93-649: The Boeing–Saab T-7 Red Hawk , initially known as the Boeing T-X (later Boeing–Saab T-X ), is an American–Swedish transonic advanced jet trainer produced by Boeing with Saab . In September 2018, the United States Air Force (USAF) selected it for the T-X program to replace the Northrop T-38 Talon as the service's advanced jet trainer. The USAF's Air Education and Training Command (AETC) began developing
186-748: A Mississippi River expedition led by Laclède, who searched for a location to base the company's fur trading operations. Though Ste. Genevieve was already established as a trading center, he sought a place less prone to flooding. He found an elevated area overlooking the flood plain of the Mississippi River, not far south from its confluence with the Missouri and Illinois rivers. In addition to having an advantageous natural drainage system, there were nearby forested areas to supply timber and grasslands which could easily be converted for agricultural purposes. Laclède declared that this place "might become, hereafter, one of
279-991: A U.S. manufacturing facility for the T-X in Indiana in the Purdue University -affiliated Discovery Park District in West Lafayette, Indiana. In September 2019, the USAF named the aircraft the "T-7A Red Hawk" as a tribute to the Tuskegee Airmen , who painted their airplanes' tails red, and to the Curtiss P-40 Warhawk , an aircraft flown by the 99th Fighter Squadron , the U.S. Army Air Force's first black fighter squadron. The aircraft entered series production in February 2021. In April 2021, Saab Group delivered one aft section of T-7A aircraft to
372-514: A customs house was constructed in the Greek Revival style in 1852, but was demolished and replaced in 1873 by the U.S. Customhouse and Post Office . Because much of the city's commercial and industrial development was centered along the riverfront, many pre-Civil War buildings were demolished during construction of the Gateway Arch. The city's remaining architectural heritage of the era includes
465-508: A far distance they are invariably supersonic. Supernovae explosions are accompanied by supersonic flows and shock waves. Bow shocks formed in solar winds are a direct result of transonic winds from a star. It had been long thought that a bow shock was present around the heliosphere of our solar system, but this was found not to be the case according to IBEX data published in 2012. St. Louis St. Louis ( / s eɪ n t ˈ l uː ɪ s , s ən t -/ saynt LOO -iss, sənt- )
558-532: A greater population than New Orleans. Settled by many Southerners in a slave state , the city was split in political sympathies and became polarized during the American Civil War . In 1861, 28 civilians were killed in a clash with Union troops . The war hurt St. Louis economically, due to the Union blockade of river traffic to the south on the Mississippi River. The St. Louis Arsenal constructed ironclads for
651-494: A multi-block district of cobblestone streets and brick and cast-iron warehouses called Laclede's Landing . Now popular for its restaurants and nightclubs, the district is located north of Gateway Arch along the riverfront. Other industrial buildings from the era include some portions of the Anheuser-Busch Brewery , which date to the 1860s. St. Louis saw a vast expansion in variety and number of religious buildings during
744-529: A pan-tribal alliance to counter British control over the region but received little support from the indigenous residents of St. Louis. By 1765, the city began receiving visits from representatives of the British, French, and Spanish governments. St. Louis was transferred to the French First Republic in 1800 (although all of the colonial lands continued to be administered by Spanish officials), then sold by
837-404: A program costing up to US$ 9.2 billion (~$ 11 billion in 2023) that would purchase 351 aircraft, 46 simulators, maintenance training and support. This contract has options for up to 475 airplanes in total. In 2018, Boeing recorded a $ 691-million (~$ 826 million in 2023) pre-tax charge during the third quarter, in part because of the T-X program. In May 2019, Saab announced that it would open
930-590: A public corridor of 300 feet fronting the river, but later this area was released for private development. For the city's first few years, it was not recognized by any governments. Although the settlement was thought to be under the control of the Spanish government, no one asserted any authority over it, and thus St. Louis had no local government. This vacuum led Laclède to assume civil control, and all problems were disposed in public settings, such as communal meetings. In addition, Laclède granted new settlers lots in town and
1023-591: A recount of the votes in November, officially did so in March 1877. The 1877 St. Louis general strike caused significant upheaval, in a fight for the eight-hour day and the banning of child labor. Industrial production continued to increase during the late 19th century. Major corporations such as the Anheuser-Busch brewery, Ralston Purina company and Desloge Consolidated Lead Company were established at St. Louis which
