two major ground explosions, twelve B-57Es were reconfigured as combat-capable B-57Bs at the Martin factory in late 1965 and were deployed to Southeast Asia for combat bombardment operations. Six other B-57Es were converted to RB-57E "Patricia Lynn" tactical reconnaissance aircraft in 1966 during the Vietnam War , operating from Tan Son Nhut Air Base until 1971. The Bomarc Missile Program delivered
4033-551: The compressibility characteristics of fluid flow : the fluid (air) behaves under the influence of compressibility in a similar manner at a given Mach number, regardless of other variables. As modeled in the International Standard Atmosphere , dry air at mean sea level , standard temperature of 15 °C (59 °F), the speed of sound is 340.3 meters per second (1,116.5 ft/s; 761.23 mph; 1,225.1 km/h; 661.49 kn). The speed of sound
4142-616: The continental United States . It was activated in 1968 and disbanded in 1980. Its predecessor, Air Defense Command , was established in 1946, briefly inactivated in 1950, reactivated in 1951, and then redesignated Aerospace rather than Air in 1968. Its mission was to provide air defense of the Continental United States (CONUS). It directly controlled all active measures, and was tasked to coordinate all passive means of air defense. Continental United States air defense forces during World War II were initially under
4251-400: The sound barrier ), a large pressure difference is created just in front of the aircraft . This abrupt pressure difference, called a shock wave , spreads backward and outward from the aircraft in a cone shape (a so-called Mach cone ). It is this shock wave that causes the sonic boom heard as a fast moving aircraft travels overhead. A person inside the aircraft will not hear this. The higher
4360-473: The " 4 continental air forces " for deploying interceptor aircraft which used command guidance for ground-controlled interception . The USAAF inactivated the aircraft warning network in April 1944. Continental Air Forces (CAF) was activated on 12 December 1944, including the four Air Forces, to bring the continental air defense task under one command. AAF Regulation 20-1, dated 15 September 1945, specified
4469-573: The 1950s, went into decline. BOMARC, for example, was dropped from the weapons inventory, and the F-101 and F-102 passed from the regular Air Force inventory into the National Guard. To save funds and manpower, drastic reductions were made in the number of long range radar stations, the number of interceptor squadrons, and in the organizational structure. By 1968 the DOD was making plans to phase down
Lockheed YF-12 - Misplaced Pages Continue
4578-531: The 1954 Pinetree Line and 1957 Mid-Canada Line .) 64th Air Division personnel were assigned to main stations of the 1957 DEW Line and annually inspected auxiliary/intermediate DEW stations maintained by the "DEW M&O Contractor ." On 1 March 1957 CONAD reduced the number of ADC interceptor squadrons on alert for the Air Defense Identification Zone . "At the end of 1957, ADC operated 182 radar stations…32 had been added during
4687-441: The 2.5-year program was US$ 14 million (~$ 37.4 million in 2023). The YF-12 and SR-71 originally suffered from severe control issues that affected both the engines and the physical control of the aircraft. Wind testing at NASA Dryden and YF-12 research flights developed computer systems that nearly completely solved the performance issues. Testing revealed vortices from the nose chines interfering with intake air, which led to
4796-583: The 4677th DSES was redesignated as the 17th Defense Systems Evaluation Squadron . This unit was inactivated in July 1979 and was the last to fly B-57s in the active duty USAF. It shared the Defense Systems Evaluation mission with the Kansas and Vermont Air National Guard. Defense Systems Evaluation operations were also carried out by the 6091st Reconnaissance Squadron , Yokota AB, Japan; later
4905-560: The A-12's reconnaissance equipment were converted to carry Hughes AIM-47 Falcon (GAR-9) missiles. One bay was used for fire control equipment. The first YF-12A flew on 7 August 1963. President Lyndon B. Johnson announced the existence of the aircraft on 24 February 1964. The YF-12A was announced in part to continue hiding the A-12, its still-secret ancestor; any sightings of CIA/Air Force A-12s based at Area 51 in Nevada could be attributed to
5014-543: The ABM missile fire was considered "the heart of the entire [planned] ballistic missile defense system (conceived to have Nike Zeus and Wizard missiles .) On 19 October 1959, HQ USAF assigned ADC the "planning responsibility" for eventual operations of the Missile Defense Alarm System to detect ICBM launches with infrared sensors on space vehicles. ADC's BMEWS Central Computer and Display Facility
