The Lockheed L-1011 TriStar is an American medium-to-long-range, wide-body trijet airliner built by the Lockheed Corporation. It was the third wide-body airliner to enter commercial operations, after the Boeing 747 and the McDonnell Douglas DC-10. The airliner has a seating capacity of up to 400 passengers and a range of over 4,000 nautical miles. 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 aircraft has an autoland capability, an automated descent control system, and available lower deck galley and lounge facilities.
Lockheed L-1011 TriStar
TWA Lockheed L-1011-1 Tristar twin-aisle cabin in 1972
L-1011 with an S-duct engine
Prototype L-1011 TriStar being prepared for its first flight test in 1970
A trijet is a jet aircraft powered by three jet engines. In general, passenger airline trijets are considered to be second-generation jet airliners, due to their innovative engine locations, in addition to the advancement of turbofan technology. Trijets are more efficient than quadjets, but not as efficient as twinjets, which replaced trijets as larger and more reliable turbofan engines became available.
One of the first trijets was the Boeing 727 airliner.
Dassault Falcon 900EX. The 900 and its derivatives, the Falcon 7x and 8x, are the only trijets in the world currently in production.
"Straight-through" central engine layout on the DC-10-based KC-10
The McDonnell Douglas MD-11 is the most recent airliner-size trijet produced.