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#17330855785151116-607: A single GE F404 turbofan engine, but produces three times the total thrust of the T-38 twinjet. Boeing aims to sell over 2,700 Red Hawks globally. In addition to the USAF, the company is also targeting Serbia as a possible replacement for its G-4s and J-22 trainer aircraft and Australia to replace 33 BAE Hawk Mk 127 Lead-in Fighter (LIF) jet trainers through the Royal Australian Air Force LIFT program. The T-7B variant
1209-492: A symbol of failure in public housing, and was torn down less than two decades after it was built. Since the 1980s, several revitalization efforts have focused on Downtown St. Louis . The urban revitalization projects that started in the 1980s continued into the new century. The city's old garment district , centered on Washington Avenue in the Downtown and Downtown West neighborhoods, experienced major development starting in
1302-616: A test pilot with the 416th Flight Test Squadron at Edwards Air Force Base , California, and Steve Schmidt, Boeing's chief T-7 test pilot. On 21 September 2023, the first Red Hawk (tail number APT-2) was shipped to the US Air Force. It was deployed at Edwards Air Force Base for testing. Two additional units (APT-1 and APT-3) were delivered late 2023, with a fourth (APT-4) delayed into 2024. In total, five Red Hawks in engineering and manufacturing development configuration will be delivered for its test program. As of February 2024, assembly of
1395-853: A water route to the Pacific Ocean, but the party had to go overland in the Upper West. They reached the Pacific Ocean via the Columbia River in summer 1805. They returned, reaching St. Louis on September 23, 1806. Both Lewis and Clark lived in St. Louis after the expedition. Many other explorers, settlers, and trappers (such as Ashley's Hundred ) would later take a similar route to the West. The city elected its first municipal legislators (called trustees) in 1808. Steamboats first arrived in St. Louis in 1817, improving connections with New Orleans and eastern markets. Missouri
1488-521: Is Mach 1 and the Prandtl–Glauert singularity . In astrophysics, wherever there is evidence of shocks (standing, propagating or oscillating), the flow close by must be transonic, as only supersonic flows form shocks. All black hole accretions are transonic. Many such flows also have shocks very close to the black holes. The outflows or jets from young stellar objects or disks around black holes can also be transonic since they start subsonically and at
1581-412: Is added to the forward-sweeping [leading] side of the rotor, possibly causing localized transonics). Issues with aircraft flight relating to speed first appeared during the supersonic era in 1941. Ralph Virden, a test pilot, crashed in a fatal plane accident. He lost control of the plane when a shock wave caused by supersonic airflow developed over the wing, causing it to stall. Virden flew well below
1674-589: Is an independent city in the U.S. state of Missouri . It is located near the confluence of the Mississippi and the Missouri rivers. In 2020, the city proper had a population of 301,578, while its metropolitan area , which extends into Illinois , had an estimated population of over 2.8 million. It is the largest metropolitan area in Missouri and the second-largest in Illinois. The city's combined statistical area
1767-587: Is an example of the Polish Cathedral style . Among the other major designs of the period were St. Alphonsus Liguori (known as The Rock Church ) (1867) in the Gothic Revival and Second Presbyterian Church of St. Louis (1900) in Richardsonian Romanesque . By the 1900 census , St. Louis was the fourth largest city in the country. In 1904, the city hosted a world's fair at Forest Park called
1860-407: Is fundamentally untrue for transonic flows because the disturbance caused by an object is much larger than in subsonic or supersonic flows; a flow speed close to or at Mach 1 does not allow the streamtubes (3D flow paths) to contract enough around the object to minimize the disturbance, and thus the disturbance propagates. Aerodynamicists struggled during the earlier studies of transonic flow because
1953-639: Is home to sixteen Fortune 1000 companies, six of which are also Fortune 500 companies. Federal agencies headquartered in the city or with significant operations there include the Federal Reserve Bank of St. Louis , the U.S. Department of Agriculture , and the National Geospatial-Intelligence Agency . Major research universities in Greater St. Louis include Washington University in St. Louis , Saint Louis University , and
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#17330855785152046-517: Is one of the contenders for the United States Navy 's Tactical Surrogate Aircraft program, with a possible sale of 64 aircraft. A navalised version is also a contender for the USN's Undergraduate Jet Training System program, with a minimum order of 145 aircraft to replace existing T-45 Goshawks . Procurement of the winner of the program is expected to occur as early as 2026. The F/T-7X, a variant of
