Can you imagine airliners with engines that have no nacelles? Airbus can. In fact, the potential of “open fan engine architecture” to increase engine efficiency and reduce CO2 emissions is so tempting, Airbus and CFM International have launched a flight test demonstrator program.
Following extensive ground testing, a double-decker Airbus A380—the world’s largest airliner—will be used to mature and accelerate development of open fan engines, the company announced Tuesday at the Farnborough International Airshow in England. Flight test validation is expected to take place at GE Aviation’s Flight Test Operations Center in Victorville, California.
Airbus and CFM—which is jointly owned by GE Aviation and Safran Aircraft Engines—said open fan engines could provide up to a “20 percent reduction in CO2 emissions compared to today’s most efficient engines,” using traditional jet-A. CO2 reduction for aircraft burning sustainable aviation fuels (SAF) could be even higher, Airbus said.
“New propulsion technologies will play an important role in achieving aviation’s net-zero objectives, along with new aircraft designs and sustainable energy sources,” said a released statement by Sabine Klauke, Airbus chief technical officer. “By evaluating, maturing, and validating open fan engine architecture using a dedicated flight test demonstrator, we are collaboratively making yet another significant contribution to the advancement of technology bricks that will enable us to reach our industry-wide decarbonization targets.”
How It Works
The engineering behind the open fan concept involves counter-rotating fans and increasing the flow of thrust-producing cooler air through the engine, according to Safran. Eliminating the nacelle exposes the engine to cooler air, making the engine work less to produce thrust. As a result, an open fan engine would allow an aircraft to achieve the same speeds as conventional engines, while decreasing fuel consumption.
Eliminating the engine nacelle would decrease the overall weight of the aircraft—also saving fuel.
In a nutshell, open fan architecture would allow engineers to increase the size of an engine and the quantity of cooler airflow through it—without increasing the airplane’s weight.
The basic concept surrounding open fan engines is not new. GE Aviation has designed and tested open fan engines since the 1980s. However, significant technological leaps in advanced manufacturing and materials have brought the idea closer to fruition.
The announcement comes five months after both companies unveiled a program to use an A380 as a flight test demonstrator for a hydrogen combustion engine that could enter service as soon as 2025.
Airbus offered several reasons why it’s moving forward to study and develop open fan architecture, including:
- to learn more about engine/wing integration and the aerodynamic performance of propulsive system efficiency
- to validate the concept’s promise of better fuel efficiency
- to study the acoustic dynamics surrounding the technology
- to research its compatibility with 100 percent SAF