Douglas DC-8
The Douglas DC-8 is a four-engine jet airliner Douglas Aircraft Company. It is a low-wing monoplane with a conventional tail unit.
Between 1959 and 1972 a total of 556 aircraft were delivered. The DC-8 was the first passenger jet reached supersonic speed. On August 21, 1961 DC-8- 43 by breaking the sound barrier in descent (Mach 1.0124 ). This occurred during a test flight, proving that the DC-8 this is aerodynamically capable.
- 5.1 Current operators
- 5.2 Military operators
Use
The DC -8 was mainly used by airlines as a passenger aircraft. From the 1960s there was a growing use as cargo or as cargo / passenger combi machine. A total of 48 airlines in 28 countries were supplied with these machines. A testament to the strength of the series is that some of the machines completed more than 100,000 flight hours.
In addition to civilian use, the DC-8 was also used by the armed forces of France, Gabon, Spain and Togo - mainly as a "VIP" - or transport aircraft. The U.S. Navy has a machine as a representation of enemy aircraft. NASA uses a DC-8- 72 and flying laboratory (DC -8 Airborne Laboratory) for the inspection of space sensors, atmospheric research and other scientific missions, such as the exploration of the polar ice, a since 1985.
Technical design
The fuselage of the DC-8 is carried out in all-metal construction and pressure- ventilated and is designed as a double circular cross section. The cantilevered wings have two bars. On the wings upper side there are spoilers. To increase lift mounted double slotted flaps.
The wings are defrosted with hot bleed air. The tail is also made of all-metal construction and self-supporting. The landing gear is retractable and consists of a twin-wheel, steerable nose wheel and main landing gear with two legs and four wheels. The main landing gear is braked by means of disc brakes. For landing is also a thrust reverser available.
Originally built in the DC-8 turbojet engines of the type JT3C, later versions were given the turbofan engine JT3D or the General Electric / SNECMA CFM56. Furthermore, the machine could be equipped with the JT8.
Background
The development of the DC-8 began in 1952 with preliminary studies for an aircraft which, in addition to the passenger transport, the emerging demand of the U.S. Air Force after a tanker for in-flight refueling of their jet-propelled strategic bomber fleet could satisfy. In the summer of 1953 the basic key data of the machine were defined. However, the U.S. Air Force chose the Boeing KC- 135th
Civilian airlines still showed no great interest for a jet passenger plane because of negative experiences with DeHavilland Comet aircraft and the fledgling stocks not yet written off four -engined piston-engine propeller aircraft. Therefore, Douglas went with the airlines on the offensive and held intensive discussions on the concrete wishes for a jet aircraft. In particular, this was because Douglas was startled by the announced development of the Boeing 707. In order to offer six seats in a row, the trunk diameter was slightly increased, which in turn required changes to the wing and on the tail. Ultimately, Douglas had already taken first in the early stages of development. The machine was delivered relatively late, had teething problems in terms of reach and consumption and has been developed in rapid succession in eight versions to satisfy all desires. The DC-8 was a success for Douglas, but not in economic terms.
Development
The DC-8 was officially announced on June 7, 1955, the decision to build was on July 5, 1955., The design called for a 45.90 -meter long aircraft with a wingspan of 43 m. Depending on the drives and the fuel capacity of the starting weight should be 120-139 tons. It initially offered four variants. The breakthrough for the DC-8 was when Pan American with 20 Boeing 707s and 25 Douglas DC-8 ordered at the same time. Then also ordered United, National, KLM, Eastern, JAL, SAS, Delta Air Lines, Swissair, Alitalia, TAI, Trans-Canada Air Lines and UAT copies of the aircraft. As the first charter airline Trans International Airlines ordered two machines in 1960.
For the production of the machine a new assembly plant was built in Long Beach. The first series aircraft left in April 1958 and started production in Long Beach in front of 60,000 spectators and staff on May 30, 1958 its first flight.
To quickly gain admission, ten machines were used for test flights. There were during the test flights still some changes. The measures provided for air brakes proved to be inadequate and have been omitted with the introduction of the thrust reverser. Thus, the DC-8 is one of the few aircraft where the thrust reversers can also be activated in flight. To improve the slow flight characteristics, slats were mounted. However, the machine proved to be in cruise slower than calculated. Therefore, the wing tips had again be changed in order to reduce air resistance. The approval was granted on 31 August 1959.
