Boeing 707

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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.

History

The 707 was based on a prototype Boeing aircraft known as the Boeing 367-80. The "Dash 80," as it was called within Boeing, cost $16 million to develop and took less than two years from project launch in 1952 to rollout on May 14, 1954. The prototype was the basis for both the KC-135, an air tanker used by the United States Air Force, and the 707. To enable the fitting of six-abreast seats, the 707's fuselage was widened by 6 inches (150 mm) compared to the original 367-80.

On August 6th, 1955, Boeing test pilot Tex Johnston performed a "Barrel roll" in the Dash-80 at 500 feet (he gained altitude to 1500 feet during the roll) not once, but twice (this story appears on a video called 'Frontiers of Flight - The Jet Airliner', produced by the National Air and Space Museum in association with the Smithsonian Institution in 1992). To date Tex is the only pilot to have performed this in a four engine jet transport (of course, other big four engine jet aircraft have done barrel rolls. The Vulcan XA890 was rolled by Roly Falk on the first day of the '55 Farnborough Airshow, but it was a subsonic bomber).

Pan Am was the first airline to operate the 707; the aircraft's first commercial flight was from New York to Paris on October 26, 1958. American Airlines operated the first transcontinental 707 flight on January 25, 1959. Many other airlines followed, and the 707 quickly became the most popular jetliner of its time, edging out its main competitor, the Douglas DC-8.

As the 1960s drew to a close, the exponential growth in air travel led to the 707 being a victim of its own success. It had become obvious that the 707 was now too small to handle the passenger densities on the routes for which it was designed. Stretching the fuselage was not a viable option because the 707's limited ground clearance made the installation of a larger undercarriage almost impossible. Boeing's answer to the problem was the first twin aisle airliner - the 747. The 707's first-generation engine technology was also rapidly becoming obsolete in the areas of noise and fuel economy.

Production of the passenger 707 ended in 1978 (the 767 acted as its partial replacement). In total, 1,010 707s were built for civil use. The military versions remained in production until 1991.

Traces of the 707 are still in many of Boeing's current products, most notably the 737, which uses a modified version of the 707's fuselage. In fact, if the 707 were still in production it would have probably evolved into what is now the 737-900, which is arguably a modernized 707 with two Turbofan high bypass ratio engines replacing the original four Turbojet engines. Interestingly the Chinese government sponsored development of the Shanghai Y-10 during the 1970s, which was a near carbon-copy of the 707.

Subtypes

File:Caf.b707.640pix.jpg
Canadian Armed Forces Boeing 707 (CC-137)

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.

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.

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.

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.

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.

Operators

File:Usaf.kc135.750pix.jpg
A KC-135 Stratotanker refuels a F/A-22 Raptor

Although 707s are no longer employed by major US airlines, many can still be found in service with smaller non-US airlines, charter services and air cargo operations.

The first two aircraft built to serve as Air Force One were custom-built Boeing 707s, with designation VC-137; these were also used by high-ranking federal officials on official trips. Many other countries use the 707 as a VIP transport, including Argentina, Brazil, Chile, the Republic of Congo, Egypt, Indonesia, Israel, Italy, Jordan, Libya, Morocco, Pakistan, Saudi Arabia, Sudan, and Venezuela. The Royal Australian Air Force (RAAF) operated a number of 707's that were specially modified for VIP use before replacing them with modified 737's.

The U.S. and other NATO-aligned countries, as well as South Africa and Israel, have used the 707 platform for aerial refueling (KC-135) and AWACS (E-3 Sentry), although many of these aircraft are now being phased out. The Royal Australian Air force (RAAF) operates 707's as refuellers for Australia's FA/18 Hornets; these are soon to be replaced by Airbus A330 MRTT's. The 707 is also the platform for the United States Air Force's Joint STARS project, and the United States Navy's E-6 Mercury.

American actor John Travolta owns, and is qualified to fly, an ex-Qantas 707-138, registration N707JT.

See also: List of Boeing 707 operators

Specifications

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General characteristics

707-120B 707-320B
Passengers
(2 class)
110 147
Passengers
(1 class)
179 189
Max. takeoff weight 257,000 lb (116,570 kg) 333,600 lb (151,320 kg)
Empty weight 122,533 lb (55,580 kg) 146,400 lb (66,406 kg)
Operating range (Max Payload) 3,680 nautical miles (6,820 km) 3,735 nautical miles (6,920 km)
Crusing speed 540 kt (1000 km/h) 525 kt (972 km/h)
Length 144 ft 6 in (44.07 m) 152 ft 11 in (46.61 m)
Wingspan 130 ft 10 in (39.90 m) 145 ft 9 in (44.42 m)
Tail height 42 ft 5 in (12.93 m)
Powerplants Four 75.6 kN (17,000 lbf) Pratt & Whitney JT3D-1 turbofans. Four 80 kN (18,000 lbf) JT3D-3s or four 84.4 kN (19,000 lbf) JT3D-7s.

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