[HN Gopher] MIT engineers fly first-ever plane with no moving pa...
       ___________________________________________________________________
        
       MIT engineers fly first-ever plane with no moving parts (2018)
        
       Author : pen2l
       Score  : 323 points
       Date   : 2022-06-30 13:59 UTC (9 hours ago)
        
 (HTM) web link (news.mit.edu)
 (TXT) w3m dump (news.mit.edu)
        
       | WalterBright wrote:
       | I bet I could make an airplane to fly 60 meters with no moving
       | parts using a solid fuel rocket motor.
       | 
       | Just take a glider and attach an Estes engine!
        
       | culanuchachamim wrote:
       | How much energy it needs to fly vs energy needed by propelled
       | plane?
        
       | djtriptych wrote:
       | I've been birding over the pandemic and learning about how they
       | fly. Watching them, it starts to become clear just how skilled
       | and efficient they are.
       | 
       | This tech demo is amazing, but my mind immediately compares it to
       | things like the ruby-throated hummingbird migration, in which a 5
       | gram bird[0] flies 500+ MILES nonstop over open water, on maybe 2
       | grams of fat storage.
       | 
       | Then they feed by hovering so accurately that they can reliably
       | thread a 1/8" beak into a moving 1/4" target.
       | 
       | They can do this directly into 20 mph headwinds [0]. Also in
       | rainstorms where they are constantly getting pelted with their
       | bodyweight in wet missiles every few seconds.
       | 
       | They can also fly 30mph in level flight, which in body lengths /
       | second is ~4x times faster than an SR-71.
       | 
       | [0] US nickels weigh 5 grams, for comparison.
       | 
       | [1] https://www.kqed.org/science/28759/what-happens-when-you-
       | put...
        
         | Gordonjcp wrote:
         | The other one that amazes me is the Petrel family, that digest
         | fish and process oil from them and store it in their foregut.
         | This allows them to fly long distances - like, Falkland Islands
         | to Svalbard kind of distances - without really stopping.
         | 
         | The thing that gets me about it is they brew this fish oil into
         | something with the energy density of *diesel* that they can
         | then digest, and I have this mental picture of some kind of
         | Endura-DI Shearwater flapping, clattering and smoking, all the
         | way across the Atlantic in search of its breeding grounds...
        
         | hinkley wrote:
         | While hummingbirds are amazing, I think we will have to model
         | out systems more closely to birds of prey. Most birds can't
         | carry much extra weight, until you get to raptors and some sea
         | birds.
         | 
         | We would be after something that can carry a payload such as a
         | salmon, a coconut, or a human.
        
           | Amhurst wrote:
           | Or a moose. My sister was bitten by a moose once.
        
         | samvher wrote:
         | You might enjoy this book:
         | https://mitpress.mit.edu/books/simple-science-flight-revised...
         | 
         | (I did, a lot.)
        
           | jcims wrote:
           | Cool six minute video from SmarterEveryDay on dragonfly
           | flight mechanics -
           | https://www.youtube.com/watch?v=oxrLYv0QXa4
           | 
           | If you don't watch the whole thing, fast forward to the slow
           | mo at ~4:35. I still remember watching this for the first
           | time 9 years ago...geez.
        
           | jamiek88 wrote:
           | There is a crappy pdf of this floating around that I read
           | before buying this. Deffo worth it but for those who want to
           | try before you buy it's worth 'binging' it.
        
           | dragosmocrii wrote:
           | Thank you, this definitely goes on my reading list!
        
           | djtriptych wrote:
           | oh wow. thanks!
        
         | jacquesm wrote:
         | Nature is lightyears ahead of tech when it comes to power
         | efficiency.
        
       | worik wrote:
       | This is awesome.
       | 
       | I am disappointed at the "MIT are boasting, nothing really to
       | show" comments here.
       | 
       | This is not Earth shattering. But it is an achievement worthy of
       | our respect.
       | 
       | This vehicle is self contained, has no external power supply,
       | unlike all the other examples quoted.
       | 
       | I am very impressed
        
       | dr_dshiv wrote:
       | I've been curious about using high heat combustion plus RF to
       | create denser plasmas (ionized air) plus pulsed magnets to push
       | the air. It seems impossible for earthly flight, but maybe with
       | lightweight super conductors.
       | 
       | I've also been curious about using very large-area weak ionizers
       | for future zeppelins.
       | 
       | Plasma propulsion has been used for zeppelin flight at a small
       | scale. Plasmas are also used for flow control on wings and
       | propellers. There doesn't seem to be much unclassified research
       | in the area, though.
        
