Boeing 747

Development

Background

In 1963, the United States Air Force (USAF) began a series of study projects on an extremely 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 (81.6 t) and a speed of Mach 0.75 (430 kn; 800 km/h), and an unrefueled range of 5,000 nautical miles (9,300 km; 5,800 mi) with a payload of 115,000 pounds (52.2 t). 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 several 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 carried the nose door and raised cockpit concepts over to the design of the 747.

Proposal

The 747 was conceived while air travel was increasing in the 1960s. The era of commercial jet transportation, led by the enormous popularity of the Boeing 707 and Douglas DC-8, had revolutionized long-distance travel. In this growing jet age, Juan Trippe, president of Pan American Airways (Pan Am), one of Boeing's most important airline customers, asked for a new jet airliner 2+1⁄2 times size of the 707, with a 30% lower cost per unit of passenger-distance and the capability to offer mass air travel on international routes. Trippe also thought that airport congestion could be addressed by a larger aircraft.

In 1965, Joe Sutter was transferred from Boeing's 737 development team to manage the design studies for the new airliner, already assigned the model number 747. Sutter began a study with Pan Am and other airlines to better understand their requirements. At the time, many thought that long-range subsonic airliners would eventually be superseded by supersonic transport aircraft. Boeing responded by designing the 747 so it could be easily adapted to carry freight and remain in production even if sales of the passenger version declined.

In April 1966, Pan Am ordered 25 Boeing 747-100 aircraft for US$525 million (equivalent to $3.9 billion in 2024 dollars). During the ceremonial 747 contract-signing banquet in Seattle on Boeing's 50th Anniversary, Juan Trippe predicted that the 747 would be "…a great weapon for peace, competing with intercontinental missiles for mankind's destiny". As launch customer, and because of its early involvement before placing a formal order, Pan Am was able to influence the design and development of the 747 to an extent unmatched by a single airline before or since. Once additional orders for the aircraft were filed by Japan Airlines and Lufthansa, approval for production of the 747 was given in July 1966.

Initial design

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 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 feature produced the 747's distinctive "hump". In early models, what to do with the small space in the pod behind the cockpit was not clear, and it was initially specified as a "lounge" area with no permanent seating. (A different configuration that had been considered to keep the flight deck out of the way for freight loading had the pilots below the passengers, and was dubbed the "anteater".)

One of the principal technologies that enabled an aircraft as large as the 747 was the high-bypass turbofan engine.