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Boeing 707-320 WORK

Although it was not the first commercial jetliner in service, the 707 was the first to be widespread and is often credited with beginning the Jet Age.[5]It dominated passenger air transport in the 1960s, and remained common through the 1970s, on domestic, transcontinental, and transatlantic flights, as well as cargo and military applications.It established Boeing as a dominant airliner manufacturer with its 7x7 series.The initial, 145-foot-long (44 m) 707-120 was powered by Pratt & Whitney JT3C turbojet engines.The shortened long-range 707-138 and the more powerful 707-220 entered service in 1959.The longer range, heavier 707-300/400 series have a larger wing and are stretched slightly by 8 feet (2.4 m).Powered by Pratt & Whitney JT4A turbojets, the 707-320 entered service in 1959, and the 707-420 with Rolls-Royce Conway turbofans in 1960.

Boeing 707-320


The 720, a lighter short-range variant, was also introduced in 1960.Powered by Pratt & Whitney JT3D turbofans, the 707-120B debuted in 1961 and the 707-320B in 1962.The 707-120B typically flew 137 passengers in two classes over 3,600 nmi (6,700 km), and could accommodate 174 in one class.With 141 passengers in two classes, the 707-320/420 could fly 3,750 nmi (6,940 km) and the 707-320B up to 5,000 nmi (9,300 km).The 707-320C convertible passenger-freighter model entered service in 1963, and passenger 707s have been converted to freighter configurations.Military derivatives include the E-3 Sentry airborne reconnaissance aircraft and the C-137 Stratoliner VIP transport.A total of 865 Boeing 707s were produced and delivered, not including 154 Boeing 720s.

The initial standard model was the 707-120 with JT3C turbojet engines. Qantas ordered a shorter-bodied version called the 707-138, which was a -120 with six fuselage frames removed, three in front of the wings, and three aft. The frames in the 707 were set 20 in (510 mm) apart, so this resulted in a shortening of 10 ft (3.0 m) to a length of 134 ft 6 in (41.0 m). With the maximum takeoff weight the same as that of the -120 (247,000 lb (112 t)), the -138 was able to fly the longer routes that Qantas needed.[17] Braniff International Airways ordered the higher-thrust version with Pratt & Whitney JT4A engines, the 707-220. The final major derivative was the 707-320, which featured an extended-span wing and JT4A engines, while the 707-420 was the same as the -320, but with Conway turbofan engines.

Though initially fitted with turbojet engines, the dominant engine for the Boeing 707 family was the Pratt & Whitney JT3D, a turbofan variant of the JT3C with lower fuel consumption and higher thrust. JT3D-engined 707s and 720s were denoted with a "B" suffix. While many 707-120Bs and -720Bs were conversions of existing JT3C-powered machines, 707-320Bs were available only as newly built aircraft, as they had a stronger structure to support a maximum takeoff weight increased by 19,000 lb (8,600 kg), along with modifications to the wing. The 707-320B series enabled nonstop westbound flights from Europe to the West Coast of the United States and from the US to Japan.

The final 707 variant was the 707-320C, (C for "Convertible"), which had a large fuselage door for cargo. It had a revised wing with three-sectioned leading-edge flaps, improving takeoff and landing performance and allowing the ventral fin to be removed (although the taller fin was retained). The 707-320Bs built after 1963 used the same wing as the -320C and were known as 707-320B Advanced aircraft.

The only rival in intercontinental jet aircraft production at the time was the British de Havilland Comet. However, this was never real competition for the American market as the Comet series had been the subject of fatal accidents (due to design flaws) early in its introduction, withdrawn from service, virtually redesigned from scratch, and reintroduced as version -4. It was also smaller and slower than the 707. Several major airlines committed only to the (second place in the production race) Douglas DC-8. Airlines and their passengers at the time preferred the more established Douglas Aircraft maker of passenger aircraft. Douglas had decided to wait for a larger and more fuel efficient engine (Pratt & Whitney JT4A) and to design a larger and longer range aircraft around this engine. To stay competitive, Boeing made a late and costly decision to redesign and enlarge the 707's wing to help increase range and payload. The new version was the 707-320.[27]

Trans World Airlines flew the last scheduled 707 flight for passengers by a US carrier on October 30, 1983,[34] although 707s remained in scheduled service by airlines from other nations for much longer. Middle East Airlines of Lebanon flew 707s and 720s in front-line passenger service until the end of the 1990s. Since LADE of Argentina removed its 707-320Bs from regular service in 2007, Saha Airlines of Iran was the last commercial operator of the Boeing 707.[3][35] After suspending its scheduled passenger service in April 2013,[2] Saha continued to operate a small fleet of 707s on behalf of the Iranian Air Force.[3][36]