2139-463: Is the 20th-largest in the United States. The land that became St. Louis had been occupied by Native American cultures for thousands of years before European settlement . The city was founded on February 14, 1764, by French fur traders Gilbert Antoine de St. Maxent , Pierre Laclède , and Auguste Chouteau . They named it for King Louis IX of France , and it quickly became the regional center of
2232-456: Is the Mississippi River, which separates Missouri from Illinois. The Missouri River forms the northern line of St. Louis County, except for a few areas where the river has changed its course. The Meramec River forms most of its southern line. The urban area of St. Louis has a humid subtropical climate ( Köppen : Cfa ); however, its metropolitan region even to the south may present a hot-summer humid continental climate ( Dfa ), which shows
2325-761: Is the tallest building in St. Louis. During the 1990s, St. Louis saw the construction of the largest United States courthouse by area, the Thomas F. Eagleton United States Courthouse (2000). The Eagleton Courthouse is home to the United States District Court for the Eastern District of Missouri and the United States Court of Appeals for the Eighth Circuit . The most recent high-rise buildings in St. Louis include two residential towers: One Hundred in
2418-469: Is the use of swept wings , but another common form is a wasp-waist fuselage as a side effect of the Whitcomb area rule . Transonic speeds can also occur at the tips of rotor blades of helicopters and aircraft. This puts severe, unequal stresses on the rotor blade and may lead to accidents if it occurs. It is one of the limiting factors of the size of rotors and the forward speeds of helicopters (as this speed
2511-644: The Illinois Country (also known as Upper Louisiana) were built by the French during the 1690s and early 1700s at Cahokia , Kaskaskia , and Fort de Chartres . Migrants from the French villages on the east side of the Mississippi River , such as Kaskaskia, also founded Ste. Genevieve in the 1730s. In 1764, after France lost the Seven Years' War , Pierre Laclède and his stepson Auguste Chouteau founded what
2604-593: The Louisiana Purchase Exposition , also known as the St. Louis World's Fair, and the Summer Olympics . St. Louis is designated as one of 173 global cities by the Globalization and World Cities Research Network . The GDP of Greater St. Louis was $ 209.9 billion in 2022. St. Louis has a diverse economy with strengths in the service, manufacturing, trade, transportation, and aviation industries. It
2697-508: The Louisiana Purchase Exposition . Its architectural legacy is somewhat scattered. Among the fair-related cultural institutions in the park are the St. Louis Art Museum designed by Cass Gilbert , part of the remaining lagoon at the foot of Art Hill, and the Flight Cage at the St. Louis Zoo . The Missouri History Museum was built afterward, with the profit from the fair. But 1904 left other assets to
2790-654: The Missouri History Museum , and Tower Grove Park and the Botanical Gardens. After the Civil War, social and racial discrimination in housing and employment were common in St. Louis. In 1916, during the Jim Crow Era , St. Louis passed a residential segregation ordinance saying that if 75% of the residents of a neighborhood were of a certain race, no one from a different race was allowed to move in. That ordinance
2883-539: The Missouri River . The Chouteau brothers gained a monopoly from Spain on the fur trade with Santa Fe . French colonists used African slaves as domestic servants and workers in the city. During the negotiations for the 1763 Treaty of Paris , French negotiators agreed to transfer France's colonial territories west of the Mississippi and Missouri rivers to New Spain to compensate for Spanish territorial losses during
Boeing–Saab T-7 Red Hawk - Misplaced Pages Continue
2976-709: The St. Louis BattleHawks of the United Football League . The city's attractions include the 630-foot (192 m) Gateway Arch in Downtown St. Louis , the St. Louis Zoo , the Missouri Botanical Garden , the St. Louis Art Museum , and Bellefontaine Cemetery . [REDACTED] Kingdom of France 1690s–1763 [REDACTED] Kingdom of Spain 1763–1800 [REDACTED] French First Republic 1800–1803 [REDACTED] United States 1803–present The area that became St. Louis
3069-458: The Union Navy . Slaves worked in many jobs on the waterfront and on the riverboats. Given the city's location close to the free state of Illinois and others, some slaves escaped to freedom. Others, especially women with children, sued in court in freedom suits , and several prominent local attorneys aided slaves in these suits. About half the slaves achieved freedom in hundreds of suits before
3162-609: The University of Missouri–St. Louis . The Washington University Medical Center in the Central West End neighborhood hosts an agglomeration of medical and pharmaceutical institutions , including Barnes-Jewish Hospital . St. Louis has four professional sports teams : the St. Louis Cardinals of Major League Baseball , the St. Louis Blues of the National Hockey League , St. Louis City SC of Major League Soccer , and
