It was the third wide-body airliner to enter commercial operations, after the Boeing and the McDonnell Douglas DC Its trijet configuration has three Rolls-Royce RB 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 aircraft has an autoland capability, an automated descent control system, and available lower deck galley and lounge facilities. The L TriStar was produced in two fuselage lengths. The original L first flew in November and entered service with Eastern Air Lines in
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It was the third wide-body airliner to enter commercial operations, after the Boeing and the McDonnell Douglas DC Its trijet configuration has three Rolls-Royce RB 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 aircraft has an autoland capability, an automated descent control system, and available lower deck galley and lounge facilities.
The L TriStar was produced in two fuselage lengths. The original L first flew in November and entered service with Eastern Air Lines in The shortened, longer range L first flew in and entered service with British Airways a year later. The original-length TriStar was also produced as the high gross weight L, up-rated engine L, and further upgraded L Post-production conversions for the L with increased takeoff weights included the L and L The L 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.
Between and , Lockheed manufactured a total of TriStars, assembled at the Lockheed plant located at the Palmdale Regional Airport in southern California north of Los Angeles. After production ended, Lockheed withdrew from the commercial aircraft business due to its below-target sales. In the s, American Airlines approached Lockheed and competitor Douglas later McDonnell Douglas with the need for an airliner which could carry passengers on transcontinental routes.
In the s the Electra was designed for turboprop propulsion, which Lockheed had successfully used on the C Hercules military transport. 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 and Douglas DC Boeing lost the military contract, but its private-venture captured what would become a much larger civilian airliner market for wide-body airliners. Having experienced difficulties with some of their military programs, Lockheed was eager to re-enter the civilian market with a smaller wide-body jet, and their response was the L TriStar.
Douglas Aircraft answered American Airlines with the DC , which had a similar three-engine configuration and dimensions. By contrast, Lockheed would "take the most advanced technology of the day and when that technology was lacking, Lockheed created it" for the L  in order to give it lower noise emissions in the early s, Eastern Air Lines nicknamed the L "WhisperLiner" , improved reliability, and higher efficiency over first-generation jet airliners.
The TriStar name was selected in a Lockheed employee naming contest for the airliner. It has been said [ by whom? The TriStar's design featured a twin-aisle interior with a maximum of passengers and a three-engine layout. 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 main visible difference between the TriStar and its similar trijet competitor, the McDonnell Douglas DC, is the central tail engine configuration: the DC'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 for reduced drag and improved stability.
The S-duct design also reduced the total empty aircraft weight. The research undertaken during the design of the L indicated that losses of using an S-duct were more than compensated for by the above savings. In theory, the triple spool would produce the same or more power as existing double spool engines while having a smaller cross section that would reduce drag. American Airlines opted for the Douglas DC, although they showed considerable interest in the L American intended to convince Douglas to lower their price for the DC, which they did.
Although the TriStar's design schedule closely followed that of its competitor, McDonnell Douglas beat Lockheed to market by a year due to delays in powerplant development. In February , after massive development costs associated with the RB, Rolls-Royce went into receivership.
The British government agreed to approve a large state subsidy to restart Rolls-Royce operations on condition the U. The TriStar's internal Lockheed model number is L Lockheed discovered fairly early on that the TriStar suffered from higher than estimated structural weight, engine weight, and specific fuel consumption. However, the weight problems affected the weight and desirability of early production L aircraft, known as Group 1 serial numbers through to These aircraft, in general, also have different center of gravity envelopes with the forward center of gravity limit on the early aircraft being more restrictive at higher gross weights.
Groups 1 and 2 aircraft serial numbers to are upgradeable only to or specifications, although the Group 1 aircraft up to serial number still maintain their operating disadvantages.
All L aircraft from serial number onwards are Group 3 aircraft and are fully upgradeable to all variants up to specification. Under state control, costs at Rolls-Royce were tightly controlled and their efforts largely went into the original TriStar engines, which needed considerable modifications between the L's first flight and service entry. The competition, notably General Electric, was very quick to develop their CF6 engine with more thrust, which meant that a heavier "intercontinental" DC could be more quickly brought to market.
The flexibility afforded to potential customers by a long-range DC put the L at a serious disadvantage. Rolls-Royce went on to develop the high-thrust RB for the L and , but this took many years. The resultant delay in Lockheed and Rolls-Royce offering a high gross variant with a longer range, coupled with the TriStar's delayed introduction, meant that only TriStars were sold compared to some DCs.
The TriStar's failure to achieve profitability caused Lockheed to withdraw from the civilian aircraft business. Lockheed lacked the resources to follow up with several proposals based on the TriStar wing and airframe, including a wide-body twinjet and a stretched quad-jet one of the quadjet proposals consisting of two underwing engines and two rear fuselage-mounted engines.
