Flight of an aeroplane with solid-state propulsion - Page 1
Forum section: electronics / general

author: rfeecs
author_rank: Frequent Contributor
timestamp: November 21, 2018, 07:07:54 pm
content: So it's an ion engine propelled model airplane.https://www.nature.com/articles/s41586-018-0707-9(Paywalled article)Quotehttps://www.technologyreview.com/s/612451/an-electric-plane-with-no-moving-parts-has-made-its-first-flight/(Free article with a short video)

author: Domagoj T
author_rank: Frequent Contributor
timestamp: November 21, 2018, 07:25:56 pm
content: I am not convinced that the video shows a sustained flight. The plane was launched from a raised platform using a catapult. Without proper measurements, it's hard to tell if it maintains both airspeed and altitude, or just uses the initial kinetic energy from the catapult to fly for those few seconds of the video.In any case, not only energy storage tech is nowhere near the needed level for full scale applications, this seems to be a very low efficiency approach to thrust generation.There have been talks about battery powered airliners using conventional ducted fans, but even those, while realistically possible, are facing issues that make them non competitors to jets, mainly due to the need to haul all those heavy batteries during the entire flight, reducing the autonomy and negatively affecting safety during landing.I call it a gimmick.

author: Urs42
author_rank: Unknown
timestamp: November 22, 2018, 05:48:46 am
content: Quote from: rfeecs on November 21, 2018, 07:07:54 pmsci-hub helps with the paywall:http://sci-hub.tw/https://www.nature.com/articles/s41586-018-0707-9

author: Berni
author_rank: Super Contributor
timestamp: November 22, 2018, 07:29:38 am
content: A full sized human carrying airplane with solid state propulsion has already been built by the Russians in 1961.https://en.wikipedia.org/wiki/Tupolev_Tu-95LALIts basically a bomber that had a nuclear reactor strapped to its wings. Air would simply flow trough the hot reactor core, rapidly expand and create more thrust out the back.But one could argue solid-state flight was achieved even before that. The first supersonic jet engine used a similar method of operation where it was pretty much a hollow pipe where they would squirt jet fuel into. The contours of the pipe manipulates the air speed inside to below supersonic to allow a stable burn before using the extra volume of hot air to speed it back up and throw it out the back. Its not quite solid state since you have to push liquid fuel into it but its pretty close.Pulsejet engines also only squirt in fuel and burn it and they ware also used to fly a plane. The Germans used them to create unnamed planes with explosive strapped to them as a early alternative to long range missiles.

author: helius
author_rank: Super Contributor
timestamp: November 22, 2018, 07:38:08 am
content: "Solid-state" is being used in a very misleading way here. The term properly refers to devices which utilize the electronic or magnetic properties of materials in the solid phase (as opposed to the liquid, gas, or plasma phases). Ion propulsion obviously does not qualify as it is plasma based. Neither do jet engines as their thrust is provided by a gas.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: November 22, 2018, 05:43:34 pm
content: The only interpretation I can find: yet another MIT backslide."Lifters" have been known among high voltage enthusiasts fordecades. I don't see how any of this can be original and new; how did it get published? What did they establish or refine?I shouldn't be so negative. Maybe it's a review of the literature on the subjects, and the demonstration is incidental to the paper?Tim

author: rstofer
author_rank: Super Contributor
timestamp: November 22, 2018, 05:54:45 pm
content: It is just a teaser to get DARPA interested. Think about totally silent drones - how cool is that?

author: BrianHG
author_rank: Super Contributor
timestamp: November 22, 2018, 06:27:03 pm
content: Quote from: rstofer on November 22, 2018, 05:54:45 pmThis is the 1 big thing about it. However, thrust is just enough to keep it off the ground, so, a launcher will be needed...Though, I wonder how weather and humidity will affect it. Rain alone may destroy the thrust. Also, in the evening, there may be a visible aura...

author: SiliconWizard
author_rank: Super Contributor
timestamp: November 22, 2018, 06:37:27 pm
content: QuoteUh huh. It may fail to mention whatever else is emitted, though.

