Boeing 747

The Boeing 747 is a wide-body commercial airliner and cargo transport aircraft, often referred to by its original nickname, Jumbo Jet, or Queen of the Skies. It is among the world's most recognizable aircraft,[4] and was the first wide-body 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,[5] 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.[6] 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.[7] The 747 in particular was expected to become obsolete after 400 were sold,[8] but it exceeded its critics' expectations with production passing the 1,000 mark in 1993.[9] By September 2012, 1,448 aircraft had been built, with 81 of the 747-8 variants remaining on order.[2] The 747-400, the most common passenger version in service, is among the fastest airliners in service with a high-subsonic cruise speed of Mach 0.850.855 (up to 570 mph, 920 km/h). It has an intercontinental range of 7,260 nautical miles (8,350 mi or 13,450 km).[10] The 747-400 passenger version can accommodate 416 passengers in a typical three-class layout, 524 passengers in a typical two-class layout, or 660 passengers in a high density one-class configuration.[11] The newest version of the aircraft, the 747-8, is in production and received certification in 2011. Deliveries of the 747-8F freighter version to launch customer Cargolux began in October 2011; deliveries of the 747-8I passenger version to Lufthansa began in May 2012.

The 747 is to be replaced by the Boeing Y3 (part of the Boeing Yellowstone Project) in the future. 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.[12] 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.[12] 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.[13] 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.[12] The nose door and raised cockpit concepts would be carried over to the design of the 747.