121-545: The Lockheed A-12 is a retired high-altitude, Mach 3+ reconnaissance aircraft built for the United States Central Intelligence Agency (CIA) by Lockheed 's Skunk Works , based on the designs of Clarence "Kelly" Johnson . The aircraft was designated A-12, the twelfth in a series of internal design efforts for "Archangel", the aircraft's internal code name. In 1959, it was selected over Convair 's FISH and Kingfish designs as
242-631: A batch reactor with an inert atmosphere at a temperature of 1,000 °C. Dilute hydrochloric acid is then used to leach the salt from the product. The processing of titanium metal occurs in four major steps: reduction of titanium ore into "sponge", a porous form; melting of sponge, or sponge plus a master alloy to form an ingot; primary fabrication, where an ingot is converted into general mill products such as billet , bar, plate , sheet , strip, and tube ; and secondary fabrication of finished shapes from mill products. Because it cannot be readily produced by reduction of titanium dioxide, titanium metal
363-464: A carbon monoxide atmosphere with chlorine gas before reducing it to titanium metal by the use of sodium. Pure metallic titanium (99.9%) was first prepared in 1910 by Matthew A. Hunter at Rensselaer Polytechnic Institute by heating TiCl 4 with sodium at 700–800 °C (1,292–1,472 °F) under great pressure in a batch process known as the Hunter process . Titanium metal was not used outside
484-425: 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
605-624: A component of smoke screens and catalysts ; and titanium trichloride (TiCl 3 ), which is used as a catalyst in the production of polypropylene . Titanium can be alloyed with iron , aluminium , vanadium , and molybdenum , among other elements. The resulting titanium alloys are strong, lightweight, and versatile, with applications including aerospace ( jet engines , missiles , and spacecraft ), military, industrial processes (chemicals and petrochemicals, desalination plants , pulp , and paper ), automotive, agriculture (farming), sporting goods, jewelry, and consumer electronics . Titanium
726-439: 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
847-687: A couple of dozen are readily available commercially. The ASTM International recognizes 31 grades of titanium metal and alloys, of which grades one through four are commercially pure (unalloyed). Those four vary in tensile strength as a function of oxygen content, with grade 1 being the most ductile (lowest tensile strength with an oxygen content of 0.18%), and grade 4 the least ductile (highest tensile strength with an oxygen content of 0.40%). The remaining grades are alloys, each designed for specific properties of ductility, strength, hardness, electrical resistivity, creep resistance, specific corrosion resistance, and combinations thereof. In addition to
968-484: A day for steak, Maine lobster , or other requests). In June 1964, the last A-12 was delivered to Groom Lake, from where the fleet made a total of 2,850 test flights. A total of 18 aircraft were built through the program's production run. Of these, 13 were A-12s, three were prototype YF-12A interceptors for the U.S. Air Force (not funded under the OXCART program), and two were M-21 reconnaissance drone carriers . One of
1089-407: 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
1210-622: A lustrous transition metal with a silver color , low density , and high strength, resistant to corrosion in sea water , aqua regia , and chlorine . Titanium was discovered in Cornwall , Great Britain , by William Gregor in 1791 and was named by Martin Heinrich Klaproth after the Titans of Greek mythology . The element occurs within a number of minerals , principally rutile and ilmenite , which are widely distributed in
1331-438: A mixture of oxides and deposits coatings with variable refractive index. Also known is Ti 2 O 3 , with the corundum structure, and TiO , with the rock salt structure , although often nonstoichiometric . The alkoxides of titanium(IV), prepared by treating TiCl 4 with alcohols , are colorless compounds that convert to the dioxide on reaction with water. They are industrially useful for depositing solid TiO 2 via
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#17327759553781452-434: A reducing agent in organic chemistry. Owing to the important role of titanium compounds as polymerization catalyst, compounds with Ti-C bonds have been intensively studied. The most common organotitanium complex is titanocene dichloride ((C 5 H 5 ) 2 TiCl 2 ). Related compounds include Tebbe's reagent and Petasis reagent . Titanium forms carbonyl complexes , e.g. (C 5 H 5 ) 2 Ti(CO) 2 . Following
1573-472: A sample of manaccanite and confirmed that it contained titanium. The currently known processes for extracting titanium from its various ores are laborious and costly; it is not possible to reduce the ore by heating with carbon (as in iron smelting) because titanium combines with the carbon to produce titanium carbide. An extraction of 95% pure titanium was achieved by Lars Fredrik Nilson and Otto Petterson . To achieve this they chlorinated titanium oxide in
1694-412: A series of violent yawing and pitching actions was followed very rapidly with the aircraft becoming uncontrollable. Mel Vojvodich was scheduled to take aircraft number 126 on a performance check flight which included a rendezvous beacon test with a KC-135 tanker and managed to eject safely 150 to 200 ft (46 to 61 m) above the ground. A post-crash investigation revealed that the primary cause of
1815-466: 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
1936-416: A smooth steady roll to the left. Lockheed test pilot Bill Park could not overcome the roll. At about a 45-degree bank angle and 200 ft (61 m) altitude he ejected and was blown sideways out of the aircraft. Although he was not very high off the ground, his parachute opened and he landed safely. On 28 December 1965, the third A-12 was lost when "Article 126" crashed 30 seconds after takeoff when
