The Douglas DC-8 is a four-engined jet airliner, manufactured from 1958 to 1972.
Background
Background
When the world's first jet airliner, the De Havilland Comet, was introduced in 1949, Douglas held a commanding position in the aircraft market. Although Boeing had pointed the way to the modern all-metal airliner in 1933 with the 247, it was Douglas that, more than any other company, made the promise a reality. Douglas produced a succession of piston-engined commercial aircraft through the 1930s, 1940s and 1950s: 138 DC-2s, 10,928 DC-3s (mostly for military service in World War II), 1453 DC-4s, 537 DC-6s and 226 DC-7s.
Given the success of their designs, Douglas took the view that there was no reason to rush into anything new, as did their rivals Lockheed and Convair. Most air transport manufacturers expected that there would be a gradual switch, from piston engines to turbines and that it would be to the more fuel-efficient turboprop engines rather than pure jets.
In contrast, Boeing took the bold step of starting to plan a pure jet airliner as early as 1949. Boeing's military arm had gained extensive experience with large, long-range jets through the B-47 Stratojet (first flight 1947) and the B-52 Stratofortress (1952). With thousands of their big jet bombers on order or in service, Boeing had developed a close relationship with the U.S. Air Force Strategic Air Command (SAC), and could count on having preference when the time came to replace SAC's fleet of piston-engined KC-97 Stratotankers.
For Boeing, this was a golden opportunity: an aircraft built to provide air-to-air refueling capacity for strategic bombers could be turned into a commercial transport with very little extra effort. Boeing could now plan on building a commercial jetliner — which might or might not sell — but either way the Air Force would pay for most of the development cost.
De Havilland's pioneering Comet entered airline service in 1952. Initially it was a success, but a series of fatal crashes in 1953 and 1954 resulted in the type being grounded until the cause could be discovered. Airlines cancelled orders for it, public confidence in the idea of jet transport plummeted, and it would take de Havilland four years to find and fix the problem. The cause of the Comet crashes was nothing to do with jet engines: it was rapid metal fatigue failure brought on by the stress of cycling a pressurized cabin to high altitudes and back. A new 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 contrast, Boeing took the bold step of starting to plan a pure jet airliner as early as 1949. Boeing's military arm had gained extensive experience with large, long-range jets through the B-47 Stratojet (first flight 1947) and the B-52 Stratofortress (1952). With thousands of their big jet bombers on order or in service, Boeing had developed a close relationship with the U.S. Air Force Strategic Air Command (SAC), and could count on having preference when the time came to replace SAC's fleet of piston-engined KC-97 Stratotankers.
For Boeing, this was a golden opportunity: an aircraft built to provide air-to-air refueling capacity for strategic bombers could be turned into a commercial transport with very little extra effort. Boeing could now plan on building a commercial jetliner — which might or might not sell — but either way the Air Force would pay for most of the development cost.
De Havilland's pioneering Comet entered airline service in 1952. Initially it was a success, but a series of fatal crashes in 1953 and 1954 resulted in the type being grounded until the cause could be discovered. Airlines cancelled orders for it, public confidence in the idea of jet transport plummeted, and it would take de Havilland four years to find and fix the problem. The cause of the Comet crashes was nothing to do with jet engines: it was rapid metal fatigue failure brought on by the stress of cycling a pressurized cabin to high altitudes and back. A new 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.
Development
Air Canada DC-8 at Montréal-Dorval International AirportIn 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 and was still two years away from commercial service. The Comet disasters, and the consequent airline lack of interest in jets, seemed to demonstrate the wisdom of their staying with propeller aircraft. Nevertheless, with one eye on the USAF tanker market, Douglas secretly began jet transport project definition studies in mid-year, and by mid-1953 had decided on something very like the final form: an 80-seat, low-wing aircraft with four Pratt & Whitney JT3C turbojet engines, 30-degree wing sweep, and an internal cabin diameter of exactly 11 feet (3.35 m) to allow five abreast seating. Maximum weight was to be 95 tons, and range was estimated at somewhere between 3,000 and 4,000 miles (4,800 to 6,400 km).
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