On September 18, 1959 finally the first machines for United and Delta went into service.
Early series
- The DC-8 series 10 was with the 60.50 kN thrust Pratt & Whitney delivered JT3C -6 engines delivered. These machines were designed primarily for domestic U.S. flights. The first series of DC-8- 11 also had the wing tips with the high air resistance. These machines were gradually converted to DC-8 -12, which possessed in addition to the modified wing tips and leading edge slats and increased to 123 tons of takeoff weight (MTOW ). Of this series 28 machines were produced.
- The DC-8 series 20 was with the 70.80 kN thrust Pratt & Whitney delivered JT4A -3 engines delivered. The take-off weight increased to 125 tons. 34 machines were produced. The first flight of this series took place on 29 November 1958.
- The DC-8 series 30 was with the 72.50 kN thrust Pratt & Whitney delivered JT4A -9 engines delivered. In addition, however, the fuel capacity was increased by about 33 percent to serve transcontinental routes can. The first flight took place on 21 February 1959. Purpose, the fuselage and landing gear had to be reinforced. The first machines of this series, the DC-8 -31, their approval received on February 1, 1960, with a starting weight of 136 tons. The DC 8-32 was similar, but had a takeoff weight of 140 tons. The type DC 8-33 possessed 78.40 kN supplied JT4A -11 engines, a change in the flaps, which allowed a lower fuel consumption at cruising altitude. The flaps could be moved to a cruising position of 1.5 °. The chassis has been further strengthened, so that now a takeoff weight of 143 tons was possible. Later, many machines of the type were -31 and -32 to -33 rebuilt.
- The DC-8 Series 40 was the first passenger airliner ever equipped with turbofan engines, which were considerably quieter and more economical compared to the previous turbojets. The smoke was much lower. For use Rolls -Royce Conway engines came with 78.40 kN thrust. The first flight took place on 23 July 1959 the admission on 24 March 1960. The DC 8-41 had a takeoff weight of 136 tons, the DC-8- 42 of a 140 tons. The DC 8-43 had the same damper change such as the DC-8- 33rd In addition, the wing was changed to make it even a little more fuel capacity and, above all, meant a drag reduction, the range increased by eight percent, and travel speed to 10 knots increased. The starting weight was 143 tons. These changes were also incorporated in all other DC-8 types. From the series 40 32 machines were built.
- The DC-8 Series 50 also had turbofan engines, there were Pratt & Whitney JT3D -1 with 76.10 kN thrust or JT3D -3B used with 80.60 kN thrust. The series DC-8- 51, DC-8 -52 and DC - 8-53 differed in their starting weights of 126, 138 respectively 142 tons. Late versions of the DC 8-53 exhibited the stronger cells and chassis freight versions and had a takeoff weight of 147 tons. The first flight took place on 20 December 1960. 88 machines were built of this series.
- DC-8 Jet Trader series were freighter versions of the DC-8- 50th They had a front cargo area with a large cargo door, a reinforced cabin floor and behind cabin for first 54 passengers. This arrangement has been a short time later replaced by a movable device for separating the cargo compartment, which allowed to carry 25 to 114 passengers. The first flight took place on 29 October 1962, its approval on 29 January 1963. The first aircraft was delivered on 26 April 1963, the Trans International Airlines. There was also a version without cabin windows, but only 15 of the machines were sold to United Airlines. The DC -8F -54 had a takeoff weight of 143 tons, while the DC -8F -55 had a takeoff weight of 147 tons. Both types have been driven by JT3D -3B engines with 80.60 kN thrust. A DC-8- 54F was rebuilt by the U.S. Navy to simulate as EC -24 for training purposes enemy communications and radar systems.
After the excellent start of the series sales were running soon slow. Reason was the manufacturer Douglas business decision, despite the large number of options initially offer any shortened or extended cab, because the development department busy entirely with the development of the Douglas DC-9. In 1964, only 14 machines and these were in turn sold a large part of the cargo planes. Boeing with the 707 showed up in the cabin length adaptable and always achieved higher market shares.
After completion of the development of the DC-9 and its first flight on February 25, 1965 Douglas finally responded in April 1965 and gave the cab extension for DC-8 with three new models announced. Until the appearance of the Boeing 747 in 1970 called Super Sixties were over 250 seats, the largest aircraft of its time.