2057-599: 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
2178-769: 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
2299-725: A variety of conditions, such as embrittlement , which reduce the integrity of the assembly welds and lead to joint failure. Titanium is very difficult to solder directly, and hence a solderable metal or alloy such as steel is coated on titanium prior to soldering. Titanium metal can be machined with the same equipment and the same processes as stainless steel . Common titanium alloys are made by reduction. For example, cuprotitanium (rutile with copper added), ferrocarbon titanium (ilmenite reduced with coke in an electric furnace), and manganotitanium (rutile with manganese or manganese oxides) are reduced. About fifty grades of titanium alloys are designed and currently used, although only
2420-655: A very tense period following seizure of the Navy intelligence ship Pueblo on 23 January. The aim was to discover whether the North Koreans were preparing any large scale hostile move following this incident and to actually find where the Pueblo was hidden. The ship was found anchored in an inlet in Wonsan Bay attended by two North Korean patrol boats and guarded by three Komar class missile boats . Chinese tracking of
2541-421: Is positron emission (with the exception of Ti which undergoes electron capture ), leading to isotopes of scandium , and the primary mode for isotopes heavier than Ti is beta emission , leading to isotopes of vanadium . Titanium becomes radioactive upon bombardment with deuterons , emitting mainly positrons and hard gamma rays . The +4 oxidation state dominates titanium chemistry, but compounds in
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#17327759553782662-472: Is 60% denser than aluminium, but more than twice as strong as the most commonly used 6061-T6 aluminium alloy . Certain titanium alloys (e.g., Beta C ) achieve tensile strengths of over 1,400 MPa (200,000 psi). However, titanium loses strength when heated above 430 °C (806 °F). Titanium is not as hard as some grades of heat-treated steel; it is non-magnetic and a poor conductor of heat and electricity. Machining requires precautions, because
2783-461: 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
2904-642: 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
3025-473: Is about 4 picomolar in the ocean. At 100 °C, the concentration of titanium in water is estimated to be less than 10 M at pH 7. The identity of titanium species in aqueous solution remains unknown because of its low solubility and the lack of sensitive spectroscopic methods, although only the 4+ oxidation state is stable in air. No evidence exists for a biological role, although rare organisms are known to accumulate high concentrations of titanium. Titanium
3146-548: Is also considered one of the most biocompatible metals, leading to a range of medical applications including prostheses , orthopedic implants , dental implants , and surgical instruments . The two most useful properties of the metal are corrosion resistance and strength-to-density ratio , the highest of any metallic element. In its unalloyed condition, titanium is as strong as some steels , but less dense. There are two allotropic forms and five naturally occurring isotopes of this element, Ti through Ti, with Ti being
3267-500: Is also very hard, is found in cutting tools and coatings. Titanium tetrachloride (titanium(IV) chloride, TiCl 4 ) is a colorless volatile liquid (commercial samples are yellowish) that, in air, hydrolyzes with spectacular emission of white clouds. Via the Kroll process , TiCl 4 is used in the conversion of titanium ores to titanium metal. Titanium tetrachloride is also used to make titanium dioxide, e.g., for use in white paint. It
3388-854: Is an extremely rare mineral consisting of titanium dioxide. Of these minerals, only rutile and ilmenite have economic importance, yet even they are difficult to find in high concentrations. About 6.0 and 0.7 million tonnes of those minerals were mined in 2011, respectively. Significant titanium-bearing ilmenite deposits exist in Australia , Canada , China , India , Mozambique , New Zealand , Norway , Sierra Leone , South Africa , and Ukraine . About 210,000 tonnes of titanium metal sponge were produced in 2020, mostly in China (110,000 t), Japan (50,000 t), Russia (33,000 t) and Kazakhstan (15,000 t). Total reserves of anatase, ilmenite, and rutile are estimated to exceed 2 billion tonnes. The concentration of titanium
3509-637: Is contained in meteorites , and it has been detected in the Sun and in M-type stars (the coolest type) with a surface temperature of 3,200 °C (5,790 °F). Rocks brought back from the Moon during the Apollo 17 mission are composed of 12.1% TiO 2 . Native titanium (pure metallic) is very rare. Naturally occurring titanium is composed of five stable isotopes : Ti, Ti, Ti, Ti, and Ti, with Ti being
3630-489: Is corroded by concentrated acids. Titanium is a very reactive metal that burns in normal air at lower temperatures than the melting point. Melting is possible only in an inert atmosphere or vacuum. At 550 °C (1,022 °F), it combines with chlorine. It also reacts with the other halogens and absorbs hydrogen. Titanium readily reacts with oxygen at 1,200 °C (2,190 °F) in air, and at 610 °C (1,130 °F) in pure oxygen, forming titanium dioxide . Titanium
3751-426: 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. Titanium Titanium is a chemical element ; it has symbol Ti and atomic number 22. Found in nature only as an oxide , it can be reduced to produce
