A helicopter is a type of rotorcraft in which lift and thrust are supplied by rotors. This allows the helicopter to take off and land vertically, to hover, to fly forward and laterally; these attributes allow helicopters to be used in congested or isolated areas where fixed-wing aircraft and many forms of VTOL aircraft cannot perform. The English word helicopter is adapted from the French word hélicoptère, coined by Gustave Ponton d'Amécourt in 1861, which originates from the Greek helix "helix, whirl, convolution" and pteron "wing". English language nicknames for helicopter include "chopper", "copter", "helo", "heli", "whirlybird". Helicopters were developed and built during the first half-century of flight, with the Focke-Wulf Fw 61 being the first operational helicopter in 1936; some helicopters reached limited production, but it was not until 1942 that a helicopter designed by Igor Sikorsky reached full-scale production, with 131 aircraft built. Though most earlier designs used more than one main rotor, it is the single main rotor with anti-torque tail rotor configuration that has become the most common helicopter configuration.
Tandem rotor helicopters are in widespread use due to their greater payload capacity. Coaxial helicopters, tiltrotor aircraft, compound helicopters are all flying today. Quadcopter helicopters pioneered as early as 1907 in France, other types of multicopter have been developed for specialized applications such as unmanned drones; the earliest references for vertical flight came from China. Since around 400 BC, Chinese children have played with bamboo flying toys; this bamboo-copter is spun by rolling a stick attached to a rotor. The spinning creates lift, the toy flies when released; the 4th-century AD Daoist book Baopuzi by Ge Hong describes some of the ideas inherent to rotary wing aircraft. Designs similar to the Chinese helicopter toy appeared in some Renaissance paintings and other works. In the 18th and early 19th centuries Western scientists developed flying machines based on the Chinese toy, it was not until the early 1480s, when Italian polymath Leonardo da Vinci created a design for a machine that could be described as an "aerial screw", that any recorded advancement was made towards vertical flight.
His notes suggested that he built small flying models, but there were no indications for any provision to stop the rotor from making the craft rotate. As scientific knowledge increased and became more accepted, people continued to pursue the idea of vertical flight. In July 1754, Russian Mikhail Lomonosov had developed a small coaxial modeled after the Chinese top but powered by a wound-up spring device and demonstrated it to the Russian Academy of Sciences, it was powered by a spring, was suggested as a method to lift meteorological instruments. In 1783, Christian de Launoy, his mechanic, used a coaxial version of the Chinese top in a model consisting of contrarotating turkey flight feathers as rotor blades, in 1784, demonstrated it to the French Academy of Sciences. Sir George Cayley, influenced by a childhood fascination with the Chinese flying top, developed a model of feathers, similar to that of Launoy and Bienvenu, but powered by rubber bands. By the end of the century, he had progressed to using sheets of tin for rotor blades and springs for power.
His writings on his experiments and models would become influential on future aviation pioneers. Alphonse Pénaud would develop coaxial rotor model helicopter toys in 1870 powered by rubber bands. One of these toys, given as a gift by their father, would inspire the Wright brothers to pursue the dream of flight. In 1861, the word "helicopter" was coined by Gustave de Ponton d'Amécourt, a French inventor who demonstrated a small steam-powered model. While celebrated as an innovative use of a new metal, the model never lifted off the ground. D'Amecourt's linguistic contribution would survive to describe the vertical flight he had envisioned. Steam power was popular with other inventors as well. In 1878 the Italian Enrico Forlanini's unmanned vehicle powered by a steam engine, rose to a height of 12 meters, where it hovered for some 20 seconds after a vertical take-off. Emmanuel Dieuaide's steam-powered design featured counter-rotating rotors powered through a hose from a boiler on the ground. In 1887 Parisian inventor, Gustave built and flew a tethered electric model helicopter.
