![]() Lockheed engineers were able to maintain straight-through engine performance by limiting the curve of the S-duct to less than a quarter of the radius of the engine intake diameter. The main visible difference between the TriStar and its similar trijet competitor, the McDonnell Douglas DC-10, is the central tail engine configuration: the DC-10's engine is mounted above the fuselage for simplicity of design and more economical construction, while the TriStar's engine is mounted to the rear fuselage and fed through an S-duct (similar to the Boeing 727) for reduced drag and improved stability. Also, before the establishment of Extended Operations standards by the FAA in the 1980s, commercial jets with only two engines were not allowed to fly more than 30 minutes away from an airport, making trans-oceanic flights impossible. The TriStar was originally conceived as a "jumbo twin", but a three-engine design was ultimately chosen to give the aircraft enough thrust to take off from existing runways. The TriStar's design featured a twin-aisle interior with a maximum of 400 passengers and a three-engine layout. ![]() The advanced technology that went into the TriStar resulted in a high purchase price. The TriStar name was selected in a Lockheed employee naming contest for the airliner. By contrast, Lockheed would "take the most advanced technology of the day and when that technology was lacking, Lockheed created it" for the L-1011 in order to give it lower noise emissions, improved reliability, and higher efficiency over first-generation jet airliners. McDonnell, who had recently taken over Douglas Aircraft, directed DC-10 development on a "very firm budget, and cost overruns were unacceptable – even at the expense of safety", and the conservative approach meant reusing Douglas DC-8 technology. Despite their similarities, the L-1011 and DC-10's engineering approach differed greatly. Douglas Aircraft answered American Airlines with the DC-10, which had a similar three-engine configuration and dimensions. Having experienced difficulties with some of its military programs, Lockheed was eager to re-enter the civilian market with a smaller wide-body jet, and its response was the L-1011 TriStar. Boeing lost the military contract, but its private-venture 747 captured what would become a much larger civilian airliner market for wide-body airliners. Lockheed won contracts for jet military transports with the C-141 StarLifter, and pioneered very large jet transports with the large C-5 Galaxy with its high-bypass turbofan engines. Even after the Electra overcame vibration problems that caused several crashes early in its career, the market for large airliners would soon shift over to jet airliners such as the Boeing 707 and Douglas DC-8. In the 1950s the Electra was designed for turboprop propulsion, which Lockheed had successfully used on the C-130 Hercules military transport. ![]() Lockheed had not produced civilian airliners since 1961 with the L-188 Electra. In the 1960s, American Airlines approached Lockheed and competitor Douglas (later McDonnell Douglas) with the need for an airliner which could carry 250 passengers on transcontinental routes. After L-1011 production ended, Lockheed withdrew from the commercial aircraft business due to its below-target sales. Between 19, Lockheed manufactured a total of 250 TriStars, assembled at the Lockheed plant located at the Palmdale Regional Airport in southern California north of Los Angeles. The L-1011 TriStar's sales were hampered by two years of delays due to developmental and financial problems at Rolls-Royce, the sole manufacturer of the aircraft's engines. Post-production conversions for the L-1011-1 with increased takeoff weights included the L-1011-50 and L-1011-150. The original-length TriStar was also produced as the high gross weight L-1011-100, up-rated engine L-1011-200, and further upgraded L-1011-250. The shortened, longer range L-1011-500 first flew in 1978 and entered service with British Airways a year later. The original L-1011-1 first flew in November 1970 and entered service with Eastern Air Lines in 1972. The L-1011 TriStar was produced in two fuselage lengths. The aircraft has an autoland capability, an automated descent control system, and available lower deck galley and lounge facilities. Its trijet configuration has three Rolls-Royce RB211 engines with one engine under each wing, along with a third engine center-mounted with an S-duct air inlet embedded in the tail and the upper fuselage. ![]() The airliner has a seating capacity of up to 400 passengers and a range of over 4,000 nautical miles (7,410 km). It was the third wide-body airliner to enter commercial operations, after the Boeing 747 and the McDonnell Douglas DC-10. The Lockheed L-1011 TriStar, also known as the L-1011 (pronounced "El-ten-eleven") and TriStar, is an American medium-to-long-range, wide-body trijet airliner built by the Lockheed Corporation. ![]()
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