The EU’s Clean Aviation body has provided more detail on the two new narrowbody engine concepts it plans to fund in its second phase, readying them for service entry around 2035.
In December, Clean Aviation said its third call for proposals – due for release in February – would contain projects relating to the flight testing of an open-fan engine, and ground testing and preparations towards flight test of an ultra-high-bypass-ratio (UHBR) ducted geared turbofan.
But the funding body has now disclosed a more precise breakdown of its requirements for each project, above the headline 30% reductions in emissions and fuel burn against a 2020 state-of-the-art engine.
In both cases, Clean Aviation expects the thrust of the developmental powerplants to be in the 25,000-30,000lb (111-133kN) range and capable of powering a 200-250-passenger aircraft on routes of up to 3,000nm (5,560km).
Clean Aviation will allocate up to €100 million ($102 million) for the open-fan flight testing – a figure to be more than matched by industry.
It says the flight of the engine aboard a “relevant aircraft platform” should take place by the end of 2028, bringing the open-rotor engine to technology readiness level (TRL) 6 at “propulsion system architecture level” by the end of the up-to-48-month project.
Justifying the need for such a project, Clean Aviation says “large-scale flight demonstrations” are required to meet the 2035 service-entry goal due to the “disruptive architecture of the unducted propulsion system”.
It expects proposals from “consortia that include aircraft manufacturers, propulsion system OEMs and their supply chain” who have a “proven track record” in the development and delivery of “globally competitive” powerplants.
In effect, the only realistic contender for the requirement will be Safran Aircraft Engines, which is developing the RISE open-fan concept through its CFM International joint venture with GE Aerospace.
Safran has already benefitted from €100 million of funding through Clean Aviation’s first phase, leading a project called OFELIA.
Running until 31 December next year, OFELIA “aims to demonstrate at TRL5”, including a ground-test campaign, the open-fan architecture CFM is developing through the RISE programme.
Other members of the OFELIA consortium include Airbus and multiple European GE subsidiaries.
In addition to the flight-test programme envisaged in the second phase, the consortium should develop “a clear route towards certification, exploitation and industrialisation” – alongside the “identification of operational requirements” to permit a successful service entry, says Clean Aviation.
Meanwhile, it will allocate up to €70 million for ground testing of an UHBR ducted geared turbofan engine, raising the concept to TRL5 by 2029.
“Applicants should propose and build a demonstration plan aiming to validate a propulsion architecture on ground by end of 2029 and subsequently in flight by end of 2030,” says Clean Aviation.
The UHBR engine proposal should feature “including advanced core engine and combustion technologies, advanced thermodynamic (variable) cycle and hybridisation”, it says.
In addition, a “new-generation power gearbox”, scaled for narrowbody operations, should form part of the concept, “delivering new standards of transfer efficiency, and facilitating highest propulsive efficiency”.
Clean Aviation is seeking applications from a similar consortium to that envisaged for the open-fan programme, involving close collaboration between an engine maker and airframer.
Rolls-Royce would seem a likely contender for the project, having already benefitted from Clean Aviation funding to scale its 80,000lb-thrust-class UltraFan demonstrator to narrowbody size.
On top of the engine development, the project’s second objective is to “prepare the fully instrumented and modified flight demonstration platform”.
“Engine integration activities on the flight test demonstrator should be performed up to critical design review phase,” the topic description says.
In all, Clean Aviation will allocate €380 million in the next call for proposals, part of a total €910 million budget across three second-phase calls.