McDonnell Douglas was also financially weakened and could only develop the MD , a refinement of the DC, instead of an all-new design to challenge the next generation of twinjets like the Boeing The L featured a highly advanced autopilot system and was the first widebody to receive FAA certification for Cat-IIIc autolanding , which approved the TriStar for completely blind landings performed by the aircraft's autopilot in zero- visibility weather. It also had a unique direct lift control DLC system, which allowed for smooth approaches when landing, without having to use significant pitch changes while on the approach path.
Thus, rather than maintaining the descent by adjusting pitch, DLC helps control the descent while maintaining a more consistent pitch angle, using four redundant hydraulic systems.
The production also used a unique "autoclave" system for bonding fuselage panels together; this made the L extremely resistant to corrosion.
The prototype first flew on November 16, Dees pilot , Ralph C. Cokely copilot , and G. Fisher development engineer. In a demonstration by test pilots LeVier and Charles Hall, crew members, employees, and reporters embarked on the TriStar for a 4-hour, minute flight from Palmdale to Dulles Airport "with the TriStar's AFCS [Automatic Flight Control System] feature engaged from takeoff roll to landing", and Lockheed touted it as "a groundbreaking moment: the first cross-country flight without the need for human hands on the controls".
TWA heralded the TriStar as one of the safest aircraft in the world in promotional literature in the s when concern over the safety record of the McDonnell Douglas DC , flown by rival airlines, was at its peak.
Delta Air Lines was the type's largest customer. Cathay Pacific eventually became the largest non-U. TWA withdrew its last TriStar from service in To secure the Japanese market, Lockheed secretly bribed several members of the Japanese government to subsidize All Nippon Airways ' purchase of Ls; this caused a significant scandal when the bribes were uncovered.
The Soviet Union at that time lacked a widebody airliner. Development of its own Ilyushin Il was delayed;   consequently, in the mids, the Soviets started negotiations to buy 30 TriStars and license-produce up to a year. In recent years [ when? These operators mainly do their business in the ad hoc charter and wet leasing businesses. The last commercial TriStar flight operated on January 7, The British Royal Air Force had nine aircraft of four variants.
In the early s, Orbital Sciences began to use a converted L named Stargazer to launch Pegasus rockets into orbit around Earth. This venture effectively rendered the small Scout rocket obsolete. The earlier versions of the L, such as the -1, , and can be distinguished from the later models by the design of the middle engine nacelles. The earlier version nacelle has a round intake, whereas the later models have a small vertical fin between the bottom of the middle engine intake and the top of the fuselage.
The two L aircraft delivered to Pacific Southwest Airlines were configured with internal airstair doors that led into an entry hall in what was normally the forward lower baggage hold. This was to allow operations from airfields that did not have terminal buildings with jet bridges. The L FAA certification L was the first production model of the L, designed for short- and medium-range flights.
This variant served as the basis for subsequent variants. Pacific Southwest Airlines purchased two L models with lower deck seating. Launch orders for the L were placed by Saudia and Cathay Pacific , for two each, in May Deliveries began in June The first two Ls serial numbers and were delivered new to Saudia with the same fuel capacity as the L FAA certification L ; these were later upgraded to L specification.
Fuel capacity was not increased. The was available only as a conversion package for the L and was never built new. It was available only as a conversion for the L Although otherwise similar to the , the uses Rolls-Royce RB. Gulf Air used models to replace its earlier-generation Vickers VC10 fleet.
Saudi Arabian Airlines Saudia was a launch customer for the series and operated a sizable fleet until A total of 24 L aircraft were built new, with the first delivered to Saudia on May 28, Like other TriStar improvements, a conversion program has also been offered. The L was an upgrade developed for late-model L aircraft and all L and L aircraft. The more powerful engines, lengthened wing, active-load-control ailerons and other systems that had been developed for the L were adapted into the baseline model.
This variant also used the upgraded RBB4I engine, which could be easily retrofitted to the existing RBB powerplants of the L, but it required a re-engining on the L and L, which used the original RBB. Although it applied to all L models, the upgrade was only undertaken by Delta on six late-model L aircraft.
It was a longer-range variant first flight-tested in Its fuselage length was shortened by 14 feet 4. The variant was popular among international operators and formed a significant portion of the L fleet of Delta and British Airways.
However, its late introduction resulted in many potential customers buying the DC instead. Lockheed developed some aerodynamic improvements for the TriStar which included a modified wing-to-body fairing, a fillet below the central intake, extended wingtips, and "active ailerons" or active control system ACS. The new fairing reduced drag, while the fillet reduced noise in the rear cabin.
The wingtip extensions increased aspect ratio, thus reducing induced drag, but resulted in increased bending. The ACS developed to solve this, provided gust alleviation, improving ride during flight, reduced fuel burn, and increased fatigue life. Earlier TriStar s were delivered with the standard wing; these were later retrofitted with ailerons and extended wingtips. Pan Am was the first customer to order the with the extended wingtips and active ailerons.
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