Air apparent

5 min read

Prof Phil Withers believes his aerospace research team has the right mix of expertise to help make air travel greener. Berenice Baker reports

It’s crunch time for the civil aviation industry. As demand for air travel continues to grow, calls for the industry to ‘green up’ its act are becoming ever more strident.

Add to this heady mix rising fuel costs, security concerns and incidents such as last month’s baggage handling debacle at Heathrow and the challenge facing the industry looks daunting to say the least.

As ever, engineers can provide many of the solutions. But with such a varied set of problems to address, the answers don’t always lie in the core engineering disciplines. What’s required, it seems, is a multidisciplinary approach that draws on the skills of mechanical engineers, materials specialists, physicists and mathematicians.

Prof Phil Withers, who heads Manchester University’s Aerospace Research Institute (UMARI) believes the centre, launched late last year, has just the right mix of expertise to help make air travel greener, faster and safer.

UMARI’s goal is to establish Manchester as a global force in aerospace innovation, bringing together the university’s various existing capabilities, adding to them, and taking advantage of the north-west’s strong position in the industry.

Withers, an effusive Cambridge-educated natural scientist, is passionate about materials research. And no stone is left unturned in the search for structural integrity. As a PhD student, Withers pioneered the use of penetrating X-ray synchrotron and neutron beams to analyse engineering structures, and he is keen on using similar techniques today to map the stresses within components.

He explained that the UMARI team is currently using the ISIS pulsed neutron source in Oxford and the Diamond Synchrotron at Harwell to work with both Rolls-Royce on its engines and British Energy on nuclear power plants. ‘You measure the spaces between atoms using Bragg’s equation [which relates to the scattering of X-rays from crystals], and use them as an atomic strain gauge,’ he said.

‘Because the beam goes deep inside the materials, we can measure the stresses and produce maps of the stresses. The trick is to make sure they’re high where they’re not a structural integrity concern, and low in places where you need less stresses.’

The group has also been working with Airbus on the structural integrity of components and systems on the A380. ‘There are about 100,000 rivets on every large wing set, which raises many structural integrity issues — it’s like flying a colander. We’ve been looking at the riveting process on traditional A380-style superjumbos, how it creates stresses around the holes and how to make the holes resistant to cracking.

‘We also worked with Airbus on improving welding technologies. When you weld something, you get stresses between the bit that was hot and that which was cold, so we’ve been developing technologies to minimise the stresses in welds.’

As well as probing aircraft at the atomic level, UMARI also gives Withers the opportunity to take a step back and attempt to address the bigger picture.

‘The biggest driver at the moment is to minimise the impact of aerospace-based travel on the environment,’ he said. ‘That is a tremendous challenge to us all given the social and economic importance of aerospace travel within an ever-increasing global environment.

‘Of course, it cuts across a huge range of technologies and areas — everything from the take-up of composites for aerospace structures through to the logistics of managing air traffic control. It’s a huge aspect which includes other areas such as the legislation regarding aviation fuel tax and a number of other social-political issues.’

Clearly, reducing the weight of aircraft is a key factor in reducing fuel consumption, and one of the most radical changes to aerospace at the moment is the growing use of composites on both civil airliners — such as Boeing’s delayed 787 — and military aircraft such as the Lockheed F-22.

Withers explained that UMARI is working with composite suppliers to react to this trend. ‘We’re working on the whole range of new technologies associated with really one of the most radical changes in aerospace that has taken place in the past 100 years. We moved from cotton and wood through to aluminium, and we’re now moving from aluminium through to composites — it’s a huge challenge.’

Composite repair is a particularly pressing issue. ‘If you run a baggage cart into composite panels on an aircraft, you get barely visible impact damage on the outside, but you’ve damaged the internal structure of the material,’ he explained. ‘This presents a real issue for aerospace with all the composite parts going into production at the moment. The identification and repair of damage in composites is an area that is going to need much attention in the next 15 years, and a number of techniques are being used to image damage and understand how it develops through the life of a component.’

In something of a departure for an aerospace engineering department, UMARI’s remit also spreads to what happens on the ground, and the institute is working with airports and security companies to develop fast and efficient ways of scanning people and baggage safely as they move through airports. The importance of airport logistics has been in sharp focus over recent weeks, and UMARI hopes to play a role in helping them run more smoothly.

‘This is an interesting programme because it involves mathematicians to calculate new algorithms to produce 3D images of baggage and people, electrical engineers involved in sensor design and a whole range of technologies,’ said Withers. ‘But it’s very important because moving people through airports is largely constrained by the ability to examine them and ensure they’re travelling safely.’

Withers said the university is currently working with US security giant Rapiscan — whose scanners are a familiar sight in many airports — on the development of new algorithms for reconstructing images.

Away from the world of passenger aircraft, Withers also believes that small, pilotless aircraft are set to play an increasingly important and varied role in the future of aviation. UMARI is currently working with BAE Systems on UAV projects and is also part of a consortium including BAE, EADS, Qinetiq, Rolls-Royce and Thales that is working on the £32m ASTRAEA UAV research programme.

ASTRAEA aims to develop the technologies and systems that will allow UAVs to move from their current specialist status to a commonplace role in the mainstream.

‘One of the most novel and exciting areas will be the increase in UAVs,’ said Withers. ‘These have been used in the military arena for some time, but they’re being developed for everything from coastal monitoring to traffic control. In the future, I see them carrying cargo for UPS or FedEx. Though whether these little planes can deliver that note that says, “We called but you were out” remains to be seen!’

‘You can imagine small aircraft kitted out for their particular tasks — to monitor the environment, to observe traffic movements, to work for the police or under defence scenarios, or even to monitor crops and agricultures,’ he continued.

‘There are phenomenal questions to be asked about how you organise and manage that, and clearly safety is paramount, so there will be huge logistical and informational challenges to be met in how we manage air transport, and how the smaller aircraft will interact with one another.’

If these challenges can be cracked, he believes that UAV technology could help save significant amounts of money. ‘It costs a huge sum for a police force to keep a helicopter in the air, whereas small vehicles could be very cost effective and efficient.’

With such a wide range of projects on the boil, there seems little doubt in Withers’ mind that despite the mounting restrictions on air travel, the skies of the future will be abuzz.