A UK-based composite structures specialist, Carbon ThreeSixty, is leading a project to develop a revolutionary all composite helicopter wheel. The project, which started on 1st January and will run for the next 18 months, is co-funded by Innovate UK, the UK’s innovation agency.
The project is being delivered in partnership with the National Composites Centre, collaborating with Leonardo and ultimately aims to improve the performance, safety and full ownership cost of helicopter wheels. The consortium will combine its expertise to design, develop and manufacture an ultra-low mass, robust, proof-of-concept carbon fibre reinforced plastic (CFRP) wheel for rotary wing aircraft.
The current global market for helicopter wheels uses metallic light-alloy materials, usually made from aluminium or magnesium. These wheels offer sufficient strength and stiffness from a relatively low density.
However, a wheel made of CFRP will offer enhanced mechanical properties at approximately half the density of metallic wheels. Compared to aluminium alloys, a CFRP wheel will be lighter, with higher performance and an extended working life.
Existing light metal alloy helicopter wheels can suffer from fatigue failures and have to endure relatively harsh environments. This requires regular preventative and corrective maintenance throughout the life of the aircraft.
The fibrous microstructure and resin stability of advanced composites mean that fatigue life and corrosion resistance can be much improved when optimally designed. They also offer weight savings of around 30-40% over forged aluminium and improved NVH (noise, vibration and harshness) performance.
Weight reductions enable airframers to deliver efficiency, range and payload improvements and provide an option for lower power density propulsion systems, such as battery-electric power. The composite wheels will also be interchangeable with existing wheels, making them suitable for retrofit applications.
Ed Allnutt, managing director of Carbon ThreeSixty said, “Our experience with other composite wheel applications has shown that weight savings of 30 to 40% are achievable over forged aluminium solutions. We believe the key selling point, however, will be the improvements in fatigue life and failure mode, which will extend life and improve safety.”
The project will use cutting-edge composite manufacturing technology such as tailored fibre placement (TFP), braiding, and out-of-autoclave processes to ensure repeatability and scalability while utilising novel product and process design to enable the partners to protect the intellectual property required to successfully manufacture the products.
Alex Doyle, technology project lead at the National Composites Centre explained, “Composite wheels have only become viable in the last 10 years due to improvements in resin system toughness, lower carbon fibre prices and improvements in process automation. We can see this in the automotive wheel market, where they are now proven.
“However, aerospace applications are more challenging. The shift in cost, combined with the technical improvements are the reason why now is the time composite wheels are feasible for aerospace rotorcraft applications.”
The scope of the project covers the specification, design, development, manufacture, inspection and testing of a proof-of-concept helicopter wheel, considering full aerospace requirements in line with the specification provided by Leonardo for an undisclosed platform.
Adrian Smith, R&T portfolio delivery at Leonardo Helicopters UK said, “We are very keen to be involved in developing this technology. Composites are expected to save around 1.5kg over each 5kg alloy wheel. This 6kg weight saving overall represents almost 1,000 gallons of fuel saved over a typical 12,000 hour service life and equates to around 12 tonnes of CO2.”
The project is expected to last around 18 months, with a total budget of around £250k. Deliverables will include 12 fully tested proof of concept wheels, and a methodology for design and manufacture.