author: Gyro
author_rank: Super Contributor
timestamp: November 22, 2018, 06:55:19 pm
content: QuoteHaving done the experiment (lifter), I can say that it kicks out a hell of a lot of Ozone!https://www.eevblog.com/forum/dodgy-technology/ionic-lifters-has-anyone-else-around-here-build-one/

author: rdl
author_rank: Super Contributor
timestamp: November 22, 2018, 07:02:20 pm
content: Short article at Ars Technica with a bit more info:Ion drive meets drone, as small plane flies with no moving parts

author: Domagoj T
author_rank: Frequent Contributor
timestamp: November 22, 2018, 07:38:49 pm
content: Quote from: Gyro on November 22, 2018, 06:55:19 pmSo the marketing department doesn't even have a right to stick a "non-polluting" sticker on it.EDIT:What's the power consumption and thrust of such a device?

author: Gyro
author_rank: Super Contributor
timestamp: November 23, 2018, 10:16:19 am
content: QuoteIt depends very heavily on construction and complexity. A rough estimate from existing lifter designs is anything from 50W for 0.1 Newtons thrust, to 300W for 2.5 Newtons. That actually comparesveryfavorably with the Ion thrusters that NASA experiments with / uses for Space, those are in the order of 100kW for 5.4 Newtons thrust!You'll find useful links in my thread that I already linked:https://www.eevblog.com/forum/dodgy-technology/ionic-lifters-has-anyone-else-around-here-build-one/For such low thrust devices, it certainly makes sense to turn them on their side and use them to power something aerodynamic, with wings and control surfaces, rather that straight vertical takeoff - as applies to all aircraft.I'm still surprised that they've made something capable of lifting its own power source (presumably Lipo + inverter) - something that has certainly eluded vertical lifters (although one has managed to lift Orville the mouse). I wonder what its flight duration is, I guess that with sufficient scaling, solar power could become feasible.

author: MarkR42
author_rank: Regular Contributor
timestamp: November 23, 2018, 10:32:50 am
content: I'm very disappointed with the general lack of scepticism and accuracy of reporting.The media I've seen generally talk about fancy applications such as manned aircraft, without considering any of the problems inherent in this system.It's an interesting device, but as far as I can tell, it's extremely inefficient, generates a lot of ozone, and has a very poor thrust/weight.I can't see how it can compete on efficiency or thrust with a simple electrically driven propeller, which we already have. There might be some niche applications (which have been discussed) but otherwise, it's just a curiosity.Add that to the fact that the tech isn't particularly new, the researchers were probably just the first ones to build a working aircraft with it. Which is not surprising because it's so bad (see above).

author: GeorgeOfTheJungle
author_rank: Super Contributor
timestamp: November 23, 2018, 10:37:11 am
content: Quote from: MarkR42 on November 23, 2018, 10:32:50 amNah, 100kW buys you 5.4 full newtons of pure thrust, says in the other thread :-)

author: Gyro
author_rank: Super Contributor
timestamp: November 23, 2018, 10:46:39 am
content: Quote from: GeorgeOfTheJungle on November 23, 2018, 10:37:11 amNo, that's for Vacuum Ion thrusters (Nasa) - not saying the 'lifter' technology they're demonstrating is anything approaching efficient, but it's orders of magnitude higher!EDIT: I indicated the currently demonstrated power/thrust range in my post above - looking at the 'plane' construction, it think it would be somewhere in the middle.

author: dmills
author_rank: Super Contributor
timestamp: November 23, 2018, 11:41:17 am
content: It is orders of magnitude higher because Isp is not something that matters for air breathing engines!When you have to carry your own reaction mass, throwing it out the back quickly matters far more then the electrical power required to do so, where in an aero engine it is the power consumption per unit thrust (at whatever velocity is appropriate) that matters, not mass consumed per newton/second. The optimisation problem is very different.Regards, Dan.

