Naya aviation news- report Boeing 747--The Boeing 747 is a widebody commercial airliner and cargo transport, often referred to by its original nickname, Jumbo Jet, orQueen of the Skies. It is among the world's most recognizable aircraft, and was the first widebody ever produced. Manufactured by Boeing's Commercial Airplane unit in the United States, the original version of the 747 was two and a half times the size of the Boeing 707, one of the common large commercial aircraft of the 1960s. First flown commercially in 1970, the 747 held the passenger capacity record for 37 years.The four-engine 747 uses a double deck configuration for part of its length. It is available in passenger, freighter and other versions. Boeing designed the 747's hump-like upper deck to serve as a first class lounge or (as is the general rule today) extra seating, and to allow the aircraft to be easily converted to a cargo carrier by removing seats and installing a front cargo door. Boeing did so because the company expected supersonic airliners (whose development was announced in the early 1960s) to render the 747 and other subsonic airliners obsolete, while believing that the demand for subsonic cargo aircraft would be robust into the future. The 747 in particular was expected to become obsolete after 400 were sold but it exceeded its critics' expectations with production passing the 1,000 mark in 1993. As of June 2010, 1,418 aircraft have been built, with 109 more in various configurations remaining on order.
The 747-400, the latest version in service, is among the fastest airliners in service with a high-subsonic cruise speed of Mach0.85–0.855 (up to 570 mph, 920 km/h). It has an intercontinental range of 7,260 nautical miles (8,350 mi or 13,450 km). The 747-400 passenger version can accommodate 416 passengers in a typical three-class layout or 524 passengers in a typical two-class layout. The newest version of the aircraft, the 747-8, is in production and flight testing in late 2010. Deliveries of the 747-8F freighter version are scheduled to begin in mid-2011, with the 747-8I passenger version to follow in late 2011. The 747 is to be replaced by the Boeing Y3 (part of the Boeing Yellowstone Project) in the future.
Development
In 1963, the United States Air Force started a series of study projects on a very large strategic transport aircraft. Although the C-141 Starlifter was being introduced, they felt that a much larger and more capable aircraft was needed, especially the capability to carry outsized cargo that would not fit in any existing aircraft. These studies led to initial requirements for the CX-Heavy Logistics System (CX-HLS) in March 1964 for an aircraft with a load capacity of 180,000 pounds (81,600 kg) and a speed of Mach 0.75 (500 mph/805 km/h), and an unrefueled range of 5,000 nautical miles (9,260 km) with a payload of 115,000 pounds (52,200 kg). The payload bay had to be 17 feet (5.18 m) wide by 13.5 feet (4.11 m) high and 100 feet (30.5 m) long with access through doors at the front and rear.[
Featuring only four engines, the design also required new engine designs with greatly increased power and better fuel economy. On May 18, 1964, airframe proposals arrived from Boeing,Douglas, General Dynamics, Lockheed and Martin Marietta; while engine proposals were submitted by General Electric, Curtiss-Wright, and Pratt & Whitney. After a downselect, Boeing, Douglas and Lockheed were given additional study contracts for the airframe, along with General Electric and Pratt & Whitney for the engines.
All three of the airframe proposals shared a number of features. As the CX-HLS needed to be able to be loaded from the front, a door had to be included where the cockpit usually was. All of the companies solved this problem by moving the cockpit to above the cargo area; Douglas had a small "pod" just forward and above the wing, Lockheed used a long "spine" running the length of the aircraft with the wing spar passing through it, while Boeing blended the two, with a longer pod that ran from just behind the nose to just behind the wing. In 1965 Lockheed's aircraft design and General Electric's engine design were selected for the new C-5 Galaxy transport, which was the largest military aircraft in the world at the time The nose door and raised cockpit concepts would be carried over to the design of the 747
Design effort
Ultimately, the high-winged CX-HLS Boeing design was not used for the 747, although technologies developed for their bid had an influence. The original design included a full-length double-deck fuselage with rows of eight-across seating and two aisles on the lower deck and seven-across seating and two aisles on the upper deck. However, concern over evacuation routes and limited cargo-carrying capability caused this idea to be scrapped in early 1966 in favor of a wider single deck design. The cockpit was, therefore, placed on a shortened upper deck so that a freight-loading door could be included in the nose cone; this design feature produced the 747's distinctive "bulge".In early models it was not clear what to do with the small space in the pod behind the cockpit, and this was initially specified as a "lounge" area with no permanent seating.
Development and testing
Before the first 747 was fully assembled, testing began on many components and systems. One important test involved the evacuation of 560 volunteers from a cabin mock-up via the aircraft's emergency chutes. The first full-scale evacuation took two and a half minutes instead of the maximum of 90 seconds mandated by theFederal Aviation Administration, and several volunteers were injured. Subsequent test evacuations achieved the 90-second goal but caused more injuries. Most problematic was evacuation from the aircraft's upper deck; instead of using a conventional slide, volunteer passengers escaped by using a harness attached to a reel. Tests also involved taxiing such a large aircraft. Boeing built an unusual training device known as "Waddell's Wagon" (named for a 747 test pilot, Jack Waddell) that consisted of a mock-up cockpit mounted on the roof of a truck. While the first 747s were still being built, the device allowed pilots to practice taxi maneuvers from a high upper-deck position.