         | dr_orpheus wrote:
         | Nothing earthbound that I know of, but it sounds like you are
         | describing something similar to the electric propulsion
         | thrusters that PhaseFour makes: https://phasefour.io/rf-
         | thruster/
        
       | api_or_ipa wrote:
       | Sounds cool, but the headline is pretty bait-y. First, the
       | aircraft has no control surfaces, so it's limited to flying in a
       | straight line. So the headline should read "MIT engineers fly
       | first-ever plane with no moving parts in propulsion". And then,
       | even that's not true, since ramjets[0] have been a thing for a
       | long time.
       | 
       | 0 https://en.wikipedia.org/wiki/Ramjet
        
       | beanjuice wrote:
       | There is a comment from Pubpeer [0] on this research [1] if
       | anyone is curious:
       | 
       | "This is not the first flight of an ion-drive aircraft. Seversky
       | was patenting and flying ionocraft in the 1960s [2], hobbyists
       | have been building them for decades under the name "lifter", and
       | a self-contained device that carries its own power supply was
       | developed by Ethan Krauss in 2006.
       | 
       | MIT's device may be the first ionocraft to use wings for lift,
       | however. The previous devices behaved more like helicopters than
       | airplanes, and did not need wings to stay aloft."
       | 
       | [0] https://www.nature.com/articles/s41586-018-0707-9
       | 
       | [1]
       | https://pubpeer.com/publications/020C19C112F2605CEC4B34CA320...
       | 
       | [2] https://www.youtube.com/watch?v=GijJmIz1G7U
        
         | CSSer wrote:
         | So is this just MIT being MIT (overhyping everything) or did
         | this guy and his team somehow miss all of this? Is our
         | scientific knowledge really that scattered?
        
           | aj7 wrote:
           | See this 2013 article. https://news.mit.edu/2013/ionic-
           | thrusters-0403 In the 2018 article this submission is based
           | on, you're seeing 5 years of progress.
        
           | Beldin wrote:
           | I dunno about the findings from the 60s, but non-moving
           | rotors would not keep a helicopter in the air... so at least
           | some progress.
           | 
           | It's not clear whether this thing can steer (by changing ion
           | balance?), if this prototype can't but the concept might, or
           | if it's forward only. If they can steer (change direction at
           | will) without moving parts, that definitely sounds
           | innovative.
        
           | portyllo wrote:
           | This made it to the cover of Nature with a similar headline
           | [0]. I guess that they are also "overhyping everything".
           | 
           | [0] https://pbs.twimg.com/media/DsmahXYXoAAkaoI?format=jpg&na
           | me=...
        
             | lupire wrote:
             | That same Nature cover has an overyhyped BS headline about
             | quantum computers and cryptocurrency.
        
           | lupire wrote:
           | The OP article explains.
           | 
           | The new device flies with no moving parts and with onboard
           | power.
        
           | scarby2 wrote:
           | Well the headline i believe is technically accurate. Given
           | that lifter type devices are aircraft but not aeroplanes.
           | 
           | It's certainly an iteration rather than a complete revolution
           | but seems like an important step. Certainly something like
           | this would have more practical application, a basically
           | silent drone that could fly over a battlefield would be a
           | huge win.
        
           | pclmulqdq wrote:
           | I'm not sure that the guy who patented this is considered a
           | "serious" scientist. After all, he did patent a technology
           | from the 60's.
           | 
           | Otherwise, this just seems to be MIT being MIT: creating a
           | trivial improvement on an old technology (in this case,
           | moving the boost converter onto the airplane to avoid a
           | tether wire), and publicizing the hell out of it because it's
           | cool.
        
             | tytso wrote:
             | Keep in mind that the MIT Press office != the professors at
             | MIT. It's actually quite common for any University's press
             | office to be clueless about the research being done at the
             | university, and it is their job to make as big of a splash
             | as possible.
             | 
             | This is much like the oft-cited issue that the reporters
             | aren't responsible for the headlines --- that is picked by
             | the editors to make as big of a splash as possible.
             | 
             | As far as "patenting a technology from the 60's", even an
             | incremental improvement on an old idea is still patentable.
             | The real test is whether the patent cited the prior art,
             | and you can bet that MIT Press Office didn't read the
             | patent application before breathlessly sending out the
             | press release.
        
