CFM’s RISE demonstrator offers excellent fuel burn

CFM International is a joint venture between SAFRAN Aircraft Engines of France and GE Aerospace in the US. The RISE engine demonstrator is an open fan solution connected via a gear to a traditional turbine engine. The exact design is not yet set, and many internal and external technologies remain secret. The key metrics that are known, though, are that the RISE engine will deliver better than 20% lower fuel burn than today’s aero engines. To understand how much of a leap forward that is, consider that the current state-of-the-art engines on single-aisle aircraft deliver over 16% lower fuel burn than the previous generation. What does that look like? The chart below lists fuel burn over the past decades, and the improvement is impressive. [caption id="attachment_85744" align="aligncenter" width="580"] AirInsight[/caption] The 1Q24 number for single aisles is 78.9 seat miles per gallon. Filtering the data to reflect 737 MAX, A320neo, and A220 aircraft, the average rises to 99 seat miles per gallon. The RISE will deliver over 20% on the baseline 99 seat miles per gallon. Therefore, we consider ~120 seat miles per gallon as the anticipated performance. Speaking with GE’s Arjan Hegeman, General Manager Future of Flight at GE Aerospace, we got an idea of how disruptive this new development program is. The program consists of several technological advances. We have learned that the RISE is a watershed moment for aero engines. The aircraft OEMs target the early 2030s for the next generation of aircraft. The RISE is being developed in concert with these plans. Engine technologies enable novel designs and lead aircraft design. The JV partners are comfortable that they have solved the noise challenge, which was a big issue with the earlier generation of open fans. GE has extensively used internal and external supercomputing facilities to test their models. These tests confirm the engineers can understand airflow over and through the engine to unprecedented levels. The demonstrators that have been displayed do not show the final blade design. That design is the key to noise reduction. The open fan also allows for higher bypass, which is crucial to improved fuel burn. Lacking a fan case means no drag from that structure. Moreover, because the open fan has a larger diameter than we see on aircraft now, the RISE allows for a “blown wing,“ which, in effect, further reduces drag. The engine casing behind the open fan is compact and likely smaller than current engine designs. One reason for this is that the RISE does not require reverse thrust, which is provided by rotating the blades on the engine. As Hegeman explained, the 20%+ target fuel burn improvement is at the aircraft level. The combination of the Open Fan and other engine technologies being developed, like compact core, helps enable this substantial improvement. The JV engineering team has grown confident as tests have proved their theories. Of course, the future requires the RISE technologies to scale. Hegeman explains that some scaling is possible, but it’s early days. Going down to a regional or business jet level is less challenging than scaling up to a GE9X size engine. The RISE project promises to move fuel burn to the next level. A blown wing could also impact how aircraft OEMs think about their designs.

US Flight Planner - US DoT On-Time Data	Airbus vs Boeing - Official OEM Data
US Airline Schedule Performance - US DoT Data	Daily OEM Production & Deliveries -

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