EXPRESS #4 - December 13, 2018
Carbon zero flight propulsion is here! But the “ionic wind” aircraft only weights 2.3 Kg
Aviation has been given a free pass in the fight to reduce carbon emissions. That’s because lifting hundreds of tonnes into the air, cost-effectively, with renewable fuels is unviable for the foreseeable future. But what if someone invented an aircraft with no propellers or jet engines, just a blue glow out the back like something out of Star Trek. Long believed impossible, or at least impractical, that technology is now real. The “ionic wind” aircraft is here.
MIT aerospace engineer Steven Barrett led a team in a nine-year research effort to design, build and fly an aircraft propelled by “ionic wind”. The engine generates enough thrust to propel the plane over a sustained, steady flight.
But the aircraft weighs only about 2.3 Kg, and has a 5-meter wingspan. The fuselage of the plane holds a stack of lithium-polymer batteries, which is the cause of its main problem: weight.
The team flew the plane a distance of 60 meters (the maximum distance within the gym they did the tests in) and found the plane produced enough ionic thrust to sustain flight the entire time. They repeated the flight 10 times, with similar performance.
Barret expects that in the near-term, such ion wind propulsion systems could be used to fly less noisy drones. Further out, he envisions ion propulsion paired with more conventional combustion systems to create more fuel-efficient, hybrid passenger planes and other large aircraft.
“Ionic wind” is also known as electro-aerodynamic thrust: a physical principle that was first identified in the 1920s and describes a thrust that is produced when a current is passed between a thin and a thick electrode. If enough voltage is applied, the air in between the electrodes can produce enough thrust to propel a small aircraft.
Barret’s aircraft carries an array of thin wires, which are strung like horizontal fencing along and beneath the front end of the plane’s wing. It requires no moving parts.
Once the wires are energised, they attract and strip away negatively charged electrons from the surrounding air molecules, like a giant magnet attracting iron filings. The air molecules that are left behind are newly ionized, and are in turn attracted to the negatively charged electrodes at the back of the plane. As the newly formed cloud of ions flows toward the negatively charged wires, each ion collides millions of times with other air molecules, creating a thrust that propels the aircraft forward.
The inspiration: Star Trek
The team is not shy to admit their inspiration comes partly from the movie and television series, “Star Trek,” which they watched avidly as children. They were particularly drawn to the futuristic shuttlecrafts that effortlessly skimmed through the air, with seemingly no moving parts and hardly any noise or exhaust.
But it’s still out of reach for now. What’s holding them back is the weight, and insufficient currents flowing through the wires. So once again it’s over to the battery sector (and possibly the superconductor wire engineers) to make it work for airlines. Sometime this century, we hope.