Narrow-Body / Single Aisle Aircraft
The arrangement of the cabin of a "narrow-body" transport such as the 707 or 727 is divided into a small first-class compartment with four-abreast seating and a large tourist-class cabin with six-abreast seating. A single aisle runs the entire length of the cabin with three seats located on either side. For an aircraft of large passenger capacity, the fuselage of the narrow-body type tends to become very long, which, in turn, may dictate a long, heavy landing gear in order to permit the desired rotation angle on takeoff without scraping the rear end of the fuselage on the runway. The long aisle also causes lengthy delays in passenger loading and difficulty for the cabin attendants in serving meals and refreshments.
The age of jet transportation began on May 5, 1952, with the inauguration of scheduled service from London to Johannesburg, South Africa. Later in the year, service was established from London to Ceylon and from London to Singapore. Then, in April 1953, scheduled flights were begun from London to Tokyo, a distance of 10 200 miles. The flying time was 36 hours, as compared with 85 hours for the propeller-driven aircraft then in use on the route. The pioneering jet transport that began commercial operations in 1952 was the DeHavilland Comet 1. The design of the Comet airliner had its origins in the waning days of World War II, and the layout of the aircraft was completed in 1947. Prospects for the Comet dimmed, however, when three accidents occurred in which the aircraft disintegrated in flight. All Comet 1 aircraft, over 20 in number, were withdrawn from service in 1954. Extensive laboratory studies were undertaken in an effort to diagnose the problem. Fatigue failure and subsequent rupture of the pressurized fuselage as a result of pressure recycling was finally identified as the cause of the accidents. The Comet was completely reengineered and emerged as a much changed and improved aircraft in 1958.
The Tupolev Tu-104 is the second of the pioneer jet transports. This aircraft was first flown on June 17, 1955, and went into scheduled airline operations in 1956 on the Moscow-Omsk-Irkutsk route. In 1957, an improved version of the aircraft, the Tu-104A, captured a number of records for speed, altitude, distance, and load-carrying capability. The Tu-104 transport was developed from the "Badger" bomber and utilized the same wings, tall surfaces, engines and inlets, landing gear, and fuselage nose section as the earlier bomber aircraft.
Both the DeHavilland Comet and the Tupolev Tu-104 were pioneers in a new and exciting concept of air transportation, and both have a well-deserved place in the history of aeronautical development. In many respects, however, the design of these aircraft reflected the philosophy of contemporary propeller-driven aircraft. For example, the low wing loadings, unsophisticated high-lift devices, and simple control systems are typical of high-performance propeller-driven transports.
The Boeing 707 transport was the first of the long-range and, for its day, high-passenger-capacity aircraft that marked the real beginning of the revolutionary jet age in air transportation. Even today, many people consider the terms 707 and jet transport to be synonymous. The prototype of this remarkable aircraft first flew in July 1954, and an early production version first entered airline service in the fall of 1958. Over 900 Boeing 707 commercial transports have been built, but by 1980 the 707 was no longer in production as a commercial transport. A tanker version of the aircraft, the KC-135, has been built in large numbers for the USAF; and the Airborne Warning and Control System aircraft (AWACS) now being delivered to the Air Force utilizes the basic 707 airplane. The prototype of the 707 was known in the Boeing Company as the model 367-80, and within the company it has always been referred to as the Dash-Eighty.
The second long-range, high-passenger-capacity transport that, along with the Boeing 707, initiated the jet revolution in air transportation was the McDonnell Douglas DC-8 (originally the Douglas DC-8). This aircraft was ordered by Pan American World Airlines in 1955, and first flight was made in 1958. The aircraft entered airline service in August 1959. The DC-8 was built in many different versions; one of the principal modifications incorporated in the aircraft was a stretched fuselage to provide increased passenger capacity. Over 550 DC-8 aircraft were built before production was terminated in 1972.
Two other aircraft of this first generation of large jet transports are nearly the same in configuration as the Boeing 707 a the McDonnell Douglas DC-8. In fact, when seen at the airport, the Convair 880 and 990 are often confused with one or the other of the more familiar 707 or DC-8 aircraft. The Convair 880 first flew in 1959, and the first flight of the more advanced Convair 990 was in 1961. The maximum cruising Mach number of the 990 is 0.89, which is the highest of any of the subsonic jet transports. Both the 880 and the 990 are somewhat smaller and lighter in weight than are the 707 and the DC-8. The gross weight of the 880 is 192 700 pounds and that of the 990 is 253 000 pounds. The range of neither aircraft is really intercontinental, and both aircraft became available to the airlines somewhat later than the 707 and the DC-8. Only a relatively small number of Convair jet transports were built.
The French Sud-Aviation Caravelle was the first really successful short-range jet transport to be developed in the western world. First flight of the prototype took place in May 1955, and the aircraft entered airline service in Europe in April 1959. As with most successful jet transports, the Caravelle was produced in a number of versions; a total of 280 aircraft of all versions were produced before production was terminated in the early 1970's. Many are still in operation in various parts of the world.
The second-generation jet transports are considered to be those which first flew in prototype form in the 1960's. Most of the aircraft listed are representative of about the same level of technology and have no large state-of-the-art advances over the first-generation jet transports previously discussed. All the aircraft are equipped with turbofan engines of relatively low bypass ratio that are of about the same level of technical sophistication as the fan engines that powered the first - generation transports. Basically, with a few evolutionary refinements, the second - generation aircraft represent an application of the technology developed in the first - generation aircraft to transports specifically tailored to various types of airline route structures and payload requirements. All the aircraft, except the Boeing 737, employ aft-fuselage-mounted engines in either two - , three - , or four-engine configurations. Four of the aircraft are briefly described in the following paragraphs; they are the three-engine Boeing 727, the twin-engine McDonnell Douglas DC-9, the twin-engine Boeing 737, and the four-engine British Aircraft Corporation VC-10.
