A Dream Run – Rolls-Royce Trent Engine

In 1990 Rolls-Royce introduced the Trent engine series to the aviation world. The engine promised to lower atmospheric pollution in the most economical and technologically advanced way.

Today, the engine that is a part of Rolls-Royce’s high-bypass turbofan family, stemming from developments made on the earlier RB211 engine, has a whole new significance. The emergence of a new-world (and corporate) climate of environmental awareness and the slow but sure rise of carbon markets have given rise to a new market for the Trent engine, and made it a more significant piece of aerospace engineering than anyone back then could have thought.

TRENT ENGINE INNOVATION

Rolls-Royce has created a variety of Trent engines, each with their own unique characteristic: the Trent series 500, 700, 800, 900, the latest Trent 1000 and the Trent XWB. The whole Trent family is designed to power jets including the Airbus A330, the iconic high-capacity Airbus A380 (which entered service in 2007), the Boeing 787 (entering service in 2008) and the Airbus A350 XWB.

Like its predecessor the RB211, the Trent uses a three-spool design rather than two. And while the Trent is a more complex engine, it benefits from a lighter weight, and a shorter, more rigid engine which suffers less performance degradation.

Through innovative technologies the Trent engines and their three-shaft architecture allow high-pressure, mid-pressure and low-pressure systems to be individually scaled from existing designs, providing maximum operational flexibility. This provides lower developmental costs, ensuring optimised, high-performance engines for specific aircraft applications with class leading economics that are primarily engineered to minimise environmental impact.

With the introduction of the diffusion bonded / super plastically formed (DB/SPF) wide-chord fan on the Trent 700, Rolls-Royce has made technological advances on all Trent family engines. Three-dimensional aerodynamics and tiled combustors were brought in to improve durability and lower maintenance on the Trent 500, and the Trent 900 saw the launch of the contra-rotating high-pressure system engine and uses a low
NOx combustor, and a 116in swept fan, all of which have been designed to reduce fuel consumption.

REACHING A MARKET

In 1990, environment, and even more so corporate responsibility, was an issue already being highlighted to the aerospace industry, especially where passengers were involved. But no one could have guessed how important both issues would become to future flight.

Carbon markets (carbon credits and carbon trading) tackle climate change, and works by setting industry a quota of permits to emit carbon dioxide. Under the model – the EU already has its emissions trading scheme in place – companies can trade, buy or sell emissions tokens. If a quota is outrun, fines are handed out. Carbon trading has, hence, allowed the Trent engine to meet both financial and environmental concerns.

Statistics show the Trent engines produce 15% lower emissions than their counterparts. This fuel economy and the lowering of carbon dioxide emissions into the atmosphere sees the Trent engine family at the top of the market, as reflected in global orders and contracts.

But unlike some environmentally friendly modifications made in other forms of transport, the Trent engine actually improves power and performance, instead of lowering it. It also helps reduce engine audibility, helping airlines fight back against noise complaints.

TRENT 700

The Trent 700, for example, was specifically designed for the A330 Airbus, with a 97.4in-diameter fan, and was the first engine in the Trent family. Rolls-Royce says it is also the quietest and cleanest option for the A330 twinjet Airbus. This results in better lifetime performance for the engines, along with improved reliability and maintenance costs. It has the lowest fuel burn, which is analogous to lower emissions.

The 700 had its first run in 1990 and was certified in 1994 and although The Trent 700 has 53% of the market in general, in the last five years Rolls-Royce has secured 70% of all orders in this space. It is predicted that, over the next three years approximately 60% of A330 deliveries will be Trent 700 powered, and the number of Trent engines delivered will be equivalent to 80% of the entire number delivered to date.

THE TAKERS

Thai Airways is the latest airline to show its support of the Rolls-Royce Trent engine. It chose the Trent 900 in May 2008 for its six-strong fleet of Airbus A380s. At engine list prices, the deal is worth $500m. Overall the Trent 900 has 58% of the engine market stitched up for the A380.