3255-444: The 1970s, leading to a court challenge and interdistrict desegregation agreement. Students have been bused mostly from the city to county school districts to have opportunities for integrated classes, although the city has created magnet schools to attract students. St. Louis, like many Midwestern cities, expanded in the early 20th century due to industrialization, which provided jobs to new generations of immigrants and migrants from
3348-413: The 19th and 20th century, most major cities aggressively annexed surrounding areas as residential development occurred away from the central city; however, St. Louis was unable to do so. Several urban renewal projects were built in the 1950s, as the city worked to replace old and substandard housing. Some of these were poorly designed and resulted in problems. One prominent example, Pruitt–Igoe , became
3441-524: The American Civil War. The printing press of abolitionist Elijah Parish Lovejoy was destroyed for the third time by townsfolk. He was murdered the next year in nearby Alton, Illinois . After the war, St. Louis profited via trade with the West, aided by the 1874 completion of the Eads Bridge , named for its design engineer. Industrial developments on both banks of the river were linked by the bridge,
3534-655: The Boeing St. Louis plant. In July 2021, Saab had delivered the second aft section to the Boeing St. Louis plant. Boeing will splice Saab's aft section with the front section, fins, wings and tail assembly to become a complete test aircraft for use in the EMD's flight test program. As of 2021, the plan was that on completion of the Engineering and Manufacturing Development (EMD) phase, Saab's new facility in West Lafayette, Indiana
3627-619: The Central West End neighborhood and One Cardinal Way in the Downtown neighborhood. The city is divided into 79 officially-recognized neighborhoods. According to the United States Census Bureau , St. Louis has a total area of 66 square miles (170 km ), of which 62 square miles (160 km ) is land and 4.1 square miles (11 km ) (6.2%) is water. The city is built on bluffs and terraces that rise 100–200 feet above
3720-537: The French Illinois Country . In 1804, the United States acquired St. Louis as part of the Louisiana Purchase . In the 19th century, St. Louis developed as a major port on the Mississippi River; from 1870 until the 1920 census, it was the fourth-largest city in the country. It separated from St. Louis County in 1877, becoming an independent city and limiting its political boundaries. In 1904, it hosted
3813-562: The French to the U.S. in 1803 as part of the Louisiana Purchase . St. Louis became the capital of, and gateway to, the new territory. Shortly after the official transfer of authority was made, the Lewis and Clark Expedition was commissioned by President Thomas Jefferson. The expedition departed from St. Louis in May 1804 along the Missouri River to explore the vast territory. There were hopes of finding
Boeing–Saab T-7 Red Hawk - Misplaced Pages Continue
3906-515: The NFL in 2017, alleging the league breached its own relocation guidelines to profit at the expense of the city. In 2021, the NFL and Rams owner Stan Kroenke agreed to settle out of court with the city for $ 790 million. The architecture of St. Louis exhibits a variety of commercial, residential, and monumental architecture . St. Louis is known for the Gateway Arch , the tallest monument constructed in
3999-460: The South. It reached its peak population of 856,796 at the 1950 census. Suburbanization from the 1950s through the 1990s dramatically reduced the city's population, as did restructuring of industry and loss of jobs. The effects of suburbanization were exacerbated by the small geographical size of St. Louis due to its earlier decision to become an independent city, and it lost much of its tax base. During
4092-530: The T-7 into an armed combat aircraft. Conceptually dubbed the F-7, such a jet could provide roughly the same capability as a fourth-generation fighter which could maintain force numbers as F-16s are retired, and could replace older Northrop F-5 and Dornier Alpha Jet platforms on the export market. Boeing intends to offer an armed version of the T-7 to replace aging Northrop F-5 and Dassault/Dornier Alpha Jet fleets around
4185-478: The T-7, is one of the contenders for the USAF's Advanced Tactical Trainer program, with possible sales of 100 to 400 aircraft. Boeing has pitched the T-7 to the Brazilian Air Force . The Japanese Air Self Defense Force has expressed interest in the T-7 (or a derivative of it) to replace their aging Kawasaki T-4 jet trainers. By November 2023, the USAF was actively considering the possibility of turning
4278-412: The United States at 630 feet (190 m). The Arch pays homage to Thomas Jefferson and St. Louis's position as the gateway to the West. Architectural influences reflected in the area include French Colonial , German , early American , and modern architectural styles. Several examples of religious structures are extant from the pre-Civil War period, and most reflect the common residential styles of
