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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."
This plane's wingspan is already five meters, for just 2.5kg of weight, most of it going to the battery pack. To make it carry more weight, one will have to make it much bigger, which will require much stronger wings, which will make it heavier. And to make things worse, batteries do not get lighter as they discharge.
It's a great toy, but it will be a while before it is useful.
I would be fascinated to know how much thrust that is producing. How variable the thrust is etc.
Does the thrust increase with airspeed? I'd get about 2 mins of flight time on those numbers with a standard battery I use in my wings. But I get about 10-15 mins of flight depending on how much I'm caning it.
In my dream world, this would be used to silently propel solar-powered zeppelins around the world. The zeppelin's buoyancy would support the weight of the batteries used for night-time propulsion.
Of course the problem with that is lithium batteries well-known flammability. But what's the odds of something going wrong with something a simple as a zeppelin?
Because their air cleaners were the first thing I thought of.
I cannot see this as immediately useful for plane construction but I can imagine some uses for it. Most notably, one could power this from a real fuel-powered motor rather than a battery and use it as a secondary propulsion mechanism. So for example, this could maybe eliminate the second rotor on choppers (which is a source of major mechanical complexity and does not do much lifting, just torque balancing).
This looks a lot like the Ionic lifters that were popular in the "anti gravity" circles about 15 years ago. I built a few and they were fun to build, but there isn't any anti-gravity going on here just ion wind. The high voltage was entertaining and the corona was beautiful when the lights were turned off.
The folks at MIT are doing great things. I love it!
https://en.wikipedia.org/wiki/Biefeld–Brown_effect
> "my ass" ... "paper airplanes"
Is it a hint on how you use toilet paper?
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I was pondering what 600 watts at 40,000 volts would be like when it meets a flock of geese.
> 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.
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I do believe this is a solution begging for a problem, but I would not say there are hard limits on this application due to batteries in the distant future. We have to extrapolate from current technology that the future will offer wireless power transmission systems. Consider a matrix of ground-based microwave transmitters drawing from solar power that can beam energy to an aircraft such as this in bursts that can charge a meager capacitor. The aircraft is catapult launched, so it only needs to maintain enough energy on board for travelling between energy nodes within the matrix. Actual propulsion would be more efficiently accomplished via traditional means (propeller) for such an aircraft, but my intention here is to highlight that battery scalability should not suppress our freedom to dream of electric aircraft.
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Ah, but you are not supposed to notice the moving parts in the catapult that launched it ;)
And anyway, its far from the first.
A water rocket has 'no moving parts' in the same way, and in summer thousands of them get launched by children daily...
And they dont need a catapult or a perfectly still air environment.
So no, hardly the first.
This is true of any lifting gas. But hydrogen is a lot easier to replace than helium...
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Is it plausibly useful for very high altitude drones, mars aircraft and the like? What is the effective exhaust velocity? eg is there any regime where it is more efficient than an electric motor and propeller?
Still its a cute concept, even if it isn't practical.
Imagine a plane with a rectangular fuselage 10x1x1. Its volume would be ten units, and the weight proportional. "Doubling the size" would be 20x2x2.
Doubling the size would be 20x1x1. That you allow you to carry twice as much cargo... Probably a lot more than 2x as much since the 10x1x1 aircraft would have fixed size equipment and mechanical stuff that doesn't scale proportionally.
What you suggest is multiplying the size by 8. In practice very large aircraft are economical and not as impractical as your numbers would suggest. Per unit of cargo (e.g. per person) an A380 compares well to a small business jet.
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A modern airship using Hydrogen would be orders of magnitude safer then the Hindenburg. That being said, still not safe enough. Just use helium and deal with the reduced efficiency.
Weird. It's almost as if you believe that helium is cheap and unlimited.
You know that no ship is watertight, right? It's much easier to pump out a bit of water once a day than it is to get a perfect seal.
Blimps could do the same thing, ie. have some tanks of hydrogen on board to keep themselves topped up when some escapes.
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Fixed that for ya'.
That's not really the same. The water is in the plane on launch.
In this plane the ions are generated from the air, there is no loss of mass, so nothing "moving" off the plane (just energy)
Right, because weighing less on take off (no fuel) is somehow worse..
You always need fuel. In this case your fuel is electricity stored in batteries. Not sure if you're aware, but I hear those tend to weigh a fair bit. You could in theory use fuel cells and compressed or liquid hydrogen instead of, but I'm not sure that would get you much in the way of weight reduction either. So in either scenario you'll have to seriously beef up your landing gear and brakes, which means added weight, which further reduces efficieny and/or max payload.
You want to minimize wear and tear on landing.. Not on takeoff AND landing.
Yes, that's what I said. By dragging batteries around you are not doing that. Your plane weigh just as much on takeoff as on landing.
idiot.
You seem terribly confused.
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.
Well, the on-board batteries will have less energy in them, so there's that.
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Can you reverse the principle to make a solid state windmill that generates power with no moving parts?
> You build a bigger plane, but don't double wall thickness of your material.
Actually you DO have to double the strength of the walls, and square the strength of certain joints. That's because you've doubled, squared, and cubed the loads they have to withstand.
Consider the wing. A wing 20x2x2 is 8 times as much material as a 10x1x1 wing. Where the wing attaches to the fuselage, a wing root 2 units long is only twice as long as one 1 units. You've only doubled the number of fasteners but multiplied, so each fastener would need to hold four times as much weight, right? Four times the force trying to pull through the material on each fastener? Nope, it's even worse than that - the wing is a lever against the root. So 8x the weight acting via a lever twice as long = 16 times as much force trying to rip the rivets out. But only twice as many rivets.
So you *do* have to double the wall thickness. Or switch to stronger and heavier materials without doubling the thickness.