author: GeorgeOfTheJungle
author_rank: Super Contributor
timestamp: November 23, 2018, 12:21:12 pm
content: Quote from: Gyro on November 23, 2018, 10:46:39 amOk.Quote1 kg (force) = 9.8 Newtons => you'd need 300*(9.8[N/kg]/2.5) = 1176 W/kg ? That's no too shabby!( The other end of the scale: 50*(9.8[N/kg]/0.1) = 4900 W/kg )

author: Domagoj T
author_rank: Frequent Contributor
timestamp: November 23, 2018, 08:53:48 pm
content: Ion thrusters for space have different requirements that atmospheric engines.When it comes to space travel, pretty much everything boils down to mass, the less of it, the better.Ion engines are good for space probes because they have insane specific impulse compared to chemical rockets, so if you can live with low thrust and long burn times, high power usage is more than offset by advantage that this high ISP brings to the equation.

author: Berni
author_rank: Super Contributor
timestamp: November 23, 2018, 09:15:58 pm
content: Yes Ion engines in space and this "electrostatic fan" are two very different things. The ion engine is trying to shoot out ions as close to the speed of light as possible to maximize ISP for the limited fuel it has. This air operating ion engine does not care about ISP since it has all the air it wants around it. It just needs to grab and throw as much of it as possible.These "electrostatic fans" do have the potential to be pretty efficient since while the voltage to run them in extremely high the current is very low. The problem they have is that they don't scale very well for large amounts of thrust. They become more powerful as you increase the voltage, but at some point the air arcs over. This means you have to move your ion producing wire farther away, but at the same time this makes the electric field gradient weaker so you don't get as much electrostatic force on your ion. At some point the voltages just become so ridiculously high that the dimensions of the thing become huge. Its also a safety concern running these exposed high voltage wires all over the plane.The concept is certainly pretty cool but we are going to need some serious technological advances before we can manage to build an engine even remotely powerful enough for a drone.

author: rfeecs
author_rank: Frequent Contributor
timestamp: November 23, 2018, 10:23:13 pm
content: Another longer video:https://youtu.be/boB6qu5dcCw

author: Vtile
author_rank: Super Contributor
timestamp: November 23, 2018, 10:37:20 pm
content: Quote from: T3sl4co1l on November 22, 2018, 05:43:34 pmMy thoughts, put out.

author: GeorgeOfTheJungle
author_rank: Super Contributor
timestamp: November 25, 2018, 10:39:52 am
content: Quote from: GeorgeOfTheJungle on November 23, 2018, 12:21:12 pmLet's do some more math:1) A 5Ah 18650 weights ~50g2) => 1kg of 18650s is 20 cells3) 20*5Ah*3.7V = 370 Wh4) => 60*370/1176 = 18.9 minutesA 1kg ion-driven drone could fly for 18 minutes? (I find it hard to believe)

author: Berni
author_rank: Super Contributor
timestamp: November 25, 2018, 10:49:20 am
content: Yeah i did say this has the potential to be pretty efficient since you are sort of directly accelerating air with an electric field.The hard part is how do you build one of these electrostatic engines powerful enough to produce 1kg of thrust. (Without being the size of a car)EDIT:To put things into perspective this is the smallest ion lifter they managed to build to be powerful enough to carry one mouse as cargo:http://jnaudin.free.fr/lifters/orville/index.htmTho the efficiency they got is not as high using 350W to produce over 180g of lift, but keeping 35kV contained can be tricky so a good deal of this might have also been leakage.

author: GeorgeOfTheJungle
author_rank: Super Contributor
timestamp: November 25, 2018, 11:27:29 am
content: Quote from: Berni on November 25, 2018, 10:49:20 amThe pesky details... lolQuote from: Berni on November 25, 2018, 10:49:20 amThat's not too bad, look: 350*1000/180 => 1944 W/kg ! But yeah, the payload is just a tiny fraction of the total weight, those pesky details ruin the party.