The 737 fuselage appears short and stubby, due to its large upper-fuselage diameter, which is the same as for the 707 and the 727, and its short length, which is less than for the 707 or the 727. The higher fineness ratio fuselage and greater length of the DC-9 results from the use of a five-abreast seating arrangement and consequent smaller fuselage diameter. The short fuselage length of the 737 along with the wide lateral separation of the underwing-mounted engines result in the large vertical tall on the aircraft.
The second new Boeing jetliner of the 1980's, designated the 757-200, made its initial flight in February 1982 and is scheduled to enter airline service in the spring of 1983. Intended as a fuel-efficient replacement for the long-lived Boeing 727 on short-range route segments, the 757-200 can accommodate as many as 239 passengers in a single-aisle six-abreast cabin arrangement. Average route segments are expected to be about 575 miles or less and to require less than 2 hours' flight time. A narrow six-abreast single-aisle configuration usually has slightly less wetted area, and thus less drag, than a six-abreast twin-aisle arrangement designed for the same number of passengers. Apparently, passengers are willing to accept the single-aisle layout for short flights but prefer the more spacious wide-body design for flight times greater than several hours.
The Airbus A320, the first commercial passenger jet to employ a digital fly-by-wire control system, was one of the most audacious civil airplane since the Wright brothers' Flyer. By optimizing the plane's technical performance under any given set of parameters, the fly-by-wire system radically redefines the relationship between pilots and flight. aircraft that would rely on flight control sensors and computers rather than mechanical and hydraulic systems. The fly-by-wire system would not allow a pilot to execute a maneuver that would push the plane beyond its capabilities and cause it to stall or break up. The result was an intelligent airplane that was both more automated and more forgiving of pilot errors.
In 1999, narrow-body aircraft and wide-body aircraft accounted for 67.7 and 32.3 percent of the all-cargo jet fleet, respectively. The number of wide-body aircraft is forecast to grow much faster than that of narrow-body aircraft and account for more than half the fleet by 2011. A key issue will be the capacity of existing infrastructure to handle the increasing air cargo movement efficiently. In the USA, by 2010 narrow-body aircraft represent 96 percent of all domestic passenger flights, and approximately one-quarter of all cargo on passenger aircraft travels on narrow-body aircraft.
Boeing and McDonnell Douglas dominated the global market in 1970s and 1980s. In the 1990s, Airbus became a serious competitor and remained Boeing's sole competitor as of 2010. Other civil jet transport manufacturers with a significant global presence, especially Bombardier (Canada) and Embraer (Brazil), didi not produce aircraft comparable to Boeing and Airbus. Various companies have announced projects that will compete with Boeing and Airbus in the narrow-body market. The first of these, the Bombardier CSeries, is expected to be delivered in 2013. China and Russia have also announced LCA projects, with deliveries projected to begin in 2016. As a result of this market pressure, both Boeing and Airbus are considering re-engining their current-generation narrow-body aircraft. Embraer expects to make a decision on whether to enter the narrow-body market by the end of 2010.
The People's Republic of China is investing significant resources to become a competitor in the civil aircraft industry. With its regional jet program in the flight testing phase, the Chinese are embarking on a new program to develop a 150-seat narrow-body aircraft that would compete with aircraft currently sold by Boeing and Airbus. The effort to create a competitive civil aircraft production program in China is in part motivated by growth in domestic demand for air transportation, which should lead to orders for over 3,770 new aircraft by 2028.
In February 2010 Republic Airways said it will spend $3.1 billion on CSeries jets from Canadian manufacturer Bombardier, becoming the first U.S. customer for the narrow-body aircraft seen as a challenge to market leaders Boeing and Airbus. The 40-plane order from Republic "shows that there's momentum" to replace aging fleets of single-aisle aircraft, according to a Bombardier executive. Both Boeing and Airbus are weighing new engines for their narrow-body offerings in order to compete with the cost savings offered by the CSeries.
The future strategy of fragmenting more long-haul flights and airport-pairings is one of the reasons for the projected increase in demand of short-haul flights. Aircraft passengers will prefer to reach their destinations as quick as possible, with reduced number of hub connections and numerous flight segments. Where possible, airlines will provide passengers point-to-point service on busy routes. When this is not economically feasible, passengers will prefer carriers who move them over a single hub with one-stop connecting service to their final destination. Generally, the long-haul flights will be fragmented into one long-range flight (maybe interregional route) and a short domestic or regional connecting flight. In order to provide a competitively quick connecting service, the airlines will have to increase the frequency of its short-haul flights service and this strategy has been touted as the future "primary form of nonprice competition" between airlines.
In October 2011 Rolls-Royce Holdings PLC started a joint venture with the Pratt & Whitney unit of United Technologies Corp. to develop engines for future narrow-body aircraft using Pratt's geared turbofan technology. It will compete with General Electric Co. to develop more efficient engines for the single aisle aircraft segment, in which the companies expect demand to be around 20,000 new aircraft over the next 20 years. Future narrow-body aircraft demand is much bigger than for wide-bodies. The move came after Rolls-Royce declined to develop new engines for the latest upgrades to A320 neo, produced by Airbus.
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