Dubai Air Show

Europe on the cusp of Clean Sky effort

 - November 6, 2007, 6:41 AM

The European Union is about to launch a massive seven-year, ?1.6 billion ($2 billion) research program dubbed Clean Sky, which will include developing six demonstrators for greener technologies. The European Council of Ministers is expected to formally adopt the comprehensive project next month.

The so-called joint technology initiative (JTI) will include follow-ons to several ongoing research projects managed in a more integrated fashion.
“Work in the integrated technology demonstrators [ITDs] will begin in May or June next year,” Loïc Michel, air transport manager and JTI contact at the Aerospace and Defense Industries Association of Europe (ASD), told AIN. In the meantime, the EU must hire an executive director for Clean Sky.

Michel clarified that the European Commission has approved the JTI as part of its
7th Framework Program for research (FP7), and all that is now required for a go-ahead is a vote by government ministers from the EU’s 25 member states.
What makes the industry-driven program special is its technology evaluator tool and the synergies it aims to achieve. “This is the glue of the JTI,” Michel emphasized. “The technology evaluator is a fundamental tool and it is based not only on computer-aided functions, it uses human resources.”

The idea is to avoid any discrepancy between ITDs, which means close monitoring. “We will permanently assess the consistency of what is being developed,” Michel said. The EU has allotted ?30 million ($40 million) in funding for the technology evaluator aspect of the program.

Half of the total budget will come from European Commission funds. The other half are contributions from project stakeholders– companies, laboratories and universities that provide staff and facilities. Clean Sky promoters have committed to a target participation of 6 percent, measured over the total budget, for small and medium enterprises (SMEs).

There are six ITDs:

  • smart fixed-wing aircraft, led by Airbus and Saab;
  • green engine, led by Rolls-Royce and Snecma;
  • green rotorcraft, led by AgustaWestland and Eurocopter;
  • systems for green operations, led by Thales and Liebherr Aerospace;
  • green regional aircraft, led by Alenia and EADS CASA; and
  • eco-design, led by Dassault Aviation and German-based research center Fraunhofer.

The “smart fixed-wing aircraft” ITD focuses on active wing technologies that sense the airflow and adapt the wing’s shape as required. The idea is to control both flow and load. Researchers will look at new aircraft configurations to incorporate these novel wing concepts. A Falcon 900 trijet may become a flying testbed for this project, featuring micro-electromechanical systems (MEMS) sensors and actuators. MEMS is expected to prevent the onset of turbulence.

The “green engine” ITD will be directed toward reducing weight and noise in engines, while improving efficiency. One of the most spectacular fields of research in this ITD is the return of open rotors; more precisely, contra-rotating fans are to be evaluated. Another new configuration will be heat transfer via intercoolers.

“Green rotorcraft” ITD researchers will work on innovative rotor blades and engine installation for noise reduction. They will also try to curb airframe drag. In addition, they will investigate more electric architectures. Environmentally friendly flight paths will be part of the work as well.

The “systems for green operations” ITD will focus on all-electric aircraft equipment and systems architectures. This involves work on thermal management. There will be studies on “green” trajectories and missions. Improved ground operations will be researched via, for example, the use of a powered landing gear–rather than flight-optimized turbofans–during taxi.

The “green regional aircraft” is focused on low-weight configurations and smart structures, such as damage monitoring sensors. Researchers will also study noise attenuation and will consider the integration of technology developed in other ITDs, such as engines, energy management and new configurations. One of the target bottom lines is a 20- to 38-percent cut in carbon dioxide (CO2) emissions.

Arguably, the most original ITD is the ?117 million ($160 million) “eco-design” project. “Green airframe research will take into account the entire life cycle,” Myriam Goldsztejn, Dassault’s vice president for European Commission business development, told AIN. They will build two major airframe subassemblies, such as wings. One will be made of metal, the other of composite materials. Some ground trials will be performed and the airframe will then be dismantled.

“We want to conceive environmentally friendly airframes and materials,” Goldsztejn said. First, researchers will endeavor to find significant energy and water savings in the manufacturing process, for example, by having one-shot processes rather than breaking them into several phases.

Second, the eco-design team will try to reduce the amount of protection on an airframe. “You can find up to four layers of primer and paint,” Goldsztejn pointed out. Simultaneously, they will try to make stripping easier. Current chemical stripping is toxic for human health and the environment.

At the end of the life cycle, material recycling is becoming a bigger issue. “The increasing use of composites is good for lightening an airframe and thus reducing fuel burn; but when it comes to recycling, they are a huge problem,” Goldsztejn said. Composite recycling is therefore to be explored, whereas aluminum recycling processes are well known.

The second part of eco-design  targets systems. “We are going to study all-electric architectures for business jets, regional aircraft and helicopters,” Goldsztejn explained. The idea is to get rid of polluting liquids such as hydraulic fluids, which currently, can be found on brakes, landing gears and flight controls. The latter, even the fly-by-wire type, use hydraulic actuators to move control surfaces.

However, a major issue with electric power is heat management. One advantage of the hydraulic systems is a fluid circulation. Waste heat is collected and driven to a heat exchanger. Heat draining is easy and cooling is naturally centralized.

In an electric architecture, waste heat is not directly drained. “To avoid temperature spots and overheating, it is necessary to [explore] a new concept for the aircraft’s thermal management,” Goldsztejn explained. Such architectures may be considered for aircraft that will enter into service around 2015-2017.

She added that this will necessitate the development of new computational design tools. Also, eco-design partners will use a thermal bench, working in conjunction with a conventional iron bird.