Engineering news
The £1 million project to develop the smart wing, led by aircraft manufacturing giant Dassault Aviation, has proved successful following “crucial” wind tunnel tests run in the US by Nasa.
The composite wings are embedded with “innovative electric heaters and power controls” on the leading edge – the foremost edge of an airfoil section.
A section of the wing was tested in the Nasa wind tunnel which can cause icing and measure its effect on the wing’s aerodynamics. Tests showed that the technology could prevent ice from even forming, but would also shed ice if it did appear on the wing.
The Electro-thermal Laminar Wing Ice Protection System Demonstrator (ELWIPS) programme brought together researchers from the University of Sheffield Advanced Manufacturing Research Centre (AMRC) with Boeing and aerospace companies Meggitt and AeroTex UK. The companies involved said they hoped to use the technology in future aircraft.
The AMRC designed and built a composite wing structure in the leading edges which incorporates “innovative electric heating technology” and power control systems developed by Meggitt subsidiaries in the UK and France, while icing prevention and prediction company AeroTex, determined the sizing, zoning, power rating and control strategy for the heaters.
A number of different systems are currently used to protect aircraft against icing, which the researchers said can “drastically affect wing aerodynamics and has led to crashes in the past”.
One common system for jet airliners bleeds hot air from the aircraft engine and routes it along ducts in the leading edges, while another, seen on turboprop regional airliners and utility aircraft, uses rubber “boots” on the leading edges which can be inflated to force ice off.
Icing protection is really only needed on a limited number of flights and for typically short periods of time, according to Tim Swait, technical Lead at the AMRC Composite Centre. “You are carrying all that extra weight for no reason a lot of the time,” he explained.
Swait added that aircraft of the future won’t be able to use bleed air, since manufacturers are optimising their engines to “extract every last bit of performance”.
Boeing’s 787 Dreamliner is the only large passenger aircraft to use an electrical system to keep wings free from ice and electric heating has been difficult to implement on smaller aircraft because systems currently require substantial amounts of power.
The researchers said that the ELWIPS project solves that problem by only using power “when and where it is needed”, instead of heating the leading edge of the whole wing.
A pure electrical system will save weight and allow the wing’s leading edge to be composite rather than metallic, removing the need for ribs, spars and fasteners and reducing weight further.
According to Swait the system will be more reliable, allow the engines to run more efficiently and allow designers to improve smooth airflow over the wing, boosting flight performance even more.
Swait said that the heating technology developed by Meggitt is “very impressive and has great commercial potential”.
If the system is developed commercially it will be “a major step forward for lighter aircraft and could have implications for the construction of greener large commercial aircraft,” he added.