5123-612: The AN/FSQ-7 used the Automatic Target and Battery Evaluation (ATABE) to determine which bombers/formations to assign to which manned interceptor base (e.g., using nuclear air-to-air missiles), which to assign to Bomarcs (e.g., with W-40 nuclear warheads ) and if available, which to assign to the region's Nike Army Air Defense Command Post (that also had ATABE software for efficiently coordinating fire from multiple Hercules missile batteries.) Bomarc missiles bases were along
5232-668: The Air Force was increasingly of the opinion that unmanned intercontinental ballistic missiles could accomplish the mission of the B-70 Valkyrie/F-108 Rapier combination much more effectively and at far lower cost. Consequently, the F-108A project was cancelled in its entirety on 23 September 1959, before any prototypes could be built. In 1968, ADCOM began the phaseout of the F-101 and F-102 interceptors from active duty units, with both types mostly being transferred to
5341-621: The Air National Guard. The F-101 would remain in a limited role on active duty until 1982, serving in such roles as towed target carrier aircraft and simulated enemy radar contacts for Airborne Weapons Controller students training for duties aboard the E-3 Sentry AWACS. The F-102 would see service until the mid-1980s as the PQM-102 aerial target drone. The F-106 Delta Dart was the primary air defense interceptor aircraft for
5450-808: The Long Range Interceptor Experimental (LRI-X) program, the North American XF-108 Rapier , an interceptor with Mach 3 speed, was selected. However, the F-108 program was canceled by the Department of Defense in September 1959. During this time, Lockheed's Skunk Works was developing the A-12 reconnaissance aircraft for the U.S. Central Intelligence Agency (CIA) under the Oxcart program. Kelly Johnson ,
5559-399: The Mach number is defined as the ratio of two speeds, it is a dimensionless quantity. If M < 0.2–0.3 and the flow is quasi-steady and isothermal , compressibility effects will be small and simplified incompressible flow equations can be used. The Mach number is named after the physicist and philosopher Ernst Mach , in honour of his achievements, according to a proposal by
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#17327722703305668-493: The Reserve-owned aircraft. Besides monitoring Cuban waters, these last Warning Stars also operated from NAS Keflavik , Iceland. Final EC-121 operations ended in September 1978. The United States Army Air Forces activated Air Defense Command (ADC) in 1946, with a Numbered Air Force of the former Continental Air Forces , from which it took its mission of air warning and air defense. In September 1947, it became part of
5777-641: The Sabre, the F-86D . Despite the demands its complexity made upon a single pilot, the F-86D was backed by senior Air Force officials. Some 2,504 would be built and it would in time be the most numerous interceptor in the Air Defense Command fleet, with more than 1,000 in service by the end of 1955 The F-86D was not ideal, however; its afterburner consumed a great deal of fuel in getting it to altitude, and
5886-747: The US Air Force during the 1970s and early 1980s. It was also the last dedicated interceptor in U.S. Air Force service to date. It was gradually retired during the 1980s, though the QF-106 drone conversions of the aircraft were used until 1998 as aerial targets under the FSAT program. B-57E Canberra dedicated Air Defense Command target towing aircraft were used for training of F-86D Sabre , F-94C Starfire , and F-89D Scorpion interceptors firing 2.75-inch Mk 4/Mk 40 Folding-Fin Aerial Rockets . Due to
5995-480: The XF-108 with two infrared search and track sensors located in the chine leading edge, and the addition of the second cockpit for a crew member to operate the fire control radar for the air-to-air missile system. The modifications changed the aircraft's aerodynamics enough to require ventral fins to be mounted under the fuselage and engine nacelles to maintain stability. Three of the four bays previously used to house
6104-456: The aeronautical engineer Jakob Ackeret in 1929. The word Mach is always capitalized since it derives from a proper name, and since the Mach number is a dimensionless quantity rather than a unit of measure , the number comes after the word Mach. It was also known as Mach's number by Lockheed when reporting the effects of compressibility on the P-38 aircraft in 1942. Mach number is a measure of
