Douglas DC-8

"DC-8" redirects here. For the earlier, never-built piston-engined airplane, see Douglas DC-8 (piston airliner).
DC-8
An Air Jamaica DC-8-62H approaching London Heathrow Airport in 1978
Role Narrow-body jet airliner
National origin United States
Manufacturer Douglas Aircraft
McDonnell Douglas
First flight May 30, 1958
Introduction September 18, 1959 with United Airlines and Delta Air Lines
Status In limited cargo and transport service
Primary users United Airlines (historical)
UPS Airlines (historical)
Meridian Airways
Produced 1958–1972
Number built 556


The Douglas DC-8 (also known as the McDonnell Douglas DC-8) is a four-engine long-range narrow-body jet airliner built from 1958 to 1972 by the Douglas Aircraft Company. Launched after the competing Boeing 707, the DC-8 nevertheless kept Douglas in a strong position in the airliner market, and remained in production until 1972 when it began to be superseded by larger wide-body designs, including the Boeing 747, McDonnell Douglas DC-10 and Lockheed L-1011 TriStar. The DC-8's design allowed it a slightly larger cargo capacity than the 707 and some re-engined DC-8s are still in use as freighters.

Development

Background

After World War II Douglas had a commanding position in the commercial aircraft market. Boeing had pointed the way to the modern all-metal airliner in 1933 with the 247, but Douglas, more than any other company, made commercial air travel a reality. Douglas produced a succession of piston-engined aircraft (DC-2, DC-3, DC-4, DC-5, DC-6, and DC-7) through the 1930s, 1940s and 1950s. When de Havilland flew the first jet airliner, the Comet, in 1949, Douglas felt no need to rush into anything new. Their U.S. competitors at Lockheed and Convair felt the same way: that there would be a gradual switch from piston engines to turbines, and that the switch would be to the more fuel-efficient turboprop engines rather than pure jets. All three companies were working on a new generation of piston-engined designs, with an eye to turboprop conversion in the future.

De Havilland's pioneering Comet entered airline service in 1952. Initially it was a success, but it was grounded after several fatal crashes in 1953 and 1954. The cause of the Comet crashes had nothing to do with jet engines; it was a rapid metal fatigue failure brought on by cycling the high stresses in corners of the near-square windows from pressurizing the cabin to high altitudes and back. The understanding of metal fatigue that the Comet investigation produced would play a vital part in the good safety record of later types like the DC-8. In 1952 Douglas remained the most successful of the commercial aircraft manufacturers. They had almost 300 orders on hand for the piston-engined DC-6 and its successor, the DC-7, which had yet to fly. The Comet disasters, and the airlines' subsequent lack of interest in jets, seemed to show the wisdom of their staying with propeller-driven aircraft.

Competition

Boeing took the bold step of starting to plan a pure-jet airliner as early as 1949. Boeing's military arm had gained experience with large, long-range jets through the B-47 Stratojet (first flight 1947) and the B-52 Stratofortress (1952). With thousands of jet bombers on order or in service, Boeing had developed a close relationship with the US Air Force's Strategic Air Command (SAC). Boeing also supplied the SAC's refueling aircraft, the piston-engined KC-97 Stratofreighters, but these were too slow and low flying to easily work with the new jet bombers. The B-52, in particular, had to descend from its cruising altitude and then slow almost to stall speed to work with the KC-97.

Believing that a requirement for a jet-powered tanker was a certainty, Boeing started work on a new jet aircraft for this role that could be adapted into an airliner. As an airliner it would have similar seating capacity to the Comet, but its swept wing would give it higher cruising speed and better range. First presented in 1950 as the Model 473-60C, Boeing failed to generate any interest at the airlines. Boeing remained convinced that the project was worthwhile, and decided to press ahead with a prototype, the Boeing 367-80 ("Dash-80"). After spending $16 million of their own money on construction, the Dash-80 rolled out on May 15, 1954, and flew the next month. Boeing's plans became obvious, despite the misleading older model number.

Design

Douglas secretly began jet transport project definition studies in mid-1952. By mid-1953 these had developed into a form similar to the final DC-8; an 80-seat, low-wing aircraft with four Pratt & Whitney JT3C turbojet engines, 30° wing sweep, and an internal cabin diameter of 11 feet (3.35 m) to allow five-abreast seating. Maximum weight was to be 190,000 lb (86 metric tons), and range was estimated to be about 3,000–4,000 miles (4,800–6,400 km).