In July 1901, the maiden flight of Hermann Ganswindt's helicopter took place in Berlin-Schöneberg. A movie covering the event was taken by Max Skladanowsky. In 1885, Thomas Edison was given US$1,000 by James Gordon Bennett, Jr. to conduct experiments towards developing flight. Edison built a helicopter and used the paper for a stock ticker to create guncotton, with which he attempted to power an internal combustion engine; the helicopter was damaged by explosions and one of his workers was badly burned. Edison reported that it would take a motor with a ratio of three to four pounds per horsepower produced to be successful, based on his experiments. Ján Bahýľ, a Slovak inventor, adapted the internal combustion engine to power his helicopter model that reached a height of 0.5 meters in 1901. On 5 May 1905, his helicopter flew for over 1,500 meters. In 1908, Edison patented his own design for a helicopter powered by a gasoline engine with box kites attached to a mast by cables for a rotor, but it never flew.
In 1906, two French brothers and Louis Breguet, began experimenting with airfoils for helicopters. In
Springfield is the capital of the U. S. state of Illinois and the county seat of Sangamon County. The city's population of 116,250 as of the 2010 U. S. Census makes it the state's sixth most populous city, it is the largest city in central Illinois. As of 2013, the city's population was estimated to have increased to 117,006, with just over 211,700 residents living in the Springfield Metropolitan Statistical Area, which includes Sangamon County and the adjacent Menard County. Present-day Springfield was settled by European Americans in the late 1810s, around the time Illinois became a state; the most famous historic resident was Abraham Lincoln, who lived in Springfield from 1837 until 1861, when he went to the White House as President. Major tourist attractions include multiple sites connected with Lincoln including his presidential library and museum, his home, his tomb at Oak Ridge Cemetery; the capital is centrally located within the state. The city lies in a plain near the Sangamon River. Lake Springfield, a large artificial lake owned by the City Water, Light & Power company, supplies the city with recreation and drinking water.
Weather is typical for middle latitude locations, with hot summers and cold winters. Spring and summer weather is like that of most midwestern cities. Tornadoes hit the Springfield area in 1957 and 2006; the city governs the Capital Township. The government of the state of Illinois is based in Springfield. State government entities include the Illinois General Assembly, the Illinois Supreme Court and the Office of the Governor of Illinois. There are three private high schools in Springfield. Public schools in Springfield are operated by District No. 186. Springfield's economy is dominated by government jobs, plus the related lobbyists and firms that deal with the state and county governments and justice system, health care and medicine. Springfield was named "Calhoun", after Senator John C. Calhoun of South Carolina; the land that Springfield now occupies was settled first by trappers and fur traders who came to the Sangamon River in 1818. The first cabin was built by John Kelly, it was located at what is now the northwest corner of Jefferson Street.
In 1821, Calhoun was designated as the county seat of Sangamon County due to fertile soil and trading opportunities. Settlers from Kentucky and North Carolina came to the developing city. By 1832, Senator Calhoun had fallen out of the favor with the public and the town renamed itself as Springfield after Springfield, Massachusetts. At that time, the New England city was known for industrial innovation, concentrated prosperity, the Springfield Armory. Kaskaskia was the first capital of the Illinois Territory from its organization in 1809, continuing through statehood in 1818, through the first year as a state in 1819. Vandalia was the second state capital of Illinois from 1819 to 1839. Springfield became the third and current capital of Illinois in 1839; the designation was due to the efforts of Abraham Lincoln and his associates. The Potawatomi Trail of Death passed through here in 1838, as the Native Americans were forced west to Indian Territory by the government's Indian Removal policy. Lincoln arrived in the Springfield area when he was a young man in 1831, though he did not live in the city until 1837.
He spent the ensuing six years in New Salem, where he began his legal studies, joined the state militia and was elected to the Illinois General Assembly. In 1837 Lincoln spent the next 24 years as a lawyer and politician. Lincoln delivered his Lyceum address in Springfield, his farewell speech when he left for Washington is a classic in American oratory. Winkle examines the historiography concerning the development of the Second Party System and applies these ideas to the study of Springfield, a strong Whig enclave in a Democratic region, he chiefly studied poll books for presidential years. The rise of the Whig Party took place in 1836 in opposition to the presidential candidacy of Martin Van Buren and was consolidated in 1840. Springfield Whigs tend to validate several expectations of party characteristics as they were native-born, either in New England or Kentucky, professional or agricultural in occupation, devoted to partisan organization. Abraham Lincoln's career reflects the Whigs' political rise, but by the 1840s, Springfield began to be dominated by Democratic politicians.
