British Aircraft Corporation VC-10
Two long-range, four-engine, heavy jet transports were developed in the 1960's. These were the British VC-10 developed by Vickers Armstrongs, which later was absorbed into the British Aircraft Corporation, and the Soviet Ilyushin Il-62. The two aircraft closely resemble each other in configuration and employ an engine arrangement different from any existing four-engine jet transport. On each aircraft, the four engines are mounted at the aft end of the fuselage, two on either side, in a four-engine adaptation of the twin aft-engine configuration pioneered by the Caravelle. Both aircraft weigh over 300 000 pounds, and both were designed for long-range operation.
The VC-10 was developed in response to a requirement of the overseas division of British Airways, formerly the British Overseas Airways Corporation (BOAC), for use on its long-range routes to Africa, India, and Australia. First flight took place in June 1962, and the type entered service with BOAC in April 1964. Production of the aircraft was terminated in 1974 after 54 units were manufactured.
The VC-10 has turned out to have great passenger appeal but for sound economic reasons to be unsalable to most airlines. It was conceived as part of a package deal in which BOAC could buy fifteen Boeing 707s if it also bought twenty equivalent British aircraft. So a jet Vanguard, which the then Vickers company had been trying to sell to BEA, was made first into an Empire-routes and then into a trans-Atlantic design. While the result was an aircraft technically ahead of the Boeing and Douglas designs, it was actually six years behind and somewhat more costly. At the same time the break-even point was unrealistically figured at 20 aircraft versus the American giants' reckoning of 300.
The four aft-mounted engines are, of course, the most distinctive feature of the configuration. The power is supplied by Rolls-Royce Conway turbofan engines of 21 000 pounds thrust each. These engines have a bypass ratio of 0.6 and employ a four-stage front-mounted fan. Like all aircraft that employ the aft-mounted engine arrangement, the wing of the VC-10 appears quite clean and uncluttered. Although the sweep angle is slightly less than that of the Boeing 707, the wing-plan-form geometry employed on the two aircraft is nearly the same. The high-lift system consists of trailing-edge Fowler flaps, which are similar to the double-slotted flap shown in figure 10.25(b) with the small middle element removed, and leading-edge slats. Three leading-edge fences are employed on each wing. Lateral control is provided by a combination of ailerons and spoilers. The spoilers are also used as air brakes and can be seen deployed as such in figure 13.18. All control surfaces are hydraulically actuated.
A comparison of the performance data of the VIC-10 and the Boeing 707-320B indicates that the maximum payload and corresponding range are significantly less than those of' the Boeing 707-320B. The cost-economical cruising speeds of the two aircraft are also about the same; however, the maximum cruising speed of' the 707 is somewhat higher than that of the VC-10. Many of the airports served by British Airways are located in tropical or subtropical areas characterized by high temperatures. Such temperatures increase the ground speed required for takeoff and reduce the maximum thrust produced by the engines. The VC-10 was accordingly designed to cope with these difficult takeoff conditions that, in some cases, were aggravated by airport elevations considerably above sea level. As a consequence, the takeoff field length for "standard day" conditions given in table VII is about 2000 feet shorter for the VC-10 than for the 707.
The VC-10 is no longer in airline service, but a few remained in the Royal Air Force inventory. The economics of' the aircraft apparently could not compete successfully with those of the Boeing 707 and McDonnell Douglas DC-8; hence, the VC-10 enjoyed a relatively limited production run.
|Join the GlobalSecurity.org mailing list|