Douglas remained lukewarm about the jet airliner project, but believed that the Air Force tanker contract would go to two companies for two different aircraft, as several USAF transport contracts in the past had done. In May 1954, the USAF circulated its requirement for 800 jet tankers to Boeing, Douglas, Convair, Fairchild, Lockheed, and Martin. Boeing was just two months away from having their prototype in the air. Just four months after issuing the tanker requirement, the USAF ordered the first 29 KC-135s from Boeing. Besides Boeing's ability to provide a jet tanker promptly, the flying-boom air-to-air refueling system was also a Boeing product from the KC-97: developing the KC-135 had been a safe bet.

Donald Douglas was shocked by the rapidity of the decision which, he said, had been made before the competing companies even had time to complete their bids. He protested to Washington, but without success. Having started on the DC-8 project, Douglas decided that it was better to press on than give up. Consultations with the airlines resulted in a number of changes: the fuselage was widened by 15 inches (38 cm) to allow six-abreast seating. This led to larger wings and tail surfaces and a longer fuselage. The DC-8 was announced in July 1955. Four versions were offered to begin with, all with the same 150-foot-6-inch (45.87 m) long airframe with a 141-foot-1-inch (43.00 m) wingspan, but varying in engines and fuel capacity, and with maximum weights of about 240,000–260,000 lb (109–118 metric tons). Douglas steadfastly refused to offer different fuselage sizes. The maiden flight was planned for December 1957, with entry into revenue service in 1959. Well aware that they were lagging behind Boeing, Douglas began a major marketing push.

First orders

Douglas' previous thinking about the airliner market seemed to be coming true; the transition to turbine power looked likely to be to turboprops rather than turbojets. The pioneering 40–60-seat Vickers Viscount was in service and proving popular with passengers and airlines: it was faster, quieter and more comfortable than piston-engined types. Another British rival was the 90-seat Bristol Britannia, and Douglas's main rival in the large airliner market, Lockheed, had committed to the short/medium range 80–100-seat turboprop Electra, with a launch order from American Airlines for 35 and other orders flowing in. Meanwhile, the Comet remained grounded, the French 90-passenger twin jet Sud Aviation Caravelle prototype had just flown for the first time, and the 707 was not expected to be available until late 1958. The major airlines were reluctant to commit themselves to the huge financial and technical challenge of jet aircraft. However, no one could afford not to buy jets if their competitors did.

There the matter rested until October 1955, when Pan American placed simultaneous orders with Boeing for 20 707s and Douglas for 25 DC-8s. To buy one expensive and untried jet-powered aircraft type was brave: to buy both was, at the time, unheard of. In the closing months of 1955, other airlines rushed to follow suit: Air France, American, Braniff, Continental and Sabena ordered 707s; United, National, KLM, Eastern, JAL and SAS chose the DC-8. In 1956 Air India, BOAC, Lufthansa, Qantas and TWA added over 50 to the 707 order book, while Douglas sold 22 DC-8s to Delta, Swissair, TAI, Trans Canada and UAT. By the start of 1958, Douglas had sold 133 DC-8s compared to Boeing's 150 707s.

Basic price of a JT4 powered "domestic" version of the DC-8 was around US$5.46 million (£1.95 million) in 1960.[1]

Production and testing

The first DC-8 N8008D which first flew on 30 May 1958 as a Series 10 aircraft. Converted to Series 51 and operated by Trans International Airways at London Gatwick Airport in 1966
United Airlines chose the DC-8 over the Boeing 707. This Douglas DC-8-50 was photographed at Boston in 1973.

