Article Source: IMechE
A long-haul flight emits more carbon dioxide per person than the average annual emissions caused by people living in many countries around the world.
With a UK commitment to ‘net zero’ carbon emissions by 2050 and a boom forecast in air travel, electric aircraft are at the forefront of conversation. Such a radical change from conventional technology requires a new approach, however.
At the University of Strathclyde’s Advanced Forming Research Centre (AFRC), we are working with the department of electronic and electrical engineering to form the Scottish arm of a hub that is combining expertise in electrical machines and manufacturing for the first time, aiming to put the UK at the forefront of an electrical revolution. The Future Electrical Machines Manufacturing (Femm) hub from the Engineering and Physical Sciences Research Council is a collaborative research project including the universities of Sheffield and Newcastle. It is looking at electrical machines for high integrity applications, one of which is propulsion systems for aircraft. We aim to revolutionise the design of these machines by bringing manufacturing to the start of the design process.
The standard manufacturing route follows a design, model, validate, manufacture trajectory. When manufacture at the prototype stage doesn’t work, a part reverts to the design phase. If we alter our approach, giving equal weighting to design and manufacture from the start, we can reduce the time spent making modifications along the way and work together to design a part that is structurally sound with an optimised manufacturing route.
This altered approach works well for electric aircraft. We could retrofit aeroplanes, removing combustion engines and installing electric powertrains within aircraft that are not designed for it. Alternatively, we can design an optimised electric aircraft system, including electric propulsion and power systems. Electric aircraft could be completely redesigned around the new power source – this is a challenge that requires a melting pot of expertise to question every decision from all angles.
Altering in a linear order will allow small changes, but we need to collaborate and change the way we look at the core problem to reach the 2050 target. We can do more by using modern manufacturing techniques such as additive manufacturing, radial forging and flow forming, which weren’t widely available 20 years ago.
Through the Femm hub, a short-term goal is to lightweight electrical machines by using novel manufacturing techniques to manufacture non-active components. Currently, around 50% of the total mass of machines consists of casings and housings that protect active components from the environment. Optimising the manufacture of these non-active components will allow us to remove weight while improving performance, enabling us to create electric engines that can go further.
The power that can be generated by an electrical machine is dependent on factors such as the diameter of the machine and the speed at which it can be revved, so the heavier the machine, the more power needed. If you can lightweight it by 20-30%, you can generate more power, allowing an aircraft more time off the ground.
We’re looking at the possibilities to achieve this, and our sister centre within the National Manufacturing Institute Scotland, the Lightweight Manufacturing Centre, aims to develop lighter, more efficient, components for high-value industries, including automotive and aerospace. It won’t be one size fits all, however. We need to balance lightweighting with the structural integrity of parts.
Design and manufacture will complement each other throughout the process. We expect situations where it will be advantageous to use composites over metals, for example, but this won’t be the only solution available, with high integrity metals still of critical importance and the use of hybrid structures still to be fully realised. A combination of a variety of solutions for each part will be required to create the optimal machine. We will have to be innovative and controlled in our approach to weighing up alternatives.
Time to act
While 2050 is 30 years away, we must act now to ramp up research, development and innovation across the UK. We need to review what we already have, to decide if we can upgrade existing models or redesign. In the short term through the Femm hub, the AFRC will develop projects in aerospace and other relevant sectors, aiming to remove mass from non-active components.
Short term, collaboration will allow us to look at existing problems from a different view to develop solutions that will move the electric revolution forward. In the long term, there is a massive opportunity to revolutionise other major sectors and ensure the future of innovative manufacturing in the UK.