               | pclmulqdq wrote:
               | That is a good point. MIT professors are usually very
               | aware of the context of their work and the actual
               | contributions they are making. Nevertheless, the MIT
               | press office is a particularly egregious organization in
               | terms of its tendency to exaggerate - my dad's lab cured
               | cancer about 10 times in the early 2000's if you believe
               | the press releases.
               | 
               | In this case, I'm not sure the MIT professor was aware of
               | the "crackpot" invention that effectively pre-empted him.
               | Many professors don't read patents (and there are lots of
               | reasons why they shouldn't), and I'm not sure there was a
               | paper.
               | 
               | One thing about patents is that if an invention is
               | obvious in light of other inventions, it might not be
               | patentable. In this case, I'm pretty sure that this
               | combination of a technology from the 60's, a boost
               | converter, and a LiPo battery may be "obvious" given the
               | prevalence of other drones: it is a combination of two
               | past inventions that fit together naturally (a drone + a
               | propulsion technology). Of course, it will take millions
               | of dollars worth of arguing for someone to say either
               | way.
        
               | lupire wrote:
               | Where is the "breathless" part?
        
             | Dylan16807 wrote:
             | Making it work on its own without a tether wire sounds like
             | a substantial improvement to me.
        
           | goatcode wrote:
           | Or perhaps, as is becoming pretty ubiquitous in tech: the
           | people who communicate things don't have nearly as much
           | understanding as the people who do them. It was not always
           | this way, but it seems the communication department in an
           | organization is becoming the dumping ground for people who
           | flunked out of doing the hands-on hard work but for one
           | reason or another, have some support to retain them.
           | 
           | Note: I'm not criticizing tech writing. Just what tech
           | writing has become.
        
           | vpribish wrote:
           | I'm baffled that MIT's PR is so cringeworthy. They had a
           | priceless, universally recognized and irreplaceable brand and
           | they are just trashing it with a sustained campaign of cheap
           | clickbait seemingly aimed at a technologically ignorant
           | audience. WTF? WHY? The Fools!
        
             | frognumber wrote:
             | University reputations have a few decades lag. MIT did it's
             | greatest work in the 20th century. It's since brought in
             | people attracted to fame, power, fortune, and, again, fame.
             | 
             | I don't think it will dig itself out again.
        
               | pen2l wrote:
               | Harvard and MIT have a lot of clout, and it's partly
               | because of how incredibly massive they are. The Harvard
               | network has more professors than some universities have
               | pupils, (above two-thousand). Consequently just the
               | _amount_ of output due to a large number of people
               | working there gets it placed high up in rating indices
               | and such.
               | 
               | It's tough to say if it can keep up with its reputation.
               | In some ways this phenomenon is comparable to
               | gentrification: the beauty and soul of a place sometimes
               | dies when the people who made that place what it is are
               | displaced, like how Somerville and Berlin changed/are
               | changing. It makes no sense for someone to remain
               | committed in an academic career track when they're paying
               | the kind of rent they do when around MIT/Harvard area
               | with the income they make, so I agree with you that it's
               | no longer attracting the kind of people that made MIT
               | what it once was.
               | 
               | There are some institutions, that not many know about
               | yet, that I'm confident in a couple of decades everyone
               | will know about like U of Copenhagen and KIT & U of
               | Stuttgart in Germany, and I think some in the midwest
               | (Purdue, UMich, etc.) will one day have their day to
               | shine too.
        
               | april_22 wrote:
               | TU Munich is also getting really strong, they've been
               | winning Elon Musk's Hyperloop for the past years I think
        
               | nosianu wrote:
               | Just an aside on the topic of German research.
               | 
               | In Germany a lot of research is not done at the
               | universities but at various institutes such as Max-
               | Planck, Fraunhofer, Helmholtz, Leibniz and a lot more.
               | 
               | General overview, research institutes being one item:
               | https://www.research-in-germany.org/en/research-
               | landscape.ht...
               | 
               | Ca. 400 universities - but ca. 1,000 publicly funded
               | research institutions (https://www.research-in-
               | germany.org/en/research-landscape/re...).
               | 
               | So, the ranking of the universities overall may not be
               | completely comparable.
        