Waves of new European immigrants changed the city's demographics and became aligned with the Democrats. By the 1860 presidential election, Lincoln was able to win his home city. Winkle examines the impact of migration on political participation in Springfield during the 1850s. Widespread migration in the 19th-century United States produced frequent population turnover within Midwestern communities, which influenced patterns of voter turnout and office-holding. Examination of the manuscript census, poll books, office-holding records reveals the effects of migration on the behavior and voting patterns of 8,000 participants in 10 elections in Springfield. Most voters were short-term residents who participated in only one or two elections during the 1850s. Fewer than 1% of all voters participated in all 10 elections. Instead of producing political instability, rapid turnover enhanced the influence of the more stable residents. Migration was selective by age, occupation and birthplace. Longer-term or persistent voters, as he terms them, tended to be wealthier, more skilled, more native-born, more stable than non-persisters.
Officeholders were particularly
Convair CV-240 family
The Convair CV-240 is an American airliner that Convair manufactured from 1947 to 1954 as a possible replacement for the ubiquitous Douglas DC-3. Featuring a more modern design with cabin pressurization, the 240 series made some inroads as a commercial airliner, had a long development cycle that produced various civil and military variants. Though reduced in numbers by attrition, various forms of the "Convairliners" continue to fly in the 21st century; the design began with a requirement by American Airlines for an airliner to replace its Douglas DC-3s. Convair's original design, the unpressurised Model 110, was a twin-engine, low-wing monoplane of all-metal construction, with 30 seats, it was powered by Whitney R-2800 Double Wasp radial engines. It had a tricycle landing gear, a ventral airstair for passenger boarding; the prototype Model 110, registration NX90653, first flew on July 8, 1946. By this time, American had changed the requirements to include pressurization and deemed the design too small.
Convair used the first prototype for 240 series development work before it had it broken up in 1947. To meet the requirements of airlines for a pressurized airliner, Convair produced a revised design—the Model 240; this had a longer but thinner fuselage than the Model 110, accommodating 40 passengers in the first pressurized, twin-engined airliner. The 240 first flew on March 16, 1947; the Model 240 was followed by the Model 340, which had a longer fuselage, longer-span wings, more powerful engines. The 340 first flew on October 5, 1951. In 1954, in an attempt to compete with turboprop-powered airliners like the Vickers Viscount, Convair produced the Model 440 Metropolitan, with more streamlined cowlings, new engine exhausts, better cabin soundproofing; as the "Super 240" evolved into the CV-340 and CV-440, the design reached the limit of piston-engine performance, future development centered on conversion to turboprop power. Convair delivered the first production Convairliner to American on February 29, 1948.
They delivered a total of 75 to American—and another 50 to Western Airlines, Continental Airlines, Pan American Airways, Lufthansa, KLM, Swissair and Trans Australia Airlines. A CV-240 was the first private aircraft used in a United States presidential campaign. In 1960, John F. Kennedy used; this aircraft is now preserved in the National Space Museum. After aborted negotiations with TWA and Eastern for "Super 240" orders, Convair temporarily halted 240 series production. In response to a United inquiry, Convair redesigned the Super 240, calling it the CV-340. United ordered 55, more US orders came from Braniff, Delta and National. Other orders came from abroad, the CV-340 was popular in South America; the CV-340 earned a reputation for reliability and profitability, was developed into the CV-440 Metropolitan, the final piston-engined variant of the Convairliners. Kelowna Flightcraft Air Charter, the major remaining operator of this model holds the type certificate for this aircraft. Used price for a Convair 240 in 1960 was around £40,000.
Data from: General Dynamics Aircraft and their predecessors Convair Model 110 Unpressurized prototype with seats for 30 passengers. 89 ft wingspan, 71 ft length, powered by two 2,100 hp Whitney R-2800-SC13G engines. One built. Convair CV-240 Initial production version, with seats for 40 passengers in a pressurised fuselage. Powered by two Pratt & Whitney 2,400 kW R-2800 engines. 176 built (excluding military derivatives. Convair CV-240-21 TurbolinerTurboprop-powered conversion fitted with Allison T38 engines, it became the first turboprop airliner to fly in the United States, but problems with the engines resulted in development being terminated. Used as a test bed before being converted back to piston power. Convair CV-300 A conversion from a Convair CV-240 with two R-2800 CB-17 engines and nacelles as used on the CV-340. Convair CV-340 Built for United Airlines and other operators including KLM, the CV-340 was a CV-240 lengthened to hold an additional four seats; the wingspan was extended for better performance at higher altitudes.
