Drone Startup Claims It Flew Its Ion-Propulsion Drone On 4.5-Minute Test Flight (interestingengineering.com) 65
An anonymous reader quotes a report from Interesting Engineering: Florida-based tech startup Undefined Technologies announced its unique ionic propulsion drone has passed an outdoor flight test, meaning it's on track for commercial release in 2024, according to a report from New Atlas. The drone, called Silent Ventus, uses proprietary technology to ionize the oxygen and nitrogen molecules in the surrounding air to create an "ionic wind" that propels the machine in the direction it wants to go. According to Undefined, the drone could be used for cargo. Though it's not been used for large-scale drone projects on Earth before, ionic propulsion isn't a new technology. In fact, it's currently one of the best technologies humans currently possess for deep space exploration propulsion and other space applications. According to Undefined, its "Air Tantrum" ionic propulsion technology produces up to 150 percent more thrust than current ion thruster technologies.
Earlier this year, the company released footage of a two-and-a-half-minute indoor flight test, saying the drone emitted 85 decibels of noise. Now, it claims it's flown a prototype for four and a half minutes, though it's only released one minute, 17 seconds of footage. The drone firm also says it achieved a noise level below 75 dB. It's now aiming to secure further investment to build a zero-emissions cargo delivery drone by 2023 that could fly for 15 minutes and make less than 70 dB. Undefined claims its "silent" 70-dB drones will lead to far fewer noise complaints in areas that will be served by urban cargo delivery drones in the future. However, it's worth pointing out that Undefined had yet to test its drone with large payloads, which will require extra thrust and will likely make more noise.
Earlier this year, the company released footage of a two-and-a-half-minute indoor flight test, saying the drone emitted 85 decibels of noise. Now, it claims it's flown a prototype for four and a half minutes, though it's only released one minute, 17 seconds of footage. The drone firm also says it achieved a noise level below 75 dB. It's now aiming to secure further investment to build a zero-emissions cargo delivery drone by 2023 that could fly for 15 minutes and make less than 70 dB. Undefined claims its "silent" 70-dB drones will lead to far fewer noise complaints in areas that will be served by urban cargo delivery drones in the future. However, it's worth pointing out that Undefined had yet to test its drone with large payloads, which will require extra thrust and will likely make more noise.
Location of investor money? (Score:1)
Re:Location of investor money for this bizx ad? (Score:5, Interesting)
Whenever I see oxygen and ions in the same place, I have to wonder. Does this thing create toxic ozone? There has to be a lot of energy involved to power a drone, so curious minds have to ask it.
If you scale up the tech and are spraying O3 at low altitudes, you're going to get some complaints eventually.
Re: Location of investor money for this bizx ad? (Score:2)
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Lightning [Re: Location of investor money for...] (Score:2)
The amount of ozone or nitrogen tetroxide produced would be absolutely trivial compared to the amount produced in a single lightning bolt.
https://agupubs.onlinelibrary.... [wiley.com]
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Does this thing create toxic ozone?
Would that make it Silent But Deadly?
"Silent Ventus" indeed.
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Totally BUSTED! [youtube.com]
Wikipedia (Score:2)
"Ion thrust engines are practical only in the vacuum of space and cannot take vehicles through the atmosphere because ion engines do not work in the presence of ions outside the engine; additionally, the engine's minuscule thrust cannot overcome any significant air resistance. Moreover, notwithstanding the presence of an atmosphere (or lack thereof) an ion engine cannot generate sufficient thrust to achieve initial liftoff from any celestial body with significant surface gravity."
https://en.wikipedia.org/wi [wikipedia.org]
Re:Wikipedia (Score:5, Informative)
Ion propulsion is not the same as an ion thrust engine. Ion propulsion requires air. Two different technologies with (possibly deliberately) confusingly similar names.
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I assume this is the same technology as those Dyson ionic "fans"?
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No, the video shows a craft with actual ionic wind thrust devices. The Dyson bladeless fan has a conventional fan hidden in the base blowing through a ring-shaped outlet.
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Wow. First it was terminators, now it's false advertising. That Dyson guy really sucks.
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Wow. First it was terminators, now it's false advertising. That Dyson guy really sucks.
He makes vacuum cleaners and fans, so it's accurate to say he both sucks and blows.
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Really? I assumed the Dyson it was just a large bladed bearing track inside the circular shroud. No wonder it's as loud as it is.
Re:Wikipedia (Score:4)
https://youtu.be/gcx2mAu4NjY [youtu.be]
True the blade is hidden, there is actually more to it. The fan moves more air than the hidden fan can move. There is actually some pretty clever physics at work here.
The word is ION (Score:1)
Ion propulsion is not the same as an ion thrust engine. Ion propulsion requires air.
How is it confusing unless you are obtuse to the definition of ION -- they both use IONS i.e. IONIZES THE PROPELLANT to propel, not AIR.
An ion thruster ionizes propellant by adding or removing electrons to produce ions.