Sichuan Airlines of China chose the Trent 700 for its small fleet of the Airbus A330 – 200 twinjets from AerCap. It is the 53rd customer or operator to select the A330 and will take delivery of its first aircraft in 2010. The Trent 700 has a 100% share in mainland China, with 138 Trent powered A330s delivered, or on order, as of April this year. Sichuan Airlines followed US Airways which also selected the Trent 700 to power its 30 Airbus A330s. It will take delivery of its first Trent-powered A330 in 2009.

But invariably, it has been engines designed, like the Trent 900, for aircraft released in the last year that have that have enjoyed the most attention. The Trent 900 may be the stuff of ‘super’ heroes, but the 1000, for many operators, is the stuff of dreams.

DREAMLINER AND THE TRENT 1000

The Trent was developed especially to power the Boeing 787 Dreamliner, designed especially for better fuel economy. The first test run for the Trent 1000 was on 14 February 2006, and to the joy of Rolls-Royce it went without a hitch.

The Trent 1000 is a bleedless design, with power take-off from the intermediate pressure spool instead of the high-pressure spool as is the case with the other Trent engines. It also has a 112in diameter swept-back fan, with a smaller diameter hub, to help maximise airflow.

The bypass ratio has been increased over previous variants by suitable adjustments to the core flow. Contra-rotating the intermediate pressure and high-pressure spools improve intermediate-pressure turbine efficiency.

The Trent 1000 started (electrically) first time, using a new design feature called IP power off-take, which reduces fuel burn, brake wear and noise output. This involves dual-use starter generators that act as both electrical starters on the ground and power generators whilst airborne.

In flight, power is created by mechanically driving the generators using the engines intermediate pressure compressor, including power for the cabin environmental conditioning system (ECS), rather than taking conventional bleed air.

Each Trent 1000 engine is capable of generating about 0.5MW of electrical energy to power the increased number of electrical systems used in the Boeing 787. It has 15% lower fuel burn than engines from a decade ago, and when first developed, delivered 40% fewer emissions into the atmosphere than was required by international legislation.

With a range of thrust from between 53,200lb to 75,000lb, the Trent 1000 is capable of powering all versions of the 787 Dreamliner. Further developments for the Trent 1000 engine on the Boeing 787 include the use of intelligent engine health monitoring (IEHM) systems. This utilises predictive maintenance technology, which reduces maintenance disruption and increases wing time.

The Trent 1000 will begin commercial operations with ANA (All Nippon Airways) soon (mid 2008). But when initial production began in 2006 there were already firm orders in place for the Trent 1000 engine. For example, clients such as Air New Zealand, Icelandair and LOT Polish Airlines, to name a few, have already placed orders. In January 2008 the Trent 1000 had captured 41% of the market, owing to British Airways purchasing a further 24 engines.

BEYOND COMMERCIAL USE

The world’s air force contingent is said to emit far more CO2 than commercial operations. So it was no surprise when in March, Rolls-Royce welcomed the UK Ministry of Defence’s £13bn contract for its Trent 772B engines for the Airtanker consortium for the UK’s future strategic tanker aircraft.

This ongoing 27-year contract, estimated to be worth more than £700m, will see Rolls-Royce (a shareholder in the Airtanker consortium) provide the RAF with its air transport and air-to-air refuelling requirements for 23 years from 2011.

The RAF, on the other hand, will benefit from high levels of fuel efficiency and the highest thrust available on the A330 resulting in increased operational flexibility. Also, it is the only engine with a full-length cowl, known for reducing infrared signatures.

Rolls-Royce is working hard to improve the environmental impact of its engines. Last year for example, Rolls-Royce (and partners) invested £800m in research and development – two-thirds of which is aimed at reductions in carbon emissions and noise.

Whatever the outcome of the law with regard to carbon trading and emissions, the release and evolution of the various Trent engines has had the desired effect of lowering the output of carbon pollution globally. The Trent engine’s ultimate success in the aviation market hinges on this very important fact.