Now plans are being drawn up for a second, larger research program, Clean Sky 2, to run in 2014-20. If approved, this would take technologies to higher readiness through more integrated large-scale demonstrators, as well as developing more advanced ideas for future aircraft. Proposals are to be submitted in November.
With €800 million in government funding and €800 million from industry, Clean Sky is the largest aviation research program in Europe. Focused on the environment, it includes a range of ground and flight demonstrators for laminar-flow wings, fuel-efficient engines, low-emissions helicopters, more-electric systems and lightweight recyclable structures.
Clean Sky is aimed at developing technologies to meet goals European industry has itself set for 2020, including a 50% reduction in carbon-dioxide emissions versus a year 2000 baseline. Clean Sky 2 will be shaped by a longer-range vision to reduce air transport CO2 emissions 75% by 2050, while also increasing mobility and safety.
“We are close to the middle of the program, with another four years to the final demonstrations,” says Eric Dautriat, executive director of the Clean Sky joint undertaking. The program is on target to complete its work in 2017 and Dautriat says, “by the end of this year, we will have spent more than 50%” of the budget.
The first formal assessment of the technologies being developed under Clean Sky shows the program is on track to reduce CO2 emissions by 30% and significantly reduce noise, making the program the largest single contributor to meeting the industry's goals for 2020.
The first two Clean Sky demonstrators, a three-shaft turbofan led byand a helicopter turboshaft led by , will run this year. “Most of the demonstrators are on time. Delays are in months, not years,” Dautriat says, and largely due to priority issues within companies between Clean Sky and other projects. “That's the real life of research,” he says.
There have been some adjustments. Of two open-rotor engines under Clean Sky, only the demonstrator led bywill now be flight-tested. The engine led by Rolls has been pushed back, but replaced by a lean-burn demonstrator “that brings more to Clean Sky and aligns with Rolls-Royce's strategy. We can now tackle the NOx parameter,” he says.
Clean Sky was conceived to bring a range of emissions-reducing technologies to sufficient readiness by mid-decade to allow their use in development of next-generation aircraft entering service around 2020. Postponement of plans byto develop an all-new single-aisle aircraft “has not led to any significant reorientation,” says Dautriat.
But each of the six integrated technology demonstrations within Clean Sky is completing a review of progress toward the technology readiness levels (TRL) targeted by the program's end. “If we have to prioritize, we will give priority to the highest TRLs,” he says. Already there has been a “natural downselect” of technologies. “We have kept the most promising, some have been put aside, and some are not within the timescale.”
Some projects could continue into Clean Sky 2. “Rolls-Royce will probably proceed with open rotor and go to a full ground demonstration in a couple years more, but it will not be completed within the Clean Sky budget and schedule,” says Dautriat.
Clean Sky 2 would be part of the Horizon 2020 program, under which the EC plans to spend a total of €7.2 billion over seven years on transport research. This is more than the €4.8 billion allocated under Framework 7 (FP7), but must cover all modes of transport and not just aviation. Still, any follow-on is expected to be a larger program. “Most probably Clean Sky 2 will be significantly bigger than Clean Sky and that is the assumption under which we are building the content,” Dautriat says.
There will be two sets of targets. The first will be to continue the Clean Sky work toward meeting the 2020 environmental goals, taking the technologies to higher maturity through a limited number of highly integrated, aircraft-level ground and flight demonstrations. “We need to keep the same CO2 and noise targets, but increase the TRL,” he says.
“Higher-TRL large demonstrations have proven an effective way of working together, but we need to go one step beyond when required for technology integration,” Dautriat says. Clean Sky has separate flight demonstrators for the natural laminar-flow wing and open-rotor engine. “It makes sense to put them together and test the wing on one side and a powerplant on the other to uncover possible interactions,” he says.
The second target set will involve developing new technologies that address longer-term goals. “We need to do both; to increase the environmental goals and increase the TRL,” Dautriat says. Although aligned with the objectives set by industry for 2050, Clean Sky 2 will be aimed at an intermediate first step of 2030-35, he says, adding that “2050 is too far. An intermediate target of 2035 makes sense for Clean Sky 2.”
As the joint undertaking draws up its proposal for Clean Sky 2, it is incorporating lessons learned from Clean Sky, which got underway slowly because of the complexity of its collaborative research approach. “To avoid a lengthy start, we need to have a structure that is close enough to Clean Sky to avoid reinventing the wheel,” he says.
But there will be a shift in Europe's research funding philosophy with Horizon 2020, so there may have to be changes. Clean Sky 2 would come under the “smart, green, integrated transport” theme of Horizon 2020 and “the focus will be slightly changed from FP7,” including a greater emphasis on how the research results can be used, says Remy Denos, program officer with the EC's research and innovation directorate.
Under Clean Sky, the EC refunds industry for 50% and academia for 75% of the cost of research, but this could change under Horizon 2020. “The funding rate is a bit of a question mark, but we consider for a public-private joint undertaking that 50:50 is simple, makes sense and is a symbol of the partnership,” says Dautriat.
Because the programs would overlap, Clean Sky 2 beginning in 2014 and Clean Sky wrapping up in 2017, Dautriat does not see the need to start all the new projects at the same time. “Clean Sky 2 will be ready to start from a legal standpoint in 2014, but the projects should start when needed. That could be 2016, depending on strategic needs and resources available.”
|Flight Path 2050||-75%||-90%||-60%|
|Clean Sky current status||-30%||n/a||-30%|
|Source: Advisory Council for Aeronautics Research in Europe (Acare) and Clean Sky Joint Undertaking|