The CV-340 replaced the DC-3 in United service. The airline flew 52 340s for 16 years without a fatality. KLM operated the type from early 1953 until mid-1963. Many CV-340 aircraft were converted to CV-440 standard. Convair CV-440 Metropolitan CV-340 with improved soundproofing and an option for weather radar. Maximum weight rose to 49,700 lbs. An optional increase from 44 to 52 passengers was facilitated by the replacement of the carry-on luggage area with two more rows of seats, marked by the addition of an extra cabin window; this option was taken up by several airlines including Swissair, Lufthansa and SAS. Finnair operated the type from 1953 until 1980 without a single accident. Convair CV-540 Conversion from a Convair CV-340 aircraft with two Napier Eland turboprop engines in place of the piston engines. Six aircraft were converted by Napier for Allegheny Airlines. Cost for the conversions was £160,000 per-aircraft. 12 built as new-builds by Canadair for RCAF as CC-109 in 1960 for £436,000 per-aircraft.
First flight February 9, 1955. Convair CV-580 Conversion from Convair CV-340 or CV-440 aircraft with two Allison 501 D13D/H turboprop engines with four-blade propellers, in place of piston engines with three-blade propellers, an enlarged vertical fin and modified horizontal stabilizers; the conversions were performed by Pacific Airmotive on behalf of the Allison Engine Company. Cost of the conversions took 60 days; the CV-580 served with the original Frontier Airlines and North Central Airlines for m
Spirit of St. Louis Airport
Spirit of St. Louis Airport is a public airport located 17 miles west of the central business district of St. Louis, in St. Louis County, United States, it is named after the famous Spirit of St. Louis aircraft. Spirit of St. Louis Airport covers an area of 1,300 acres and contains two parallel runways: 8L/26R measuring 5,000 x 75 ft and 8R/26L measuring 7,485 x 150, an all-weather, ILS-equipped runway. For the 12-month period ending December 31, 2017, the airport had 94,764 aircraft operations, an average of 260 per day: 86% general aviation, 12% air taxi, 2% military and less than 1% commercial service. In March 2018, there were 394 aircraft based at this airport: 242 single-engine, 54 multi-engine, 78 jet and 20 helicopters. In 2007, the airport finished a multimillion-dollar expansion project to add a parallel taxiway to the north of 8L/26R; this added land is available to lease with taxiway access. The Spirit of St. Louis Air Show returned to the airport, May 3–4, 2014 after being absent since 2007.
It featured a Veteran's Village. The US Navy Blue Angels headlined the event. Resources for this airport: FAA airport information for SUS AirNav airport information for KSUS ASN accident history for SUS FlightAware airport information and live flight tracker NOAA/NWS latest weather observations SkyVector aeronautical chart, Terminal Procedures
Metro Transit (St. Louis)
Metro Transit is an enterprise of Bi-State Development, an interstate compact formed by Missouri and Illinois in 1949. Its operating budget in 2016 was $280 million, funded by sales taxes from the City of St. Louis and St. Louis County, the St. Clair County Illinois Transit District and state grants and subsidies, through fare paying passengers. Metro owns and operates the St. Louis Metropolitan region's public transportation system, which includes MetroLink, the region's light rail system. Bi-State Development owns and operates St. Louis Downtown Airport and the adjoining industrial business park, paddlewheel-style river excursion boats, the tram system leading to the top of the Gateway Arch. Metro carries over 55 million passengers each year. Bi-State Development was established on September 20, 1949, by an interstate compact passed by the state legislatures in Illinois and Missouri, approved by the governors of the two states; the Compact, approved by the United States Congress and signed by President Harry S. Truman on August 31, 1950, created an organization that has broad powers in seven counties.