Most "thrusters" ionize propellant by electron bombardment.
How you are modded 5 is hilarious.
Re:Wikipedia (Score:5, Informative)
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wikipedia is only useful if used correctly
Re:Gonna switch from one pollutant to another. (Score:5, Informative)
No, this *IS* NOx !!
It takes non-ionized N2 and O2, rips those dimers apart to make them attractive to an electrified grate, shoots them out the back as exhaust.
What do you suppose ionized nitrogen and oxygen atoms turn into?
Basically, this thing is a flying smog factory.
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You can ionise molecules without splitting them into their constituent atoms other most chemical reactions would cease to function you muppet.
Re:Gonna switch from one pollutant to another. (Score:5, Informative)
You do realize that the very thing that makes the N2 dimer very nonreactive, is that it has a fully complete triple covalent bond between the atoms?
Removing outer valence electrons to make it carry a charge, makes it reactive.
Similar story with O2 molecules.
It just so happens, that the two species of ions, tend to be produced at annode and cathode, respectively,
This means the two species of ions will be very attracted to each other, as they are opposite charge, and are VERY likely to react.
What kind of compound is produced from reactive nitrogen and reactive oxygen again?
Yes-- NOx compounds.
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But, being a "muppet", dont just take my word for it.
It's not like this has been researched a long fucking time ago or anything.
https://royalsocietypublishing... [royalsocie...ishing.org]
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Hmm...reading this brought THIS [youtube.com] to mind...
And...you're welcome for the "ear worm".
Happy Monday!
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No shit. And you got modded up for that? You must have friends with mod points.
Quoting you:
"It takes non-ionized N2 and O2, rips those dimers apart"
No, it doesn't rip them apart, it ionises them and I'm fully well aware of their chemical activity hence my comment about checmical reactions.
Jesus H, its obviously mouth breather week on here.
Re:Gonna switch from one pollutant to another. (Score:4, Insightful)
Re:Gonna switch from one pollutant to another. (Score:4, Informative)
wiki article mentions such compounds, with footnote 14.
The footnote refers to this paper:
https://agupubs.onlinelibrary.... [wiley.com]
Within that paper, there is a section:
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The N2 dimer is 2 nitrogen atoms, held together by 3 covalent bonds.
The outer configuration of N atom, is 3 or 5 electrons.
Electrons very much like to be in pairs. This is why nitrogen readily forms a triple covalent bond with itself, which then satisfies the pairing affinity, and the electron shell configuration affinity.
Taken together, the two atoms have a stable outer valence configuration. This is why it is VERY stable, and VERY nonreactive.
However, when you go ripping electrons off it, to make it into
Neat I guess (Score:2)
Pretty neat thing. I am not sure if they'll outdo traditional propeller based drones, but it's a neat project none-the-less. The force generated is mostly tied to the electric current and space between the anode and the corona wire. The content of the air really only becomes a significant value in higher altitudes (> 10k feet) or (and the really important part) if it's anything BUT a clear sunny day. Moisture makes the air gap a better conductor which sort of isn't what you really want here, not to m
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There MIGHT be an application in closed spaces
The literal killer app would be silent assassinations.
Half Truths (Score:2)
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there's being skeptical, and then there's just being fucking stupid
Noise Pollution Thoughts? (Score:2, Interesting)
So, assume a device operates in a neighborhood with background sound-level measures of 40dB. A "silent" ion-propulsion device comes flying in at 70dB (supposedly quiet). That is a 30dB different in sound-levels. Since decibel units represent logarithmic scales, that is about 2^5 relative difference and suggests a relative, human-perceived, sound-level increase of 32 times.
For comparison, assume that the same neighborhood has a posted speed limit of 35MPH. The analog would be comparable to a vehicle rocketin
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The volume measured in db is nearly meaningless unless they specify a distance.
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They don't even say if they're talking about sound power or sound pressure at a given distance.
Flight test engineer's observations (Score:5, Interesting)
Just a few quick observations from a flight test engineer.
There are no "innovative physics" here, unlike what the company website claims. It's pretty rudimentary physics, actually, that's been well-known for a long time. Maybe there are some new tricks at scaling it up, but there's nothing fundamentally different at play here.
Battery life could be a real problem. The literature is somewhat mixed on efficiency, with some claiming much higher efficiency than jet propulsion.
https://www.sciencedaily.com/r... [sciencedaily.com]
But this kind of propulsion requires VERY high voltage source. Getting high voltage out of low voltage power cells requires converting DC voltage to higher levels, which itself has significant inefficiencies. No matter how many low-voltage batteries they use, they'll still need significant conversions up to the 10s or 100s of kilovolts needed to generate ionic flow.
However, the most significant compromise, in my view, seems to be the low thrust spread across a huge area, which seems to lead to controllability problems. A jet engine or propeller system has fairly small exit areas with high air velocity; this instead requires a fairly large cross section for the lower-velocity thrust exit area. This results in a fairly large platform, but with low thrust spread across its surface. When you get into the physics, or more specifically the mass dynamics, the problem is a large moment of inertia with a low force to control it.
