Propellers and turbines may soon be obsolete when it comes to powering airplanes: new research suggests that in the future, a sustainable new method of powering aircraft may replace current jet engines and propulsion techniques.
Researchers at the Massachusetts Institute of Technology (MIT) have recently tested the breakthrough method, known as electroaerodynamic propulsion, on a model aeroplane. The five-pound model plane had a five-meter wingspan and was tested with a series of flights through an indoor gym at MIT. In their report, the researchers compare their own test flights – about 55 meters long and lasting 12 seconds – to the first flight tests conducted by the Wright brothers, which were 35 meters over 11 seconds.
The team from MIT hopes their research may eventually lead to work almost as groundbreaking in the technology of flying. The success of the test flights shows that long-held concerns over electroaerodynamic propulsion can be overcome, and demonstrates a proof-of-concept for applying electroaerodynamic propulsion techniques to larger aircraft and flying systems.
Traditional planes are powered by propellers or turbines: moving parts which require fuel to generate thrust. Electroaerodynamic propulsion, in contrast, uses an electric field to accelerate ions, causing momentum in the ambient air and generating a thrust in the opposite direction of the flow of ions.
Electroaerodynamic propulsion doesn’t rely on fossil fuels, produces no emissions, and would power a flying device without making noise. Clearly, electroaerodynamic propulsion, also called ionic wind, is an attractive option for powering aircraft.
Until now, ionic wind was considered infeasible for powering large aircraft. The propulsion system must be capable of producing strong enough thrust to move the aircraft, so generating the thrust cannot require too much weight or surface area: excess weight and surface area both resist motion. On the model plane, positive- and negative-charged wires, used as electrodes, were stored under the wings and powered by a lithium ion battery. When the wires were charged, they generated a current and created an ionic thrust to power the plane.
Though the team of researchers at MIT only tested ionic wind on a model airplane, the properties of their plane, such as being heavier-than-air, mean their success serves as a proof-of-concept that can be extended to larger aircraft.
Current work on ionic wind technology mainly focuses on attempts to make the propulsion system more energy efficient, and to increase the scale of the aircraft it can power. The test plane managed to convert less than three percent of its electrical energy to thrust, and a better energy efficiency would be needed to power larger airplanes. In addition, the thrust density achieved by the test plane demonstrated that devices such as drones and other smaller aerodynamic craft could be powered by electroaerodynamic propulsion. However, larger aircraft require a bigger thrust density, another challenge to powering commercial jets using ionic wind.
Even so, these new results suggest that ionic wind-powered drones and smaller craft may soon be viable. And now that researchers have shown the potential of this technology, more research – and progress – is sure to follow.
Steven Barrett, associate professor of aeronautics and astronautics at MIT, expressed his excitement for this potentially promising new power source in an MIT news release.
“This is the first-ever sustained flight of a plane with no moving parts in the propulsion system,” Barrett said in the press release. “This has potentially opened new and unexplored possibilities for aircraft which are quieter, mechanically simpler, and do not emit combustion emissions.”