On September 30, 1968, the first 747 was rolled out of the Everett assembly building before the world's press and representatives of the 26 airlines that had ordered the airliner. Over the following months, preparations were made for the first flight, which took place on February 9, 1969, with test pilots Jack Waddell and Brien Wygle at the controls and Jess Wallick at the flight engineer's station. Despite a minor problem with one of the flaps, the flight confirmed that the 747 handled extremely well. The 747 was found to be largely immune to "Dutch roll", a phenomenon that had been a major hazard to the early swept-wing jets.
During later stages of the flight test program, flutter testing showed that the wings suffered oscillation under certain conditions. This difficulty was partly solved by reducing the stiffness of some wing components. However, a particularly severe high-speed flutter problem was solved only by inserting depleted uranium counterweights as ballast in the outboard engine nacelles of the early 747s. This measure caused anxiety when these aircraft crashed, as did China Airlines Flight 358 at Wanli in 1991 and El Al Flight 1862 at Amsterdam in 1992.
The flight test program was hampered by problems with the 747's JT9D engines. Difficulties included engine stalls caused by rapid movements of the throttles and distortion of the turbine casings after a short period of service. The problems delayed 747 deliveries for several months and stranded up to 20 aircraft at the Everett plant while they awaited engine installation. The program was further delayed when one of the five test aircraft suffered serious damage during a landing attempt at Renton Municipal Airport, site of Boeing's Renton plant. The test aircraft was being taken to have its test equipment removed and a cabin installed when pilot Ralph C. Cokely undershot the short runway and sheared off the 747's landing gear. However, these difficulties did not prevent Boeing from taking one of the test aircraft to the 28th Paris Air Show in mid-1969, where it was displayed to the general public for the first time. The 747 achieved its FAA airworthiness certificate in December 1969, making it ready for introduction into service.
The huge cost of developing the 747 and building the Everett factory meant that Boeing had to borrow heavily from a banking syndicate. During the final months before delivery of the first aircraft, the company had to repeatedly request additional funding to complete the project. Had this been refused, Boeing's survival would have been threatened. Ultimately, the gamble succeeded, and Boeing held a monopoly in very large passenger aircraft production for many years.
Design:The Boeing 747 is a large, wide-body (two-aisle) airliner with four wing-mounted engines. The wings have a high sweep angle of 37.5 degrees for a fast, efficient cruiseof Mach 0.84 to 0.88, depending on the variant. The sweep also allows the 747 to use existing hangars. Seating capacity is more than 366 with a 3–4–3 seat arrangement (a cross section of 3 seats, an aisle, 4 seats, another aisle, and 3 seats) in economy class and a 2–3–2 arrangement in first class on the main deck. The upper deck has a 3–3 seat arrangement in economy class and a 2–2 arrangement in first class.
Raised above the main deck, the cockpit creates a hump. The raised cockpit is to allow front loading of cargo on freight variants. The upper deck behind the cockpit provides space for a lounge or extra seating. The "stretched upper deck" became available as an option on the 747-100B variant and later as standard on the 747-300.
The 747's maximum takeoff weight ranges from 735,000 pounds (333,400 kg) for the −100 to 970,000 lb (439,985 kg) for the −8. Its range has increased from 5,300 nautical miles (6,100 mi, 9,800 km) on the −100 to 8,000 nmi (9,200 mi, 14,815 km) on the −8I.
The 747 has multiple structural redundancy including four redundant hydraulic systems and four main landing gears with four wheels each, which provide a good spread of support on the ground and safety in case of tire blow-outs. The redundant main gear allows for landing on two opposing landing gears if the others do not function properly. In addition, the 747 has split control surfaces and sophisticated triple-slottedflaps that minimize landing speeds and allow the 747 to use standard-length runways. For transportation of spare engines, 747s can accommodate a non-functioning fifth-pod engine under the port wing of the aircraft between the nearest functioning engine and th
One of the principal technologies that enabled an aircraft as large as the 747 to be conceived was the high-bypass turbofan engine. The engine technology was thought to be capable of delivering double the power of the earlier turbojets while consuming a third less fuel. General Electric had pioneered the concept but was committed to developing the engine for the C-5 Galaxy and did not enter the commercial market until later. Pratt & Whitney was also working on the same principle and, by late 1966, Boeing, Pan Am and Pratt & Whitney agreed to develop a new engine, designated the JT9D to power the 747.
The project was designed with a new methodology called fault tree analysis, which allowed the effects of a failure of a single part to be studied to determine its impact on other systems. To address concerns about safety and flyability, the 747's design included structural redundancy, redundant hydraulic systems, quadruple main landing gear and dual control surfacesAdditionally, some of the most advanced high-lift devices used in the industry were included in the new design, in order to allow it to operate from existing airports. These included leading edge flaps running almost the entire length of the wing, as well as complex three-part slotted flaps along the rear. The wing's complex three-part flaps increase wing area by 21 percent and lift by 90 percent when fully deployed compared to their non-deployed configuration.
Boeing agreed to deliver the first 747 to Pan Am by the end of 1969. The delivery date left 28 months to design the aircraft, which was two-thirds of the normal time. The schedule was so fast paced that the people who worked on it were given the nickname "The Incredibles". Developing the aircraft was such a technical and financial challenge that management was said to have "bet the company" when it started the project
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