page_title: Boeing 747
section_title: Background
hierarchical_section_title: Boeing 747 / Development / Background
caption_attribution_description: AirBridgeCargo Airlines Boeing 747-200F nose loading door open and cargo loader at Sheremetyevo International Airport
context_page_description: The Boeing 747 is a large, long–range wide-body airliner and cargo aircraft manufactured by Boeing Commercial Airplanes in the United States.
  After introducing the 707 in October 1958, Pan Am wanted a jet 2½ times its size, to reduce its seat cost by 30% to democratize air travel. In 1965, Joe Sutter left the 737 development program to design the 747, the first twin aisle airliner. In April 1966, Pan Am ordered 25 747-100 aircraft and in late 1966, Pratt & Whitney agreed to develop its JT9D, a high-bypass turbofan.
  On September 30, 1968, the first 747 was rolled out of the custom-built Everett Plant, the largest building in the world by volume.
  The first flight took place on February 9, 1969 and the 747 was certified in December of that year. It entered service with Pan Am on January 22, 1970; it was the first airplane dubbed a "Jumbo Jet".
  The 747 is a quadjet airliner, initially powered by JT9D turbofan engines, then GE CF6 and Rolls-Royce RB211 engines for the original variants. With a ten-abreast economy seating, it typically accommodates 366 passengers in three travel classes.
context_section_description: 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, officials believed that a much larger and more capable aircraft was needed, especially to carry 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 or 800 km/h), and an unrefueled range of 5,000 nautical miles (9,300 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 m) long with access through doors at the front and rear.
  The desire to keep the number of engines to four required new engine designs with greatly increased power and better fuel economy. In May 1964, airframe proposals arrived from Boeing, Douglas, General Dynamics, Lockheed, and Martin Marietta; engine proposals were submitted by General Electric, Curtiss-Wright, and Pratt & Whitney. Boeing, Douglas, and Lockheed were given additional study contracts for the airframe, along with General Electric and Pratt & Whitney for the engines.
  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 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. Boeing would carry the nose door and raised cockpit concepts over to the design of the 747.
caption: Cargo nose door open with cargo loader
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