6213-628: The aircraft would fly attack profile missions at unexpected, random times and attempt to evade coverage by flying at low altitudes and randomly flying in different directions to confuse interceptors. The aircraft were modified to carry electronic countermeasures (ECM) gear to attempt to confuse radar operators. In 1957, the propeller-driven aircraft were phased out and replaced by Martin B-57 medium bombers which were being phased out of Tactical Air Command. Initially RB-57As from reconnaissance units were modified to have their former camera bays refitted to carry out
6322-606: The annex of building P4. Operational BMEWS control of the Thule Site J RCA AN/FPS-50 Radar Sets transferred from RCA to ADC on 5 January 1962 ( the 12MWS activated in 1967.) By 30 June 1962, integration of ADC's BMEWS CC&DF and the SPADATS Center was completed at Ent AFB, and the Air Forces Iceland transferred from Military Air Transport Service to ADC on 1 July 1962. The 9th ADD established
6431-433: The closely related SR-71 Blackbird ), and is the world's largest, heaviest and fastest crewed interceptor. Following its retirement by the USAF, it served as a research aircraft for NASA for a time, which used it to develop several significant improvements in control for future supersonic aircraft. In the late 1950s, the United States Air Force (USAF) sought a replacement for its F-106 Delta Dart interceptor. As part of
6540-614: The command of the four air districts – Northeast Air District , Northwest Air District , Southeast Air District , and Southwest Air District . The air districts were established on 16 January 1941, before the Pearl Harbor attack . The four air districts also handled USAAF combat training with the Army Ground Forces and "organization and training of bomber, fighter and other units and crews for assignments overseas". The air districts were redesignated on 26 March 1941 as
6649-431: The control of supersonic aircraft in flight. At such high speeds even minor changes in direction caused the aircraft to change position by thousands of feet, and often had severe temperature and pressure changes. CAPCS reduced these deviations by a factor of 10. The overall improvements increased range of the SR-71 by 7 percent. Of the three YF-12As, AF Ser. No. 60-6934 was damaged beyond repair by fire at Edwards AFB during
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#17327722703306758-423: The current air defense system and transition to a new system which included an Airborne Warning and Control System (AWACS), Over-the-Horizon Backscatter (OTH-B) radar, and an improved F-106 interceptor aircraft. The changing emphasis in the threat away from the manned bomber and to the ballistic missile brought reorganization and reduction in aerospace defense resources and personnel and almost continuous turmoil in
6867-483: The development of a computer control system to open the forward bypass doors. A computer system to reduce unstarts was also developed. They also developed a flight engineering computer program called Central Airborne Performance Analyzer (CAPA) that relayed engine data to the pilots and informed them of any faults or issues with performance and indicated the severity of malfunctions. Another system called Cooperative Airframe-Propulsion Control System (CAPCS) greatly improved
6976-599: The east and west coasts of North America and the central areas of the continent (e.g., Suffolk County Missile Annex was on Long Island, New York .) The supersonic Bomarc missiles were the first long-range anti-aircraft missiles in the world, and the longer range BOMARC B models required less time after erected until they could be launched. "Faker", or simulated target aircraft flew mock penetrations into air defense sectors to exercise GDI stations, Air Defense Direction Centers , and interceptor squadrons. Initially using modified B-25 Mitchell and B-29 Superfortress bombers,
7085-419: The equation, and for practical purposes a root-finding algorithm must be used for a numerical solution (the equation is a septic equation in M and, though some of these may be solved explicitly, the Abel–Ruffini theorem guarantees that there exists no general form for the roots of these polynomials). It is first determined whether M is indeed greater than 1.0 by calculating M from the subsonic equation. If M
7194-432: The first CIM-10 Bomarc supersonic surface-to-air missile to ADC during September 1959 at Fort Dix 's BOMARC Base No. 1 near the missile launch control center on McGuire AFB (groundbreaking for McGuire's Air Defense Direction Center to house the IBM AN/FSQ-7 Combat Direction Central for Bomarc ground-controlled interception had been in 1957.) To ensure probability of kill before bombers could drop their weapons,
7303-408: The flow field around the object includes both sub- and supersonic parts. The transonic period begins when first zones of M > 1 flow appear around the object. In case of an airfoil (such as an aircraft's wing), this typically happens above the wing. Supersonic flow can decelerate back to subsonic only in a normal shock; this typically happens before the trailing edge. (Fig.1a) As the speed increases,