               | divbzero wrote:
               | MIT was established 161 years ago and Harvard was
               | established 386 years ago, both young relative to
               | Cambridge established 813 years ago and Oxford
               | established 926 years ago. The clout of universities will
               | ebb and flow, but I wouldn't bet on 100+ year
               | institutions losing their ability to attract talent
               | anytime soon.
        
               | admiral33 wrote:
               | I agree - network effects predate the internet after all.
               | As long as good universities keep producing talented
               | graduates it will be hard to undermine their reputation.
               | And I don't think ambitious people being driven towards
               | certain universities for clout is a negative. I say this
               | as someone who went to an increasingly recognized yet
               | still underdog state school. Maybe instead of discarding
               | MIT's reputation a nudge in the direction of increasing
               | editorial oversight can suffice. Though sensationalism
               | seems to be a prerequisite for visibility these days
        
             | tytso wrote:
             | I very much doubt whether the MIT Press Office cares about
             | what Hacker News thinks of their brand. What they do care
             | about is what Sarah J. Student's parents think when they
             | are trying to encourage their progency to attend Harvard vs
             | Yale vs Stanford. And positive press is good towards
             | achieving that mission, even if it is a bit click-baity.
             | And since all universities are playing this game to one
             | degree or another, it's asking quite a lot for one
             | univesity to unilaterally agree to disarm.
             | 
             | The other "brand" that universities care about is the their
             | reputation by their professor's peers when it comes to
             | hiring the best talent for their departments, and with the
             | granting agencies who are deciding which research proposals
             | they should fund. And here, what matters is the peer-
             | reviewed publications at various academic journals and
             | conferences. Whether a university's press office puts out a
             | press release, which then gets mangled by various
             | newspapers, doesn't really have negative or positive effect
             | when it comes to how a university's research work is
             | measured by the People Who Really Matter --- namely, other
             | professors and the people who dispense the cash. Hacker
             | News falls into neither of these two categories.
        
           | vilhelm_s wrote:
           | I'd absolutely expect the guy and his team to know about
           | prior work, but the article comes from the university "news
           | office". In my experience university PR releases are always
           | extremely overhyped, particularly from the elite
           | universities.
        
             | closetohome wrote:
             | Grad student: Look guys I built a little plane
             | 
             | News office: MIT SUPER-SCIENTIST INVENTS AIR TRAVEL
        
         | rcstank wrote:
         | Did any of these have moving parts?
        
           | [deleted]
        
           | nomel wrote:
           | The one I built when I was a kid didn't. I don't know of any
           | designs that do.
        
             | zxexz wrote:
             | I did the same! IIRC, I went off a design from the first
             | edition of Electronic Gadgets for the Evil Genius[0].
             | Excellent book for the budding electronics hacker.
             | 
             | [0] https://www.abebooks.com/signed-first-
             | edition/Electronic-Gad...
        
           | jolmg wrote:
           | At least the one from 1964 in the linked YouTube video
           | doesn't.
        
             | hinkley wrote:
             | Lifters typically have a tether don't they? So I think it
             | depends on whether you consider the tether a moving part.
             | It has to move for the craft to move...
             | 
             | A self contained unit like the MIT one is an improvement on
             | the lifter, because the ion drive is itself an improvement
             | on the lifter. Or at least, a production version of one.
             | What they've done is get the mass to thrust ratio below a
             | threshold that allows for flight in atmosphere. That's
             | definitely worth some points, but not all the points.
        
               | nomel wrote:
               | The tether is there to supply power and hold it down.
               | Lifters require a power to weight ratio greater than one,
               | which probably isn't possible with an on-board power
               | supply. This MIT plane integrates the power supply and
               | uses wing lift to reduce the required power, just as all
               | planes do, and as the ionic propulsion planes did before
               | (as others have linked to).
               | 
               | This is just the MIT press department embarrassing
               | themselves again, or perhaps proving that sensationalism
               | is a required part of science/funding these days.
        
               | toast0 wrote:
               | > This is just the MIT press department embarrassing
               | themselves again.
               | 
               | Is the MIT press department capable of being embarrassed?
               | Maybe they embarrass MIT, or at least people associated
               | with MIT, but I don't think they embarrass themselves or
               | they'd have changed their behavior.
        
