When it was first released, the Lockheed L-1011 Tristar was the most advanced widebody aircraft. It was the second long-range widebody tri-jet to be introduced, competing directly with McDonnell Douglas’ DC-10. The Tristar was the most advanced aircraft at the time of its release and remains the sole commercial jet passenger transport aircraft produced by the Lockheed Corporation.
The L-1011 Tristar, much like the DC-10, is equipped with three engines, two on the wings and one at the top of the fuselage’s end. It has the capacity to carry 256 passengers in a mixed-class configuration and boasts a range from 4,963 km (L-1011-1) to 9,899 km (L-1011-500). It is powered by three Rolls Royce RB-211 turbofan engines, each offering a maximum thrust between 42,000 lbf and 50,000 lbf.
Lockheed constructed the L-1011 in Palmdale, California, just north of Los Angeles, in two fuselage lengths. The models were the L-1011-1 and L-1011-500. Lockheed offered the L-1011-1 at high gross weights until the Rolls Royce RB211-524 engine became available. Existing L-1011-1s could also receive upgrade kits.
In total, only 250 Lockheed L-1011 Tristar aircraft were built. Production ended in 1984.
Difference between the Lockheed L-1011 Tristar and the McDonnell Douglas DC-10
The main distinction between the L-1011 Tristar and the DC-10 was in the layout of the Number 2 engine, located at the rear of the fuselage. Whereas McDonnell Douglas mounted their engine above the fuselage as part of the tail, Lockheed chose an internal fuselage mount.
The Lockheed system resembled the Boeing 727 a lot. The engine was housed inside the tail cone of the fuselage, and the air intake was an S-bend that brought air from the top of the fuselage down into the engine. The curves of the S-bend were gentle enough not to obstruct airflow. Any performance loss from this configuration was offset by the absence of weight penalties associated with external mounts and nacelles.
The L-1011 was also more advanced than the DC-10. At the time of its launch, it was equipped with these advanced technologies:
- Advanced Auto Pilot – Cat-IIIc auto landing was rated for the advanced auto-pilot. In other words, the auto-pilot on the L1011 was capable of landing in zero visibility conditions.
- Direct Lift Control – The DLC system made landing approaches much smoother. Instead of large changes in pitch as the aircraft progressed through the approach stages, the wing slats were automatically deployed and adjusted to achieve the same result. This allowed for a more stable pitch during the landing phase.
These technologies enabled the plane to land by itself on autopilot. However, all these advancements in the Tristar meant that the aircraft was more expensive than its competitor, the DC-10. This did not sit well with the market, as customers preferred to add a little more and opt for a Boeing 747 instead.
Another disadvantage of the L-1011 Tristar was Lockheed’s insistence on only one engine option, the Rolls Royce RB211. Whereas McDonnell Douglas offered more flexibility with engine options for the DC-10, Lockheed remained committed to cutting-edge technology. The RB211 concept was undoubtedly superior to other available options at the time, but it came at a high cost.
Delays and losing to the DC-10
Because of the high development costs, Rolls Royce went into receivership. It was only because of heavy subsidies from the British government that development could continue. To ensure that their funding of Rolls Royce was not wasted, the British government required the US government to guarantee any loans needed by Lockheed to complete the L-1011 project.
From this point forward, Rolls Royce was run much like a government department. This ensured that the RB211 project was completed, but it hampered any additional development. As a result, the more powerful RB211-524 arrived on the market many years later, well behind General Electric’s CF6.
Because of these challenges, sales were delayed by two years. Lockheed was unable to secure American Airlines as a launch customer, and the airline instead chose the DC-10.
Lockheed produced 250 Tristars between 1968 and 1984, out of a total of 500 required to break even. Perhaps this is a classic example of a product targeting too small a market. Following the completion of the Tristar, Lockheed exited the commercial aviation market. While McDonnell Douglas met their target with the DC-10, they failed to follow up with the MD-11 and eventually merged with Boeing.
Tri-jets were gradually replaced by ultra-long-haul, twin-engine ETOPS (Extended-range Twin-engine Operations Performance Standards) rated wide-body aircraft such as the Boeing 777, Boeing 787, Airbus A330neo, and the Airbus A350.
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