Imagine, if you will, a rod about five feet long, with a bowling ball at the center (the mass of the system, mainly the batteries and cargo in this case). And there are small thrusters way out at the tips of the rod (like one axis of a quadcopter). You can easily imagine it doesn't take much force on the tips of the rod to make that system rotate. All the mass is at the center. But now imagine the bowling ball mass and the thrust force spread out along the entire length of the rod. If you want to quickly affect the angle of that system, you need a fairly large force differential between the two sides, and it's going to take a while for that force to have an effect. So it is with this system: the mass is spread across a very wide area, and so is the force. Even if the batteries and cargo sit at the middle, you've still got the large structure to hold the thrust components, and the thrust is not concentrated out at the tips where it would have the most effect. At best it can be imagined as effectively only halfway out to the tips.
I'm also worried about response time. Any system like this inherently uses the thrust to create control forces. Now, the real beauty of a propeller-based drone driven by electric motors is the almost instantaneous thrust response, which is why a typical quad or hex copter can be absolutely rock-steady in the air, even with turbulence. (This is also a reason why you don't see jet-engine-based quadcopters: jet thrust is very slow-responding.) But when your thrust response is spread across square meters at very low local airflow speeds, and depends on voltage changes to induce nearly undetectable airflow changes, response time suffers significantly. When you slow down the response time of your control system, you lower the dynamic stability of the system. And the stability decreases with gain in any system - the harder or faster you try to maneuver, the lower the stability.
So from my perspective, there are two inherent challenges that will lead to control problems: a hugely distributed thrust area, plus slow response time. The result, as you can easily see in the video, is instability. The thing never ever stops rocking back and forth, and when they get close to touchdown the amplitude of the oscillation increases noticeably. And that was with a basically zero-load condition. Size this thing up to carry cargo, and it will only get worse. You can try to filter it, but that just leads to larger errors and overshoots in desired position or angle. You can't have
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I don't know whether this thing makes sense or not but there's no fan in the box [youtube.com].
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I figured you were watching the video where it's got the shroud on it.
They would be hard pressed to get enough thrust out of those dinky little cones to keep it aloft without a jet engine.
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Re:Flight test engineer's observations (Score:4, Informative)
There's clearly a fan in all the actual test flights they have footage of. the Ionic drive thing only seems to be used to stabilize the drone or control pitch and roll (I don't see any yaw control yet). At most it contributes a tiny amount to the lift. Anyone that's familiar with EDF units in RC aircraft will recognize the sound of the EDF in these videos.
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They were hoping this almost-obligatory /. post didn't show up until AFTER the meeting with the VC whales....
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Even more so, is the physics of thrust in general. Since it's air-driven, thrust is based on mass air flow vs weight. In the video you when the vehicle is close to the ground you don't see the grass moving at all (mind that a kick up of debris). All absent as one would expect the grass to be moving wildly from the air mass being "thrusted" onto the ground like any other VTOL that moves air mass to lift the weight. Instead it's antigravity?
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Replying to myself: one of the replies to my post indicated that someone spotted flaps underneath the thrust-producing grid. That makes sense - you could set up an arrangement that would use actuated flaps (little servo motors would be sufficient) to block or open part of the thrust produced by the grid, providing a fairly fast and effective rolling or pitching or even yawing moment. That would probably be much better than modulating the thrust in real time. It does come with the tradeoffs of weight and com
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If it provides some gains in efficiency or noise it may be worthwhile anyway.
Not silent at all, just a little quieter, maybe (Score:2)
Ion propulsion engines appear to be all the rage these days. But silent, they are not. The company appears to be playing on the general ignorance of that even in their product's name, Silent Ventus.
The article claims the current prototype produces 70 dB of noise. And that the prototype can't carry any payload yet. The requirements for additional thrust to carry payload would suggest 70 dB is a lower limit.
A quick search online provides this very nice page comparing the loudness of typical drones to othe
Ionic wind (Score:2)
The drone, called Silent Ventus, uses proprietary technology to ionize the oxygen and nitrogen molecules in the surrounding air to create an "ionic wind" that propels the machine ...
I think I saw this in the Sharper Image catalog -- "What can't those guys ionize?" (Michael, "The Good Place")
Birds (Score:2)
How the hell do birds fly so silently? I mean, imagine if an eagle made that much noise?
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That they do, but only when in motion. Speaking from personal experience, hummingbirds don't make any audible sound while hovering.
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No cargo? Watch this: https://www.youtube.com/shorts... [youtube.com]
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Birds of the same weight as a drone don't make the same amount of noise (even with cargo, see the video I pasted of the eagle flying away with a fox). Also, hummingbirds are pretty silent. A drone the size of a hummingbird will be much louder.
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Re: Birds (Score:1)
Is this a joke? (Score:2)
Will not scaleup successfully (Score:2)