The Compact gives BSD the ability to plan, maintain and operate bridges, tunnels and terminal facilities and establish policies for sewage and drainage facilities and other public projects, issue bonds and exercise such additional powers as conferred upon it by the legislatures of both states. Funding is received from local and federal sources through grant and sales tax revenue. BSD does not have taxing authority but is authorized to collect fees from the operation of its facilities. Today, BSD is organized as one parent organization with several business operating units including St. Louis Downtown Airport, Gateway Arch Riverfront, Metro, Bi-State Development Research Institute, Arts In Transit, Inc. and St. Louis Regional Freightway. BSD has three selfinsurance funds that support operations and operates Arts in Transit, Inc. a 501 organization that ensures the integration of local art and design on our region's transit system. Metro was founded in 1963 when BSD purchased and consolidated 15 owned transit operations by using a $26.5 million bond issue to sustain efficient and reliable bus service in the region.
Today, BSD provides three modes of public transportation services in the St. Louis region: MetroBus, bus operations; the MetroBus fleet consists of 400 vehicles operating on 79 MetroBus routes. The MetroLink light rail system has 46 miles of 37 stations and 21 Park and Ride lots; the Metro Call-A-Ride fleet has 120 vans which provide curb-to-curb van service for Americans with Disabilities Act eligible customers. In addition, Arts in Transit, Inc. facilitates public art programs and community engagement projects that ensure excellence in art and design that weave transit into the community. BSD expanded into light rail transportation in July 1993; the original 17-mile corridor was constructed between Lambert International Airport in Missouri and Fifth and Missouri Streets in East St. Louis, Illinois. MetroLink doubled in length with the 2001 expansion to Southwestern Illinois College in Illinois and the 2003 expansion to Shiloh, home of Scott Air Force Base; the most recent light rail expansion occurred in August 2006 when the Cross County extension was completed.
This expansion added another eight miles on the Blue Line through Clayton south to Shrewsbury, Missouri. In 1987, Metro Call-A-Ride began demand response service to fill a need for alternative transportation service to customers with physical or cognitive disabilities who are unable to independently use regular fixed route bus or light rail service. BSD has created programs to certify all paratransit users. BSD spearheaded the regional Transportation Management Association, which consists of private for-profit and non-profit transportation providers working together to provide regional paratransit services. Today, East-West Gateway Council of Government, the region's metropolitan planning organization, is involved in consideration of several MetroLink expansion options for the future while Metro transit continues to implement its long-range plan with projects like the new North County Transit Center, as well as projects in the works like the Civic Center Transit Center expansion and construction of a new MetroLink station to serve the Cortex Innovation Community which will open in 2018.
Bi-State Development was established on September 20, 1949, by an interstate compact passed by the state legislatures of Illinois and Missouri and approved by both governors. The compact was approved by the U. S. Congress and signed by President Harry S. Truman on August 31, 1950. A 10-member Board of Commissioners sets direction for the organization; the governor of Missouri appoints five commissioners and the County Boards of St. Clair and Madison Counties in Illinois appoint five commissioners. All commissioners must be resident voters of their respective state and must reside within the Bi-State Metropolitan District; each term is for five years and each serves without compensation. Kevin Cahill - Secretary Constance Gully Lewis L. McKinney Jr. Hugh Scott III New Member to be appointed Jeffrey K. Watson Fonzy Coleman David A. Dietzel - Treasurer Tadas Kicielinski Michael Buehlhorn Collectively, St. Louis County and St. Lou
Chesterfield is a city in St. Louis County, United States, a western suburb of St. Louis; as of the 2010 census, the population was 47,484. The broader valley of Chesterfield was referred to as "Gumbo Flats", derived from its soil, which though rich and silty, became like a gumbo when wet. Chesterfield is located 25 miles west of St. Louis. According to the United States Census Bureau, the city has a total area of 33.52 square miles, of which 31.78 square miles is land and 1.74 square miles is water. Portions of Chesterfield are located in the floodplain of the Missouri River, now known as Chesterfield Valley as Gumbo Flats; this area was submerged during the Great Flood of 1993. Chesterfield Valley is the location of Spirit of St. Louis Airport, used for corporate aviation, as well as the longest outdoor strip mall in America; the remainder of Chesterfield is located on the bluffs above the floodplain, includes residential and retail development. Chesterfield is home to several mid- to high-rise buildings, the tallest being the Drury Plaza Hotel, 12 stories and 125 feet tall.
