game-changing technologies drive engine efficiencies

March 12, 2019

The next generation of powerplants is the most efficient and most reliable generation of aircraft jet engines yet. Thanks to the implementation of new technologies into business aircraft engines, manufacturers now have access to more power, better performance and increased fuel efficiency. Volker K. Thomalla reports

Business aircraft manufacturers are demanding customers: they want engine manufacturers to constantly enhance their products in terms of efficiency, reliability and sustainability. They also tend to get what they want. The next generation of business aircraft powerplants, which are about to enter into service, use less fuel and have lower emission all while offering more power, better performance and higher reliability. Below, we take a look at some of these high-tech engines.

Rolls-Royce

Rolls-Royce introduced the Rolls-Royce Pearl 15 turbofan, the first member of a new engine family specially designed for business jets, at EBACE 2018. In terms of value, the British company is the world’s leading engine supplier for Business Aviation, powering over 3,000 aircraft and owning a 42% market share. The Pearl family should help keep – or even expand – this market share in the future.

The new engine, which was developed at Rolls-Royce’s Centre of Excellence for Business Aviation Engines in Dahlewitz, Germany, is already EASA certified. It has also been selected by Bombardier Business Aircraft to power its ultralong-range Global 5500 and Global 6500.

The Pearl builds on the legacy of the highly successful BR700 engine family and benefits from technologies that Rolls-Royce has developed and matured with its Advance2 demonstrator program. The Pearl’s fan consists of 24 lightweight titanium blades, delivering a bypass ratio of 4.8:1. The fan’s diameter is 48.5 inches (1.23 meters). The engine features an Advance2 core with a 10-stage high pressure compressor, as well as a new two-stage shroudless high pressure turbine. This turbine was especially designed for the Pearl 15 and provides enhanced aerodynamics and blade cooling. The high-efficiency, low pressure turbine was designed for low noise emissions, contributing to the overall quietness of the engine. It is designed to deliver 2 decibels less noise than the BR700 turbofans.

Advanced materials like nickel alloys and ceramic coatings have found their way into the engine core to enhance efficiency by allowing higher operating temperatures and pressures. The Pearl’s overall pressure ratio is at 43:1, while the bypass ratio is at 4.8:1.

The advanced digital engine health monitoring system (EHM) is constantly collecting engine data that is analyzed and offers flight and maintenance crews an unprecedented level of engine intelligence. An advanced engine vibration detection feature helps operators detect developing problems at the earliest stage.

The Pearl 15 offers 15,125 lbs (67.3 kN) of thrust and a 7% reduction in specific fuel consumption compared to today’s engines. In terms of emissions, the Pearl engine family will set new standards, too. With the Pearl 15, Rolls-Royce has introduced a new ultra-low emissions combustion system, including a tiled combustion chamber that reduces engine emissions well below today’s – and even tomorrow’s – regulatory standards.

“Our teams have worked hard behind the scenes to develop this new engine and we are proud, once again, to lead the way in Business Aviation,” says Rolls-Royce President of Civil Aerospace Chirs Cholerton. “The Pearl engine is a pioneering product, bringing together the most eco-friendly and efficient technologies available today.”

The Rolls-Royce Pearl is being tested at Bombardier’s Flight Test Center in Wichita, Kansas. It is expected to enter into service in late 2019 with the Global 6500. Rolls-Royce expects that the Pearl 15 will have accumulated about 2,000 cycles and over 6,000 hours by Entry Into Service (EIS). So far, the company has delivered over 1,700 engines to Bombardier.

Pratt & Whitney Canada

In terms of units delivered, Pratt & Whitney Canada is Business Aviation’s leading engine manufacturer, celebrating the delivery of its 100,000th engine last year. This year, the Canadian manufacturer is celebrating the EIS of its newest and largest turbofan, the PW800 PurePower, with the Gulfstream G500. Gulfstream has also chosen the PW800 for the G600, the larger sibling of the G500, while Dassault Aviation has selected the PW800 for its newest long-range Falcon 6X. P&WC has a team of about 150 employees dedicated to the smooth EIS of the powerplant.

The PW800 covers the 10,000 to 20,000 lbs class of turbofans and was originally developed for the Cessna Citation Columbus, which was cancelled in 2009. Gulfstream’s G500 received its type certificate from the FAA in July 2018. Powered by two PW814G turbofans, each rated with 15,144 lbs of take-off thrust, the G500 exceeded its originally-guaranteed performance specifications. The G500 can fly 5,200 nm (9,630 km) at its long-range cruise speed of Mach 0.85, providing operators even greater mission flexibility over the aircraft’s original 5,000 nm (9,260 km) range. At its high-speed cruise of Mach 0.90, the G500 will offer 4,400 nm (8,149 km) of range – a 600 nm (1,111 km) increase over its projected range of 3,800 nm (7,038 km).

The PurePower engines are future-proof. Their advanced TALON X combustors are, for example, designed to use new types of sustainable fuels that are set to shape the future of aircraft fuel. Gulfstream is already doing all their company flying using a 30/70 blend of biofuel and Jet-A-fuel.

The PW800 PurePower turbofan is optimized for high-flying, fast, long-range business jets and shares the same proven core technology used in Pratt & Whitney’s PurePower family of geared turbofan commercial engines that power the Airbus A320neo family, as well as the Embraer E2 family. The advanced common core technology, employed in 16 different PurePower engine applications, has amassed more than 750,000 in-service hours.

