Monday, 20 June 2022


 BOEING 747 

The Boeing 747 is a large, long-range wide-body airliner designed and manufactured in the United States by Boeing Commercial Airplanes. Pan Am wanted a jet twice the size of the 707 after introducing it in October 1958 in order to reduce seat costs by 30% and democratise air travel. Joe Sutter left the 737 development programme in 1965 to design the 747, the world's first twin-aisle airliner. Pan Am ordered 25 Boeing 747-100 aircraft in April 1966, and Pratt & Whitney agreed in late 1966 to develop its JT9D engine, a high-bypass turbofan. The first 747 rolled out of the Everett Plant, the world's largest building by volume, on September 30, 1968.

The 747 made its first flight on February 9, 1969, and was certified in December of that year. On January 22, 1970, it began service with Pan Am. The 747 was the first wide-body airliner and was dubbed the "Jumbo Jet."

The 747 is a four-engined jet aircraft that was originally powered by Pratt & Whitney JT9D turbofan engines, then General Electric CF6 and Rolls-Royce RB211 engines. It typically seats 366 passengers in three travel classes, with ten-abreast economy seating. It has a pronounced 37.5° wing sweep, which allows for a cruise speed of Mach 0.85 (490 kn; 900 km/h), and its heavy weight is supported by four main landing gear legs, each with a four-wheel bogie. The partially double-deck aircraft was designed with a raised cockpit so that it could be converted to a freighter plane by installing a front cargo door, as it was initially thought that supersonic transports would eventually replace it. Cargo airlines continue to favour 747 freighter variants.

Boeing introduced the -200 in 1971, with more powerful engines for a heavier maximum takeoff weight (MTOW) of 833,000 pounds (378 t), up from 735,000 pounds (333 t), and a longer 6,560-nautical-mile (12,150 km) range up from 4,620 nautical miles (8,560 km). In 1976, it was shortened for the longer-range 747SP, and the 747-300, with a stretched upper deck for up to 400 seats in three classes, followed in 1983. The 747-400, which has improved RB211 and CF6 engines or the new PW4000 engine (the JT9D successor) and a two-crew glass cockpit, was introduced in 1989 and is the most common variant. The stretched 747-8 was launched on November 14, 2005, with new General Electric GEnx engines, and the first deliveries were made in October 2011. The 747 serves as the foundation for several government and military variants, including the VC-25 (Air Force One), E-4 Emergency Airborne Command Post, Shuttle Carrier Aircraft, and experimental testbeds like the YAL-1 and SOFIA airborne observatories.

1,570 aircraft had been delivered by May 2022, with three 747-8Fs still on order. After a 54-year production run, the 747 will be phased out in 2022. The smaller trijet widebodies, such as the Lockheed L-1011 (introduced in 1972), McDonnell Douglas DC-10 (1971), and later MD-11, provided early competition (1990). Airbus competed with later variants with the heaviest versions of the A340 until the A380, delivered between 2007 and 2021, surpassed the 747 in size. As of 2020, 61 Boeing 747s had been destroyed in accidents, killing a total of 3,722 people.





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