Smaller lighter engines, 3D printed parts, and more electrical engineers are needed for the next era of flight
THE INSTITUTEThe aerospace industry is under intense pressure to reduce its impact on the environment. Between 2021 and 2035, the industry will have to offset a total of 2.6 billion metric tons of carbon dioxide under the Carbon Offsetting and Reduction Scheme for International Aviation, an emissions mitigation approach for the industry.
GE Aviation is one company that is working to meet the mandates by increasing the electrification of the aircraft it builds. The company produces 65 percent of all commercial airplane engines. It also has a large market share of components and integrated systems for commercial, business, and general aviation aircraft. Every two seconds, an aircraft powered by GE technology takes off somewhere in the world, the company says.
Its electrical power technology chief, IEEE Fellow Hao Huang, along with his colleagues, is developing hybrid electric propulsion systems and exploring additive manufacturing of airplane parts.
He is the recipient of this year’s IEEE Transportation Technologies Award for his “quest to develop ‘more electric aircraft,’ with electric systems in place of today’s pneumatic and hydraulic ones for quieter, more fuel-efficient, and environmentally friendly flight.”
In this interview with The Institute, Huang discusses some of GE’s current projects that have been made public and talks about challenges facing the aerospace industry, including a shortage of skilled engineers.
Conventional jetliners have engines or propellers that rotate to move the aircraft forward or take off. In addition to the engines, there are three other systems. The hydraulic system uses pressurized fluid to move and actuate landing gear, brakes, and flight control surfaces, which are aerodynamic devices allowing a pilot to adjust and control the aircraft’s flight attitude. The pneumatic system bleeds air off the engines to power environmental control and protection from ice. The electrical system provides power to the engines as well as to equipment in the cabin.
The auxiliary power unit (APU), generally located at the rear of the aircraft, produces energy to power systems when the plane is on the ground as well as supplying energy needed to start the engines.
To make today’s planes ‘more electric’ requires changing the systems, Huang says. For example, the engine needs to be more electrical, the aircraft’s body more “actively” aerodynamic, and materials lighter to improve efficiency.
Huang points to the Boeing 787 Dreamliner, which uses electricity instead of pneumatics to power its environmental control system, to start its engine, and protect the wings from ice. The plane uses six generators to create more electricity. Two are located on each engine, and two are on the APU. The 787 also features a frame constructed primarily of composite materials.
PROJECTS IN THE WORKS
Huang and his team are working on multiple electrification projects that have the potential to save fuel. One of its programs aims to eliminate the pneumatic bleed system and other parts to make planes lighter. Components such as bleedless turbo fans, high-speed generators that operate at around 270 DC volts, and high-speed solid-state DC circuit breakers are expected to reduce a plane’s weight by about 450 kilograms, Huang says.
GE has demonstrated engines that can more efficiently convert fuel to electricity. The company modified an F110 engine to generate 1 megawatt of electric power, for example. A megawatt of power is equivalent to 1,341 horsepower. The high-power-density device was tested at the company’s US $51 million Electrical Power Integrated System Center—or EPISCenter—in Dayton, Ohio, followed by additional evaluation at its test site in Peebles, Ohio, where it was used to drive a 3.4-meter-diameter Dowty propeller from a Saab 340 turboprop aircraft.
Adding electrical components can make planes heavier. Lightening the load requires new technology, materials, and design approaches, Huang says. High-voltage materials, for example, are needed to make electrical cables thinner. Another solution is to reduce the weight of parts. GE is looking into manufacturing them using additive technology such as 3D printing.
The company is working on hybrid electric aircraft concepts. Huang referenced an report published last year in Aviation Week and Space Technology on GE developing gas turbines for emerging hybrid-electric propulsion architectures, which play a big part in so-called flying cars. The electric, self-piloted, vertical-takeoff and -landing passenger aircraft are expected to replace short-range urban transportation such as cars and trains. Flying cars are projected to cost less than helicopters and be quieter to boot.
Huang expects flying cars to be used in congested cities such as San Francisco, where it can take two hours to drive 40 kilometers. “People are busy and don’t want to waste their time sitting in traffic,” he says. “Flying cars can vertically take off and land, so you could arrive in 20 minutes. I predict we’ll see these small aircraft in the next decade, but of course these planes will first need to undergo rigorous safety tests.”
The aerospace industry needs more engineers to achieve its goals.
“We are in the beginning of a new aviation era,” Huang says. “The growing industry needs skilled electrical engineers to design, build, and test components. We also need mechanical engineers and thermal engineers. There’s a lot of work to do. Companies need to get aircraft ready for the next decade.”
Huang encourages engineers who want to learn more about the industry to join IEEE, attend its conferences, subscribe to its publications, join its societies, and take advantage of the networking opportunities the organization presents.
“I joined IEEE in 1986, and the organization has helped me tremendously,” he says. “I cannot imagine where I would be today without IEEE. It’s really a wonderful organization to associate with. Its societies have helped me to broaden my knowledge.
“I’m a big fan.”