4371-481: The aft section with the wings. The digital build process allows technicians to build the aircraft with minimal tooling and drilling during the assembly process. The first production T-7 was rolled out on 28 April 2022. In May 2023, the Government Accountability Office released a report on the T-7 program detailing problems with the software and safety systems and other delays that saw the USAF delay
4464-560: The area encountered by early Europeans included the Siouan -speaking Osage people , whose territory extended west, and the Illiniwek . European exploration of the area was first recorded in 1673, when French explorers Louis Jolliet and Jacques Marquette traveled through the Mississippi River valley. Five years later, La Salle claimed the region for France as part of La Louisiane , also known as Louisiana . The earliest European settlements in
4557-447: The area, and parts of the city are karst in nature. This is particularly true of the area south of downtown, which has numerous sinkholes and caves. Most of the caves in the city have been sealed, but many springs are visible along the riverfront. Coal, brick clay , and millerite ore were once mined in the city. The predominant surface rock, known as St. Louis limestone , is used as dimension stone and rubble for construction. Near
4650-434: The behavior of transonic flow over a double wedge airfoil , the first to do so with only the assumptions of thin-airfoil theory. Although successful, Guderley's work was still focused on the theoretical, and only resulted in a single solution for a double wedge airfoil at Mach 1. Walter Vincenti , an American engineer at Ames Laboratory , aimed to supplement Guderley's Mach 1 work with numerical solutions that would cover
4743-474: The central corridor has seen major investment starting in the early 2010s. Between 2013 and 2018, over $ 50 million worth of residential construction has been built in the neighborhood. The population of the neighborhood has increased by 19% from the 2010 to 2020 Census. The St. Louis Rams of the National Football League controversially returned to Los Angeles in 2016. The city of St. Louis sued
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#17330855785154836-402: The city hosted the World's Fair and the Olympics , becoming the first non-European city to host the games. The formal name for the 1904 World's Fair was the Louisiana Purchase Exposition . Permanent facilities and structures remaining from the fair are located in Forest Park , and other notable structures within the park's boundaries include the St. Louis Art Museum , the St. Louis Zoo and
4929-435: The city, like Theodore Link 's 1894 St. Louis Union Station , and an improved Forest Park. One US Bank Plaza , the local headquarters for US Bancorp , was constructed in 1976 in the structural expressionist style. Several notable postmodern commercial skyscrapers were built downtown in the 1970s and 1980s, including the former AT&T building at 909 Chestnut Street (1986), and One Metropolitan Square (1989), which
5022-488: The construction of the Gateway Arch to publicize their effort to gain entry for African Americans into the skilled trade unions, where they were underrepresented. The Department of Justice filed the first suit against the unions under the Civil Rights Act of 1964 . Between 1900 and 1929, St. Louis, had about 220 automakers, close to 10 percent of all American carmakers, about half of which built cars exclusively in St. Louis. Notable names include Dorris, Gardner and Moon. In
5115-407: The contract award not expected before FY2016. Shrinking budgets and higher-priority modernization projects pushed the IOC of the T-X program winner to "fiscal year 2023 or 2024". Although the program was left out of the FY 2014 budget entirely, the service still viewed the trainer as a priority. Boeing teamed up with Swedish aerospace firm Saab to compete for the T-7 program. On 13 September 2016,
5208-448: The early 19th century. The original St. Louis courthouse was built in 1826 and featured a Federal style stone facade with a rounded portico. However, this courthouse was replaced during renovation and expansion of the building in the 1850s. The Old St. Louis County Courthouse (known as the Old Courthouse ) was completed in 1864 and was notable for having a cast iron dome and for being the tallest structure in Missouri until 1894. Finally,
5301-651: The effect of the urban heat island in the city. The city experiences hot, humid summers and chilly to cold winters. It is subject to both cold Arctic air and hot, humid tropical air from the Gulf of Mexico . The average annual temperature recorded at nearby Lambert–St. Louis International Airport , is 57.4 °F (14.1 °C). 100 and 0 °F (38 and −18 °C) temperatures can be seen on an average 3 and 1 days per year, respectively. Precipitation averages 41.70 inches (1,100 mm), but has ranged from 20.59 in (523 mm) in 1953 to 61.24 in (1,555 mm) in 2015. The highest recorded temperature in St. Louis
5394-426: The finest cities in America". He dispatched his 14-year-old stepson, Auguste Chouteau , to the site, with the support of 30 settlers in February 1764. Laclède arrived at the future town site two months later and produced a plan for St. Louis based on the New Orleans street plan. The default block size was 240 by 300 feet, with just three long avenues running parallel to the west bank of the Mississippi. He established