The 707-320 Intercontinental is a stretched version of the turbojet-powered 707-120, initially powered by JT4A-3 or JT4A-5 turbojets producing 15,800 lbf (70.3 kN) each (most eventually got 17,500 lbf (77.8 kN) JT4A-11s). The interior allowed up to 189 passengers, the same as the -120 and -220 series, but improved two-class capacity due to an 80-in fuselage stretch ahead of the wing (from 138 ft 10 in (42.32 m) to 145 ft 6 in (44.35 m) ), with extensions to the fin and horizontal stabilizer extending the aircraft's length further.[41] The longer wing carried more fuel, increasing range by 1,600 miles (2,600 km) and allowing the aircraft to operate as true transoceanic aircraft. The wing modifications included outboard and inboard inserts, as well as a kink in the trailing edge to add area inboard.[17] Takeoff weight was increased to 302,000 lb (137,000 kg) initially and to 312,000 lb (142,000 kg) with the higher-rated JT4As and center section tanks. Its first flight was on January 11, 1958; 69 turbojet 707-320s were delivered through January 1963, the first passengers being carried (by Pan Am) in August 1959.

The 707-320B had the application of the JT3D turbofan to the Intercontinental, but with aerodynamic refinements. The wing was modified from the -320 by adding a second inboard kink, a dog-toothed leading edge, and curved low-drag wingtips instead of the earlier blunt ones.[17] These wingtips increased overall wingspan by 3.0 ft. Takeoff gross weight was increased to 328,000 lb (149,000 kg). The 175 707-320B aircraft were all new-build; no original -320 models were converted to fan engines in civilian use. First service was June 1962, with Pan Am.

The 707-320B Advanced is an improved version of the -320B, adding the three-section leading-edge flaps already seen on the -320C. These reduced takeoff and landing speeds and altered the lift distribution of the wing, allowing the ventral fin found on earlier 707s to be deleted. From 1965, -320Bs had the uprated -320C undercarriage allowing the same 335,000 lb (152,000 kg) MTOW. These were often identified as 707-320BA-H.

The 707-700 was a test aircraft used to study the feasibility of using CFM International CFM56 engines on a 707 airframe and possibly retrofitting existing aircraft with the engine. After testing in 1979, N707QT, the last commercial 707 airframe, was restored to 707-320C configuration and delivered to the Moroccan Air Force as a tanker aircraft via a "civilian" order. Boeing abandoned the retrofit program, since it felt it would be a threat to the Boeing 757 and Boeing 767 programs.[44] The information gathered from testing led to the eventual retrofitting of CFM56 engines to the USAF C-135/KC-135R models, and some military versions of the 707 also used the CFM56. The Douglas DC-8 "Super 70" series with CFM56 engines was developed and extended the DC-8's life in a stricter noise regulatory environment. As a result, significantly more DC-8s remained in service into the 21st century than 707s.[citation needed]

The 707-620 was a proposed domestic range-stretched variant of the 707-320B. The 707-620 was to carry around 200 passengers while retaining several aspects of the 707-320B. It would have been delivered around 1968 and would have also been Boeing's answer to the stretched Douglas DC-8 Series 60. Had the 707-620 been built, it would have cost around US$8,000,000.[45] However, engineers discovered that a longer fuselage and wing meant a painstaking redesign of the wing and landing-gear structures. Rather than spend money on upgrading the 707, engineer Joe Sutter stated the company "decided spending money on the 707 wasn't worth it". The project was cancelled in 1966 in favor of the newer Boeing 747.[46]

The 707-820 was a proposed intercontinental stretched variant of the 707-320B. This 412,000-pound MTOW (187,000 kg) variant was to be powered by four 22,500-pound-force thrust (100 kN) Pratt & Whitney JT3D-15 turbofan engines, and it would have had a nearly 10-foot (3.0 m) extension in wingspan, to 155.5 feet (47.4 m). Two variations were proposed, the 707-820(505) model and the 707-820(506) model. The 505 model would have had a fuselage 45 feet (14 m) longer than the 707-320B, for a total length of 198.6 feet (60.5 m). This model would have carried 209 passengers in mixed-class configuration and 260 passengers in all-economy configuration. The 506 model would have had a fuselage 55 feet (17 m) longer than the 707-320B, to 208.6 feet (63.6 m) in length. This second model would have carried 225 passengers in mixed-class configuration and 279 passengers in all-economy configuration. Like the 707-620, the 707-820 was also set to compete with the stretched DC-8-60 Super Series models. The design was being pitched to American, TWA, BOAC, and Pan Am at the time of its proposal in early 1965.[47] The 707-820 would have cost US$10,000,000.[45] Like the 707-620, the 707-820 would have required a massive structural redesign to the wing and gear structures. The 707-820 was also cancelled in 1966 in favor of the 747.[46] 041b061a72


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