Donald Douglas proposed to build and test the DC-8 at Santa Monica Airport, which had been the birthplace of the DC-3 and home to a Douglas plant that employed 44,000 workers during World War II. In order to accommodate the new jet, Douglas asked the city of Santa Monica, California to lengthen the airport's 5,000-foot runway. Following complaints by neighboring residents, the city refused, so Douglas moved its airliner production line to Long Beach Airport.[2] The first DC-8 N8008D was rolled out of the new Long Beach factory on 9 April 1958 and flew for the first time, in Series 10 form, on 30 May for two hours seven minutes with the crew being led by A.G.Heimerdinger.[3] Later that year an enlarged version of the Comet finally returned to service, but too late to take a substantial portion of the market: de Havilland had just 25 orders. In August Boeing had begun delivering 707s to Pan Am. Douglas made a massive effort to close the gap with Boeing, using no less than ten aircraft for flight testing to achieve FAA certification for the first of the many DC-8 variants in August 1959. Much was needed to be done: the original air brakes on the lower rear fuselage were found ineffective and were deleted as engine thrust reversers had become available; unique leading-edge slots were added to improve low-speed lift; the prototype was 25 kn (46 km/h) short of its promised cruising speed and a new, slightly larger wingtip had to be developed to reduce drag. In addition, a recontoured wing leading edge was later developed to extend the chord 4% and reduce drag at high Mach numbers.[4]

On September 18, 1959, the DC-8 entered service with Delta Air Lines and United.[5] By March 1960, Douglas had reached their planned production rate of eight DC-8s a month. Despite a large number of DC-8 early models available, all used the same basic airframe, differing only in engines, weights and details; in contrast, Boeing's rival 707 range offered several fuselage lengths and two wingspans: the original 144-foot (44 m) 707-120, a 135-foot (41 m) version that sacrificed space to gain longer range, and the stretched 707-320, which at 153 feet (47 m) overall had 10 feet (3.0 m) more cabin space than the DC-8. Douglas' refusal to offer different fuselage sizes made it less adaptable and forced Delta and United to look elsewhere for short/medium range types. Delta ordered Convair 880s but United went for the newly developed lightweight 707-020 but prevailed on Boeing to rename the new variant the "720" in case people thought they were dissatisfied with the DC-8. Significantly, Pan Am never reordered the DC-8 and Douglas gradually lost market share to Boeing. After an excellent start, 1962 DC-8 sales dropped to just 26, followed by 21 in 1963 and 14 in '64; many were for the Jet Trader rather than the more prestigious passenger versions. In 1967, Douglas merged with McDonnell Aircraft Corporation to become McDonnell Douglas.

On August 21, 1961 a Douglas DC-8 broke the sound barrier at Mach 1.012 (660 mph/1,062 km/h) while in a controlled dive through 41,000 feet (12,497 m) and maintained that speed, for 16 seconds. The flight was to collect data on a new leading-edge design for the wing, and while doing so, this DC-8 became the first civilian jet – and the first jet airliner – to make a supersonic flight.[6] The aircraft was a DC-8-43 later delivered to Canadian Pacific Air Lines as CF-CPG. The aircraft, crewed by Captain William Magruder, First Officer Paul Patten, Flight Engineer Joseph Tomich and Flight Test Engineer Richard Edwards, took off from Edwards Air Force Base in California, and was accompanied to altitude by an F-104 flown by Chuck Yeager.[7]

Further developments

Air Canada DC-8-61

In April 1965, Douglas announced belated fuselage stretches for the DC-8 with three new models known as the Super Sixties. The DC-8 program had been in danger of closing with fewer than 300 aircraft sold, but the Super Sixties brought fresh life to it. By the time production ceased in 1972, 262 of the stretched DC-8s had been made. With the ability to seat 269 passengers, the DC-8 Series 61 and 63 had the largest passenger-carrying capacity available. That remained so until the Boeing 747 arrived in 1970.

All the earlier jetliners were noisy by modern standards. Increasing traffic densities and changing public attitudes led to complaints about aircraft noise and moves to introduce restrictions. As early as 1966 the Port Authority of New York and New Jersey expressed concern about the noise to be expected from the then still-unbuilt DC-8-61, and operators had to agree to operate it from New York at lower weights to reduce noise. By the early 1970s, legislation for aircraft noise standards was being introduced in many countries, and the 60 Series DC-8s were particularly at risk of being banned from major airports.

In the early 1970s several airlines approached McDonnell Douglas for noise reduction modifications to the DC-8 but nothing was done. Third parties had developed aftermarket hushkits but there was no real move to keep the DC-8 in service. Finally, in 1975, General Electric began discussions with major airlines with a view to fitting the new and vastly quieter Franco-American CFM56 engine to both DC-8s and 707s. MDC remained reluctant but eventually came on board in the late 1970s and helped develop the Series 70.