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3872-406: Is heated to this transition temperature but then falls and remains fairly constant for the β form regardless of temperature. Like aluminium and magnesium , the surface of titanium metal and its alloys oxidize immediately upon exposure to air to form a thin non-porous passivation layer that protects the bulk metal from further oxidation or corrosion. When it first forms, this protective layer
3993-829: Is manufactured using a flow production process known as the Armstrong process that is similar to the batch production Hunter process . A stream of titanium tetrachloride gas is added to a stream of molten sodium; the products (sodium chloride salt and titanium particles) is filtered from the extra sodium. Titanium is then separated from the salt by water washing. Both sodium and chlorine are recycled to produce and process more titanium tetrachloride. Methods for electrolytic production of Ti metal from TiO 2 using molten salt electrolytes have been researched and tested at laboratory and small pilot plant scales. The lead author of an impartial review published in 2017 considered his own process "ready for scaling up." A 2023 review "discusses
4114-418: 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
4235-426: Is not the case. It is paramagnetic and has fairly low electrical and thermal conductivity compared to other metals. Titanium is superconducting when cooled below its critical temperature of 0.49 K. Commercially pure (99.2% pure) grades of titanium have ultimate tensile strength of about 434 MPa (63,000 psi ), equal to that of common, low-grade steel alloys, but are less dense. Titanium
4356-565: Is obtained by reduction of titanium tetrachloride (TiCl 4 ) with magnesium metal in the Kroll process. The complexity of this batch production in the Kroll process explains the relatively high market value of titanium, despite the Kroll process being less expensive than the Hunter process. To produce the TiCl 4 required by the Kroll process, the dioxide is subjected to carbothermic reduction in
4477-511: Is one of the few elements that burns in pure nitrogen gas, reacting at 800 °C (1,470 °F) to form titanium nitride , which causes embrittlement. Because of its high reactivity with oxygen, nitrogen, and many other gases, titanium that is evaporated from filaments is the basis for titanium sublimation pumps , in which titanium serves as a scavenger for these gases by chemically binding to them. Such pumps inexpensively produce extremely low pressures in ultra-high vacuum systems. Titanium
4598-469: Is only 1–2 nm thick but it continues to grow slowly, reaching a thickness of 25 nm in four years. This layer gives titanium excellent resistance to corrosion against oxidizing acids, but it will dissolve in dilute hydrofluoric acid , hot hydrochloric acid, and hot sulfuric acid. Titanium is capable of withstanding attack by dilute sulfuric and hydrochloric acids at room temperature, chloride solutions, and most organic acids. However, titanium
4719-483: Is surrounded by six oxide ligands that link to other Ti centers. The term titanates usually refers to titanium(IV) compounds, as represented by barium titanate (BaTiO 3 ). With a perovskite structure, this material exhibits piezoelectric properties and is used as a transducer in the interconversion of sound and electricity . Many minerals are titanates, such as ilmenite (FeTiO 3 ). Star sapphires and rubies get their asterism (star-forming shine) from
4840-621: 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,
4961-681: Is the ninth-most abundant element in Earth 's crust (0.63% by mass ) and the seventh-most abundant metal. It is present as oxides in most igneous rocks , in sediments derived from them, in living things, and natural bodies of water. Of the 801 types of igneous rocks analyzed by the United States Geological Survey , 784 contained titanium. Its proportion in soils is approximately 0.5–1.5%. Common titanium-containing minerals are anatase , brookite , ilmenite , perovskite , rutile , and titanite (sphene). Akaogiite
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5082-471: Is used in steel as an alloying element ( ferro-titanium ) to reduce grain size and as a deoxidizer , and in stainless steel to reduce carbon content. Titanium is often alloyed with aluminium (to refine grain size), vanadium , copper (to harden), iron , manganese , molybdenum , and other metals. Titanium mill products (sheet, plate, bar, wire, forgings, castings) find application in industrial, aerospace, recreational, and emerging markets. Powdered titanium
5203-514: Is widely used in organic chemistry as a Lewis acid , for example in the Mukaiyama aldol condensation . In the van Arkel–de Boer process , titanium tetraiodide (TiI 4 ) is generated in the production of high purity titanium metal. Titanium(III) and titanium(II) also form stable chlorides. A notable example is titanium(III) chloride (TiCl 3 ), which is used as a catalyst for production of polyolefins (see Ziegler–Natta catalyst ) and
5324-716: The Defense National Stockpile Center , until the stockpile was dispersed in the 2000s. As of 2021, the four leading producers of titanium sponge were China (52%), Japan (24%), Russia (16%) and Kazakhstan (7%). The Hunter process was the first industrial process to produce pure metallic titanium. It was invented in 1910 by Matthew A. Hunter , a chemist born in New Zealand who worked in the United States. The process involves reducing titanium tetrachloride (TiCl 4 ) with sodium (Na) in
5445-409: The Earth's crust and lithosphere ; it is found in almost all living things, as well as bodies of water, rocks, and soils. The metal is extracted from its principal mineral ores by the Kroll and Hunter processes. The most common compound, titanium dioxide , is a popular photocatalyst and is used in the manufacture of white pigments. Other compounds include titanium tetrachloride (TiCl 4 ),