               | hinkley wrote:
               | One is self propelled and the other is a toy that was
               | abandoned 60 years ago as unworkable.
               | 
               | That doesn't sound the same to me.
        
               | nomel wrote:
               | I think you misread. I wasn't comparing the lifter to a
               | plane, I was comparing other ionic propulsion planes to
               | their plane.
               | 
               | > and as the ionic propulsion planes did before (as
               | others have linked to).
        
               | hinkley wrote:
               | Ground effect planes and to a lesser extent gliders are
               | cheating and we can't forget that.
               | 
               | But taking an ion propulsion system that previously only
               | worked in vacuum and making it work at sea level is not
               | nothing. I haven't seen anything here to convince me it's
               | pure parlor trick. It's part parlor trick for sure, but
               | the sort that opens wallets.
        
               | nomel wrote:
               | > to a lesser extent gliders are cheating
               | 
               | How were they cheating? Lifters don't use ground effect
               | at all. With a proper power supply, they have a
               | power/weight ratio much greater than one. Does a
               | helicopter or F22 Raptor cheat to fly?
               | 
               | > taking an ion propulsion system that previously only
               | worked in vacuum
               | 
               | You misunderstand what this is. This ionizes air and
               | accelerates it towards a surface with opposite charge.
               | This design will _not_ work in a vacuum, since it
               | requires atmosphere [1] as a propellant. I built one of
               | these thrusters when I was a kid using an old TV power
               | supply. It takes some wire, aluminum foil, tens of
               | thousands of volts, and a stomach for inefficiency (for
               | example, the mentioned plane has a thrust of 6.25N /kW,
               | the motor/prop on a drone is nearly 10x that). The only
               | difference between a lifter and this is the direction of
               | thrust, and the use of wings to supply lift, which all
               | aircraft with a power to weight ratio less than 1.0
               | necessarily do. The accomplishment, and it is impressive,
               | is the engineering to make it all light/efficient, given
               | the terrible efficiency of these types of motors, while
               | using the advancements in the energy density of batteries
               | to allow it to be integrated.
               | 
               | > I haven't seen anything here to convince me it's pure
               | parlor trick
               | 
               | I don't understand this. I don't think anyone is saying
               | it's a parlor trick. It's impressive engineering. I just
               | don't think it's accurate to say it's the first [2]. 20
               | years ago, there were sites with people attaching these
               | to gliders (although, I can't find them anymore).
               | 
               | 1. Theory of operation for the generation of the thrust:
               | https://en.wikipedia.org/wiki/Ion-
               | propelled_aircraft#Electro...
               | 
               | 2. https://en.wikipedia.org/wiki/Ion-
               | propelled_aircraft#cite_no...
        
       | pen2l wrote:
       | I like the video in the article quite a lot! The gentleman
       | speaking in it is one of the scientists working on the project,
       | and manages to convey an excitement and basic idea that the
       | layman can kind of understand, as well as some fun history. Wish
       | more articles could have this kind of interviews!
        
       | c0n5pir4cy wrote:
       | Older news as other people have mentioned, if you want to see how
       | it works and see it flying here is a YouTube link:
       | https://youtu.be/boB6qu5dcCw?t=85
        
         | nico wrote:
         | That video is 3 years old.
         | 
         | Do you know if there's anything new with this
         | project/technology?
        
           | dr_dshiv wrote:
           | Here's the latest: https://newatlas.com/drones/ion-
           | propulsion-drone/
        
             | birktj wrote:
             | That looks pretty impressive, but I am quite skeptical of
             | the fact that this craft uses ion propulsion for any
             | significant proton of its thrust. A reddit user [1]
             | suggests that it uses ducted fans which I am way more
             | inclined to believe. The very high pitched noise is typical
             | of a high velocity propeller blowing high velocity air.
             | Which seems wildly incompatible with those large grids
             | where one would expect relatively low velocity air with
             | very little noise. There are also four very suspicious
             | tubes running along the body of the craft.
             | 
             | [1] https://www.reddit.com/r/Futurology/comments/o6h1bc/com
             | ment/...
        
             | memco wrote:
             | Interesting to see the development over the past few years
             | and how theory is comparing to practice. One of the
             | theorized benefits from the MIT video was quieter drones.
             | This article says the ionic propulsion demoed is about 85db
             | which sounds like it's just as loud as current drones.
        
