The Clean Sky programme will make air transport in Europe more environmentally friendly. This research will also have a major influence on rotary wing aircraft, which are being used for more and more applications.

The European Clean Sky programme was officially launched on 5 February 2008. Clean Sky is the logical and expected continuation of the Vision 2020 analysis begun in Europe in 2001 on the future of air transport, in particular the solutions needed in order to meet the environmental challenge.
“This initiative is of interest to the whole aeronautical industry, which obviously includes rotary wing aircraft,” explains François Toulmay, the man in charge of preparing European research programmes at Eurocopter. Organised around six major platforms or integrated technology demonstrators (ITD), the research work will lead to the development of in-flight or ground demonstrators. The Green Rotorcraft platform is specifically devoted to helicopters and tilt-rotor aircraft.”

An international programme
Industrial organisations from the 27 member countries of the European Union and a few associated countries, such as Norway and Switzerland, are involved in the Clean Sky programme. Eurocopter and AgustaWestland are working together on the rotorcraft platform, which will receive 160 million euros over seven years – ten percent of Clean Sky’s total budget.
“This money will fund the work on the Green Rotorcraft ITD, but certain activities will cross over into the domain of the Systems for Green Operations ITD, for example, where the work on electrical systems also applies to rotorcraft,” stresses François Toulmay. “The same applies to the Sustainable and Green Engines ITD, which covers helicopter turbine engines.” The two helicopter manufacturers, Eurocopter and AgustaWestland, are working on the Rotorcraft ITD with various organisations, including the Polish helicopter manufacturer, PZL Swidnik, the French, German and Italian research centres – ONERA, DLR and CIRA – and SMEs and laboratories. The whole of the research work is pursuing three goals that are in line with Clean Sky’s overall objectives: to reduce gas emissions (through reductions in fuel consumption), to reduce noise, and to create a green product life cycle, from manufacturing, maintenance and overhaul to the disposal and recycling of the aircraft at the end of its service life(1). To meet these objectives, six technological projects have been defined and divided between AgustaWestland and Eurocopter.

Complementary lines of research
The first project focuses on blades, where the optimisation of shapes and the use of active control systems are intended to reduce noise and consumption. The second project concerns airframe design, which must be made more aerodynamic for more efficient power use in flight. The third project covers the integration of innovative electrical systems that will eliminate engine air bleeds and the need for hydraulic fluid. The fourth project examines the integration of diesel engines on light helicopters and will eventually lead to the production and flight testing of a demonstrator. “The turbine engine will be optimised to minimise power loss. The diesel engine has proved to be a lot more consistent, but its weight remains a real handicap for the time being,” reveals François Toulmay. “The work on the diesel engine is a flagship project for Eurocopter, and we have set our sights on reducing average consumption and carbon dioxide emissions by over 30%.” In addition to the work on the design of aircraft, research will also focus on their operational use, with the management of low noise trajectories and air traffic integration(2). The sixth but by no means least important project tackles eco-design, an area that is of equal interest to airplane manufacturers. But the Eco-Design ITD also offers certain specificities for helicopter manufacturers, such as the surface treatment of dynamic components in the power transmission system. “These six projects will be followed by the synthesis work that will technologically assess the solutions after integration. The aim of this is to show their impact over time on the environment,” explains François Toulmay.

Practical applications
Even though its scope is unprecedented, the Clean Sky programme is not enough: mature technical solutions have to be accompanied by studies of their actual application. “This means that we already need to be in close contact with the programme directors so that we can keep them informed of any technical opportunities that open up for them,” concludes François Toulmay. “We also need to know their requirements inside out, so that we can align our work better with the objectives of Clean Sky.”