The Super Seventies were a great success: roughly 70% quieter than the 60-Series and, at the time of their introduction, the world's quietest four-engined airliner. As well as being quieter and more powerful, the CFM56 was roughly 20% more fuel efficient than the JT3D, which reduced operating costs and extended the range.

Air Transport International DC-8-62F at Thule AB, Greenland.

By 2002, of the 1,032 Boeing 707s and 720s manufactured for commercial use, just 80 remained in service – though many of those 707s were converted for USAF use, either in service or for spare parts. Of the 556 DC-8s made, around 200 were still in commercial service in 2002, including about 25 50-Series, 82 of the stretched 60-Series, and 96 out of the 110 re-engined 70-Series. Most of the surviving DC-8s are now used as freighters. In May 2009, 97 DC-8s were in service following UPS's decision to retire their remaining fleet of 44.[8] In January 2013, an estimated 36 DC-8s were in use worldwide.[9] As a result of aging, increasing operating costs and strict noise and emissions regulations, the number of active DC-8s continues to decline.

Variants

Series 10

For domestic use, powered by 13,500 lb (60.5 kN) Pratt & Whitney JT3C-6 turbojets with water injection. The initial DC-8-11 model had the original, high-drag wingtips and all were converted to DC-8-12 standard. The DC-8-12 had the new wingtips and leading-edge slots, 80 inches long between the engines on each wing and 34 inches long inboard of the inner engines. These unique devices were covered by doors on the upper and lower wing surfaces that opened for low speed flight and closed for cruise. The maximum weight increased from 265,000 to 273,000 pounds (120,200 to 123,800 kg). 28 DC-8-10s were built. This model was originally named "DC-8A" until the series 30 was introduced.[10] 29 built, 22 for United and 6 for Delta, plus the prototype. By the mid sixties United had converted 15 of its 20 surviving aircraft to DC-8-20 standard and the other 5 to -50s. Delta converted its 6 to DC-8-50s.

DC-8-32 of Overseas National Airways in Zurich, 1975

Series 20

Higher-powered 15,800 lb (70.8 kN) thrust Pratt & Whitney JT4A-3 turbojets (without water injection) allowed a weight increase to 276,000 pounds (125,190 kg). 34 DC-8-20s were built plus 15 converted DC-8-10s. This model was originally named "DC-8B" but was renamed when the series 30 was introduced.[10]

Series 30

For intercontinental routes, the three Series 30 variants combined JT4A engines with a one-third increase in fuel capacity and strengthened fuselage and landing gear. The DC-8-31 was certified in March 1960 with 16,800 lb (75.2 kN) JT4A-9 engines for 300,000-pound (136,080 kg) maximum takeoff weight. The DC-8-32 was similar but allowed 310,000-pound (140,600 kg) weight. The DC-8-33 of November 1960 substituted 17,500 lb (78.4 kN) JT4A-11 turbojets, a modification to the flap linkage to allow a 1.5° setting for more efficient cruise, stronger landing gear, and 315,000-pound (142,880 kg) maximum weight. Many -31 and -32 DC-8s were upgraded to this standard. A total of 57 DC-8-30s were produced.

Series 40

Douglas DC-8-42 of Trans Canada Airlines at London Heathrow in 1962

The DC-8-40 was essentially the -30 but with 17,500 lb (78.4 kN) Rolls-Royce Conway 509 turbofan engines for better efficiency, less noise and less smoke. The Conway was an improvement over the turbojets that preceded it, but the Series 40 sold poorly because of the traditional reluctance of U.S. airlines to buy a foreign product and because the still more advanced Pratt & Whitney JT3D turbofan was due in early 1961. The DC-8-41 and DC-8-42 had weights of 300,000 and 310,000 pounds (140,000 and 140,000 kg) respectively, The 315,000-pound (142,880 kg) DC-8-43 had the 1.5° flap setting of the -33 and introduced a 4% leading edge wing extension to reduce drag and increase fuel capacity slightly – the new wing improved range by 8%, lifting capacity by 6,600 lb (3 metric tons), and cruising speed by better than 10 knots (19 km/h; 12 mph). It was used on all later DC-8s. The first DC-8-40 was delivered in 1960; 32 were built.