According to the 2007–2011 American Community Survey estimate, the median income for a household in the city was $95,006, the median income for a family was $88,568. Males had a median income of $94,322 versus $54,934 for females; the per capita income for the city was $51,725. About 1.7% of families and 4.0% of the population were below the poverty line, including 1.7% of those under age 18 and 3.3% of those age 65 or over. As of the census of 2010, there were 47,484 people, 19,224 households, 13,461 families residing in the city; the population density was 1,494.1 inhabitants per square mile. There were 20,393 housing units at an average density of 641.7 per square mile. The racial makeup of the city was 86.5% White, 2.6% African American, 0.2% Native American, 8.6% Asian, 0.7% from other races, 1.4% from two or more races. Hispanic or Latino of any race were 2.8% of the population. There were 19,224 households of which 29.3% had children under the age of 18 living with them, 62.2% were married couples living together, 5.9% had a female householder with no husband present, 2.0% had a male householder with no wife present, 30.0% were non-families.
26.1% of all households were made up of individuals and 11.6% had someone living alone, 65 years of age or older. The average household size was 2.42 and the average family size was 2.94. The median age in the city was 46.6 years. 22.3% of residents were under the age of 18. The gender makeup of the city was 47.8% male and 52.2% female. As of the census of 2000, there were 46,802 people, 18,060 households, 13,111 families residing in the city; the population density was 1,485.4 people per square mile. There were 18,738 housing units at an average density of 594.7 per square mile. The racial makeup of the city was 92.30% White, 0.86% African American, 0.12% Native American, 5.56% Asian, 0.02% Pacific Islander, 0.39% from other races, 0.74% from two or more races. Hispanic or Latino of any race were 1.55% of the population. There were 18,060 households out of which 33.2% had children under the age of 18 living with them, 65.5% were married couples living together, 5.4% had a female householder with no husband present, 27.4% were non-families.
23.6% of all households were made up of individuals and 8.8% had someone living alone, 65 years of age or older. The average household size was 2.53 and the average family size was 3.03. In the city the population was spread out with 24.6% under the age of 18, 5.9% from 18 to 24, 25.0% from 25 to 44, 29.7% from 45 to 64, 14.7% who were 65 years of age or older. The median age was 42 years. For every 100 females, there were 91.6 males. For every 100 females age 18 and over, there were 88.2 males. Present-day Chesterfield is known to have been a site of Native American inhabitation for thousands of years. A site in western Chesterfield containing artwork and carvings has been dated as 4,000 years old. A Mississippian site, dated to around the year 1000, containing the remains of what have been identified as a market and ceremonial center, is located in modern Chesterfield; the present-day city of Chesterfield is made up of several smaller historical communities, including: Bellefontaine, or as the locals called it, "Hilltown", dates to about 1837 with the arrival of August Hill.
The first post office was established as Bellemonte in 1851. Eighteen years in 1869, the town and post office name were both changed to Bellefontaine. Rinkel's Market was a familiar landmark for years, at the intersection of present-day Olive Boulevard and Chesterfield Parkway; the town of Lake started out as "Hog Hollow," in about 1850. The post office was established as Hog Hollow in 1871, but a year the town's name was changed to what some thought was the more suitable name of Lake. Zierenberg's General Merchandise and Saloon was a well-known landmark at the 18-mile marker on Olive Street Road; the original structure was destroyed by fire in 1918. It was replaced by the existing structure on the same site. Gumbo is located in the valley at the present intersection of Chesterfield Airport Road and Long Road. A notable landmark was the old Twenty Five Mile House - so named because of its
Fairchild Swearingen Metroliner
The Fairchild Swearingen Metroliner is a 19-seat, twin-turboprop airliner first produced by Swearingen Aircraft and by Fairchild Aircraft at a plant in San Antonio, United States. The Metroliner was an evolution of the Swearingen Merlin turboprop-powered business aircraft. Ed Swearingen, a Texas fixed-base operator, started the developments that led to the Metro through gradual modifications to the Beechcraft Twin Bonanza and Queen Air business aircraft, which he dubbed Excalibur. A new fuselage and vertical fin were developed, married to salvaged and rebuilt Queen Air wings and horizontal tails, Twin Bonanza landing gear. Through successive models the engines were changed to Pratt & Whitney Canada PT6 Garrett TPE331 turboprops; these were marketed as business aircraft seating eight to ten passengers. An all-new aircraft was built and named the SA226-T Merlin III with a new nose, landing gear, cruciform horizontal tail and inverted inlet Garrett engines. A stretch of the Merlin III was designed, sized to seat 22 passengers and called the SA226-TC Metro.
