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A British engineering company is leading a project to develop composite pipes for aero-engines which are half the weight of traditional metallic assemblies.
With approximately 150 suitable pipe assembly applications per engine, using composite rather than metallic pipes could offer total weight savings per engine of approximately 10kg, with the knock-on effect for the rest of the aircraft likely to offer empty weight savings of 50kg for a twin-jet aircraft.
Sigma Precision Components has been leading a Clean Sky-funded project to develop composite pipes and claims to have verified weight savings of 50% when compared to metal variants.
Mike Andreae, director of technology and improvement at Sigma, said: “The results of the programme offer a real step change in environmental performance for engine manufacturers.
“If all the engines due to be delivered over the next 20 years were made using composite pipes, conservative estimates suggest a saving of 4.5 million tonnes of CO2 could be made over the life of the engine, as well as a significant reductions in fuel costs.”
Sigma has been working with partner TWI to develop the composite pipes – known as COMPipe – over the last two and a half years. The original brief was to develop composite pipes for aeroengines in various sizes and geometries, capable of withstanding operating temperatures up to 165°C, operating pressures of up to 450 psi and a typical engine operating environment including fireproof requirements. The composite pipe assemblies also had to be significantly lighter than metallic equivalents, and cost competitive.
Andreae said: “Composite materials offer real potential for reducing aircraft weight but, as a relatively new technology, there is a lot of work to be done to develop components that can withstand the harsh operating environment of an aero-engine.
“Our COMPipe pipes use braided carbon-fibre and high-performance thermoplastics that can be manufactured much more quickly than traditional thermoset composites and also allows the material characteristics to be engineered for specific applications. One of the biggest challenges was to develop a process to form pipes into the complex 3D geometries whilst maintaining leak tightness. We have also developed a series of lightweight end fittings as part of the programme.”
Validation testing has shown that Sigma’s COMPipe technology can withstand sustained pressures of 4000 psi and operating temperatures of up to 235°C. It has also passed a variety of fire, damage, and vibration tests. “This makes it suitable aeroengines, airframes and a number of other spin-off projects that we are now investigating further,” he added.
Sigma said it was currently exploring a number of associated projects – including an Advanced Manufacturing Supply Chain-funded programme to develop composite drive shafts.