Convair 990

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Image:Convair 990 on ramp EC92-05275-30.jpg

The Convair 990 Coronado was a jet airliner produced by the Convair division of General Dynamics, a "stretched" version of their earlier Convair 880 produced in response to a request from American Airlines. The 990 was lengthened by 10 feet, which increased the number of passengers from between 88 and 110 in the 880, to between 96 and 121 (depending on the interior). This was still considerably fewer than the contemporary Boeing 707 (110 to 189) or Douglas DC-8 (105 to 173), although the 990 remained some 25 to 35mph faster than either in cruise.

The 990 entered production in 1961. One interesting change from 880 was the addition of large bulges on the upper wings (often referred to as 'Küchemann carrots', after their designer at Convair), in order to increase their critical Mach and reduce transonic drag. This allowed the heavier 990 to go slightly faster than the 880, cruising at about Mach 0.91. Originally there were plans to use the bulges as fuel tanks, but during test flights the extra weight caused the tanks to vibrate excessively. Instead the inner set of bumps also served a secondary role as fuel dump for the fuel tanks in the fuselage. The engines were also changed to the uprated General Electric CJ-805-23s, which were unique in that they used a fan stage at the rear of the engine in addition to the small one found in the original 805-3's. Like the 880, 990s were later modified with a "raceway" added to the top of fuselage to hold the wiring for additional instrumentation.

The 990s market niche was soon to be destroyed entirely by the Boeing 727 and the Boeing 720 (a derivative of the 707), and by the time the line was shut down in 1963 only 37 990s had been produced, bringing General Dynamics' entire production of commercial jet airliners to 102 airframes. The failure of the Convair 880 and 990 to be accepted by the airlines led Convair to suffer, at the time, the largest corporate losses in history, though more modern corporations have surpassed Convair's losses.

The 990's engine, the CJ-805, was a simplified civilian version of the J79, used in military fighters. Like the J79, the CJ-805 was very smoky. Although other early jet airliners were smoky, the 990 is especially remembered for it. There are stories of people calling fire departments after seeing a 990 fly over to report seeing an airplane on fire. Indeed, when viewed from an airport, where the point of view was looking the long way through the smoke trail, a 990 on final approach looked as if it were burning.

[edit] Specifications (Convair 990)

[edit] General characteristics

Crew: 3
Capacity: 96 to 121
Length: 139 ft 5 in (42.49 m)
Wingspan: 120 ft (36.58 m)
Height: 39 ft 6 in (11 m)
Wing area: m² ( ft²)
Empty: 120,560 lb (54,690 kg)
Loaded: 255,000 lb (115,700 kg)
Powerplant: 4x General Electric CJ-805-23 turbofans, 16,100 lbf (71.6 kN) each