7412-426: The head of Skunk Works, proposed to build a version of the A-12 named AF-12 by the company; the USAF ordered three AF-12s in mid-1960. The AF-12s took the seventh through ninth slots on the A-12 assembly line; these were designated as YF-12A interceptors. The main changes involved modifying the A-12's nose by cutting back the chines to accommodate the huge Hughes AN/ASG-18 fire-control radar originally developed for
7521-419: The high-drag 45' banners but hits could still be scored on them. By 1960, the rocket firing interceptors were giving way to F-102 Delta Dagger interceptors firing heat-seeking AIM-4 Falcon air-to-air missiles. This made the target towing mission of the B-57E obsolete, and the B-57Es were adapted to electronic countermeasures and faker target aircraft (EB-57E) (see below). In order to cover combat losses in
7630-529: The interceptor squadrons assigned to those bases. The 6th TTS was inactivated by late 1957 and the Canberra trainers were designated a flight of the 8th Bombardment Squadron at Johnson AB. In Europe, USAFE supported a squadron of B-57E gunnery trainers at Wheelus AB , Libya where European-based interceptors deployed for "live firing" over the vast desert range there. To provide challenges for interceptors, The B-57Es towed styrofoam, bomb-shaped radar reflectant targets. These could be towed at higher altitudes than
7739-409: The last half of the 1970s, but while some consideration was given to closing down the major command headquarters altogether and redistributing field resources to other commands, such a move lacked support in the Air Staff. In early 1977 strong Congressional pressure to reduce management "overhead", and the personal conviction of the USAF Chief of Staff that substantial savings could be realized without
7848-462: The last half of the year as low-altitude, unmanned gap-filler radars. The total consisted of 47 gap-filler stations, 75 Permanent System radars, 39 semimobile radars, 19 Pinetree stations ,…1 Lashup[-era] radar and a single Texas Tower ". After the NORAD agreement was signed on 12 May 1958, ADC became a NORAD component. By 30 June 1958, the planned ADC anti-ICBM processing facility to coordinate
7957-475: The latest ECM systems to confuse the defenders. Wing racks, originally designed for bombs, now carried chaff dispensers and the navigator position was replaced with an Electronic Warfare Officer (EWO). The modified B-57s were designated as EB-57 (E for special electronic installation). Considerable realism would be generated into these simulated aggressor attack missions being flown by the B-57 crews. Often several EB-57s were used to form separate tracks and provide
8066-641: The management structure. The headquarters of the Continental Air Defense Command (CONAD) and ADC were combined on 1 July 1973. Six months later in February 1973, ADC was reduced to 20 fighter squadrons and a complete phaseout of air defense missile batteries. Continental Air Command was disestablished on 1 July 1975 and Aerospace Defense Command became a specified command by direction of the JCS. Reductions and reorganizations continued into
8175-484: The nature of air-to-air weapon training requiring a large amount of air space, only a few locations were available for practice ranges. ADC assigned these aircraft to bases close to these large, restricted areas, and fighter-interceptor squadrons deployed to these bases for this type of "hot fire" training which took place in these ranges. The gunnery schools were located at Yuma AFB , Arizona ( 17th Tow Target Squadron (TTS)), and later moved to MacDill AFB , Florida where
8284-424: The newly established United States Air Force . The command become a subordinate organization of Continental Air Command (ConAC) on 1 December 1948. ConAC gradually assumed direct charge of ADC air defense components, and ADC inactivated on 1 July 1950. But five months later, on 10 November 1950, Generals Vandenberg and Twining notified General Ennis C. Whitehead that "the Air Force had approved activation of
8393-530: The pilot was overburdened by cockpit tasks. The F-89D was modified to accept AIM-4 Falcon guided missiles (F-89H) and AIR-2 Genie atomic warhead rockets (F-89J) as armament. The F-86D was modified (F-86L) to include an FDDL SAGE data link that permitted automatic ground control. The F-86L and F-89H became available in 1956, and the F-89J in 1957. The first of the Century Series supersonic interceptors
