Flight of an aeroplane with solid-state propulsion

[rfeecs]

So it's an ion engine propelled model airplane.

 https://www.nature.com/articles/s41586-018-0707-9 (Paywalled article)

Since the first aeroplane flight more than 100 years ago, aeroplanes have been propelled using moving surfaces such as propellers and turbines. Most have been powered by fossil-fuel combustion. Electroaerodynamics, in which electrical forces accelerate ions in a fluid^1,2, has been proposed as an alternative method of propelling aeroplanes—without moving parts, nearly silently and without combustion emissions^3,4,5,6. However, no aeroplane with such a solid-state propulsion system has yet flown. Here we demonstrate that a solid-state propulsion system can sustain powered flight, by designing and flying an electroaerodynamically propelled heavier-than-air aeroplane.

https://www.technologyreview.com/s/612451/an-electric-plane-with-no-moving-parts-has-made-its-first-flight/ (Free article with a short video)

[Domagoj T]

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.

[Urs42]

https://www.nature.com/articles/s41586-018-0707-9 (Paywalled article)

sci-hub helps with the paywall: http://sci-hub.tw/https://www.nature.com/articles/s41586-018-0707-9

[Berni]

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-95LAL

Its 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.

[helius]

"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.

[T3sl4co1l]

The only interpretation I can find: yet another MIT backslide.

"Lifters" have been known among high voltage enthusiasts for decades.  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

[rstofer]

It is just a teaser to get DARPA interested.  Think about totally silent drones - how cool is that?

[BrianHG]

Think about totally silent drones - how cool is that?

This 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...

[SiliconWizard]

We provide a proof of concept for electroaerodynamic aeroplane propulsion, opening up possibilities for aircraft and aerodynamic devices that are quieter, mechanically simpler and do not emit combustion emissions.

Uh huh. It may fail to mention whatever else is emitted, though.

[Gyro]

Uh huh. It may fail to mention whatever else is emitted, though.

Having 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/

[rdl]

Short article at Ars Technica with a bit more info:

Ion drive meets drone, as small plane flies with no moving parts

[Domagoj T]

it kicks out a hell of a lot of Ozone!

So 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?

[Gyro]

EDIT:
What's the power consumption and thrust of such a device?

It 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 compares very favorably 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.

[MarkR42]

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).

[GeorgeOfTheJungle]

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.

Nah, 100kW buys you 5.4 full newtons of pure thrust, says in the other thread :-)

[Gyro]

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.

Nah, 100kW buys you 5.4 full newtons of pure thrust, says in the other thread :-)

No, 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.

[dmills]

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.

[GeorgeOfTheJungle]

Nah, 100kW buys you 5.4 full newtons of pure thrust, says in the other thread :-)

No, 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.

Ok.

A rough estimate from existing lifter designs is anything from 50W for 0.1 Newtons thrust, to 300W for 2.5 Newtons.

1 kg (force) = 9.8 Newtons => you'd need 300[W]*(9.8[N/kg]/2.5[N]) = 1176 W/kg ? That's no too shabby!

( The other end of the scale: 50[W]*(9.8[N/kg]/0.1[N]) = 4900 W/kg )

[Domagoj T]

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.

[Berni]

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.

[rfeecs]

Another longer video:

https://youtu.be/boB6qu5dcCw

[Vtile]

The only interpretation I can find: yet another MIT backslide.

"Lifters" have been known among high voltage enthusiasts for decades.  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

My thoughts, put out. 

[GeorgeOfTheJungle]

A rough estimate from existing lifter designs is anything from 50W for 0.1 Newtons thrust, to 300W for 2.5 Newtons.

1 kg (force) = 9.8 Newtons => you'd need 300[W]*(9.8[N/kg]/2.5[N]) = 1176 W/kg ? That's no too shabby!

Let's do some more math:

1) A 5Ah 18650 weights ~50g
2) => 1kg of 18650s is 20 cells
3) 20*5Ah*3.7V = 370 Wh
4) => 60*370/1176 = 18.9 minutes

A 1kg ion-driven drone could fly for 18 minutes ? (I find it hard to believe)

[Berni]

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.htm

Tho 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.

[GeorgeOfTheJungle]

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)

The pesky details... lol

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.htm

Tho 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.

That'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.

[Ethan Krauss]

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.org
One of the Videos:

[cdev]

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.

[T3sl4co1l]

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

[IanMacdonald]

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.

[Gyro]

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.

Rather 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.

https://www.eevblog.com/forum/dodgy-technology/ionic-lifters-has-anyone-else-around-here-build-one/msg1435254/#msg1435254

What 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.

[Ethan Krauss]

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