4
$\begingroup$

The most famous example of inonocraft is the aircraft with no-moving parts propulsion made by the MIT.

3D model of a ionic propelled aircraft

A problem of ionic thrusters is that they only generate a gram of thrust for every watt, which is really inneficient.

However, if one would to make a ducted ionic thruster that worked like a ducted turbine, wouldn't the thrust increase?

The closest thing I could find was this video that went viral some time ago showing an attempt of making a multistage ionic thruster.

Photografy showing the multistage ionic thruster

The other ionic thruster that is worth talking about is an atmospheric ionic thruster satellite that will take the air from the edge of space and accelerate it. But that is an special case, since the aircraft will be sent there by a rocket and maintain orbit on its own. It won't take off on its own.

Illustration showing the atmospheric ionic thruster satellite

Improve this question
$\endgroup$
1
  • $\begingroup$ My patented Self-Contained Ion Powered (propelled) Aircrafts and Ion Propelled Vehicle, produce about 7 grams of thrust per watt at the batteries and roughly 14 grams of thrust per watt at the airframe. That is much more than one gram of thrust per watt. It has flown verifiably on camera for almost two minutes at a time with onboard power. The later MIT standard glider shaped version produced 1/2 gram of thrust per watt, according to the table on the last page of their paper. By the way Rory, please do not delete my posts! They are entirely relevant. $\endgroup$
    – Ethan Krauss
    Apr 4 at 9:29

3 Answers 3

Reset to default
9
$\begingroup$

A problem of ionic thrusters is that they only generate a gram of thrust for every watt, which is really inneficient.

The Wikipedia article says that about the early versions. I don't think it applies to the Ethan Krauss' self-contained prototype.

However, if one would to make a ducted ionic thruster that worked like a ducted turbine, wouldn't the thrust increase?

The efficiency wouldn't. To increase efficiency—of any aerodynamic engine—you need to increase the cross-section. This is because thrust is equal to the change in momentum of the airflow, and momentum is mass times velocity, but the change in kinetic energy of the flow is equal to ½ mass times velocity squared and the engine has to provide that energy.

Therefore it is better to have a lot of low-power cells side-by-side, to affect a lot of air, than to have them one after another in a duct, accelerating the air to a higher velocity. That's why the Ethan Krauss' prototype is a big hexagonal wire mesh grid.

Improve this answer
$\endgroup$
8
$\begingroup$

This is Ethan Krauss. My VTOL Ion Propelled Vehicles have onboard power. Rather than a wire mesh, they have streamline wing shaped collectors made of concentric hexagons. Those surfaces are currently metalized with a thin coating of silver. The crafts produce many grams of thrust per watt. Much of the airflow that propels these crafts generally speaking, comes in from the sides, so adding ducts not only reduces lift but adds weight. Building them with multiple stages also creates less thrust per gram, unless the stages are spaced far apart from one another.

Improve this answer
$\endgroup$
2
  • 2
    $\begingroup$ Good to have the man himself here. Welcome! $\endgroup$
    – FreeMan
    Jan 5 at 19:44
  • $\begingroup$ There is another one besides the MIT glider version. Their glider flew technically in ground effect for a few seconds, after being bungee launched. The much earlier Ion Propelled Vehicle was patented for lifting its power supply with ion propulsion. Usually tested flying in VTOL mode, for up to minutes at a time. It has also flown on its side gaining aerodynamic lift. It is less stable than a standard glider shape since it consists of concentric hexagon shaped collector/wings, but it was conceived of from the start to be an efficient ion propelled VTOL vehicle and less like a glider. $\endgroup$
    – Ethan Krauss
    Apr 4 at 9:48
6
$\begingroup$

Is it correct to ask about "inonocrafts" (the plural?) Are there any other examples besides the 5lb MIT one?

The theoretical thrust gain from a duct would have to overcome the additional weight of the duct.

And this one example is just the very first basic prototype. This is sort of like asking "Why didn't the Wright Brothers use turboprops?"

Improve this answer
$\endgroup$
6
  • 1
    $\begingroup$ The Wikipedia article links two examples. And the other one is a vertical take-off one. $\endgroup$
    – Jan Hudec
    Dec 28, 2022 at 21:45
  • $\begingroup$ I am not sure there even is any theoretical gain from a duct here. Ducted fans work because the fan blades benefit from an end-plate, but the electric field does not have any edge that could get similar benefit. $\endgroup$
    – Jan Hudec
    Dec 28, 2022 at 21:51
  • $\begingroup$ I discounted that one, because it couldn't lift its own power supply. Like an electric car prototype, but you need a really long extension cord. $\endgroup$
    – WPNSGuy
    Dec 28, 2022 at 21:54
  • $\begingroup$ Does it? The article says “The first ion-propelled aircraft to take off and fly using its own onboard power supply was a VTOL craft developed by Ethan Krauss of Electron Air in 2006.”. $\endgroup$
    – Jan Hudec
    Dec 28, 2022 at 22:01
  • $\begingroup$ Ah, I was reading/conflating the wrong one. $\endgroup$
    – WPNSGuy
    Dec 28, 2022 at 22:03

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .