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Convair 990 Coronado
The Convair 990 Coronado is a retired American narrow-body four-engined jet airliner produced between 1961 and 1963 by the Convair division of American company General Dynamics. It was a stretched version of its earlier Convair 880 produced in response to a request from American Airlines: the 990 was lengthened by 10 ft (3.0 m), which increased the number of passengers from between 88 and 110 in the 880 to between 96 and 121. This was still fewer passengers than the contemporary Boeing 707 (110 to 189) or Douglas DC-8 (105 to 173), although the 990 was 25–35 mph (40–56 km/h) faster than either in cruise.
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 after Boeing had flat out refused. They wanted a larger passenger capacity than the Convair 880 and 880M, which were the smallest of the first-generation U.S. jet airliners. The design was known as the Convair 600 and was redesignated the Convair 990 in the month of its first flight. The 990 began flight testing on 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 by reducing 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 were used to route the fuel-dump tubes from the fuel tanks, terminating in a prominent outlet.
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 turbofan version of the J79 turbojet, used in supersonic military aircraft. Like most versions of the J79, the CJ805 and CJ805-23 were smoky, although secondary operator Spantax eventually had their engines refitted with low-smoke 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.
The 990 did not meet the specifications promised, and American Airlines reduced its 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. AA began to dispose of its 990As in 1967.
During May 1961, one of the pre-production 990 aircraft, while demonstrating the margin between its operating speed and its capability during a dive at .97 Mach from 32,000 ft to 22,500 ft, reached 675 miles per hour (1,086 km/h) at an altitude of 22,000 feet (6.7 km): the fastest true airspeed ever attained by a commercial jet transport at that time. However, in level flight the maximum speed, 0.84 M, was less than that guaranteed to American Airlines, 0.89 M, because the drag levels with the anti-shock bodies were much higher than predicted. A drag reduction program was instituted during which streamlining of the engine pylon/wing interface and addition of nacelle fairings achieved 0.89 M.
In 1963, the 990A was reported to burn 13,750 pounds (6.24 t) per hour of fuel at Mach 0.84 (484 kn; 897 km/h) at 35,000 feet (11 km) at a mass of 200,000 pounds (91 t). In contrast, a modern Boeing 737 MAX 8 typically carries 162 passengers and burns 4,460 lb (2.02 t) per hour at Mach 0.78 (450 kn; 833 km/h) at sub-optimal parameters.[improper synthesis?]
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Convair 990 Coronado AI simulator
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Convair 990 Coronado
The Convair 990 Coronado is a retired American narrow-body four-engined jet airliner produced between 1961 and 1963 by the Convair division of American company General Dynamics. It was a stretched version of its earlier Convair 880 produced in response to a request from American Airlines: the 990 was lengthened by 10 ft (3.0 m), which increased the number of passengers from between 88 and 110 in the 880 to between 96 and 121. This was still fewer passengers than the contemporary Boeing 707 (110 to 189) or Douglas DC-8 (105 to 173), although the 990 was 25–35 mph (40–56 km/h) faster than either in cruise.
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 after Boeing had flat out refused. They wanted a larger passenger capacity than the Convair 880 and 880M, which were the smallest of the first-generation U.S. jet airliners. The design was known as the Convair 600 and was redesignated the Convair 990 in the month of its first flight. The 990 began flight testing on 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 by reducing 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 were used to route the fuel-dump tubes from the fuel tanks, terminating in a prominent outlet.
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 turbofan version of the J79 turbojet, used in supersonic military aircraft. Like most versions of the J79, the CJ805 and CJ805-23 were smoky, although secondary operator Spantax eventually had their engines refitted with low-smoke 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.
The 990 did not meet the specifications promised, and American Airlines reduced its 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. AA began to dispose of its 990As in 1967.
During May 1961, one of the pre-production 990 aircraft, while demonstrating the margin between its operating speed and its capability during a dive at .97 Mach from 32,000 ft to 22,500 ft, reached 675 miles per hour (1,086 km/h) at an altitude of 22,000 feet (6.7 km): the fastest true airspeed ever attained by a commercial jet transport at that time. However, in level flight the maximum speed, 0.84 M, was less than that guaranteed to American Airlines, 0.89 M, because the drag levels with the anti-shock bodies were much higher than predicted. A drag reduction program was instituted during which streamlining of the engine pylon/wing interface and addition of nacelle fairings achieved 0.89 M.
In 1963, the 990A was reported to burn 13,750 pounds (6.24 t) per hour of fuel at Mach 0.84 (484 kn; 897 km/h) at 35,000 feet (11 km) at a mass of 200,000 pounds (91 t). In contrast, a modern Boeing 737 MAX 8 typically carries 162 passengers and burns 4,460 lb (2.02 t) per hour at Mach 0.78 (450 kn; 833 km/h) at sub-optimal parameters.[improper synthesis?]