Series 50

Douglas DC-8-55 of Garuda Indonesia Airways at Hong Kong-Kai Tak in 1967

The definitive short-fuselage DC-8 with the same engine that powered the vast majority of 707s, the JT3D. Fourteen earlier DC-8s were converted to this standard. All but the -55 were certified in 1961. The DC-8-51, DC-8-52 and DC-8-53 all had 17,000 lb (76.1 kN) JT3D-1 or 18,000 lb (80.6 kN) JT3D-3B engines, varying mainly in their weights: 276,000 pounds (125,200 kg), 300,000 pounds (136,100 kg) and 315,000 pounds (142,900 kg) respectively. The DC-8-55 arrived in June 1964, retaining the JT3D-3B engines but with strengthened structure from the freighter versions and 325,000-pound (147,420 kg) maximum weight. 88 DC-8-50s were built plus the 14 converted from Series 10/30.

The unique EC-24A of the US Navy in storage

Super 60 Series

DC-8-63(F) of First International Airways landing at Perth Airport, 2004

Super seventies

BAX Global DC-8-71(F) at Boeing Field
NASA Dryden DC-8 airborne laboratory refitted with CFM56 turbofan engines

The DC-8-71 to DC-8-73 were straightforward conversions of the -61 to -63, replacing the JT3D engines with more fuel-efficient 22,000 lb (98.5 kN) CFM56-2 high-bypass turbofans in new housings built by Grumman, along with new engine pylons and fairing of the air intakes below the nose. The DC-8-71 achieved the same end but required more modification because the -61 did not have the improved wings and relocated engines of the -62 and -63. Maximum takeoff weights remained the same, but there was a slight reduction in payload because of the heavier engines. All three models were certified in 1982 and a total of 110 60-Series DC-8s were converted by the time the program ended in 1988.

Operators

A total of 4 DC-8s (all variants) were in airline service as of July 2015 with the following operators:[22]

Aircraft In Service
Airlift International 1
Bravo Cargo Services 1
Trans Air Cargo Service 2
Total 4

Accidents and incidents

As of October 2015, the DC-8 had been involved in 146 incidents,[23] including 83 hull-loss accidents,[24] with 2,256 fatalities.[25] The DC-8 has been in 46 hijackings involving 2 fatalities.[26]

Aircraft on display

The following museums have DC-8s on display or in storage:

Specifications

Variant DC-8-32 DC-8-51 DC-8-54JT (-54CF) DC-8-61 DC-8-63CF
Crew Three
Payload 176 passengers (coach)
124 passengers (mixed)
144–179 passengers (coach)
132 passengers (mixed)
132 passengers (mixed)
155–189 passengers (coach)
8 Cargo Pallets + 63 passengers (coach)
13 cargo pallets
200–212 passengers (mixed)
251–269 passengers (coach)
251–269 passengers (coach)
200–212 passengers (mixed)
Overall length 150 ft 6 in (45.87 m) 187 ft 4 in (57.10 m)
Wingspan 142 ft 5 in (43.41 m) 148 ft 5 in (45.24 m)
Overall height 43 ft 4 in (13.21 m) 43 ft 0 in (13.11 m)
Wing Area 2,771 sq ft (257.4 m2) 2,927 sq ft (271.9 m2)
Maximum Landing Weight 199,500 lb (90,500 kg) 240,000 lb (108,862 kg) 275,000 lb (124,738 kg)
Maximum Gross Weight 310,000 lb (140,614 kg) 276,000 lb (125,191 kg) 315,000 lb (142,882 kg) 325,000 lb (147,418 kg) 355,000 lb (161,025 kg)
Powerplants (4x) Pratt & Whitney JT4A-9 turbojets,
16,800 lb (74.7 kN) each
Pratt & Whitney JT3D-1 or JT3D-3 turbofans,
17,000/18,000 lb (75.61/80.06 kN) each
Pratt & Whitney JT3D-3B turbofans,
18,000 lb (80.06 kN) each
Pratt & Whitney JT3D-7 turbofans,
19,000 lb (84.51 kN) each
Maximum cruise speed 588 mph (946 km/h) 593 mph (954 km/h) 581 mph (935 km/h) 596 mph (959 km/h)
Range with max. fuel 6,278 mi (10,103 km) 5,077 mi (8,171 km) 7,543 mi (12,139 km) 5,846 mi (9,408 km) 7,008 mi (11,278 km)
Cruising altitude 35,000 ft (11,000 m)
Fuel capacity 23,400 US gal (88,579 l; 19,485 imp gal) 24,275 US gal (91,891 l; 20,213 imp gal)
Number produced 43 30 15 78 53