author: Ethan Krauss
author_rank: Newbie
timestamp: January 05, 2019, 03:24:35 pm
content: I am the inventor of the "Self Contained Ion Powered Aircraft". It is covered by US Patent No. 10,119,527, legally in effect since 2014. It is the first and only solely ion propelled aircraft ever fly to with an onboard power supply. It flies for about 2 minutes, takes off vertically, and does not need large wings of a bungee cord for assistance.There is an almost endless string of news reports mostly originating from a Nature Magazine article produced by Barrett and his students incorrectly claiming that they are the first in history to fly any type of ion propelled device with onboard power.Since my invention was widely published on Google in early 2016 by the US Patent office, it was one of the first images on Google for anyone that might type "ion" and "aircraft." I find it hard to believe therefore, that they were not aware of my patent. I can only assume that they were relying on the equations as written in their paper, that indicated that their craft was, as they essentially stated, "at the limit of what can be done with current technology." In other words, they did not think my VTOL ion propelled aircraft predating theirs was possible.Here is the website for my invention with video footage of it in flight, a list of official observers/demonstrations, a link to the US patent, and lots of clear cut verifiable information.Website:www.electronairllc.orgOne of the Videos:

author: cdev
author_rank: Super Contributor
timestamp: January 05, 2019, 03:34:53 pm
content: Very cool.Here is the problem, commonly known ideas and technology, even things which had been patented before and gone into the public domain are being stolen in what amounts to a large scale organized global theft of everything that can be stolen. In the case of IP, many patents which never should have been, are being granted because of lack of manpower.Also everything on blogs or anywhere besides official documents effectively never happened and is fair game for theft (via its patenting when its well known and commonly used and shouldn't be patentable).Or theft of ideas, important online blog posts or discussions totally being stolen, and their ideas being put into academic papers with no credit being given to the actual authors.No matter how well known or original one's work is, or how plugged into the business world one's efforts are, or aren't, their very existence in the so called 'real' world of technology attribution and patent awarding and money making, where things are seen as "mattering" is nil under this system unless you're part of it.Faculty and students at top schools are invariably going to by default be believed when they claim to have invented some 'breakthrough' and get credit for everything they claim, even if they are old ideas or have some hidden issue and don't work. People who realize what they're doing often look the other way because of the abysmal situation in some countries, and polarization of other battles which aren't of any relevance to this issue.There is an important ethical issue here. Schools shouldn't become schools in scamming, they should be places of scientific learning and rigor. Being a student or similar, no matter how much pressure they think they are under, shouldn't become a virtual license to misappropriate others work as ones own.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: January 05, 2019, 03:40:37 pm
content: Well, there are tethers holding it there. Looks hella unstable otherwise (look how it wobbles before reaching height), but what do you expect, hover controls are complicated, and I'm guessing the thrusters aren't region controlled?No electrical connection through the tethers, then? What's used for battery?Tim

author: IanMacdonald
author_rank: Frequent Contributor
timestamp: January 05, 2019, 04:18:09 pm
content: Putting the payload on an efficient wing such as that used on sailplanes reduces the thrust required by a factor of ten, over that required for a vertical lift. A typical human-rated sailplane only requires about 15kg of thrust to maintain level flight in still air. Plus it's going somewhere instead of just hovering.

author: Gyro
author_rank: Super Contributor
timestamp: January 05, 2019, 04:24:27 pm
content: Quote from: Ethan Krauss on January 05, 2019, 03:24:35 pmRather more stable than my most basic experiment (from easily available web sources), due to much lower and wider profile. Mine definitely needed the tethers or it would flip immediately. It looks as if yours would too as soon as it had space to do so and no tethers.QuoteWhat part have you patented? The on-board power supply? Lifters have been around for donkeys years. My replica of an established web design was made in 2006.

author: Ethan Krauss
author_rank: Newbie
timestamp: January 28, 2019, 12:51:21 pm
content: Hi Tim,You are right, hover controls are much harder than keeping a glider stable. It takes serious attention to weight in this case, and one has to be really careful of power losses as well.The craft in this video has 2, 110mAh lipos on top of the center mast above the circuit there.The external power supplies that other people have been using tend to weigh almost a kg for every gram of model lifted. I had to increase the efficiency and power to weight ratio by a crazy amount to get it to take off. I have been working on the project for over 19 years so it evolved to become very lightweight and relatively efficient. The patent is really for an interdependent system, both electrical and physical. I have done most everything a bit differently than other similar devices in order to make it possible. If you look at the patent No. 10,119,527, it explains a lot of the details that are different. It was way harder than you might expect to get it to carry the power supply.Thanks!Ethan