During the 1950s, BOAC envisioned that the de Havilland DH.106 Comet would serve as its long-range pure-jet airliner, but its initial version, as the Comet 1, demonstrated its design flaw when inadequate fuselage skin gauges resulted in progressive weakening and ultimate, life-losing explosive decompression.
Although it had placed an order for a dozen slightly larger Comet 2s, accident investigation precluded its use by any operator other than the Royal Canadian Air Force.
While the larger-capacity Comet 4 seemed more promising, its late appearance and inadequate range hardly qualified it as a trans-Atlantic jetliner, leaving BOAC to deploy it on decidedly shorter routes and seek a long-range airliner elsewhere. It was therefore to Vickers that it turned.
VC10 DESIGN ORIGINS:
In 1951, the Ministry of Supply asked Vickers-Armstrongs to design a transport aircraft for the Royal Air Force, for which BOAC saw potential application. In overall configuration, it was similar to the Valiant bomber with four Rolls Royce Avon turbojets mounted to the high wing, although it was quickly concluded that such an airfoil mounting was inappropriate for passenger carriage.
Designated V.1000 as its military version and VC7 as its commercial one, it appeared to incorporate features that married the Comet with the ultimate VC10, with a forward, wrap-around circle of ten cockpit windows and a comparable fuselage, but it was decidedly larger for greater capacity. Its four 13,500 thrust-pound, aft-fan Rolls Royce Conway engines, buried in the swept wing, resulted in a clean, unobstructed surface for high lift and mirrored that of the Comet itself, and its tail was conventional.
Even on paper, its sleek appearance and high-speed performance were evident. A 100-passenger payload, along with their baggage, was calculated to result in a 500-mph speed and a range of just under 3,000 miles.
Construction of the V.1000/VC7 prototype commenced in October of 1952 and the British government instructed Vickers to produce six examples of the aircraft two years later. Despite the manufacturer’s monetary risk, which had entailed a self-investment of three million pounds Sterling, the order proved optimistic for the program’s success. Yet it quickly faded.
Because of rising development costs, the Royal Air Force cancelled the project in 1955, prompting the end of production. The wingless airframe, which had been 80 percent complete, sat in the Vickers factory like a ghost and was subsequently destroyed.
But within its ashes lurked an idea that many felt merited winged flight and could give Great Britain the once-in-a-lifetime opportunity to produce its own comparable, large-capacity, four-engine, long-range jetliner to compete with the emerging Boeing 707 and the Douglas DC-8. Powered by four aft-fan engines, however, it was seen as both superior and quieter.
Both the Royal Air Force and BOAC handicap permit , in the interim, turned to the Bristol Britannia, the country’s only existing long-range airliner. Because it was powered by four turboprop engines, it led them to conclude that it was more economical to operate than the pure-jet design would have been.
Yet it was soon apparent that the quad-engine turboprop would prove an unworthy opponent to the Boeing 367-80 that first took to the sky in 1954 and became the 707’s prototype.
Vickers nevertheless had the foresight to initiate its own design studies in 1955 and 1956 before the V.1000/VC7 was cancelled, harnessing its experience and proposing an aircraft with the Vanguard’s nose and fuselage mated with a swept wing and powered by three Rolls Royce Avon turbojets. It was designated the Vanjet.
Admitting the speed handicap of its Britannias, BOAC intermittently bought the Boeing 707-420, yet the 15-strong order came with a compromise: in order for it to be approved, it equally had to acquire 20 UK-designed jetliners. Other than the projected Vanjet, however, none existed.
While it considered the 707 the optimum equipment for its long-range transatlantic routes, it realized that neither it, nor the DC-8, could provide the type of performance required on its Empire routes to African and Middle and Far Eastern destinations that posed high-temperature, short-runway operational obstacles. Demand on these routes also fell well below the capacity of that of the US quad-jets.
Although de Havilland had proposed the ultimate Comet 5 version for such services, it refused to proceed with the program if at least 50 launch orders were not received, and it was painfully aware that the aircraft’s design would be too specifically tailored to BOAC’s routes.
Left, once again, without suitable equipment, it turned to Vickers to meet its needs. Its requirements called for an aircraft with the 707’s cruise speed, but accommodate fewer passengers, all while operating from short runways. A 32,000-pound payload and a 2,500-mile range were initially envisioned.
The solution, at least at this stage, lay with the Vanjet, whose size was increased in 1956 and whose power was augmented with the addition of a fourth nacelle-encased, aft fuselage-mounted Rolls Royce Conway turbofan, a configuration not unlike that of the later appearing, t-tailed twin- and tri-jets. Because its wings lacked any pylon-interruption, they were aerodynamically clean and could be fitted with full-span leading ledge slats and trailing edge flaps, producing the amount of lift needed for operation from high-altitude and -temperature airfields. Neither the 707 nor the DC-8 could offer such performance