5566-750: 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
5687-483: 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
5808-693: The Thailand area, and return to Kadena. Its turning radius of 86 miles (138 km) was such, however, that on some mission profiles it might intrude into Chinese airspace during the turn. Once landed, the camera film was removed from the aircraft, boxed, and sent by special aircraft to the processing facilities. Film from earlier missions was developed at the Eastman Kodak plant in Rochester , New York . Later an Air Force Center in Japan carried out
5929-617: The U-2 on time and under budget. In addition, Lockheed had experience running a "black" project . The A-12 was produced from 1962 to 1964 and flew from 1963 to 1968. It was the precursor to the twin-seat U.S. Air Force YF-12 prototype interceptor , M-21 launcher for the D-21 drone , and the SR-71 Blackbird , a slightly longer variant able to carry a heavier fuel and camera load. The A-12 began flying missions in 1967 and its final mission
6050-551: 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
6171-572: The electrochemical principles involved in the recovery of metals from aqueous solutions and fused salt electrolytes", with particular attention paid to titanium. While some metals such as nickel and copper can be refined by electrowinning at room temperature, titanium must be in the molten state and "there is a strong chance of attack of the refractory lining by molten titanium." Zhang et al concluded their Perspective on Thermochemical and Electrochemical Processes for Titanium Metal Production in 2017 that "Even though there are strong interests in
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#17327759553786292-484: The sol-gel process . Titanium isopropoxide is used in the synthesis of chiral organic compounds via the Sharpless epoxidation . Titanium forms a variety of sulfides, but only TiS 2 has attracted significant interest. It adopts a layered structure and was used as a cathode in the development of lithium batteries . Because Ti(IV) is a "hard cation" , the sulfides of titanium are unstable and tend to hydrolyze to
6413-400: 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
6534-540: The +3 oxidation state are also numerous. Commonly, titanium adopts an octahedral coordination geometry in its complexes, but tetrahedral TiCl 4 is a notable exception. Because of its high oxidation state, titanium(IV) compounds exhibit a high degree of covalent bonding . The most important oxide is TiO 2 , which exists in three important polymorphs ; anatase, brookite, and rutile. All three are white diamagnetic solids, although mineral samples can appear dark (see rutile ). They adopt polymeric structures in which Ti
6655-602: The 13 A-12s was a dedicated trainer aircraft with a second seat, located behind the pilot and raised to permit the instructor pilot to see forward. The A-12 trainer, known as "Titanium Goose", retained the J75 power plants for its entire service life. Three more A-12s were lost in later testing. On 9 July 1964, "Article 133" crashed while making its final approach to the runway when a pitch-control servo device froze at an altitude of 500 ft (150 m) and airspeed of 200 knots (230 mph; 370 km/h) causing it to begin
6776-561: The A-11 stage when the program was reviewed. The A-11 was competing against a Convair proposal called Kingfish , of roughly similar performance. However, the Kingfish included a number of features that greatly reduced its RCS, which was seen as favorable to the board. Lockheed responded with a simple update of the A-11, adding twin canted fins instead of a single right-angle one, and adding a number of areas of non-metallic materials. This became
6897-577: The A-12 became operational, its intended purpose of replacing the U-2 in overflights of the Soviet Union had become less likely. Soviet radar systems increased their blip-to-scan ratios , which rendered the A-12 vulnerable. In any event, President Kennedy had stated publicly that the United States would not resume such missions. By 1965, moreover, the photoreconnaissance satellite programs had progressed to
7018-533: The A-12 preserved in Minneapolis, Minnesota, was sent to CIA headquarters to be displayed there. Major events in the development and operation of the A-12 and its successor, the SR-71, include: See SR-71 timeline for later SR-71 events. The A-12 training variant (60-6927 "Titanium Goose") was a two-seat model with two cockpits in tandem with the rear cockpit raised and slightly offset. In case of emergency,
7139-623: The A-12. The final Black Shield mission over North Vietnam and the Demilitarized Zone (DMZ) was flown on 8 March 1968. Good quality photography was obtained of Khe Sanh and the Laos , Cambodia , and South Vietnamese border areas. No usable photography was obtained of North Vietnam due to adverse weather conditions. There was no indication of a hostile weapons reaction and no ECM systems were activated. In 1968, three missions were flown over North Korea. The first mission occurred during
7260-730: The A-12s carried out 22 sorties in support of the Vietnam War from Kadena Air Base. During 1968 further Black Shield operations were conducted in Vietnam. Additional sorties were carried out during the Pueblo Crisis with North Korea . Operations and maintenance at Kadena AB began with the receipt of an alert notification. Both a primary aircraft and pilot and a back-up aircraft and pilot were selected. The aircraft were given thorough inspection and servicing, all systems were checked, and
7381-464: The ASTM specifications, titanium alloys are also produced to meet aerospace and military specifications (SAE-AMS, MIL-T), ISO standards, and country-specific specifications, as well as proprietary end-user specifications for aerospace, military, medical, and industrial applications. Commercially pure flat product (sheet, plate) can be formed readily, but processing must take into account of the tendency of
