Developing low drag surface coatings

GKN Aerospace has joined forces with Durham University to develop and implement an ultra-sensitive test method to accurately measure improvements in airframe drag performance. The test is being used to identify surface coatings that will reduce drag by 25% when compared to traditional aircraft surfaces – and when tested in typical aircraft cruise conditions. These coatings must also demonstrate the ability to maintain this level of performance over five years, which is the lifetime of an aircraft’s external paint system.

Development phase concludes in mid-2016

Engineers at the GKN Aerospace facility in Luton, UK, started working with the team from Durham University’s school of engineering and computing sciences in May, 2015. In November, 2015 the first tests were completed, with twenty coated surfaces assessed for their drag performance. This developmental phase now continues with the detailed assessment of a number of low drag surfaces, all treated with GKN Aerospace-developed coatings. The development phase is expected to conclude in mid-2016.

Tiny changes cause air flow to become turbulent

Russ Dunn, Senior Vice President, Engineering and Technology at GKN Aerospace, explains: “Smooth and clean aerodynamic surfaces reduce the drag of the aircraft as it moves through the air. In some areas of the aircraft, for example the wing leading edge, the ‘laminar flow’ (smooth continuous flow) of the air is typically spoiled by tiny changes in geometry and surface cleanliness. This causes the air flow to become turbulent, increasing drag which in turn increases the engine power, and hence fuel, required to travel a given distance.”

Coatings need to work in the real world

Dr David Sims-Williams, from Durham University, comments: “We are pleased to be working with the engineering team from GKN Aerospace and to help prove aircraft drag reductions, and hence demonstrate savings in fuel consumption and CO₂ emissions. One of the challenges for low drag surface coatings is that they need to work in the real world, on aircraft in service, over the long term. Proving sustained, consistent performance over time is an important element of this research.”

Part of the future wing research programme

This project is part of the GKN Aerospace-led future wing research programme, VIEWS, (Validation and Integration of Manufacturing Enablers for Future Wing Structures) which aims to bring promising wing design, manufacture and assembly technologies to near market readiness. The programme has received grant funding and support from the joint government and industry funding programme for aerospace R&D, delivered in partnership by the Department for Business, Innovation and Skills, Aerospace Technology Institute (ATI) and Innovate UK.