5487-414: The first part of the century, St. Louis had some of the worst air pollution in the United States . In April 1940, the city banned the use of soft coal mined in nearby states. The city hired inspectors to ensure that only anthracite was burned. By 1946, the city had reduced air pollution by about 75%. De jure educational segregation continued into the 1950s, and de facto segregation continued into
5580-401: The first production model was anticipated to begin in the second quarter of 2024. The T-7's design allows for future missions to be added, such as the aggressor and light attack/fighter roles. In the training environment, it has been specifically designed for high-G and high-angle-of-attack maneuvers and night operations, with an emphasis on being easily maintained. The aircraft is equipped with
5673-483: The flow around the vehicle. Research has been done into weakening shock waves in transonic flight through the use of anti-shock bodies and supercritical airfoils . Most modern jet powered aircraft are engineered to operate at transonic air speeds. Transonic airspeeds see a rapid increase in drag from about Mach 0.8, and it is the fuel costs of the drag that typically limits the airspeed. Attempts to reduce wave drag can be seen on all high-speed aircraft. Most notable
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#17330855785155766-501: The late 1990s as many of the old factory and warehouse buildings were converted into lofts. The American Planning Association designated Washington Avenue as one of 10 Great Streets for 2011. The Cortex Innovation Community , located within the city's Central West End neighborhood, was founded in 2002 and has become a multi-billion dollar economic engine for the region, with companies such as Microsoft and Boeing currently leasing office space. The Forest Park Southeast neighborhood in
5859-415: The late 19th century and early 20th century. The largest and most ornate of these is the Cathedral Basilica of St. Louis , designed by Thomas P. Barnett and constructed between 1907 and 1914 in the Neo-Byzantine style. The St. Louis Cathedral, as it is known, has one of the largest mosaic collections in the world. Another landmark in religious architecture of St. Louis is the St. Stanislaus Kostka , which
5952-461: The next production decision to February 2025. The report said that a schedule provided by Boeing in January 2023 was optimistic and dependent on favorable assumptions. Notwithstanding the delayed production decision, the report noted that Boeing still planned to start producing the first T-7s in early 2024. In June 2023, the first flight of the T-7A production aircraft was conducted from St. Louis Lambert International Airport , by Major Bryce Turner,
6045-424: The north, and the grounds of the Gateway Arch, to the south. Today the road deck has been restored, allowing vehicular and pedestrian traffic to cross the river. The St. Louis MetroLink light rail system has used the rail deck since 1993. An estimated 8,500 vehicles pass through it daily. On August 22, 1876, the city of St. Louis voted to secede from St. Louis County and become an independent city, and, following
6138-501: The object's critical Mach number , but transonic flow is seen at flight speeds close to the speed of sound (343 m/s at sea level), typically between Mach 0.8 and 1.2. The issue of transonic speed (or transonic region) first appeared during World War II. Pilots found as they approached the sound barrier the airflow caused aircraft to become unsteady. Experts found that shock waves can cause large-scale separation downstream, increasing drag, adding asymmetry and unsteadiness to
6231-442: The process of applying the hodograph method to transonic flow near the end of World War II. He focused on the nonlinear thin-airfoil compressible flow equations, the same as what Tricomi derived, though his goal of using these equations to solve flow over an airfoil presented unique challenges. Guderley and Hideo Yoshihara, along with some input from Busemann, later used a singular solution of Tricomi's equations to analytically solve
6324-412: The range of transonic speeds between Mach 1 and wholly supersonic flow. Vincenti and his assistants drew upon the work of Howard Emmons as well as Tricomi's original equations to complete a set of four numerical solutions for the drag over a double wedge airfoil in transonic flow above Mach 1. The gap between subsonic and Mach 1 flow was later covered by both Julian Cole and Leon Trilling , completing
6417-436: The requirements for a replacement for the supersonic Northrop T-38 Talon as early as 2003. Originally, the replacement trainer was expected to enter service around 2020. A fatigue failure of a T-38C killed its two-person crew in 2008, and the USAF advanced the target date of initial operational capability (IOC) to 2017. In the fiscal 2013 budget proposal, the USAF suggested delaying the initial operating capability to FY2020 with
