Towards improved performance

Citation

Ford, T. (2002), "Towards improved performance", Aircraft Engineering and Aerospace Technology, Vol. 74 No. 2. https://doi.org/10.1108/aeat.2002.12774baf.001

Towards improved performance

Keywords: Surface Transforms plc, Aircraft industry, Materials

The innovative and enterprising Surface Transforms plc was formed in 1999 to manufacture and develop new products and technology based oh carbon fibre reinforced ceramic friction materials (CFRCs). The origins of the company date back to 1992 when the business was founded to exploit new material and process patents from ICI plc, which had possible applications in a number of markets. Within two years the business became involved in a DTI sponsored LINK programme for the development of a novel low cost manufacturing process for carbon composite brakes for high speed trains. This was acquired by the company, which completed a public offering and floated on the OFEX market in December 2000. Also, the company has set up links with a major global manufacturer of aircraft braking systems, and is also developing and pilot manufacturing brake pads and discs for use on high performance road cars as well as Formula 1 racing vehicles.

Surface Transforms core activity is the exploitation of proprietary technologies and these objectives: have been pursued over seven years. A new state-of-the-art manufacturing plant at the Cheshire Innovation park, part of the Shell Manufacturing Complex at Ellesmere port, has enabled the company to concentrate on full-scale product manufacturing. This has resulted in a number of significant advances in production techniques leading to increases in efficiency and cost savings.

Manufacturing and R&D

Under its managing Director Julio Faria and finance and commercial director David Lewis, the company has successfully made the transition from producing test samples utilising its own small-scale pilot plant, to manufacturing full scale products in its new facility. The new building has enabled staff to focus on a number of advancements which include its own in-house test equipment which allows for very rapid examination of sample compounds and the reduction of test programme time scales compared to conventional methods. The company continues to be active in researching and developing friction materials for various applications where the directors feel a commercial opportunity exists as well as improving existing products in order to maintain competitive advantage.

Following the in-house development of an additional product line, the firm has won a new order for carbon fibre performs. These are mats of interwoven multi-directional carbon fibres, which are the basis materials that Surface Transforms converts into ceramic brakes and discs. The European customer is a supplier of carbon-carbon materials and placed a small initial order during the latter part of 2001. If this meets its supply and quality thresholds, the company is confident of further orders.

Earlier in 2001 the company began manufacturing its own performs because it found that external suppliers could not guarantee the quality of their products nor meet defined supply dates. Since producing its own performs, the quality of its ceramic brake materials has been greatly enhanced. Thus, the company has a new market which is showing considerable potential with interest and enquires from potential customers.

Aerospace applications

The aircraft market is supplied mainly by two companies from the US and two from Europe. Rather than compete directly with these large businesses, Surface Transforms has sought to form an alliance with one and to seek revenues from product and process licensing as well as the supply of materials. This should allow Surface Transforms to enter the market quickly via an existing supply chain without the need to invest in vary large manufacturing facilities.

It is notable that the aircraft brake market is driven by the need for improved durability, increased performance and cost reduction while maintaining or improving the sectors high safety standards, and collaboration seems the sensible way to proceed. This has been helped by the company's own improved processing route that reduces carbon composite brake production time.

The value of the market for brake materials for aircraft is estimated to be worth in excess of £625 million per year for the supply of carbon-carbon, since carbon based brakes have superseded ferrous based products in the last twenty years as the preferred material. Initially, this was primarily driven by carbon products being up to 70 per cent lighter than ferrous ones and thus resulting in significant fuel savings due to aircraft weight reduction. More recently, a significant rise in fuel costs has led to aircraft operators relying more on wheel braking rather than reverse thrust during landing procedures. Virtually all new commercial and military aircraft programmes specify carbon-carbon brakes and generally last in excess of twenty years for the supply of new and replacement parts.

Aircraft brakes differ from brakes typically fitted to road vehicles in that they are arranged in heat packs where a number of discs are stacked side by side in a rotor/stator arrangement, each alternate disc having lugs on the inside diameter which mate with the brake structure which sits around the axle. The remaining half of the stack has lugs on the outer diameter which mate with the wheel. In this arrangement, half the discs are therefore free to rotate whilst the other half are free. As the brakes are applied, both faces of each disc are brought into contact with the face of the disc next to its causing the whole surface area of the disc to act as the friction area, unlike road vehicles where only the pad area acts as the friction surface.

As the energy of the stop is absorbed, the disc 'bulk' temperature will reach around 500C whilst surface temperatures can be as high as 2000C. Such temperature ranges mean the material must exhibit good thermal shock resistance characteristics. Carbon has a very low coefficient of thermal expansion and high thermal conductivity, and so is ideal for this application. In addition, because carbon has a heat capacity which is about 21/2 times greater than steel and has a strength twice as good as steel at higher temperatures, the number of landings per overhaul on a medium sized commercial aircraft can be increased from around 1500 to 2500 when carbon is used instead of steel brakes.

The wear characteristics of aircraft brakes also differ widely. Much of the wear on a disc is attributable to 'oxidative' wear rather than 'frictional wear'. Carbon oxidises readily in a hot, oxygen rich atmosphere (this is why coal is such an effective fuel), so oxidative wear occurs as the brakes are applied on landing or taxiing and become very hot then remain idle while the aircraft is stationary or in flight. Protection from oxidative wear has thus become important in preserving aircraft brakes. Brakes can last for up to 3000 landings depending upon the usage. Obviously, short haul commuter flights will have different wear profiles to long haul flights.

Sales and marketing strategy

Due to the different nature of the markets in which the company operates, different sales strategies have been adopted to suit the various market profiles. In high volume markets, Surface Transforms has aligned itself with an existing presence in the relevant sector. Where the market features low, volumes, the company's policy is to manufacture products in-house. However, in the aircraft (as noted), rail and high performance road car markets) the company has formed strategic alliances as part of its development programme.

In areas other than aerospace, such as Formula 1 and other high performance' vehicles, the company has again sought to take advantage of existing supply chains by arranging to supply products via current automotive and motor sport brake equipment suppliers. Surface Transforms is able to carry out manufacturing for this market sector in-house due to the lower volumes involved. In general, the company adopts a policy of concentrating on key strengths in design, material application and speciality manufacturing and seeks to enter into sub- contract, licensing and distribution agreements with key strategic partners where lack of expertise or high capital expenditure would prove restrictive. This seeks to reduce time on market, risk and capital requirements.

Terry Ford