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#17327759553787502-580: The Air Force agreed to take the seventh to ninth slots on the A-12 production line and have them completed in the YF-12A interceptor configuration. The M-21 , a two-seat variant, carried and launched the Lockheed D-21 , an uncrewed, faster and higher-flying reconnaissance drone. The M-21 had a pylon on its back for mounting the drone and a second cockpit for a Launch Control Operator/Officer (LCO) in
7623-611: The CIA Intelligence Star for valor to Weeks' widow and pilots Collins, Layton, Murray, Vojvodich, and Dennis B. Sullivan for participation in Black Shield. The deployed A-12s and the eight non-deployed aircraft were placed in storage at Palmdale. All surviving aircraft remained there for nearly 20 years before being sent to museums around the U.S. On 20 January 2007, despite protests by Minnesota's legislature and volunteers who had maintained it in display condition,
7744-536: The CIA decided to deploy some A-12s to Asia. The first A-12 arrived at Kadena Air Base on Okinawa on 22 May 1967. With the arrival of two more aircraft on 24 May, and 27 May this unit was declared to be operational on 30 May, and it began Operation Black Shield on 31 May. Mel Vojvodich flew the first Black Shield operation, over North Vietnam , photographing surface-to-air missile (SAM) sites, flying at 80,000 ft (24,000 m), and at about Mach 3.1. During 1967,
7865-399: 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
7986-540: The SAM site was unsuccessful with the Fan Song guidance radar used to home the missile to the target. On 28 October, a North Vietnamese SAM site launched a single, albeit unsuccessful, missile. Photography from this mission documented the event with photographs of missile smoke above the SAM firing site, and with pictures of the missile and of its contrail . Electronic countermeasures equipment appeared to perform well against
8107-448: The U-2 aircraft. We agreed ... that there should be one more round before satellites would make aircraft reconnaissance obsolete for covert reconnaissance." Under Project Gusto the designs were nicknamed "Archangel", after the U-2 program, which had been known as "Angel". As the aircraft designs evolved and configuration changes occurred, the internal Lockheed designation changed from Archangel-1 to Archangel-2, and so on. These names for
8228-486: The accident was a maintenance error; a flight-line electrician had mistakenly swapped the connections of the wiring harnesses linking the yaw- and pitch-rate gyroscopes of the Stability Augmentation System to the control-surface servos, meaning that control inputs commanding pitch changes counterintuitively caused the aircraft to yaw and control inputs commanding left or right yaw instead changed
8349-456: 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
8470-628: The aircraft a Republic F-105 Thunderchief in news articles and official records. Two nearby farmers were told that the aircraft was carrying atomic weapons to dissuade them from approaching the crash site; and local law enforcement and a passing family were strongly warned to keep quiet about the crash. Each was also paid $ 25,000 in cash to do so; the project often used such cash payments to avoid outside inquiries into its operations (the project received ample funding for many objectives: contracted security guards were paid $ 1,000 monthly with free housing on base, and chefs from Las Vegas were available 24 hours
8591-542: The aircraft more stealthy. After development and production at Skunk Works, in Burbank , California, the first A-12 was transferred to Groom Lake test facility (Area 51) . On 26 April 1962 it was taken on its first (unofficial and unannounced) flight with Lockheed test pilot Louis Schalk at the controls. The first official flight took place on 30 April and subsequent supersonic flight on 4 May 1962, reaching speeds of Mach 1.1 at 40,000 ft (12,000 m). In 1962,
8712-419: The aircraft ran out of fuel while on its descent to the test site. No precise cause could be established for the loss and it was considered most probable that a fuel quantity system error led to fuel starvation and engine flameout 67 miles (108 km) from the base. Ray ejected successfully, but was unable to separate from the seat and was killed on impact. Urban explorers installed a small monument to Ray near
8833-463: The aircraft's pitch angle. The investigation criticised the electrician's negligence, but also noted as contributory causes failures in the supervision of maintenance activity and the fact that the aircraft's design allowed for the swapped connection in the first place. The first fatality of the Oxcart program occurred on 5 January 1967, when "Article 125" crashed, killing CIA pilot Walter Ray when
8954-432: The approach of four missiles, and although they all detonated behind him, one came within 300 to 700 ft (100 to 200 m) of his aircraft. Post-flight inspection revealed that a piece of metal had penetrated the lower right wing fillet area and lodged against the support structure of the wing tank. The fragment was not a warhead pellet but may have been a part of the debris from one of the missile detonations observed by
9075-407: The biggest problems engineers faced at the time was working with titanium . In his book Skunk Works: A Personal Memoir of My Years at Lockheed , Ben Rich stated, "Our supplier, Titanium Metals Corporation, had only limited reserves of the precious alloy, so the CIA conducted a worldwide search and using third parties and dummy companies, managed to unobtrusively purchase the base metal from one of
