Convair Twins

摘要

Of the contenders for a Douglas DC-3 replacement following World War Two, Convair's CV-240,340 and 440 sold in increasing numbers, whereas the unpressurised Martin 2-0-2 and its successor, the 4-0-4, had only limited success. The only serious challenger to Convair's airliners was the Vickers Viscount, which led Convair to design a structure suitable for piston as well as turboprop power. The prototype Convair CV-110 made its first flight from San Diego's Lindbergh Field on July 8, 1946. It was a tricycle-undercarriage aircraft designed to carry 30 passengers and its circular-section fuselage, with an outside diameter of 9ft 5in (2.87m), was 6ft 6in (1.98m) longer than the DC-3's. Its low-set wing spanned 89ft Oin (27.13m), 6ft (1.83m) less than that of the DC-3. Most importantly, its Pratt & Whitney R-2800-SC13G engines, driving four-blade propellers, developed 2,080shp (l,550kW) at take-off- 70% more than the DC-3's. This allowed a 40% greater gross weight of 36,0001b (16,330kg) and 50% higher speed of 226kts (420km/h). The Convair CV-110 had a relatively high rate of climb, which allowed more time at efficient cruising altitudes on the short sectors the aircraft was designed for. However, American Airlines, which was to order 100 of the new Convairs, wanted two major changes: greater capacity and a pressurised cabin.