               | bentcorner wrote:
               | From that page here's a video of their ionic drone:
               | https://youtu.be/iihprC5Huf4
               | 
               | Interesting that it sounds pretty much like a regular
               | drone.
        
             | moffkalast wrote:
             | Ok holy shit that is on another level, the original had
             | barely enough thrust to sustain flight of that almost
             | lighter than air glider, this lifts up fuckin vertically
             | with no moving parts.
             | 
             | But I suspect the time it flies in the video is the time it
             | takes to completely empty the batteries, as is the usual
             | caveat.
        
             | hahamrfunnyguy wrote:
             | That thing is still pretty noisy! It looks like it's
             | pushing the ionized air through some kind of jet?
        
             | jdlshore wrote:
             | Are you sure that's the same group? The design is
             | completely different and it appears to be a company based
             | in Florida.
        
       | nashashmi wrote:
       | Ionizing the air? Couldn't that be used for hypersonic flight to
       | eliminate air friction plus eliminate sonic boom?
        
         | gorjusborg wrote:
         | Is the viscosity of ionized air lower than air?
         | 
         | My understanding is that the ionized air is used in tandem with
         | electric field to accelerate plain air (non-ionized) by
         | collision/friction. In other words, the ionized air is being
         | used as a gaseous propeller.
        
           | nomel wrote:
           | I thought about doing this when I was playing with lifters a
           | couple decades ago. The idea was that you could ionize the
           | boundary layer, to make it somewhat "self repulsive", to thin
           | it, to try to reduce the skin friction drag [1].
           | 
           | I remember doing some napkin math, and the added weight/power
           | would be a net loss.
           | 
           | 1. https://en.wikipedia.org/wiki/Skin_friction_drag
        
             | mrfusion wrote:
             | I believe people have found ways to reduce drag with lasers
             | and microwaves so you might be on to something.
        
           | jameshart wrote:
           | Accelerating the 'plain air' isn't really necessary to the
           | propulsion. Once you've accelerated the ions you've already
           | accomplished a momentum transfer - if those ions then go and
           | share that momentum with some non ionized air molecules
           | that's their own business.
           | 
           | I guess maybe the non ionized air acts to keep the ions
           | around between the two charged grids for longer, which means
           | that for each ion you create you can maybe exploit its
           | attractive/repulsive force for longer?
        
         | dr_dshiv wrote:
         | Look for plasma flow control for work related to this question.
        
         | mrfusion wrote:
         | It could be a new type of scram jet, right? A normal jet engine
         | has to slow down supersonic air to subsonic to combust it which
         | is inefficient.
        
       | [deleted]
        
       | joshgroban wrote:
        
         | tom-thistime wrote:
         | Ok, one moving part.
        
       | NiceWayToDoIT wrote:
       | 25 years ago there was a site Kely Net or something similar, also
       | I think there is JLN labs that is still alive, there was lot of
       | over-unity things, BS and scams, but I distinctively remember few
       | of the technologies back then that now popping up as mainstream
       | wonder ... Aluminium oxide engine, brown gas, mighty engine, ion
       | lifter, metal latices fusion ... it is kind of odd how long we
       | need to start exploring new tech.
        
       | baltimore wrote:
       | Can this tech be used to make a (quieter) room fan?
        
         | learn_more wrote:
         | Yes. Sharper Image sold one called the "Ionic Breeze". They
         | generate ozone, which is a problem however.
         | https://en.wikipedia.org/wiki/Air_ioniser
        
           | ohhhhhh wrote:
           | First thing when i saw this. Would these airplanes just be
           | flying cancer sprayers? lol
        
       | adolph wrote:
       | _Unlike turbine-powered planes, the aircraft does not depend on
       | fossil fuels to fly. And unlike propeller-driven drones, the new
       | design is completely silent._
       | 
       | I suspect that the design is silent due to its low power and that
       | something with enough thrust to perform some useful task would be
       | louder even if the noise is that of wind only.
        
         | dr_dshiv wrote:
         | Indeed, at a larger scale it is loud:
         | 
         | https://newatlas.com/drones/ion-propulsion-drone/
        
           | tqkxzugoaupvwqr wrote:
           | It's extremely loud, something I didn't expect, and sounds
           | very much like a high speed fan. Together with the black box
           | it made me suspicious if we aren't being deceived. Two
           | comments under the article think the same.
        