9196-416: The cameras equipped. Pilots received a detailed route briefing in the early evening prior to the day of flight. On the morning of the flight a final briefing occurred, at which time the condition of the aircraft and its systems was reported, last-minute weather forecasts reviewed, and other relevant intelligence communicated, together with any amendments or changes in the flight plan. Two hours prior to take-off
9317-645: The crash site in the Nevada desert. Although originally designed to succeed the U-2 overflying the Soviet Union and Cuba , the A-12 was never used for either objective. After a U-2 was shot down in May 1960 , the Soviet Union was considered too dangerous to overfly except in an emergency (and overflights were no longer necessary, thanks to reconnaissance satellites ) and, although crews trained for flights over Cuba, U-2s continued to be adequate there. The Director of
9438-416: The creation of potentially effective, selective, and stable titanium-based drugs. Titanium was discovered in 1791 by the clergyman and geologist William Gregor as an inclusion of a mineral in Cornwall , Great Britain. Gregor recognized the presence of a new element in ilmenite when he found black sand by a stream and noticed the sand was attracted by a magnet . Analyzing the sand, he determined
9559-524: The early 1950s, titanium came into use extensively in military aviation, particularly in high-performance jets, starting with aircraft such as the F-100 Super Sabre and Lockheed A-12 and SR-71 . Throughout the Cold War period, titanium was considered a strategic material by the U.S. government, and a large stockpile of titanium sponge (a porous form of the pure metal) was maintained by
9680-473: 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
9801-634: The evolving designs soon simply became known as "A-1", "A-2", etc. The CIA program to develop the follow-on aircraft to the U-2 was code-named Oxcart . A-4 through A-6 concepts applied blended wing/fuselage configurations with combinations of turbojet, ramjet, and rocket propellant. However, these concepts never met the required range. Concepts A-7 thru A-9 used a single J58 afterburning turbojet plus two Marquardt XPJ-59 ramjets burning JP-150 fuel. Design concept A-10 featured two General Electric J93-3 turbojets with 2-D underwing inlets and had better mission radius than concepts A-4 thru A-9. These designs had reached
9922-410: The failure of the CIA's Project Rainbow to reduce the radar cross-section (RCS) of the U-2 , preliminary work began inside Lockheed in late 1957 to develop a follow-on aircraft to overfly the Soviet Union. Designer Kelly Johnson said, "In April 1958 I recall having long discussions with [CIA Deputy Director for Plans] Richard M. Bissell Jr. over the subject of whether there should be a follow-on to
10043-537: The first five A-12s were initially flown with Pratt & Whitney J75 engines capable of 17,000 lbf (76 kN) thrust each, enabling the J75-equipped A-12s to obtain speeds of approximately Mach 2.0. On 5 October 1962, with the newly developed J58 engines, an A-12 flew with one J75 engine, and one J58 engine. By early 1963, the A-12 was flying with J58 engines, and during 1963 these J58-equipped A-12s obtained speeds of Mach 3.2. In 1963
10164-537: The fleet's retirement, an A-12 from Kadena, piloted by Jack Weeks, was lost over the Pacific Ocean near the Philippines while conducting a functional check flight after the replacement of one of its engines. Frank Murray made the final A-12 flight on 21 June 1968, to Palmdale, California , storage facility. On 26 June 1968, Vice Admiral Rufus L. Taylor, the deputy director of Central Intelligence, presented
10285-492: The flight was apparent, but no missiles were fired at the Oxcart. The second mission on 19 February 1968, was also the first two-pass mission over North Korea. The Oxcart vehicle photographed 84 primary targets plus 89 bonus targets. Scattered clouds covered 20 percent of the area, concealing the area in which the USS Pueblo was photographed on the previous mission. One new SA-2 site was identified near Wonsan. Even before
10406-408: 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,
10527-410: The greatest kinetic heating from the airstream, such as wing leading edges. The A-12, however, was constructed mainly of titanium. Titanium is rigid and difficult to machine, which made it difficult to form into curves given available techniques. This made it difficult to form the leading edges of the wing and similar surfaces. The solution was found by machining only small "fillets" of the material with
10648-558: The industry for finding a better method to produce Ti metal, and a large number of new concepts and improvements have been investigated at the laboratory or even at pilot plant scales, there is no new process to date that can replace the Kroll process commercially." The Hydrogen assisted magnesiothermic reduction (HAMR) process uses titanium dihydride . All welding of titanium must be done in an inert atmosphere of argon or helium to shield it from contamination with atmospheric gases (oxygen, nitrogen, and hydrogen). Contamination causes
10769-497: The initial A-12 design. On 26 January 1960, the Central Intelligence Agency officially ordered 12 A-12 aircraft with the contract signed on February 11, 1960. Lockheed charged $ 96.6 million for design, manufacture and testing of 12 aircraft. Because the A-12 was well ahead of its time, many new technologies had to be invented specifically for the Oxcart project with some remaining in use to present day. One of
10890-522: The laboratory until 1932 when William Justin Kroll produced it by reducing titanium tetrachloride (TiCl 4 ) with calcium . Eight years later he refined this process with magnesium and with sodium in what became known as the Kroll process. Although research continues to seek cheaper and more efficient routes, such as the FFC Cambridge process , the Kroll process is still predominantly used for commercial production. Titanium of very high purity
