Originally published on Telegraph on December 23rd 2015
by Paul Bray
Been on one of the latest airliners? Spotted all those passengers tapping away on their laptops, watching movies and charging phones? Then you won’t be surprised that today’s planes use a lot more electricity than their forebears. And that’s just the things you can see.
“Behind the scenes, a lot of mechanical functions are being taken over by electronic devices that potentially promise greater controllability and efficiency,” says Douglas Herbert, an electrical engineer at .
Mechanical fuel and oil pumps have to be directly attached to the engine, creating lumps and bumps that spoil its aerodynamic shape, whereas electric pumps can be sited almost anywhere. Hot air de-icing systems take air away from the engines and add to the plane’s weight with extra pipe work – electric heaters don’t.
“We call it the ‘more electric aircraft’ and it’s why planes such as the latest Boeing 787 Dreamliner use up to a megawatt of electrical power, three or four times as much as a 767,” says Mr Herbert’s line manager, electrical machines team leader Dr Ellis Chong. “To provide this power we need to design and consider the possibility of the ‘more electric engine’.”
This is still a jet, of course. Almost all of a plane’s electrical power is generated in-flight from its main engines. But the more efficiently this is done the less fuel the plane uses – one of the biggest issues facing the commercial aerospace industry today.
Which is one reason Rolls-Royce has around 1,600 engineers working on different electrical related projects worldwide – people like 25-year-old Douglas, who joined the company after being supported through university by a Rolls-Royce scholarship.
“It’s a fascinating time to be an electrical engineer as we face some huge challenges,” he says (obviously relishing the prospect). “We need to use novel technology to design generators half the size and a third of the weight of conventional ones but able to output three times the power. And we have to work out how engines can continue to meet higher levels of electrical demand when they’re throttled back, for example when pilots begin their descent.”
In the far future (aeronautical engineers think in decades, not years) commercial planes could well have all-electric propulsion systems. The gas turbine engines could be sited inside the plane, tuned to run always at their optimum level and used solely to drive generators, with electric fans providing the plane’s thrust.
These fans could be mounted in the most efficient and aerodynamic configuration – around the fuselage, say, or built into the tail. Such planes could be significantly quieter and more fuel-efficient, and Mr Herbert is thrilled that he may help to create and, ultimately, fly in one.
It’s not just planes that are going electric. While still at university Mr Herbert spent a summer internship at Rolls-Royce’s marine division in Norway where he discovered that ships, too, are moving towards more efficient, electrical subsystems and even electric propulsion.
“Rolls-Royce has already integrated electric motors into tunnel thrusters, the side-facing propellers that help large ships to manoeuvre in tight spaces,” says Dr Chong. “And we’re probably closer to all-electric propulsion systems for ships than for planes.”
“A great thing about Rolls-Royce is that you can work in a range of different sectors and transfer what you’ve learned from one to another,” says Mr Herbert. “There aren’t many companies where you can get involved in such a wide range of really interesting things.”