6510-401: The second in the Midwest over the Mississippi River after the Hennepin Avenue Bridge in Minneapolis. The bridge connects St. Louis, Missouri to East St. Louis, Illinois . The Eads Bridge became a symbolic image of the city of St. Louis, from the time of its erection until 1965 when the Gateway Arch Bridge was constructed. The bridge crosses the St. Louis riverfront between Laclede's Landing, to
6603-445: The simplest forms of the compressible flow equations were difficult to solve due to their nonlinearity . A common assumption used to circumvent this nonlinearity is that disturbances within the flow are relatively small, which allows mathematicians and engineers to linearize the compressible flow equations into a relatively easily solvable set of differential equations for either wholly subsonic or supersonic flows. This assumption
6696-541: The southern boundary of the city of St. Louis (separating it from St. Louis County ) is the River des Peres , practically the only river or stream within the city limits that is not entirely underground. Most of River des Peres was confined to a channel or put underground in the 1920s and early 1930s. The lower section of the river was the site of some of the worst flooding of the Great Flood of 1993 . The city's eastern boundary
6789-414: The speed of sound at Mach 0.675, which brought forth the idea of different airflows forming around the plane. In the 40s, Kelly Johnson became one of the first engineers to investigate the effect of compressibility on aircraft. However, contemporary wind tunnels did not have the capability to create wind speeds close to Mach 1 to test the effects of transonic speeds. Not long after, the term "transonic"
6882-507: The surrounding countryside. In hindsight, many of these original settlers thought of these first few years as "the golden age of St. Louis". In 1763, the Native Americans in the region around St. Louis began expressing dissatisfaction with the victorious British, objecting to their refusal to continue to the French tradition of supplying gifts to Natives. Odawa chieftain Pontiac began forming
6975-401: The tail of the aircraft will reach supersonic flight while the nose of the aircraft is still in subsonic flight. A bubble of supersonic expansion fans terminating by a wake shockwave surround the tail. As the aircraft continues to accelerate, the supersonic expansion fans will intensify and the wake shockwave will grow in size until infinity is reached, at which point the bow shockwave forms. This
7068-666: The team unveiled prototypes of the Boeing T-X, a single-engine advanced jet trainer with a twin tail , tandem seating, and retractable tricycle landing gear , powered with a General Electric F404 afterburning turbofan engine. The first T-X aircraft flew on 20 December 2016. The Boeing–Saab team submitted their entry after the Air Force opened the T-7 program to bids in December 2016. In September 2018, Air Force officials announced that Boeing's design would be its new advanced jet trainer, under
7161-443: The then-current theory implied that these disturbances– and thus drag– approached infinity as local Mach number approached 1, an obviously unrealistic result which could not be remedied using known methods. One of the first methods used to circumvent the nonlinearity of transonic flow models was the hodograph transformation. This concept was originally explored in 1923 by an Italian mathematician named Francesco Tricomi , who used
7254-662: The time. Among the earliest is the Basilica of St. Louis, King of France (referred to as the Old Cathedral ). The Basilica was built between 1831 and 1834 in the Federal style. Other religious buildings from the period include SS. Cyril and Methodius Church (1857) in the Romanesque Revival style and Christ Church Cathedral (completed in 1867, designed in 1859) in the Gothic Revival style. A few civic buildings were constructed during
7347-421: The transformation to simplify the compressible flow equations and prove that they were solvable. The hodograph transformation itself was also explored by both Ludwig Prandtl and O.G. Tietjen's textbooks in 1929 and by Adolf Busemann in 1937, though neither applied this method specifically to transonic flow. Gottfried Guderley, a German mathematician and engineer at Braunschweig , discovered Tricomi's work in
7440-437: The transonic behavior of the airfoil by the early 1950s. At transonic speeds supersonic expansion fans form intense low-pressure, low-temperature areas at various points around an aircraft. If the temperature drops below the dew point a visible cloud will form. These clouds remain with the aircraft as it travels. It is not necessary for the aircraft as a whole to reach supersonic speeds for these clouds to form. Typically,
7533-511: The war. These areas remained under Spanish control until 1803, when they were transferred to the French First Republic . During the American Revolutionary War , St. Louis was unsuccessfully attacked by British-allied Native Americans in the 1780 Battle of St. Louis . The founding of St. Louis was preceded by a trading business between Gilbert Antoine de St. Maxent and Pierre Laclède (Liguest) in late 1763. St. Maxent invested in