8502-480: The post-war CAF mission. For aircraft warning, in 1945 CAF had recommended "research and development be undertaken on radar and allied equipment for an air defense system [for] the future threat", e.g., a "radar [with] range of 1,000 miles, [to detect] at an altitude of 200 miles, and at a speed of 1,000 miles per hour". HQ AAF responded that "until the kind of defense needed to counter future attacks could be determined, AC&W planning would have to be restricted to
8611-688: The proposed system". (In the spring and summer of 1947, 3 ADC AC&W plans had gone unfunded. ) By 1948 there were only 5 AC&W stations, including the Twin Lights station in NJ that opened in June and Montauk NY "Air Warning Station #3 (5 July) -- cf. SAC radar stations , e.g., at Dallas & Denver Bomb Plots . ADC became a subordinate operational command of Continental Air Command on 1 December 1948 and on 27 June 1950, United States air defense systems began 24-hour operations two days after
8720-533: The same Chidlaw Building where ADCOM had been inactivated. ADC had four day-type fighter squadrons (FDS) in 1946. The ADC interceptor force grew to ninety-three (93) active Air Force fighter interceptor squadrons, seventy-six (76) Air National Guard fighter interceptor squadrons, several U.S. Navy fighter squadrons, USAF and USN airborne early warning squadrons, radar squadrons, training squadrons, and numerous support units that have played important roles in our nation's defense. The first ADC interceptor,
8829-463: The speed of sound is known, the Mach number at which an aircraft is flying can be calculated by M = u c {\displaystyle \mathrm {M} ={\frac {u}{c}}} where: and the speed of sound varies with the thermodynamic temperature as: c = γ ⋅ R ∗ ⋅ T , {\displaystyle c={\sqrt {\gamma \cdot R_{*}\cdot T}},} where: If
8938-779: The speed of sound is not known, Mach number may be determined by measuring the various air pressures (static and dynamic) and using the following formula that is derived from Bernoulli's equation for Mach numbers less than 1.0. Assuming air to be an ideal gas , the formula to compute Mach number in a subsonic compressible flow is: M = 2 γ − 1 [ ( q c p + 1 ) γ − 1 γ − 1 ] {\displaystyle \mathrm {M} ={\sqrt {{\frac {2}{\gamma -1}}\left[\left({\frac {q_{c}}{p}}+1\right)^{\frac {\gamma -1}{\gamma }}-1\right]}}\,} where: The formula to compute Mach number in
9047-418: The speed of sound. At Mach 0.65, u is 65% of the speed of sound (subsonic), and, at Mach 1.35, u is 35% faster than the speed of sound (supersonic). The local speed of sound, and hence the Mach number, depends on the temperature of the surrounding gas. The Mach number is primarily used to determine the approximation with which a flow can be treated as an incompressible flow . The medium can be
9156-405: The speed, the more narrow the cone; at just over M = 1 it is hardly a cone at all, but closer to a slightly concave plane. At fully supersonic speed, the shock wave starts to take its cone shape and flow is either completely supersonic, or (in case of a blunt object), only a very small subsonic flow area remains between the object's nose and the shock wave it creates ahead of itself. (In the case of
9265-425: The speed. The obvious result is that in order to accelerate a flow to supersonic, one needs a convergent-divergent nozzle, where the converging section accelerates the flow to sonic speeds, and the diverging section continues the acceleration. Such nozzles are called de Laval nozzles and in extreme cases they are able to reach hypersonic speeds (Mach 13 (15,900 km/h; 9,900 mph) at 20 °C). When
9374-540: The start of the Korean War . By the time ADC was inactivated on 1 July 1950, ADC had deployed the Lashup Radar Network with existing radars at 43 sites. In addition, 36 Air National Guard fighter units were called to active duty for the mission. ADC was reinstated as a major command on 1 January 1951 at Mitchel Air Force Base , New York. A rudimentary command centre was established that year from
9483-399: The temperature increases so much over the shock that ionization and dissociation of gas molecules behind the shock wave begin. Such flows are called hypersonic. It is clear that any object travelling at hypersonic speeds will likewise be exposed to the same extreme temperatures as the gas behind the nose shock wave, and hence choice of heat-resistant materials becomes important. As a flow in
9592-464: The temporary 1962 " Cuban Missile Early Warning System " for the missile crisis . Responsibility for a USAFSS squadron's AN/FPS-17 radar station in Turkey for missile test monitoring transferred to ADC on 1 July 1963 , the same date the site's AN/FPS-79 achieved IOC. By January 1963, ADC's Detachment 3 of the 9th Aerospace Defense Division (9th ADD) was providing space surveillance data from
