Airbus is pushing forward with open rotor engine development for its A320 successor, targeting late 2030s entry into service. The design exposes larger composite fan blades rather than enclosing them in a nacelle, achieving a bypass ratio of 60:1 compared to today's 11-12:1.
CFM International's RISE program claims 20% fuel efficiency gains over current LEAP engines. The physics are straightforward: conventional turbofan ducts create drag that eventually cancels out efficiency gains from larger fans. Open rotors skip the duct entirely.
Worth noting: this isn't new technology. Open rotors were tested in the 1980s and abandoned due to noise and vibration issues. CFM says those problems are solved through composite blade materials and aeroacoustic design. Simulations show noise levels below current LEAP engines, but certification under ICAO Annex 16 and 14 CFR Part 36 requirements will be the real test.
Airbus plans wind tunnel tests at ONERA in France and Filton in the UK throughout 2026, followed by full-scale A380 flight tests starting in 2028. CFM recently unveiled blade-out safety designs addressing catastrophic failure scenarios.
The company is evaluating both wing-mounted and rear fuselage installations. Some configurations may require folding wingtips to maintain gate compatibility with the larger engine diameter.
Competition remains open. Rolls-Royce is developing its UltraFan engine with ground tests planned for 2028, though the company previously explored and abandoned open rotor concepts. Pratt & Whitney continues refining geared turbofan technology.
Airbus expects to make an engine decision by 2030, with aircraft service entry around 2040. CFM has logged 500+ test hours on RISE components to date.
History suggests treating fuel efficiency claims with caution until flight-tested. But the timeline is credible, and the certification pathway exists. The industry has had 40 years to solve the noise problem. We'll see if they actually did.