The Convair 990 Coronado is an American narrow-body four-engined jet airliner produced by the Convair division of General Dynamics,
Convair 990 Coronado
Design and development
American Airlines asked Convair to design an aircraft for coast-to-coast flights, able to fly nonstop from New York City to Los Angeles against the wind. They wanted a somewhat larger passenger capacity than the 880, which was the smallest of the first-generation U.S. jet airliners. The 990 began flight testing January 24, 1961.
One change from the 880 was the large anti-shock bodies on the upper trailing edge of the wings to increase the critical Mach and reduce transonic drag. The inboard shock bodies, which were larger, were also used for additional fuel tankage. Later during the design period, Convair modified the design to include fuel in the outboard pods as well, but during the initial test flights the extra weight caused the outboard engines to oscillate in certain conditions. The pods were redesigned once more, and shortened by 28 inches (710 mm), causing increased drag. The inner set of pods also served a secondary role as fuel dumps for the fuel tanks, and the outlet pipe is prominent.
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 engines, compared to the fan stage at the front of the engine found on the Pratt & Whitney JT3D that powered the 990's competitors. The engine was a simplified, non afterburning civil version of the J79, used in military fighters. Like most versions of the J79, the CJ805 and CJ805-23 were smoky, although secondary operator Spantax eventually had their 990 aircraft refitted with smokeless combustion chambers in the 1970s.
Like the 880, 990s incorporated a dorsal "raceway" added to the top of the fuselage to house the two ADF antennas and one VHF antenna
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The 990's niche was soon captured by the Boeing 720 and Boeing 720B, derivatives of the Boeing 707, and later by the Boeing 727. By the time the assembly line 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 airlines to broadly accept the Convair 880 and 990 led Convair's parent company, General Dynamics, to suffer what at the time was one of the largest corporate losses in history. As a result, Convair exited the jet airliner business, although they later profitably built fuselages for the McDonnell Douglas DC-10, KC-10 and MD-11.
Convair 990 Coronado
The 990 did not meet the specifications promised, and American Airlines reduced their order as a result. The 990A was developed by adding fairings to the engine nacelles, among other changes. Despite the modifications from the basic 880 and those in response to drag problems in testing, the aircraft never lived up to its promise of coast-to-coast nonstop capability from JFK to LAX. American Airlines' timetables show little or no difference in scheduled time between 707 and 990A flights;
Convair 990 Coronado: Specifications
Role Narrow-body jet airliner; National origin United States
First flight January 24, 1961
Retired September, 1987 (1994 with NASA)
Primary users American Airlines; Spantax
Produced 1961-1963 Number built 37
Developed from Convair 880
Crew: Four Capacity: 149 passengers
Length: 139 ft 9 in (42.59 m)
Wingspan: 120 ft (36.58 m)
Height: 39 ft 6 in (12.04 m)
Empty weight: 113,000 lb (51,256 kg)
Loaded weight: 253,000 lb (111,674 kg)
Powerplant: 4 × General Electric CJ805-23B turbofans, 16,050 lbf (71.4 kN) each
Maximum speed: 621 mph (540 kn, 1,000 km/h) at 21,200 ft (6,460 m)
Cruise speed: 557 mph (484 kn, 896 km/h) at 35,000 ft (10,668 m)
Range: 3,595 mi (3,124 nmi, 5,785 km)
Convair 990 Coronado
When the major airlines retired their Convair 990s, they found a second life on charter airlines. Spantax of Spain had a large fleet until the mid-1980s and so did Denver Ports of Call. In 1967, Alaska Airlines purchased Convair 990 PP-VJE from Varig, and operated it as N987AS in scheduled airline service until 1975.