Sources:[29][30][31]

Deliveries

1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 Total
21 91 42 22 19 20 31 32 41 102 85 33 13 4 556

See also

Related development
Aircraft of comparable role, configuration and era
Related lists

References

Notes
  1. "Commercial Aircraft of the World: DC-8". Flight. Vol. 78 no. 2697. 18 November 1960. p. 803. Retrieved 2013-01-20.
  2. Garvey, William, Battled field, Aviation Week and Space Technology, February 24, 2014, p.18
  3. Francillon 1979, p. 582.
  4. Shevell, R. S. , "Aerodynamics Bugs: Can CFD Spray Them Away?" AIAA paper 85-4067, October 1985.
  5. Whittle 1972, p. 5.
  6. "Douglas Passenger Jet Breaks Sound Barrier". DC8.org. August 21, 1961.
  7. Wasserzieher, Bill. "I Was There: When the DC-8 Went Supersonic" / "Boeing will never try it: The day a Douglas DC-8 busted Mach 1", Air & Space/Smithsonian, August 2011, pp. 56–57.
  8. "Final UPS DC-8 flight lands at Louisville International Airport". Business First of Louisville. May 11, 2009. Retrieved May 13, 2009.
  9. Bostick, Brian (January 10, 2013). "DC-8 Operations in US Winding Down". Aviation Week. Retrieved June 19, 2014.http://aviationweek.com/blog/dc-8-operations-us-winding-down
  10. 1 2 Norris, Guy; Wagner, Mark (1999). Douglas Jetliners. MBI Publishing. ISBN 0-7603-0676-1.
  11. "EC-24A". Globalsecurity.org. Retrieved 18 October 2009.
  12. 1 2 Francillon, 1979, pp. 588–589.
  13. Taylor 1966, pp. 231–233.
  14. "Air Transport". Flight International. Vol. 91 no. 3022. 9 February 1967. p. 192.
  15. Harrison, Neil (23 November 1967). "Commercial Aircraft Survey: DC-8-61". Flight International. Vol. 92 no. 3063. p. 852.
  16. Francillon 1979, p. 598.
  17. Whittle 1972, p. 11.
  18. Francillon 1979, pp. 590–591.
  19. Francillon 1979, pp. 591–593, 598.
  20. Francillon 1979, p. 591.
  21. Francillon 1979, pp. 591–593.
  22. "World Airliner Census" (PDF). Flight International. July 2015. p. 14. Retrieved September 27, 2015.
  23. "Douglas DC-8 incidents". Aviation Safety Network. October 11, 2015.
  24. "Douglas DC-8 summary". Aviation Safety Network. October 11, 2015.
  25. "Douglas DC-8 Accident Statistics". Aviation Safety Network. October 11, 2015.
  26. "DC-8 Statistics". Aviation Safety Network. October 11, 2015.
  27. Harrison, Scott. "DC-8 for California Museum of Science and Industry". LA Times, September 14, 2012.
  28. DC-8 on Musée de l'Air Website
  29. "DC-8 Tech Data". Cox, Fred. Retrieved December 24, 2011.
  30. "McDonnell Douglas DC-8 Performance and Technical Specifications". Gothard, Tony. Retrieved December 24, 2011.
  31. "DC-8 – Technical Data (dc-8.de)". Retrieved December 24, 2011.
Bibliography
  • Francillon, Rene J., McDonnell Douglas Aircraft since 1920, Putnam & Company Ltd, 1979, ISBN 0-370-00050-1.
  • Whittle, John A., Nash, H.J., and Sievers, Harry. The McDonnell DC-8. Tonbridge, Kent, UK: Air-Britain, 1972. ISBN 0-85130-024-3.

Further reading

External links

Wikimedia Commons has media related to Douglas DC-8.
This article is issued from Wikipedia - version of the Monday, February 15, 2016. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.