carbon

Aeronautics: ever increasing composites solutions

Aeronautics: ever increasing composites solutions

Carbon fabrics help e-Go aircraft to save 53% on weight

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No80 April 2013 / jec composites magazine 33

Early in 2007, the United Kingdom’s Civil Aviation Authority announced a new class of aircraft, known as the

Single Seat De-Regulated (SSDR) class. This greatly reduces the paperwork needed to design, build and fly an aircraft, as long as certain criteria are met.

SSDR category rulesThe former Popular Flying Association (PFA, now the Light Aircraft Associa-tion, LAA) announced a competition for designs in this category, including a “cheap and easy-to-build” class and a “state-of-the-art” class. The e-Go aircraft design won the state-of-the-art competition and the immediate demand for it initiated the development process for a commercially

UK aircraft manufacturer e-Go is about to launch a Single Seat De-Regulated (SSDR) aircraft. To build an aircraft with the required weight and mechanical performance, the use of Spread Tow carbon fab-rics was essential. On certain parts, the weight saving was as much as 53%.

Giotto Castelli, Chief Designer & Technical Director, e-Go

Christian Borg, Communication & Brand Director, Oxeon

Stephen Philipson, Business Development Manager Carbon, Oxeon

ByFig. 1: Clean aerodynamics and a compact airframe will allow cruise in excess of 100 kts on 30 hp. This is an early airframe assembly trial (nose undercar-riage is a temporary one)

53% less weightTeXtreme® is used on selected parts of the e-Go aircraft, and the current weight saving amounts to 53% when compared to conventional carbon fibre reinforcements.

Painting a TeXtreme® moulded part gives further mass savings in that the texture of the raw CFRP is left with fewer pinholes to fill. Further significant weight savings are planned on the production aircraft by re-placing other CFRP parts with TeXtreme®.

In the case of e-Go airplanes, the main advantage in using TeXtreme® comes from the availability of very low areal weights in the form of CFRP – hence its specific properties of strength and stiffness. Mi-crolight aircraft, particularly in the SSDR category, tend to have low wing loading and distributed loads that require little structural material, especially in regions such as wing skins, which constitute the biggest percentage of the structural mass. Aside from stability issues, which can be tackled in different ways, the constraint there is often the availability of materials that are thin enough, and therefore light enough, to allow an optimized design. n

More information: www.textreme.com

available SSDR aircraft. The founders of e-Go, Giotto Castelli and Tony Bishop, both live in Cambridge, UK and have a long experience working in the aerospace sector during their careers Giotto as designer and Tony on the busi-ness side. Their first step after the win was to develop the design further and test the market.On the design side 3D design tools were used to ensure that the airplane would fit together properly and weigh under 115 kg to meet the SSDR category rules. The design was also made to meet the LSA, ELA and microlight standards. But more significantly, it stretches the performance boundaries of a class having the con-straints of SSDR, resulting in cruise speeds almost double that of other similar aircraft.

New category of composite rein-forcementsDuring the structural design, it was evident that conventional carbon fibre reinforcements did not allow for a more optimized solution. For many compo-nents, using TeXtreme® overcame this problem.Spread tow reinforcements (including both spread tow fabrics and spread tow UD tapes) are a relatively new category of

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34 jec composites magazine / No80 April 2013

Fig. 3: The back of the fuselage is shown here with the mock-up engine in place. The firewall is part of the fuselage lay-up which used a mix of 2x2 Twill and TeXtreme®. Details are very important to me and each one needs a reason to be.

Fig. 2: Where the loads require less CFRP per area Textreme may be used. These parts are where the weight saving is most significant. The engine cowling is shown here. It covers a large portion of the fuselage and wing fairing area and allows plenty of access for maintenance and inspection.

composite reinforcements. TeXtreme® Spread Tow fabrics are pro-duced by interlacing Spread Tow tapes of desired fibres to obtain a virtually crimp-free fabric with straight orientation of fibres. The result is a unique reinforce-ment with the mechanical performance of a cross-plied UD and the handling ease of a fabric.