Story ID: 317
Trent Engine Marks Silver Anniversary
By: Ian Goold
Caption: The first variant of the Trent engine entered service in February 1988.
Word Count: 786
Rolls-Royce's Trent high-bypass turbofan engine is 25 years old and the most-recent Trent XWB (TXWB) iteration is the latest variant. "We cannot say it is the last, as we do not know what opportunities may arise," the company told AIN.

What Rolls-Royce (Chalet N23) calls a "global aviation success story" began in April 1987 when the company returned to private hands from state ownership with a minuscule share of the widebody-engine market. It embarked on a program to build powerplants for all large-airliner programs.

Using RB211 three-shaft architecture—whose high-, intermediate-, and low-pressure systems could be individually scaled around a common core—it developed the Trent family that was launched at the 1988 Farnborough Airshow. On February 28, Rolls-Royce celebrates a quarter-century since delivering the first Trent 700s (T700s), which entered service powering a Cathay Pacific Airways Airbus A330 some 25 days later.

Today, the familiar marque comprises seven variants: Trent 500 (T500), T700, 800 (T800), 900 (T900), 1000 (T1000), TXWB, and 7000 (T7000), with Rolls-Royce claiming each has been the market leader on its designated aircraft and/or first into service on that aircraft. It says that 25 years does not represent "even half" the eventual story because Trents continue in production to meet demand and will be in service for decades.

Rolls-Royce civil-aerospace president Chris Cholerton acknowledges challenges along the way, saying "We are absolutely [committed] to dealing with any issues to ensure the Trent family remains an outstanding product." Nevertheless, with "thousands more Trent engines [in backlog] for the coming decade," the company is preparing for the future through planned UltraFan geared-engine and electrification projects.

To meet "ever-greater demand" for maintenance service, Rolls-Royce is increasing its service network, including authorized maintenance and customer-service center partners. The company is developing new inspection techniques and is investing in new facilities to further improve engine throughput.

The planned 7,500-sq-m Testbed 80 at its Derby (UK) headquarters will run Trent engines this year and the UltraFan demonstrator will start ground-testing there in 2021. UltraFan development plans, including a 25 percent improvement in fuel consumption over the very first Trents, aim for service availability "towards the end of this decade."

The Trent family has logged 145 million engine flight-hours, currently serves with 132 customers, and has made the manufacturer into a company with an 8 percent widebody-market share to one that powers almost half of the global twin-aisle fleet. 

Over the years, Rolls-Royce has developed a family of continuously improved engines, with common architecture permitting new technology to flow into mature variants from later models to enhance performance through retrospective upgrades.

Not that Rolls-Royce is resting on its laurels: a current effort towards the UltraFan has its roots early in the past decade when work began on a Trent-replacement family. As long ago as 2013, then-Rolls-Royce research and technology director Ric Parker discussed potential developments, including the RB3039, a concept that would be “quite radically different” from the RB3025. At the time, the RB3039 was Rolls-Royce's most powerful turbofan on offer for the Boeing 777X and seen with the potential to enter service by 2015.

The route to the now established seven-strong Trent family is marked by stepping stones that illustrate the engine's evolution and cross-fertilization of complementary ideas. The Trent was derived from the RB211 (developed for the Lockheed L-1011 TriStar, the initial Trent 600 having been based on the RB211-524L).

Feedback from the T700 provided upgrades for the RB211-535 and much older -524G/Hs. In turn, the T700 benefitted from T800 and T1000 development, T900 technology was applied to the T500, and the latest TXWB has fed the T1000.

Initially, the T600 was to have powered British Caledonian and Air Europe McDonnell Douglas MD-11s, but the variant was downgraded to demonstrator status after both airlines collapsed. New-engine development switched to the T680 and more-powerful T720, which was the first true Trent and first ran in August 1990 then was certificated in January 1994.

In the late 1980s, Rolls-Royce proposed the T760 when Boeing was exploring a larger 767 variant that eventually morphed into the 777. Among other "Trents that never were" is the T8104, a growth variant built for the longer-range 777-200LR and 300ER and subsequently scaled up to the 117,000-pound-thrust T8115. Rolls-Royce withdrew that engine when Boeing requested it share the risk, and the T8104 became a demonstrator engine and contributed technology to the later T1000.

A T500 replacement engine, known unofficially as the T1500, was proposed to enhance the Airbus A340-500/600 before that model was usurped by the A350. For the A350 XWB, Rolls-Royce initially considered a conventional bleed-air T1000 variant (dubbed T1700) with a throttle-push to 75,000 pounds of thrust.