11011-431: The material can gall unless sharp tools and proper cooling methods are used. Like steel structures, those made from titanium have a fatigue limit that guarantees longevity in some applications. The metal is a dimorphic allotrope of a hexagonal close packed α form that changes into a body-centered cubic (lattice) β form at 882 °C (1,620 °F). The specific heat of the α form increases dramatically as it
11132-503: The metal to springback . This is especially true of certain high-strength alloys. Exposure to the oxygen in air at the elevated temperatures used in forging results in formation of a brittle oxygen-rich metallic surface layer called " alpha case " that worsens the fatigue properties, so it must be removed by milling, etching, or electrochemical treatment. The working of titanium is very complicated, and may include Friction welding , cryo-forging , and Vacuum arc remelting . Titanium
11253-483: The missile firing. During a flight on 30 October 1967, pilot Dennis Sullivan detected radar tracking on his first pass over North Vietnam. Two sites prepared to launch missiles but neither did. During the second pass, at least six missiles were fired, each confirmed by missile vapor trails on mission photography. Looking through his rear-view periscope, Sullivan saw six missile contrails climb to about 90,000 ft (27,000 m) before converging on his aircraft. He noted
11374-403: The most abundant (73.8%). As a metal , titanium is recognized for its high strength-to-weight ratio . It is a strong metal with low density that is quite ductile (especially in an oxygen -free environment), lustrous, and metallic-white in color . Due to its relatively high melting point (1,668 °C or 3,034 °F) it has sometimes been described as a refractory metal , but this
11495-507: The most abundant (73.8% natural abundance ). At least 21 radioisotopes have been characterized, the most stable of which are Ti with a half-life of 63 years; Ti, 184.8 minutes; Ti, 5.76 minutes; and Ti, 1.7 minutes. All other radioactive isotopes have half-lives less than 33 seconds, with the majority less than half a second. The isotopes of titanium range in atomic weight from 39.002 Da ( Ti) to 63.999 Da ( Ti). The primary decay mode for isotopes lighter than Ti
11616-680: The ocean. The D-21 lived on in the form of a B-model launched from a pylon under the wing of the B-52 bomber. The D-21B performed operational missions over China from 1969 to 1971, but was not particularly successful. Six of the 15 A-12s were lost in accidents, with the loss of two pilots and an engineer: Data from A-12 Utility Flight Manual General characteristics Performance Related development Aircraft of comparable role, configuration, and era Related lists Mach number The Mach number ( M or Ma ), often only Mach , ( / m ɑː k / ; German: [max] )
11737-530: The oxide with release of hydrogen sulfide . Titanium nitride (TiN) is a refractory solid exhibiting extreme hardness, thermal/electrical conductivity, and a high melting point. TiN has a hardness equivalent to sapphire and carborundum (9.0 on the Mohs scale ), and is often used to coat cutting tools, such as drill bits . It is also used as a gold-colored decorative finish and as a barrier layer in semiconductor fabrication . Titanium carbide (TiC), which
11858-691: The pilot. The SA-2 'Guideline' was an early missile design intended to counter lower-flying and slower aircraft such as the B-52 and B-58 . In response to faster, higher-flying designs like the B-70 , the Soviets had begun development of greatly improved missile systems, notably the SA-5 'Gammon' . The Soviet Air Defence Forces ( Protivo-Vozdushnaya Oborona , PVO) cleared the SA-5 for service in 1967; if deployed to Vietnam, it would have provided an additional risk to
11979-435: The place of the A-12's Q bay. The D-21 was autonomous; after launch, it would fly over the target, travel to a predetermined rendezvous point, eject its data package, and self-destruct. A C-130 Hercules would catch the package in midair. The M-21 program was canceled in 1966 after a drone collided with the mother ship at launch. The crew ejected, but LCO Ray Torrick drowned when his flight suit filled with water after landing in
12100-569: The point that crewed flights over the Soviet Union were unnecessary to collect strategic intelligence. The A-12 program was ended on 28 December 1966 – even before Black Shield began in 1967 – due to budget concerns and because of the SR-71, which began to arrive at Kadena in March 1968. The twin-seat SR-71 was heavier and flew slightly lower and slower than the A-12. Ronald L. Layton flew the 29th and final A-12 mission on 8 May 1968, over North Korea. On 4 June 1968, just 2 + 1 ⁄ 2 weeks before
12221-475: The presence of chlorine . In this process, the chlorine gas is passed over a red-hot mixture of rutile or ilmenite in the presence of carbon. After extensive purification by fractional distillation , the TiCl 4 is reduced with 800 °C (1,470 °F) molten magnesium in an argon atmosphere. The van Arkel–de Boer process was the first semi-industrial process for pure Titanium. It involves thermal decomposition of titanium tetraiodide . Titanium powder
12342-505: The presence of titanium dioxide impurities. A variety of reduced oxides ( suboxides ) of titanium are known, mainly reduced stoichiometries of titanium dioxide obtained by atmospheric plasma spraying . Ti 3 O 5 , described as a Ti(IV)-Ti(III) species, is a purple semiconductor produced by reduction of TiO 2 with hydrogen at high temperatures, and is used industrially when surfaces need to be vapor-coated with titanium dioxide: it evaporates as pure TiO, whereas TiO 2 evaporates as