7626-529: The western banks of the Mississippi River, in the Midwestern United States just south of the Missouri -Mississippi confluence . Much of the area is a fertile and gently rolling prairie that features low hills and broad, shallow valleys. Both the Mississippi River and the Missouri River have cut large valleys with wide flood plains. Limestone and dolomite of the Mississippian epoch underlie
7719-408: The world. Data from FlightGlobal , Air & Space Forces Magazine, Boeing and Key.Aero General characteristics Aircraft of comparable role, configuration, and era Transonic Transonic (or transsonic ) flow is air flowing around an object at a speed that generates regions of both subsonic and supersonic airflow around that object. The exact range of speeds depends on
7812-526: Was a center of the Native American Mississippian culture , which built numerous temple and residential earthwork mounds on both sides of the Mississippi River. Their major regional center was at Cahokia Mounds , active from 900 to 1500. Due to numerous major earthworks within St. Louis boundaries, the city was nicknamed as the "Mound City". These mounds were mostly demolished during the city's development. Historic Native American tribes in
7905-424: Was admitted as a state in 1821. St. Louis was incorporated as a city in 1822, and continued to develop largely due to its busy port and trade connections. Immigrants from Ireland and Germany arrived in St. Louis in significant numbers starting in the 1840s, and the population of St. Louis grew from less than 20,000 inhabitants in 1840, to 77,860 in 1850, to more than 160,000 by 1860. By the mid-1800s, St. Louis had
7998-564: Was also home to several brass era automobile companies, including the Success Automobile Manufacturing Company ; St. Louis is the site of the Wainwright Building , a skyscraper designed in 1892 by architect Louis Sullivan . In 1900, the entire streetcar system was shut down by a several months-long strike , with significant unrest occurring in the city & violence against the striking workers. In 1904,
8091-660: Was defined to mean "across the speed of sound" and was invented by NACA director Hugh Dryden and Theodore von Kármán of the California Institute of Technology. Initially, NACA designed "dive flaps" to help stabilize the plane when reaching transonic flight. This small flap on the underside of the plane slowed the plane to prevent shock waves, but this design only delayed finding a solution to aircraft flying at supersonic speed. Newer wind tunnels were designed, so researchers could test newer wing designs without risking test pilots' lives. The slotted-wall transonic tunnel
8184-433: Was designed by NASA and allowed researchers to test wings and different airfoils in transonic airflow to find the best wingtip shape for sonic speeds. After World War II , major changes in aircraft design were seen to improve transonic flight. The main way to stabilize an aircraft was to reduce the speed of the airflow around the wings by changing the chord of the plane wings, and one solution to prevent transonic waves
8277-514: Was founded by B. F. Bowles in St. Louis, and at the time no other college in St. Louis County admitted black students. In the first half of the 20th century, St. Louis was a destination in the Great Migration of African Americans from the rural South seeking better opportunities. During World War II , the NAACP campaigned to integrate war factories. In 1964, civil rights activists protested at
8370-509: Was struck down in a court challenge, by the NAACP, after which racial covenants were used to prevent the sale of houses in certain neighborhoods to "persons not of Caucasian race". Again, St. Louisans offered a lawsuit in challenge, and such covenants were ruled unconstitutional by the U.S. Supreme Court in 1948 in Shelley v. Kraemer . In 1926, Douglass University , a historically black university
8463-400: Was swept wings. Since the airflow would hit the wings at an angle, this would decrease the wing thickness and chord ratio. Airfoils wing shapes were designed flatter at the top to prevent shock waves and reduce the distance of airflow over the wing. Later on, Richard Whitcomb designed the first supercritical airfoil using similar principles. Prior to the advent of powerful computers, even
8556-518: Was to become the city of St. Louis. (French lands east of the Mississippi had been ceded to Great Britain and the lands west of the Mississippi to Spain; Catholic France and Spain were 18th-century allies. Louis XV of France and Charles III of Spain were cousins, both from the House of Bourbon. ) The French families built the city's economy on the fur trade with the Osage, and with more distant tribes along
8649-499: Was to serve as the manufacturing hub for the T-7A Red Hawk’s aft section and sub-systems such as hydraulics, fuel systems and secondary power. Saab has developed new software for the T-7 to help provide for cheaper and faster development. The T-7A employed digital engineering that went from development to the first test flight within 36 months. The T-7A has an advanced and digitized production line that takes only 30 minutes to splice
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