Clean machines Part I

The twin presssures of environmental pressures and soaring fuel prices are challenging the civil aviation industry as never before. Despite improvements in aerodynamics and engine performance over the past decade, aircraft are still fuel-hungry, deplete resources and produce large amounts of carbon dioxide per passenger.

And while it is generally accepted that the increase in demand for air travel, rather than the performance of the aircraft, is the concern, the aerospace industry is investigating new technologies for more fuel-efficient flight.

There are many such projects around the world, but the largest is in Europe. Clean Sky, one of the first of a new type of public-funded collaborative research project, is bringing together most of Europe’s aerospace companies in an effort to transform passenger aircraft. Costing a total of €1.6bn (around £1.3bn) half from industry, half from European Union funds, Clean Sky could help to put a fleet of very different-looking airliners into the skies in 10 years.

Clean Sky is a joint technology initiative (JTI), a public-private partnership which aims to encourage industry to participate in research that is wider than their normal R&D subjects. European politicians are concerned that industry is too conservative about innovation and using new technologies, and it is hoped this approach would encourage companies to develop research into products. Clean Sky is one of four JTIs: the others are in hydrogen and fuel cells; innovative medicines and nano-electronics.

To identify subject areas for JTIs, the European Commission looked for sectors where innovations could lead to substantial returns for industry, both in meeting the needs of society or in simpler, economic terms. The trigger for Clean Sky was a set of goals set out by the Advisory Council for Aeronautics Research in Europe (ACARE), in 2004: to halve CO₂ emissions from aircraft, per mile; cut NOx emissions by 80 per cent; halve perceived aircraft noise; and establish green design, manufacturing, maintenance and product disposal practices, by 2020.

To achieve this, Clean Sky has been split into six parts, known as integrated technology demonstrators (ITDs). Two are for specific types of aircraft —rotorcraft, including helicopters and tilt-rotors; and regional aircraft, designed for short-range hops. Another two are looking at eco-design, emphasising materials, manufacturing, maintenance and recycling; and green operation, studying thermal management and other aspects of running civil aircraft that can be fine-tuned to save on fuel. The other two, perhaps of most interest to engineers, look at technologies for parts of the plane responsible for fuel consumption — the engines and the wings.