CFM plans propfan engine that changes the look of the aircraft.
Two of the world’s leading jet engine manufacturers, General Electric and Safran, who are already jointly producing the most advanced jet engine of the moment, the Leap, are in the process of developing a new engine that is expected to reduce fuel consumption and emissions by at least 20%.
GE Aviation and Safran start developing a new engine. In doing so, they are taking up an old technology and targeting the successors to the Airbus A320 and Boeing 737. It’s got counter-rotating propellers.
The idea is not new. Researchers began experimenting with the technology around 60 years ago, and it really flourished in the 1970s. Triggered by the oil price shock, engineers around the world looked for more efficient engines for aircraft. The Propfan – also known as the Open Rotor – promised to offer that.
With propfan engines one tries to achieve the speed and power of a turboprop engine and at the same time the fuel efficiency of a turboprop engine. They are typically equipped with a large number of short, highly twisted blades. The most striking feature is that these are on the outside. ATR 92, Boeing 7J7, Fokker FXX, a new version of the Antonov An-124 – there have been many attempts to use the technology.
The end of the oil price uptrend meant the end of many programs
In the end, none of them were implemented. Because the kerosene price had meanwhile fallen again and made a change in drive technology unattractive. And so the propfan euphoria ebbed in the 1980s. But GE Aviation and Safran bring the technology back out of the moth box. Together they announced the Rise program on Monday (June 14th). The abbreviation stands for Revolutionary Innovation for Sustainable Engines. The aim is to develop a new generation of engines that should be ready for use by the mid-2030s.
Open architecture as a central requirement
With Rise, the GE Aviation and Safran joint venture CFM wants to bring an engine onto the market that consumes more than 20 percent less fuel and thus also causes at least 20 percent less CO2 emissions than current engines. But the partners are not satisfied with that. The new engine from CFM should also be ready for use with hydrogen or sustainable fuels.
The focus of the program is the drive efficiency of the engine, “including the development of an open fan architecture”, according to CFM partners GE Aviation and Safran. This is an important prerequisite for achieving significantly improved fuel efficiency and at the same time being able to offer the same speed and the same cabin experience (i.e. no more noise) as with current narrow-body aircraft. Various innovations are planned for the new engine, including fan blades made of composite materials, heat-resistant metal alloys, ceramic matrix composites, hybrid electricity and additive manufacturing.
“Closer integration with aircraft manufacturers”
The announcement that the CFM-Propfan will be launched in the mid-2030s is no coincidence. Around then, Airbus and Boeing want their successors for the A320 and 737 respectively. And alternative fuels and hydrogen play an important role in the considerations.
The CFM partners make it clear that such an engine revolution would require close cooperation with aircraft manufacturers. The Rise program requires “closer integration with aircraft manufacturers than ever before,” they write.
Where does the propfan go?
The revolution will also change the look of aircraft quite a bit. Today’s classic engine, in which the engine is in a casing, will disappear. Suddenly propellers become visible again. Where exactly this propfan would be attached is still open. Under the wing of a shoulder wing, on the wing as it is today or at the rear of the tail unit as in earlier models – everything is possible for GE Aviation and Safran.
