115,000 flights. That, on average, was the number of commercial flights worldwide that took off each day in 2019. Millions of flights with millions of passengers on board take off each year, yet the majority of the world’s population has never flown.
100 billion gallons. That is the approximate amount of jet fuel used by the aviation industry each year. Traditional jet fuel releases a significant amount of carbon dioxide (CO2) into the atmosphere, which can be damaging to the environment.
Pratt & Whitney, a Raytheon Technologies company, is working to help the aviation industry overcome two of its largest challenges – how to make air travel more accessible and sustainable.
“Pratt & Whitney has always been committed to connecting the world. To do so, we’re making aircraft engines reliable, durable and fuel efficient, so they are more readily available, have fewer maintenance requirements and have lower operating costs,” said Frank Preli, vice president of Propulsion & Materials Technologies at Pratt & Whitney.
By improving engine technologies and fuel efficiencies, Pratt & Whitney can help lower airline operating costs, which allows airlines to keep airfares competitive for their passengers - all while helping to protect the environment.
The path forward
Pratt & Whitney is investing in a number of technology programs to achieve these goals. Each of these four programs moves the needle closer to more sustainable travel for more travelers.
1. Advanced technologies
One way to improve current engine technologies is to substitute newer, better materials into existing designs.
Ceramic matrix composites (CMCs) are one of the revolutionary materials that Pratt & Whitney engineers are using to design jet engines that last longer, withstand higher temperatures and use fuel more efficiently. CMCs are made up of hundreds of thousands of fibers that are no thicker than one-tenth the diameter of human hair. They average about one-third the density of state-of-the-art metal alloys and can withstand temperatures hundreds of degrees higher than traditional metal parts. When engines can run at higher temperatures, fuel is burned more efficiently, in turn making them more sustainable.
“When Pratt & Whitney developed the Geared Turbofan engine, we set a new standard for efficiency. CMCs will take that a step farther through the use of materials with greater thermal capabilities, lower density and increased durability,” said Richard Jones, chief engineer of Pratt & Whitney’s CMC development program.
Pratt & Whitney engineers are working on a number of fronts to put the electrification of aircraft into practice. Among them: a demonstrator known as Scalable Turboelectric Powertrain Technology (STEP-Tech). Engineers at Pratt & Whitney and Pratt & Whitney Canada work alongside teams from Collins Aerospace and the Raytheon Technologies Research Center to find complete or partial electrification solutions of aircraft, dependent on the aircraft size.
Smaller aircraft, like those produced by Pratt & Whitney Canada, have the ability to be completely electric. Hybrid solutions are offered for regional aircraft, while larger aircraft can be partially electrified.
The demonstrator platform will include full end-to-end system capabilities, including a high-efficiency turbogenerator, energy storage, power electronics and modular electrically driven propulsors. Successfully demonstrated technology could then be implemented in a range of aircraft applications.
“[STEP-Tech] is going to play a much more dominating role in the Pratt Canada applications where they have the opportunity to be 100% electric. Not as big of a fuel burn player here [Single-Aisle Market], but combining our efforts with Collins, both P&W LCE and PWC divisions and the RTRC, we really have some valuable unlock opportunities to become the world leaders in hybrid electric technology,” said Amy Comer, vice president and chief engineer for Geared Turbo Fans at Pratt & Whitney.
Another example of these technologies in action: the Hybrid-Electric Propulsion (HEP) demonstrator.
The demonstrator, a modified De Havilland Canada Dash 8-100 regional jet, has both a 1-megawatt electric motor developed by Collins Aerospace and a fuel-burning engine specially adapted for hybrid-electric operation. The result: improved efficiency and lower carbon emissions, with a reduction in fuel burn up to 30 percent compared to existing regional turboprops.
“Hybrid-electric propulsion technology offers significant potential to optimize aircraft across a range of different aircraft applications, helping our industry meet its ambitious goal for achieving net zero CO2 emissions,” said Jean Thomassin, executive director, New Products and Services, Pratt & Whitney Canada.
The ground test program is underway with flight testing targeted to begin in 2024.
3. Sustainable aviation fuel
It’s no secret that traditional fossil fuels emit high levels of CO2, which are a threat to the environment. In support of the aviation industry’s goal of net zero carbon emissions by 2050, Pratt & Whitney is making breakthroughs in the use of more sustainable fuels.
There are many pathways to producing sustainable aviation fuels (SAF). Some SAF are plant-based, others use organic waste and some even start with electricity, making it cleaner and more thermally stable than traditional fuels. All Pratt & Whitney engines are compatible with 50% SAF, and work is underway to validate operations on 100% SAF.
“Alongside our efforts to continually enhance aircraft engine efficiency, SAF has a critical role to play on the journey to achieve the aviation industry’s goal of net-zero emissions by 2050,” said Anthony Rossi, vice president, Sales and Marketing, Pratt & Whitney Canada. “While all Pratt & Whitney Canada engines have already been certified for 50% SAF blends for more than a decade, ensuring readiness to operate with 100% SAF blends in the future will allow us to maximize their potential for decarbonization."
New and innovative technologies are constantly arising that could power aircraft far into the future. One area that Pratt & Whitney have recently taken an interest in is hydrogen-burning engines. While significant industry investments in innovation and infrastructure must take place before hydrogen-powered aircraft take flight, these engines are estimated to have the capability to boost efficiency by up to 30% over today’s best-in-class geared turbofan engines. The future of hydrogen-powered engines could also be pivotal for sustainable aviation, as they produce zero carbon emissions during the combustion process.
Early development projects are in the works to enable future development of hydrogen-burning engines. To bring together an optimized hydrogen cycle, fuel distribution and fuel metering equipment and heat exchange technologies are all required.
“The key takeaway from all of this is that this is a highly disruptive space. We are charting into the unknown,” said Graham Webb, Chief Sustainability Officer at Pratt & Whitney. “There are many disruptive startups that are entering, but they lack the decades of experience and expertise that we possess at Pratt & Whitney.”
Pratt & Whitney is investing in a wide range of technologies, but all with a common theme: it takes engineers – real professional problem-solvers – to bring them to life. Because of Pratt & Whitney engineers, the future of air travel is geared to be a more sustainable and accessible experience for travelers everywhere.
“This is a company with a legacy of innovation, being the company of choice when the highest performing engines are needed,” said Preli. “We’re continuing on this path, powered by bright talent who can tackle tough problems as we move into the future of the aviation industry.”