There’s nothing like the buzz of a neighbour’s drone to ruin a good barbecue.
- Engineers have designed a prototype plane that is propelled using electrostatic forces
- This technology uses electricity to create an electrical gradient where ions flow from positive to negative, creating an ionic wind
- In the future, the technology may be useful for aircraft that need to operate by stealth such as drones
Ever since the Wright brothers flew their machine over the fields of Kitty Hawk more than 100 years ago, aircraft have been propelled using moving surfaces such as propellers and turbines.
Now, for the first time, a team of US-based scientists has designed and successfully test flown a small aircraft using technology that isn’t propelled by moving parts or fossil fuels, they report in the journal Nature.
The team of scientists, from the Massachusetts Institute of Technology, say the innovation could pave the way for quieter, cleaner fixed-wing drones and aeroplanes in the future.
Despite some early hiccups — their first flight crashed into a wall — the plane successfully completed 10 test flights of 60 metres, with an average altitude of 0.47 metres.
That’s comparable in distance to the first Wright flight of 36.6 metres in 12 seconds in 1903.
“But [ours was] hugely easier in the sense we only had to carry a control unit and not a pilot,” said Steven Barrett, who has been working on the project for the past nine years.
And while it’s a huge step forward, it will take a lot more work for this technology to fly from the lab to the real world.
How it works
In traditional aircraft, thrust is created by propellers or turbines which push fast moving air backwards, and in turn pushes the aircraft forward.
Weighing just 2.45 kilograms with a wing span of 5 metres, the prototype plane uses a technology called ionic wind, an electronic gradient from positive to negative charge, to push the craft forward.
YOUTUBE: [ The prototype plane flies using ionic wind. Source: MIT/Steven Barrett]
The technology was first proposed in the 1960s, but it was thought that it would be impossible to produce ionic winds that would be efficient enough to fly an aeroplane, Professor Barrett said.
“This is the first time we’ve achieved level flight with an aeroplane — which is a heavier-than-air flying vehicle,” he said.
The new prototype uses positively charged wires under the wings to strip electrons from nitrogen atoms in the air leaving behind positively charged ions. These ionised particles flow to the back of the plane, which is negatively charged.
“As they flow they collide with air molecules transferring momentum to them. This is how the thrust is generated,” Professor Barrett explained.
The prototype plane has positively charged wires under its wings that strip electrons off nitrogen atoms.
(Supplied: Steven Barrett)
The rate of energy consumption (provided by the 500W battery) required to generate the thrust — known as the power to thrust ratio — was comparable to commercial aircraft.
But those efficiencies may well be lost as the small craft is scaled up to commercial sizes and payload capacities.
Professor Barrett said it was unclear how much the technology could be scaled up — or down — but it could have applications for aircraft where stealth is an advantage.
“The nearest term application would be for fixed-wing drones that have wing spans of a few metres to perhaps 20 metres,” Professor Barrett said.
Evolution but will it be a revolution?
Aeronautics expert Andrew Neely, of UNSW Canberra, said the work was a “nice first step”.
“They’ve achieved something that people have talked about but no-one else seems to have achieved before,” Professor Neely, who was not involved in the research, said.
The Wright Flyer was one of the original flying machines
(Supplied: US Library of Congress)
He said the main advantage such a craft would be noise reduction.
“If you get away with moving air slowly, that helps to reduce noise and of course they’ve also removed any noise from any moving parts,” he said.
But while there may be some niche applications for the technology, Professor Neely said it still has a long way to go to be competitive with existing traditional and electrically powered aircraft.
"It’s not clear whether this would be any more efficient than some of the other ways we propel an aircraft.
“And they admit themselves that it will be a struggle to scale to be able to carry significant payloads.”
Like all electrically propelled devices, it will be a slave to limitations in batteries, he adds.
“The less efficient the propulsion system, the more battery power you have to carry,” Professor Neely said.
Professor Barrett and his team will continue to tweak the craft to make it more efficient and quieter.
But there’s bad news if you are hoping for an end to the noisy multirotor drones.
“It’s less clear if [this technology] could be used for vertical lift,” Professor Barrett said.