             | JKCalhoun wrote:
             | Yeah, lot to be skeptical of here.
        
       | amelius wrote:
       | Does this produce ozone?
        
         | make3 wrote:
         | I guess the question would be if this is more harmful than a
         | plane of similar pulling power
        
         | CSSer wrote:
         | I can't imagine how it wouldn't.
        
       | stym06 wrote:
       | It's a 2018 piece.
        
       | peter303 wrote:
       | How does the efficiency of ion-drive compared to electric motors?
        
         | CSSer wrote:
         | I tried to find a more precise answer but technically an ion-
         | drive is an electric motor, so I'm guessing it's comparable.
         | The thing is that based on the couple demos I watched the
         | flight seems really erratic. It makes me wonder if the fuel
         | supply is somewhat inconsistent i.e. air turbulence makes the
         | actual theoretical energy efficiency moot.
        
           | tom-thistime wrote:
           | An ion drive isn't really physically similar to a normal
           | electric motor using an electromagnet.
        
           | justusthane wrote:
           | I'm having trouble understanding why it would necessarily be
           | comparable to a traditional electric motor in efficiency.
           | Whether or not it's "technically" an electric motor, it's
           | operating on completely different principles. The first
           | things that come to mind are there are no moving parts to
           | generate friction and heat, and it requires much higher
           | voltage. Wouldn't those aspects alone swing the efficiency
           | one way or the other?
        
             | brianpan wrote:
             | Both use electromagnetic force to move something. They are
             | much more similar to each other than combustion, which is a
             | chemical reaction.
             | 
             | https://electronics.howstuffworks.com/brushless-motor.htm
        
             | CSSer wrote:
             | It was a big guess for sure. To be clear, I don't know. I
             | did find this in my search, which suggests it's not
             | exponential[0], so it seems you're correct. There's a drop-
             | off at higher exhaust speeds, but it's unclear to me why
             | that is.
             | 
             | [0]: https://en.wikipedia.org/wiki/Ion_thruster#Energy_effi
             | ciency
        
       | anonymousiam wrote:
       | These were popular decades ago, and were the focus of many an
       | argument over the basis in theory of how they worked. Many did
       | not understand that they depend on atmosphere to operate.
       | 
       | https://www.youtube.com/watch?v=vzZy1Aqleno
        
         | moron4hire wrote:
         | Oh man, I was just coming here to say that.
         | 
         | I seem to remember first hearing about these "lifters" in
         | highschool, so that would have been late 1990s. But that
         | recollection is based solely on remembering the dumb friend I
         | had who thought it would be a good idea to try to make one, not
         | knowing anything about high voltage electricity.
         | 
         | Luckily, we were also too distracted by video games to go
         | dumpster diving for a CRT or microwave transformer.
        
       | marginalia_nu wrote:
       | I can show MIT how to fold a sheet of paper to make a plane with
       | no moving parts.
        
         | xnorswap wrote:
         | That's a very "just used a pencil" type punchline.
        
           | Dylan16807 wrote:
           | I'd say a glider is more like having the words pre-printed on
           | the paper. Most of the elements of writing are there, but in
           | the wrong way.
        
       | nixpulvis wrote:
       | Would a paper airplane in a tornado (or nice thermal) count?
        
         | jacquesm wrote:
         | You can 'fly' semis in tornados, so no.
         | 
         | https://www.youtube.com/watch?v=WABqwKjQM_c
        
       | judge2020 wrote:
       | This was done in 50's and 60's https://en.wikipedia.org/wiki/Ion-
       | propelled_aircraft
       | 
       | > The use of EHD propulsion for lift was studied by American
       | aircraft designer Major Alexander Prokofieff de Seversky in the
       | 1950s and 1960s. He filed a patent for an "ionocraft" in 1959. He
       | built and flew a model VTOL ionocraft capable of sideways
       | manoeuvring by varying the voltages applied in different areas,
       | although the heavy power supply remained external.
        
         | beanjuice wrote:
         | Heres an old video of one such example:
         | https://www.youtube.com/watch?v=GijJmIz1G7U
        
         | teraflop wrote:
         | I think there's a big _qualitative_ difference between an
         | aircraft that can carry its own power source, and one that
         | needs to be tethered to the ground.
        
