Engineers in Britain are taking part in SWIFT, a project to develop technologies that will allow sustained growth in air travel without additional impact of CO2 on the environment.
The Scalable Wirelessly Interconnected Flow-control Technology (SWIFT) consortium aims to help the aviation industry achieve a 50 per cent reduction in fuel burn per kilometer by 2020.
The SWIFT team – made up of researchers from Sheffield University, Queen’s University Belfast, and Warwick University – believes that it can achieve this target by significantly reducing skin friction.
This will involve supporting the concept of the Active Aircraft, where a network of skin friction reduction components (smart skin patches), made up of sensors, actuators and controllers, are fitted across the wings and fuselage to perturb airflow across the aircraft and increase flight efficiency. The entire system would have to be interfaced wirelessly to communicate control information to the patches and health monitoring data from the patches.
‘We need to wire it up in some way, and already the wiring on an aircraft is incredibly complicated,’ said Prof Haydn Thompson, programme manager, Rolls-Royce Control and Systems University Technology Centre at Sheffield University. ‘This adds weight and also increases the maintenance burden on the aircraft, therefore we are looking to create a wireless nervous system for the plane.’
A wireless system offers a number of benefits, including reducing the weight and complexity of the aircraft.
In order to justify development costs, the SWIFT team is considering the possibility of integrating other existing aircraft systems including aircraft surface actuation, structural health monitoring, and anti-icing into this wireless network strategy.
Thompson said that the operational life of an aircraft is typically 25-30 years. ‘We know that over that time, parts of the smart skin system will fail. Hence, we are looking at health monitoring to identify exactly what proportion of the total system is working. This includes health monitoring of the wireless nervous system itself. The work is investigating wireless protocols that allow reconfiguration of the network on failure to maintain performance,’ he said.
‘The health monitoring systems are returning the actual health of the skin of the aircraft (the skin health index) into a performance value for the aircraft. Therefore, based on how much of the skin is working in terms of the skin friction reduction, we can actually work out how much fuel we are going to use, and how much CO2 emissions we will produce. We have done some simulation work on typical aircraft looking at the benefits of this.
‘We believe that in the future there are very big gains to be made by totally re-designing the aircraft with a skin friction control system with appropriate engines that match the aircraft.’
Thompson added that work is underway with Warwick University to test skin friction reduction techniques. This involves wind tunnel tests on a smart patch array, which is wirelessly interconnected utilising fault tolerant protocols and a health-monitoring system provided by Queen’s and Sheffield universities.
‘Following on from this we will move into a wind tunnel at Airbus,’ said Thompson.