Remembering the most popular trijet commercial planes

Three-engine widebody aircraft, also known as trijet commercial planes, are no longer seen, but they did make their mark in the aviation industry in the 1970s and 1980s. These popular trijet commercial planes are no less than the McDonnell Douglas DC-10, the Lockheed L-1011 Tristar, and the Boeing 727.

Today, trijets have been replaced by twin-engine long-range aircraft such as the Boeing 787 and the Airbus A350. However, it is nice to remember how these trijet commercial planes shaped aviation history.

Due to its advanced turbofan technology and novel engine placement, tri-jet commercial planes are categorized as second-generation jet airliners. More efficient than quadjets, trijets were phased out in favor of twinjets as bigger, more dependable turbofan engines became standard.

Why were the trijets built?

The Tupolev Tu-73 bomber prototype took to the air for the first time in 1947 as the first trijet design to do so. Hawker Siddeley Trident in 1962 and Boeing 727 in 1970 were the first commercial trijets 1963. Both the Trident and the 727 had to make concessions in order to satisfy the demands of many airlines; in the case of BEA, this meant adapting to the company’s shifting priorities. However, the manufacturers ultimately decided against working together. 

Trijets were widely considered the best configuration for the medium wide-body jet airliner, fitting between the larger and more expensive quadjets (four-engine aircraft) and the more compact and less expensive twinjets, and this sparked a flurry of trijet designs for the next generation of jet airliners.

A plane between huge 4-engine aircraft and small twin-engine planes

Although the long-range and massive size of the four-engine Boeing 747 made it a popular choice for transoceanic flights, not all routes were able to load the plane to capacity, and the Airbus A300 twinjet was initially only capable of flying short to medium distances.

For example, the McDonnell Douglas DC-10, Airbus A300, and Boeing 767 all used the General Electric CF6 engine, but the DC-10’s third engine gave it an edge over the A300 and 767 twinjets in range and/or cargo. US airlines sought for trijet designs like the DC-10 and L-1011 TriStar for local and transatlantic flights because they offered the best compromise between medium-to-long range and medium size.

In the 1980s, when trijet wide-bodies were at their peak, they made up the vast majority of all such US jet airliners thanks to the widespread adoption of the Boeing 727.

The advent of long-range twinjet widebody aircraft

The number of operational trijet commercial planes dropped from 1488 to 602. In contrast, the number of twinjets had increased by more than a factor of four during that time.

Lockheed ended production of the L-1011 in 1984 after manufacturing just half the units required to break even, while sales of the DC-10 were stalled by a succession of catastrophic accidents. Both companies had been harmed financially by competing in the widebody market.

Boeing ceased manufacture of the 727 in 1984 because updating the plane’s central engine compartment to accept quieter high-bypass turbofans would have been too costly. The A320 from Airbus and the 737 and 757 from Boeing quickly took its place.

Thanks to the development of high-bypass turbofan technology and the consequent easing of airline safety regulations, massive twinjets powered by purpose-designed engines like the General Electric GE90 on the 777 have rendered the trijet and even the quadjet almost obsolete for passenger services.

Douglas DC-10

The McDonnell Douglas DC-10 was available in three primary configurations: the Series 10 for flights up to 3,500 miles (5632 kilometers), the Series 30 for flights up to 6,000 miles (10,609 kilometers), and the Series 40 for flights over 10,000 miles (16,219 kilometers). Both the passenger/cargo convertible DC-10 and the military’s aerial tanker, the KC-10, were based on the original DC-10 design.

The three-engine DC-10 was revolutionary not just because of the comfort and space of its broad cabin, but also because of the technological leaps it represented in propulsion, aerodynamics, construction, avionics, flight control systems, and environmental compatibility.

The DC-10 began its manufacturing in January 1968. It was developed and produced in Long Beach, California. The first giant was delivered in 1971, and the last one was sent out in 1990. As of 1990, the Air Force had received 60 KC-10 tanker/cargo DC-10s while the commercial fleet had received 386 DC-10s.

The DC-10 was the largest among all trijet commercial planes.

Lockheed L-1011 Tristar

Among the trijet commercial planes, the Lockheed L-1011 TriStar was an engineering marvel. Its low-set wings and elegantly swept tail gave it a sleek appearance reminiscent of a dolphin’s. But in the air, the L-1011 was a marvel, the first commercial aircraft to be able to land without any human input whatsoever.

The L-1011 was conceived in the middle of the 1960s to carry 250 passengers on popular transcontinental routes, and it featured unprecedented comforts such as glare-resistant windows, full-sized hideaway closets for coats, and a below-deck galley that transported filet mignon and lamb chop dinners to the main cabin via two elevators.

Eastern Airlines gave the L-1011, which they flew, the nickname “Whisperliner” because of how quiet it was during takeoff and landing. Production of the plane lasted until 1983. There was a phenomenal 98.1 percent dependability rating for the L-1011 fleet.

Unfortunately, financial difficulties were too great to ignore. Lockheed constructed a total of 250 TriStar planes, and the L-1011 was the last commercial passenger aircraft it ever made. But they went out on top, having built what one pilot called “the most intelligent airplane ever to fly.”

Boeing 727

With its swoopy T-shaped tail and three turbofans in the back, the 727 stood out from the fleet of early Boeing planes. It transported many people on local and long-distance trips alike.

The 727 was Boeing’s first trijet commercial plane to feature fully powered flight controls, triple-slotted flaps, and an auxiliary power unit, and to undergo extensive fatigue testing (APU). Because of the APU, basic airports in poor nations no longer needed ground power or starting equipment.

The first 727 was completed on November 27, 1962, and it shared the Dash 80’s livery by being painted lemon yellow and copper brown. The number of orders had fallen short of the projected break-even mark of 200 by the time the plane had its first flight on February 9, 1963. Boeing deployed a 727 on a 26-nation, 76,000-mile tour to boost sales.

Boeing had intended to manufacture 250 of the aircraft initially. But demand was so high (particularly when the bigger 727-200 variant, which could seat up to 189 people, debuted in 1967) that 1,832 were manufactured in the Renton, Washington facility. Among the variants was a passenger-to-cargo version that could switch between the two modes with the use of the Quick Change (QC) feature, which included seats and galleys that were linked to detachable pallets.