Boeing 707

The Boeing 707 is a four engined commercial passenger jet aircraft developed by Boeing in the early 1950s. Although it was not the first commercial jet airliner in service (that distinction belongs to the De Havilland Comet), it was the first to be commercially successful, and is credited by many as ushering in the "Jet Age", as well as being the first of Boeing's 7x7 range of airliners.

Subtypes

The original 707, the 707-120 was designed for transcontinental routes and often required a refuelling stop when used on the North Atlantic route. It was originally fitted with four Pratt and Whitney JT3C turbojets, civilian versions of the military J57 model. The later -120B version used JT3D turbofans, which were quieter, more powerful, and more fuel efficient.

Related Topics:
Pratt and Whitney - JT3C - Turbojet - JT3D - Turbofan

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The 707-220 (also designated 707-227) was a 707-120 airframe fitted with more powerful JT4A turbojets, for hot and high operations on Braniff International's South American routes. Only 5 of these were built, due to extremely high fuel consumption. This marque was anyway rendered redundant by the arrival of the turbofan.

Related Topics:
JT4A - Hot and high - Braniff International

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The later 707-320 and 707-420 models had larger wings, heavier weight and more fuel capacity to operate as true transoceanic aircraft. The original -320 version came equipped with JT4A turbojets, while the -320B version came with JT3D turbofans. The -320C, also turbofan-engined, had a large cargo door allowing it to serve as a dual-purpose transport aircraft. The -420 version, produced originally for BOAC, was powered by Rolls-Royce Conway engines.

Related Topics:
BOAC - Rolls-Royce Conway

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The 707-700 was a one off test aircraft used to study the feasibility of using CFM International CFM56 powerplants on a 707 airframe and possibly retrofitting them to existing aircraft. After a testing in 1979 N707QT, the last commercial 707 airframe, was refitted to 707-320C configuration and delivered to the Moroccan Air Force as a tanker aircraft. (This purchase was considered a "civilian" order and not a military one.) Boeing abandoned the program, since they felt it would be a threat to the Boeing 757 programme. The information gathered in the test led to the eventual retrofitting programme of CFM-56 engines to the USAF C-135/KC-135R models. Ironically the Douglas DC-8 "Super 70" series by Cammacorp did develop commercially, extending the life of DC-8 airframes in a stricter noise regulatory environment so there are today more DC-8s in commercial service than 707s.

Related Topics:
CFM International CFM56 - 1979 - Boeing 757 - Douglas DC-8

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The Boeing 720, originally designated 707-020 but later changed for marketing reasons, was a modification of the 707-120 designed for medium-range operation from shorter runways. It was lighter and faster than the Boeing 707, and had a simplified wing design. This model had relatively few sales, but was still profitable due to the minimal R&D costs associated with modifying an existing type. At one point in the promotion stage to airlines it was known as the 717. It was used before the Boeing 727 replaced it in the market.

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