Bjorn’s Corner: Exploring Open Rotor Technology in New Engine Development – Part 8

Engine development has become a challenging task in the aviation industry, with longer timelines and larger risks of product maturity problems. The focus has shifted to Open Rotor technology, which offers increased efficiency compared to traditional turbofans.

Open Rotor engines utilize a counterrotating fan design to increase the capture area of air and compensate for reduced overspeed. This design allows for a higher thrust-to-massflow ratio, improving overall efficiency. However, the initial dual gearbox setup between the core and the counterrotating fans added complexity and weight to the engine.

In 2014, GE engineers made a breakthrough by replacing the second rotor with fixed de-swirling stator vanes, eliminating the need for the dual gearbox. This led to the development of the GE single-stage Open Fan engine, which significantly reduced complexity and weight while maintaining efficiency.

The noise levels of Open Rotor engines have also been a focus of research, with GE and NASA working together to reduce the interaction of tip vortices and blade noise. Today, Open Fan architecture is comparable to the noise levels of traditional engines like the LEAP.

SAFRAN and GE collaborated to launch the CFM RISE engine in 2021, a further development of the single Open Fan concept. This next-generation engine targets the 25klbf to 35klbf thrust segment for Single Aisle airliners, offering improved efficiency and performance.

The shift towards Open Rotor technology represents a significant advancement in engine development, with potential benefits for the aviation industry in terms of fuel efficiency, noise reduction, and overall performance. Stay tuned for more updates on the CFM RISE engine in future articles.