Other technological highlights of the PW800 include an advanced single-piece fan that offers low maintenance cost and improved noise and vibration characteristics, an advanced dual-channel FADEC (Full Authority Digital Engine Control) with advanced engine diagnostics, prognostics and health monitoring, and a mixer with an innovative design for high efficiency. The health monitoring system allows Pratt & Whitney Canada to offer a 10,000-hour time-between-overhaul (TBO) for the engine with no midlife-inspection required.

GE Aviation

GE Aviation developed the GE Passport turbofan engine for the 14,000 to 20,000 lbs thrust class. It combines game-changing technologies that the company has developed for the GEnx commercial engines that power the Boeing 787 Dreamliner, as well as for the GP7000, which powers the Airbus A380. The high-bypass engine (bypass ratio 5.6:1) features an overall pressure ratio of 45:1. Its 52 inches (1.3 meters) fan blisk is the first application of such technology on an engine of this size (blisk fans are usually found in smaller engines like the Williams FJ44 turbofans). The fan’s 18-inch-wide chord-forged titanium blades are friction-welded to the hub. The fan is about 30% lighter and its blades are much more damage-tolerant than conventional fan blades.

GE Aviation is providing the engine to OEMs as a complete system that includes the nacelle and thrust reverser. The combustor burns lean and emits ultra-low NOx. According to the company, it features the lowest overall emissions in its class. A technological masterpiece is the software that modulates the turbine clearance throughout flight, so there’s no rubbing while allowing for much tighter clearance – which enhances the overall efficiency of the engine. Passport-equipped aircraft will be neighborhood-friendly aircraft, as their noise emissions are well below certification levels. This is not only beneficial for people on the ground, but for the passengers as well, as the Passport ensures minimal cabin noise levels, thus providing a productive environment for the passengers on board.

The Passport first flew in 2015 and was certified by the FAA in 2016. It has been selected by Bombardier Business Aircraft to power the brand-new Global 7000 and Global 8000. The fifth and final flight test vehicle of the Global 7000 took to the air for the first time in January this year. Bombardier targets an EIS of its newest and largest Business Aircraft before year-end 2018. By that time, GE Aviation expects that the Passport engine will have accumulated over 4,000 flight hours and over 8,000 cycles.

GE Aviation is working to revolutionize the turboprop engine too. It is developing and testing the Catalyst turboprop engine for Textron Aviation’s new Cessna Denali single-engine turboprop, which should make its first flight early next year. The Catalyst is the first all-new, clean-sheet turboprop engine on the market. GE Aviation is testing the first two engines in its Prague, Czech Republic, facility. The new powerplant promises to deliver up to 20% better fuel burn and up to 10% more power than today’s turboprop engines.

Pilots will operate the engine with a single-lever FADEPC (Full Authority Digital Engine and Propeller Control) that controls all engine parameters, as well as the propeller. By coupling the new turboprop with GE’s software platform Predix, the GE Catalyst is the smartest engine in its class. Best-in-class connectivity and access to critical engine health information makes the Catalyst the only turboprop engine with near real-time troubleshooting and diagnostic support no matter where the operator flies the aircraft.

GE Aviation is applying a highly automated manufacturing process for the engine and is using an unprecedented level of additive manufacturing in its production. Only 12 “printed” components will replace the 855 parts typically found on a conventionally produced turboprop engine.

Silvercrest

There’s a question mark about the future of the Silvercrest turbofan. The all-new turbofan has been plagued by several technical problems, which delayed the program by several years and ultimately led to the cancellation of Dassault Aviation’s Falcon 5X. When they relaunched the aircraft as the Falcon 6X, they switched to Pratt & Whitney Canada’s PW800 turbofan instead.

Although Textron Aviation had chosen the Silvercrest for its Cessna Citation Hemisphere, in April the company announced that it had suspended all work on the program for the time being. According to Textron, the company wants to see how the engine plays out and then will make their decisions based on the performance of the engine. If Textron Aviation decides to switch from the Silvercrest to a different powerplant, it might be the end of the line for Safran Aircraft Engines.

Honeywell Aerospace

Honeywell Aerospace is expecting the Entry Into Service of Textron Aviation’s Cessna Citation Longitude in the coming weeks. All certification test flights were completed in July this year. Even if it’s a new application for Honeywell’s HTF7000 turbofan, it should be routine for the engine manufacturer, who has delivered nearly 2,000 engines of this type. The Honeywell powerplant is a mature engine with over 3.5 million flight hours. The HTF7000 already powers five different types of business jets: Bombardier Challenger 300 and Challenger 350, Embraer Legacy 450 and Legacy 500 and the Gulfstream G280. The Citation Longitude is powered by two HTF7700L turbofans, each rated at 7,550 lbs take-off thrust.

Williams International

Williams International is providing the engines for most entry-level and light jets. In February this year, the Williams FJ44-4A debuted on the Swiss-made PC-24 jet when it was delivered to its launch customer. Since then, Pilatus has delivered four additional aircraft and intends to deliver a total of 23 PC-24 this year. The FJ44-4A on the PC-24 features a unique “Quiet Power Mode”, which eliminates the need for an APU. When operated in Quiet Power Mode on the ground, the FJ44-4A provides energy to power the PC-24’s on board electrical systems, including the heating and cooling systems. This solution is quieter than an APU and offers the aircraft independence from any source of ground power. The PC-24 is the first jet that offers this feature.