Technology could be used on skin of commercial aircraft, reducing drag

At first glance, Steven Barrett’s plane itself doesn’t look light years away from other renewable aircraft, such as the Solar Impact II craft that in 2015-16 used energy from the sun to fly around the world.

Unlike Solar Impact, Barrett’s plane doesn’t have any propellers or solar panels — or any movable parts whatsoever.

Instead of engines, it is powered by a system comprising two main sections.

At the front of the plane sit a series of parallel electrodes made up of lightweight wires that produce an enormous voltage — +20,000v — supercharging the air around it and splitting away negatively charged nitrogen molecules known as ions.

At the plane’s rear are rows of aerofoils set to -20,000v. The ions automatically move from a positive to negative charge, dragging with them air particles that create the so-called “ionic wind” to provide the aircraft with lift. The technology to create ionic wind has been around since the 1960s, but it was previously thought nowhere near efficient enough to prove useful to aeronautics.

The team not only showed that it was possible for ion-driven craft to fly but also — due to the relative lack of drag created by the electrodes — predicted that efficiency would increase in lockstep with speed, potentially opening the way for bigger, faster planes in future.

“It’s clearly very early days: but the team at MIT have done something we never previously knew was possible, in using accelerated ionised gas to propel an aircraft,” said Guy Gratton, aerospace engineer and visiting professor at Cranfield University, who was not involved in the study.

Barrett said he believed the current prototype could be scaled up “a significant amount” but cautioned that there may be a limit to how much propulsion the technique can produce. The technology could be used on the skin of commercial aircraft, reducing drag and therefore the energy needed to power modern passenger jets.

“This would be much more efficient than the current situation where you have concentrated engines that generate thrust, which have to fight against a large passive airframe that generates drag,” he said.