9701-625: The test program included objectives aimed at answering some questions about implementation of the B-1 . Air Force objectives included exploration of its use in a tactical environment, and how airborne early warning and control (AWACS) would control supersonic aircraft. The Air Force portion was budgeted at US$ 4 million. The NASA tests would answer questions such as how engine inlet performance affected airframe and propulsion interaction, boundary layer noise, heat transfer under high Mach conditions, and altitude hold at supersonic speeds. The NASA budget for
9810-562: The then-secret single-seat Lockheed A-12 reconnaissance aircraft operated by the Central Intelligence Agency (CIA); unlike the A-12, it was furnished with the Hughes AN/ASG-18 fire-control radar and could be armed with AIM-47 Falcon (GAR-9) air-to-air missiles . Its maiden flight was on 7 August 1963. Its existence was publicly revealed by President Lyndon B. Johnson on 24 February 1964; this move
9919-966: The training continued over the Gulf of Mexico . With the move to Florida, the 3d TTS was formed at George AFB , California which performed training over the Mojave Desert in Southern California. Additional units were located at Biggs AFB , near El Paso, Texas (1st TTS) and the 4756th TTS was located at Tyndall AFB , Florida to support the Fighter Weapons Center located there. ADC also supported overseas training at Johnson AB , Japan (the 6th Tow Target Squadron). From Johnson AB, B-57Es deployed to Clark AB , Philippines; Andersen AFB , Guam, Naha AB , Okinawa and Itazuke AB , Misawa AB and Yokota AB , all in Japan for training of
10028-469: The transfer at CAF HQ in the expectation that 'it would become Air Defense Command.' CAF installations that were transferred to ADC included Mitchel Field (21 March 1946), Hamilton Army Airfield (21 March 1946), Myrtle Beach Army Air Field (27 March 1946), Shaw Field (1 April 1946), McChord Field (1 August 1946), Grandview Army Air Field (1 January 1952), Seymour Johnson Field (1 April 1956), and Tyndall Field (1 July 1957). Air Defense Command
10137-513: The use of available radar sets ". CAF's January 1946 Radar Defense Report for Continental United States recommended military characteristics for a post-war Air Defense System "based upon such advanced equipment", and the HQ AAF Plans reminded "the command that radar defense planning had to be based on the available equipment." Reorganization of Continental Air Forces began in 1945, when ground radar and interceptor plans were prepared for
10246-506: The well-publicized Air Force YF-12As based at Edwards Air Force Base in California. The first public showing of the aircraft was on 30 September 1964 at Edwards. On 14 May 1965, the Air Force placed a production order for 93 F-12Bs for its Air Defense Command (ADC). However, Secretary of Defense Robert McNamara would not release the funding for three consecutive years due to Vietnam War costs. Updated intelligence placed
10355-437: The zone of M > 1 flow increases towards both leading and trailing edges. As M = 1 is reached and passed, the normal shock reaches the trailing edge and becomes a weak oblique shock: the flow decelerates over the shock, but remains supersonic. A normal shock is created ahead of the object, and the only subsonic zone in the flow field is a small area around the object's leading edge. (Fig.1b) When an aircraft exceeds Mach 1 (i.e.
10464-581: Was "first conceived—and rejected—in 1946". A 1947 proposal for 411 radar stations and 18 control centers costing $ 600 million was the Project Supremacy plan for a postwar Radar Fence that was rejected by Air Defense Command since "no provision was made in it for the Alaska to Greenland net with flanks guarded by aircraft and picket ships [required] for 3 to 6 hours of warning time", and "Congress failed to act on legislation required to support
10573-585: Was "not cost effective" against ICBM warheads. —the Army Zeus deployed successors against ICBMs (SAFEGUARD System, 1975–6) and space vehicles ( Johnston Atoll, 1962–75 ). After tests of the 1959 High Virgo (at Explorer 5 ), 1959 Bold Orion ( Explorer 6 ), and 1963 Project 505 ( Nike Zeus ) anti-satellite tests (the latter's nuclear burst destroyed a satellite), the Air Force Systems Command ASM-135 ASAT collided with
10682-528: Was a component of the unified Continental Air Defense Command (CONAD) along with the Army's ARAACOM (1957 ARADCOM) and until 1965, the Navy's NAVFORCONAD . The USAF as the executive CONAD agent initially used ADC's: ADC'a Permanent System radar stations were used for CONAD target data, along with Navy picket ships ( Atlantic and Pacific Barrier until 1965) and Army Project Nike "target acquisition radars". A CONAD reorganization that started in 1956 created
