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First Ever Plane With No Moving Parts Takes Flight (theguardian.com)
An anonymous reader quotes a report from The Guardian: The first ever "solid state" plane, with no moving parts in its propulsion system, has successfully flown for a distance of 60 meters, proving that heavier-than-air flight is possible without jets or propellers. The flight represents a breakthrough in "ionic wind" technology, which uses a powerful electric field to generate charged nitrogen ions, which are then expelled from the back of the aircraft, generating thrust. Steven Barrett, an aeronautics professor at MIT and the lead author of the study published in the journal Nature, said the inspiration for the project came straight from the science fiction of his childhood.
In the prototype plane, wires at the leading edge of the wing have 600 watts of electrical power pumped through them at 40,000 volts. This is enough to induce "electron cascades", ultimately charging air molecules near the wire. Those charged molecules then flow along the electrical field towards a second wire at the back of the wing, bumping into neutral air molecules on the way, and imparting energy to them. Those neutral air molecules then stream out of the back of the plane, providing thrust. The end result is a propulsion system that is entirely electrically powered, almost silent, and with a thrust-to-power ratio comparable to that achieved by conventional systems such as jet engines. "I was a big fan of Star Trek, and at that point I thought that the future looked like it should be planes that fly silently, with no moving parts -- and maybe have a blue glow," said Barrett. "But certainly no propellers or turbines or anything like that. So I started looking into what physics might make flight with no moving parts possible, and came across a concept known as the ionic wind, which was first investigated in the 1920s."
"This didn't make much progress in that time. It was looked at again in the 1950s, and researchers concluded that it couldn't work for aeroplanes. But I started looking into this and went through a period of about five years, working with a series of graduate students to improve fundamental understanding of how you could reduce ionic winds efficiently, and how that could be optimized."
In the prototype plane, wires at the leading edge of the wing have 600 watts of electrical power pumped through them at 40,000 volts. This is enough to induce "electron cascades", ultimately charging air molecules near the wire. Those charged molecules then flow along the electrical field towards a second wire at the back of the wing, bumping into neutral air molecules on the way, and imparting energy to them. Those neutral air molecules then stream out of the back of the plane, providing thrust. The end result is a propulsion system that is entirely electrically powered, almost silent, and with a thrust-to-power ratio comparable to that achieved by conventional systems such as jet engines. "I was a big fan of Star Trek, and at that point I thought that the future looked like it should be planes that fly silently, with no moving parts -- and maybe have a blue glow," said Barrett. "But certainly no propellers or turbines or anything like that. So I started looking into what physics might make flight with no moving parts possible, and came across a concept known as the ionic wind, which was first investigated in the 1920s."
"This didn't make much progress in that time. It was looked at again in the 1950s, and researchers concluded that it couldn't work for aeroplanes. But I started looking into this and went through a period of about five years, working with a series of graduate students to improve fundamental understanding of how you could reduce ionic winds efficiently, and how that could be optimized."
Yep. From the original paper ( https://www.nature.com/article... ):
"Owing to the limited length of the indoor space (60 m), we used a bungeed launch system to accelerate the aircraft from stationary to a steady flight velocity of 5 m/s within 5 m, and performed free flight in the remaining 55 m of flight space. "
Besides the weight of the batteries, the main issue is this:
"Although we have shown that EAD thrust density is sufficient at the scale of unmanned aerial vehicles, where the available ratio of frontal area to weight is high, it is not currently sufficient for high-speed flight at the scale of commercial aviation: the area thrust density of our aeroplane was 3 N/m^2, that of a typical conventional unmanned aerial vehicle is of the order of 10 N/m^2, and that of a modern civil airliner is of the order of 1000 N/m^2."
Nevertheless it is really cool technology.
About 3N/m^2 per the article; that is about 1/300th of a modern jet airplane.
Browsing at +1 - no ACs, I ignore their posts. So refreshing!
> make it much bigger, which will require much stronger wings, which will make it heavier.
Yeah with planes, if it barely works at small scale, it can't come close to working at a much larger scale. Specifically, doubling the length and width means the weight is eight times as much. It's easy to do things at model scale that are nearly impossible at full size.
Imagine a plane with a rectangular fuselage 10x1x1. Its volume would be ten units, and the weight proportional. "Doubling the size" would be 20x2x2. That's 80 units of volume/weight! Doubling the size makes it 8 times heavier.
I can easily scratch build a model plane from Dollar Tree materials that has a thrust to weight ratio greater than 1. Probably most models have 1 or better thrust to weight. At full scale, only some fighter jets have that kind of capability.
The fact that scaling up by doubling the wingspan means 8 times as much weight means anything borderline capable at 5 meter wingspan because totally unusable at 10 meters. They'll need to either scale it up and show it works, or demo fighter jet level performance at 5 meters to show flight is possible at 10 meter wingspan.
Initially the Wrights used a weight-driven catapult
I can. Solar powered, near maintenance free, silent drones.
Just up there forever, hovering, watching, doing gods know what.
Scale model sizes are always done this way. A 1:10 model is 1/10th the length, 1/10th the width, and 1/10th the height, or 1/1000th the volume.
Yeah, I think this guy is excited in the wrong direction, (big silent electric aircraft) but he even mentions the right direction in the article. He mentions that this tech scales *down* really well. So here's your propulsion system for things like robotic bees, and other extra tiny flying devices.
I've decided to Diversify my Holdings. I've divided my cash between my left and right pockets, instead of all in one.