Ion thruster photo from NASA
A team from MIT is working on developing ionic wind thrusters as an energy-efficient, low-emission alternative to conventional propulsion technologies like jet engines. The new thrusters would use ionic energy, which is created when a current passes between two electrodes. If one electrode is thinner than the other, it creates an air current in the space between them – and if a substantial voltage is applied, the device could produce powerful thrust without the need for fuel or motors.
Ionic wind thrusters have been discussed ever since the 1960s, but up till now they’ve been dismissed as impractical or suitable only for lightweight vehicles. However the MIT research team now believes that the technology could potentially power commercial airlines.
Following a series of experiments, the MIT team announced that ionic thrusters could be more efficient than engines currently used in the aerospace industry. In their research, which was published in the Proceedings of the Royal Society, they stated that ionic wind thrusters could produce 110 newtons of thrust per kilowatt, while a jet engine would produce 2 newtons per kilowatt.
Steven Barrett, an assistant professor of aeronautics and astronautics at MIT, added that ionic thrusters are silent and invisible in infrared, as they give off no heat. “You could imagine all sorts of military or security benefits to having a silent propulsion system with no infrared signature,” says Barrett, who co-authored the paper with graduate student Kento Masuyama.
There is currently one thing blocking the future development of ionic engines – thrust density. Ionic thrusters depend on the wind produced between two electrodes, and the larger the space between the electrodes, the stronger the thrust. This means lifting a small aircraft and its power supply would require a very large air gap. The MIT team believe that this could be overcome by encompassing the entire vehicle in thrusters!
“Efficiency is probably the number one thing overall that drives aircraft design,” Barrett says. “[Ionic thrusters] are viable insofar as they are efficient. There are still unanswered questions, but because they seem so efficient, it’s definitely worth investigating further.”