10791-526: Was activated on 21 March 1946 with the former CAF Fourth Air Force, the inactive Tenth Air Force , and the tbd's Fourteenth Air Force . Second Air Force was reactivated and added on 6 June 1946. In December 1946 the "Development of Radar Equipment for Detecting and Countering Missiles of the German A-4 type " was planned, part of the Signal Corps ' Project 414A . The Distant Early Warning Line
10900-539: Was anticipated. However, by mid-1959, the Air Force was already beginning to experience some doubts about the high cost of the Rapier program. The primary strategic threat from the Soviet Union was now perceived to be its battery of intercontinental ballistic missiles instead of its force of long-range bombers. Against intercontinental ballistic missiles, the F-108A interceptor would be completely useless. In addition,
11009-650: Was built as an austere network center (instead of for coordinating anti-ICBM fire) which "at midnight on 30 September I960…achieved initial operational capability " (IOC). On 1 July 1961 for space surveillance, ADC took over the Laredo Test Site and the Trinidad Air Station from Rome Air Development Center . The " 1st Aero" cadre at the Hanscom AFB NSSCC moved 496L System operations in July 1961 to Ent's " SPADATS Center" in
11118-474: Was intended to serve as a long-range interceptor that could destroy attacking Soviet bombers over the poles before they could get near US territory. It was also to serve as the escort fighter for the XB-70 Valkyrie Mach-3 strategic bomber, also to be built by North American. The Air Force expected that the first F-108A would be ready for service by early 1963. An order for no less than 480 F-108s
11227-638: Was loaned to NASA for propulsion testing after the loss of YF-12A (AF Ser. No. 60–6936) in 1971. The YF-12C was operated by NASA until September 1978, when it was returned to the Air Force. The YF-12 had a real-field sonic-boom overpressure value between 33.5 and 52.7 N/m (0.7 to 1.1 lb/ft) – below 48 was considered "low". Data from Lockheed's SR-71 'Blackbird' Family General characteristics Performance Armament Avionics Related development Related lists Mach number The Mach number ( M or Ma ), often only Mach , ( / m ɑː k / ; German: [max] )
11336-701: Was placed on two jet-powered interceptors, the XP-87 Blackhawk and the XP-89 Scorpion . (Designations changed to XF-87 and XF-89.) They, in turn, also proved to be inadequate: the XF-87 was cancelled and the Scorpion underwent extensive redesign. The first-generation jets gave way to all-weather dedicated interceptor jets. The F-94 Starfire was pressed into service as an "interim" interceptor, and North American in 1949 pushed an interceptor version of
11445-424: Was set to begin in April 1967 at Z-50, Saratoga Springs".) As the space mission grew the command changed its name, effective 15 January 1968, to Aerospace Defense Command , or ADCOM. Under ADCOM, emphasis went to systems for ballistic missile detection and warning and space surveillance, and the atmospheric detection and warning system, which had been in an almost continuous state of expansion and improvement since
11554-599: Was stationed for training in the Northeast. The 4713th also deployed frequently to USAFE in West Germany for training of NATO forces. The other was the 4677th Defense Systems Evaluation Squadron , which concentrated on Fighter Interceptor Squadron training for units in the Western United States. In 1974, the 4713th DSES was inactivated and its EB-57s were divided between two Air National Guard units and
11663-651: Was the F-102A Delta Dagger in 1956, followed by the F-104A Starfighter in 1958. The F-101B Voodoo and F-106 Delta Dart were first received by ADC during the first half of 1959. By 1960, the ADC interceptor force was composed of the F-101, F-104, F-106, and the F-102. The North American F-108 Rapier was the first proposed successor to the F-106. It was to be capable of Mach 3 performance and
11772-559: Was to provide plausible deniability for the CIA-operated A-12 fleet, which closely resembled the prototype YF-12. During the 1960s, the YF-12 underwent flight evaluations by the USAF, but funding to put it into operational use was not forthcoming partly due to the pressing demands of the Vietnam War and other military priorities. It set and held speed and altitude world records of over 2,000 miles per hour (3,200 km/h) and over 80,000 feet (24,000 m) (later surpassed by
11881-571: Was upgraded to become the AN/AWG-9 and APG-71, which added the ability to track multiple targets. One of the Air Force test pilots, Jim Irwin , would go on to become a NASA astronaut and walk on the Moon . The program was abandoned following the cancellation of the production F-12B, but the YF-12s continued flying for many years with the USAF and with NASA as research aircraft. The initial phase of
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