This article is published in Aviation Daily part of Aviation Week Intelligence Network (AWIN), and is complimentary through Dec 26, 2024. For information on becoming an AWIN Member to access more content like this, click here.
A RISE open-fan engine concept on display at Singapore Airshow.
LIEGE, Belgium—If airframers are not interested in the open-fan architecture of the RISE demonstration program Safran and GE Aerospace are working on, RISE technology components could be used in a ducted-fan engine, a Safran executive says.
“A ducted-fan version would be more affordable but would offer lower performance,” says Eric Dalbies, Safran's CTO and executive vice president of strategy. “While RISE targets a 20% fuel burn reduction, the ducted-fan variant's benefit would stand at between 10% and 12%.” He was speaking Nov. 26 on the sidelines of the inauguration of the BeCOVER low-pressure compressor testbed in Liege, Belgium.
Safran and GE are studying the RISE as the basis for a successor to their CFM International joint venture's Leap turbofan. Safran's responsibilities under RISE include delivering the open fan; failing to find an application for the open fan would be a serious disappointment for the partners.
Safran does not disclose precise amounts for its investment in the entire RISE program or its open-fan work. In 2023, self-funded research and technology expenses stood at €598 million ($635 million), mainly geared toward decarbonization through the RISE program, according to the company's last annual report. The €100 million budget of the Open Fan for Environmental Low Impact of Aviation (OFELIA), a research program focusing on open fan propulsion technologies under Europe's Clean Aviation project, is an indicator of the sums being invested.
A scenario without an application for the open fan is unlikely. Airbus has committed to modify an A380 to test the RISE demonstrator in flight. Safran conducted wind-tunnel testing of a reduced-scale open fan engine and Airbus provided a wing section to study integration on a future narrowbody aircraft.
“We have not found a single roadblock,” Dalbies says. Airbus is working on three options—integrating the engine on a low wing, a high wing or the aft fuselage—and is putting an emphasis on the low wing configuration, he adds.
However, Airbus has yet to launch an aircraft program. Boeing's company-wide problems may lead it to avoid a high degree of sophistication in its next design. Airbus, in turn, might find just slightly better efficiency would suffice as a competitive advantage.
The European airframer might then deem the open fan as being technology overkill. Due to open fan's size, weight and aerodynamic interaction with the wing, it involves an installation rethink. In addition, an open fan design might increase maintenance costs.
A geared ducted-fan engine would reuse other RISE technologies, Dalbies suggests. Higher temperatures in the core engine and a hybrid-electric architecture to help in transient regimes are also a part of the RISE effort.
Assembly of the first open-fan RISE engine demonstrator is scheduled for next year, with ground trials scheduled to begin in 2026.
Related Content