           | YeBanKo wrote:
           | Well, there is also a huge advancement in small power sources
           | since 60s
        
         | samizdis wrote:
         | Wow. Seversky was the guy advocating for long-range air power
         | in WWII. He wrote _Victory Through Air Power_ , which inspired
         | Disney to finance an animated film on the subject out of his
         | own pocket. Seversky appears in person in the film to introduce
         | some concepts. The film is just amazing. It was available as
         | part of a Disney DVD compilation quite a few years ago (Disney
         | in the Trenches? [edit to correct title of box set: it was
         | "Walt Disney Treasures - On the Front Lines"]). The standalone
         | film is on archive.org:
         | 
         | https://archive.org/details/VictoryThroughAirPower
         | 
         | Edit to add: Here's the Wikipedia page about _Victory Through
         | Air Power_
         | 
         | https://en.wikipedia.org/wiki/Victory_Through_Air_Power
         | 
         | From the page:
         | 
         |  _Filmmaker Walt Disney read the book, and felt that its
         | message was so important that he would personally finance a
         | partly-animated short, also called Victory Through Air Power,
         | which was released in July 1943.[3] Disney 's purpose for
         | creating the film was to promote Seversky's theories to
         | government officials and the public. After seeing the film,
         | Winston Churchill and Franklin D. Roosevelt decided that
         | Seversky knew what he was talking about, changing the course of
         | the war._
        
         | danielmorozoff wrote:
         | This is exactly right, when I was in grad school we also
         | explored new ionization designs to reduce the voltage
         | requirements to achieve this. In our explorations, biggest
         | problems were weight and voltage issues.
         | 
         | Very cool to see though, you can make this at home with a very
         | basic high voltage generator and a set of needles.
         | 
         | Here's another design for DIY:
         | https://www.youtube.com/watch?v=wGq7LfjDyZM
        
       | thehappypm wrote:
       | Does this work because of the mass difference between electrons
       | and protons?
       | 
       | If you separate an electron from an atom, charge is conserved,
       | mass in conserved. Apply an electric field, then you shoot the
       | ion one way and the electron the other. The heavy ion then acts
       | like propellant. Mass still conserved, charge still conserved. At
       | some point the electron is absorbed into some random ion
       | elsewhere and the ion grabs an electron from elsewhere.
        
       | pvaldes wrote:
       | Interesting.
       | 
       | I wonder if this stuff would attract lightning
        
       | dwighttk wrote:
       | Hope it doesn't crash into anything
        
       | make3 wrote:
       | the video is really not convincing lol, it doesn't look like it's
       | doing much more than gliding from the initial launch force, which
       | is due to an external (moving) force.
       | 
       | EDIT: ok this one is more convincing
       | https://m.youtube.com/watch?v=iihprC5Huf4
        
         | jacquesm wrote:
         | I'm not buying that, that whine sounds just like a ducted fan
         | and there is a giant hole in the support base just where the
         | ducted fan needs to blow the air to avoid having that air
         | pushed sideways, if the lift was generated by the ionized air
         | it would be nearly silent.
        
         | thehappypm wrote:
         | The first video shows unpowered, just a little glide. Second
         | shows how it goes way further when powered
        
           | make3 wrote:
           | couldn't see those on my phone. Wish I could delete my
           | comment.
        
       | okasaki wrote:
       | Presumably there are moving parts involved, they are just too
       | small to see.
        
         | jdlshore wrote:
         | It operates by using a high voltage to strip electrons from
         | nitrogen atoms, then the opposite current to attract those ions
         | to the front surface of a wing. The movement of the ions causes
         | the air to move, which generates lift over the wing.
         | 
         | So no, there's no moving parts involved in generating the lift.
        
           | strongpigeon wrote:
           | I think GP was making a joke that the ions are the moving
           | part.
        
       | ajoseps wrote:
       | this news is from 2018
        
       | jonplackett wrote:
       | Ok but does it make enough lift for a flying saucer
        
         | exhilaration wrote:
         | Apparently, yes! https://www.youtube.com/watch?v=iihprC5Huf4
        
           | jonplackett wrote:
           | Awesome!
        
       | anonu wrote:
       | Article from 2018 - how has the progress on this tech been over
       | the last 4 years?
       | 
       | CUrious whether the physics can support much larger payloads.
        
       | makeworld wrote:
       | (2018)
        
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       (page generated 2022-06-30 23:00 UTC)