Because FAA regulations limited an airliner to no more than 19 seats if no flight attendant was to be carried, the aircraft was optimized for that number of passengers. The standard engines offered were two TPE331-3UW turboprops driving three-bladed propellers. A corporate version called the SA226-AT Merlin IVA was marketed and sales of this version were double that of the Metro. Prototype construction of the Metro began in 1968 and the first flight was on August 26, 1969. Swearingen Aircraft encountered financial difficulties at this stage, late in 1971 Fairchild, bought 90% of Swearingen and the company was renamed Swearingen Aviation Corporation, it was at this point that the cash-strapped company was able to put the Metro into production. In 1974, the original Metro models were replaced by the SA226-TC Metro II after about 20 Metros and about 30 Merlin IVAs had been built. Among the changes made were larger, squared-oval windows and optional provision for a small Rocket-Assisted Take Off rocket in the tail cone, this being offered to improve takeoff performance out of "hot & high" airfields in the event of an engine failure.
The Metro and Metro II were limited to a maximum weight of 12,500 pounds in the US and countries using imperial units, 5,700 kg in countries using SI units. When this restriction was lifted the Metro II was re-certified as the Metro IIA in 1980 with a maximum weight of 13,100 pounds and the Metro II's TPE331-3 engines replaced by -10 engines of increased power; the SA227-AC Metro III followed initially certified in 1980 for up to 14,000 pounds, this increasing to 14,500 pounds as engines and structures were upgraded. An option to go as high as 16,000 pounds was offered. Externally, improvements incorporated into the Metro III were a 10 ft increase in wing span, four-bladed props, redesigned "quick-access" engine cowlings and numerous drag-reducing airframe modifications, including landing gear doors that closed after the gear was extended. Once again a corporate version was offered as the Merlin IVC. A version with strengthened floors and the high gross weight option was offered as a cargo aircraft known as the Expediter.
Both the Expediter and the Merlin IVC were designated the SA227-AT. Due to reliability problems with Garrett engines in the second half of the 1980s, the Metro IIIA was offered with two Pratt & Whitney Canada PT6A-45R turboprops in place of the Garrett units. A special model was the SA227-BC Metro III built for Mexican airline AeroLitoral, which took delivery of 15 of the 18 of this model that were produced. Improvements beyond the Metro III provided better systems, more power and a further increase in takeoff weight; this design effort resulted in the SA227 CC and SA227-DC models called the Metro IV renamed Metro 23, so named as they were designed for certification under FAR Part 23 standards. A Metro 23 EF with an external pod under the lower fuselage for greater baggage capacity was offered as well as an Expediter 23 and Merlin 23; the SA227-CC was an interim model with TPE331-11U engines and only a handful were built. In the 1960s Swearingen Aircraft developed a prototype SA-28T eight-seat jet aircraft with a flapless delta wing.
It shared the cockpit with the Merlin/Metro. The two engines were to be Garrett TFE731 turbofans in development. Early flights were to be undertaken with General Electric CJ610 engines fitted. Development continued after Fairchild acquired the company, but the project was shut down nine weeks from first flight, it was cut up as scrap and the fuselage used as a Metro display at trade shows. At the 1987 Paris Air Show, Fairchild released details of proposed developments of the Metro designated the Metro V and Metro VI; these versions would have featured a longer fuselage with a taller "stand-up" cabin providing 69 in of interior height for passengers. A Merlin V corporate version of the Metro V was plan