12463-440: The presence of two metal oxides: iron oxide (explaining the attraction to the magnet) and 45.25% of a white metallic oxide he could not identify. Realizing that the unidentified oxide contained a metal that did not match any known element, in 1791 Gregor reported his findings in both German and French science journals: Crell's Annalen and Observations et Mémoires sur la Physique . He named this oxide manaccanite . Around
12584-409: The primary pilot had a medical examination, got into his suit, and was taken to the aircraft. If any malfunctions developed on the primary aircraft, the back-up could execute the mission one hour later. A typical route profile for a mission over North Vietnam included a refueling shortly after take-off, south of Okinawa, the planned photographic pass or passes, withdrawal to a second aerial refueling in
12705-453: The processing in order to place the photointelligence in the hands of American commanders in Vietnam within 24 hours of completion of a mission. There were a number of reasons leading to the retirement of the A-12, but one major concern was the growing sophistication of Soviet-supplied surface-to-air missile (SAM) sites that it had to contend with over mission routes. In 1967, the vehicle was tracked with acquisition radar over North Vietnam, but
12826-406: The program experienced its first loss when, on 24 May, "Article 123" piloted by Kenneth S. Collins crashed near Wendover, Utah . Collins safely ejected and was wearing a standard flight suit, avoiding unwanted questions from the truck driver who picked him up. He called Area 51 from a highway patrol office. The reaction to the crash illustrated the secrecy and importance of the project. The CIA called
12947-565: The required shape and then gluing them onto the underlying framework which was more linear. A good example is on the wing: the underlying framework of spars and stringers formed a grid, leaving triangular notches along the leading edge that were filled with fillets. With the move to the A-12, another improvement in RCS was made by replacing the fillets with new radar-absorbing composite materials made from iron ferrite and silicon laminate, both combined with asbestos to absorb radar returns and make
13068-640: The same time, Franz-Joseph Müller von Reichenstein produced a similar substance, but could not identify it. The oxide was independently rediscovered in 1795 by Prussian chemist Martin Heinrich Klaproth in rutile from Boinik (the German name of Bajmócska), a village in Hungary (now Bojničky in Slovakia). Klaproth found that it contained a new element and named it for the Titans of Greek mythology . After hearing about Gregor's earlier discovery, he obtained
13189-463: 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
13310-779: 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
13431-418: 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
13552-405: 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
13673-425: 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
13794-517: The success of platinum-based chemotherapy, titanium(IV) complexes were among the first non-platinum compounds to be tested for cancer treatment. The advantage of titanium compounds lies in their high efficacy and low toxicity in vivo . In biological environments, hydrolysis leads to the safe and inert titanium dioxide. Despite these advantages the first candidate compounds failed clinical trials due to insufficient efficacy to toxicity ratios and formulation complications. Further development resulted in
13915-399: 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
14036-471: The variant was designed to allow the flight instructor to take control. The YF-12 program was a limited production variant of the A-12. Lockheed convinced the U.S. Air Force that an aircraft based on the A-12 would provide a less costly alternative to the recently canceled North American Aviation XF-108 , since much of the design and development work on the YF-12 had already been done and paid for. Thus, in 1960
14157-489: The winner of Project GUSTO , and was developed and operated under Project Oxcart. The CIA's representatives initially favored Convair's design for its smaller radar cross-section , but the A-12's specifications were slightly better and its projected cost was much lower. The companies' respective track records proved decisive. Convair's work on the B-58 had been plagued with delays and cost overruns, whereas Lockheed had produced
14278-461: The world's leading exporters – the Soviet Union . The Soviets never had an inkling of how they were actually contributing to the creation of the airplane being rushed into construction to spy on their homeland." 93% of A-12's structure was titanium. Before the A-12, titanium was used only in high-temperature exhaust fairings and other small parts directly related to supporting, cooling, or shaping high-temperature areas on aircraft like those subject to
14399-437: 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.
14520-622: Was in May 1968; the program and aircraft were retired in June. The program was officially revealed in the mid-1990s. A CIA officer later wrote, "Oxcart was selected from a random list of codenames to designate this R&D and all later work on the A-12. The aircraft itself came to be called that as well." The crews named the A-12 the Cygnus , suggested by pilot Jack Weeks to follow the Lockheed practice of naming aircraft after celestial bodies. With
14641-421: Was made in small quantities when Anton Eduard van Arkel and Jan Hendrik de Boer discovered the iodide process in 1925, by reacting with iodine and decomposing the formed vapors over a hot filament to pure metal. In the 1950s and 1960s, the Soviet Union pioneered the use of titanium in military and submarine applications ( Alfa class and Mike class ) as part of programs related to the Cold War. Starting in
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