Super Sixties
This series was until the introduction of wide-body aircraft as the largest passenger aircraft in the world.
- The DC-8 Series 61 was based on the -53 with the same takeoff weight. According smaller the range compared to the -53. To increase the capacity, the front cabin has been extended by 6 m, and the rear to 5 m, giving a total length of 57 m. The cabin had to be correspondingly strengthened because of the greater loads. The chassis on the other hand did not need to be extended. These machines typically framed 210 passengers - in a condensed and seating 269 passengers could be carried. The first flight took place on March 14, 1966 the approval on September 2, 1966. It 88 machines of this type were sold.
- The DC-8 Series 62 corresponded to the -53 and was designed for the long haul. Compared to the -53, the cabin was only front and rear extended by 1.02 m. The wingtips were extended by one meter, so as to increase the fuel capacity and to reduce the aerodynamic drag to extend the range. At the same time the engine mounts and fairings were changed. The machine received over the -61 a slightly larger takeoff weight of 151 tons and had thus a range of 9630 km with a full load. The first flight took place on August 29, 1966, the approval in April 1967. From this type were built 67 machines.
- The DC-8 Series 63 was a mixture of the long cabin of -61 with the improvements of -62. The drive served JT3D -7 engines with a thrust of 85 kN. The maximum take-off weight was 159 tons, the range with maximum payload 7600 km. The first flight took place on April 10, 1967 the approval on June 30, 1967. From this type 107 aircraft were built, about half of them freighters or with the ability to convert it to the freighter.
The last machine of this type left on May 13, 1972, the assembly hall. Immediately after the production were used for the production of the McDonnell Douglas DC-10.
Super Seventies
By the early 1970s, discussions began about the increasing air traffic, particularly over the growing noise level of airport residents. The DC-8- types of the series 61 to 63 were the loudest of all jet aircraft. With the noisy DC -8 equipment they had some airports no longer allowed to fly: Over time, the noise emissions for the airlines became a problem.
Therefore, it was requested at McDonnell Douglas in the early 1970s by some airlines, if not let install quieter engines on the DC-8 machines. First, firms crowded with solutions to reduce noise emissions, so-called hush kits on the market, but did not meet all expectations. Finally, CFM International brought with the CFM56 engine, a variant into play that could shut themselves neither McDonnell Douglas nor Boeing. The development began in the late 1970s and led to the Super Seventies. Of the Super Seventies no machine has been re- produced, rather they are rebuilding their predecessors. The Super Seventies the use of reverse thrust before landing is not allowed.
The DC-8- 72 and DC - 8-73 were the DC-8 -62 and DC - 8-63 converted to the new engines without external changes. These were 98.50 kN thrust delivered CFM56- 2C5 turbofan engines with high bypass ratio. Alternatively, could also be a Pratt & Whitney PW JT8D -209 are used. The engine cowling was redesigned by Grumman. The conversion led the company Cammacorp in Los Angeles. In addition to the revised engines and auxiliary power unit (APU ) for autonomous power supply and an environmental management system were available.
The DC 8-71 originated from the DC-8- 61, but experienced major modifications, as well as the wing and the engine mounting had to be changed. Due to the higher weight of the new engines the payload capacity decreased slightly, but the maximum takeoff weight remained unchanged. The first flight of such a converted machine came on 15 August 1981. Approval was granted in 1982. Overall, by the end of 1986 110 machines of the DC-8- 60 Series modified accordingly.
The conversion reduced the noise emission by 70 percent and resulted in a 20 percent lower fuel consumption of the engines, so that the reach of the machine increased considerably.
Operator
Current operators
In June 2004, another 150 copies of the DC -8 were used mainly as cargo planes. As of March 2014, there are still world's six aircraft, four of which machines are 50's and 60 series with the original engines.
Only off two VIP aircraft of Brisair, 4 cargo planes from Ghana by Airlift International and Meridian Airways, as well as individual machines are operated by Peruvian Airlines for Heavy Lift Cargo Airlines, Skybus cargo jet and Bravo Cargo Services operated for Stabo Air
Military operators
In the past, the DC-8 continued the following countries for military use: France, Spain, Peru, the Philippines, Thailand and the USA.