Electro-Aerodynamics

[sanman]

Plasma Aerodynamics (aka. electro-aerodynamics) is an emerging field attracting interest because of its ability to reduce the drag characteristics of a surface.
When flowing around surfaces, ionized air experiences less drag compared to regular air which is a diatomic gas.

The trucking industry is for instance looking to save money through the use of plasma actuators:

In aviation, the plasma actuators can be used to smooth the air flow around a wing, and make it more laminar rather than turbulent, thus reducing drag:

Rotary-wing aircraft such as gyrocopters have much higher drag compared to fixed-wing aircraft. Their poorer glide ratio reduces their fuel efficiency and their flight range.

Could it be possible to use plasma actuators to reduce the drag on the rotary wing of a gyrocopter to improve its performance and drag characteristics?

 

[Martin W.]

Some things to consider:

--- a gyrocopter rotor turns because of drag (upflow of air) thru the blades

--- the semi truck in the first video demonstrates it driving into a headwind .... but very seldom does that happen in real life ... nearly always they see a crosswind which negates a lot of the streamlining apparatus

--- plus they say the plasma unit requires high voltage .... which requires some of the diesel engine power ... but then they say the "whole system" uses less power than a lightbulb .... unless they are referring to the smart phone controller .

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[Brian Jackson]

Interesting concept, but it's still a closed system. If fuel economy is the main concern, I'm skeptical of its efficacy. You may eat up any potential fuel savings in the energy it takes to power the ionizing system. Would like to know more about power requirements vs. payoff.

 

[WaspAir]

I wonder how it scales to rotor tip speeds.

When Ferrari tries it on an F1 car, or one of the German Akaflieg design groups adapts it to an 18 meter sailplane, I'll sit up and take notice.

 

[sanman]

Interesting concept, but it's still a closed system. If fuel economy is the main concern, I'm skeptical of its efficacy. You may eat up any potential fuel savings in the energy it takes to power the ionizing system. Would like to know more about power requirements vs. payoff.

Ionization simply requires high voltage. Voltage is not the same as power. High voltage with low current can be low power. The voltage is what ionizes the air flow.

Some things to consider:

--- a gyrocopter rotor turns because of drag (upflow of air) thru the blades

--- the semi truck in the first video demonstrates it driving into a headwind .... but very seldom does that happen in real life ... nearly always they see a crosswind which negates a lot of the streamlining apparatus

--- plus they say the plasma unit requires high voltage .... which requires some of the diesel engine power ... but then they say the "whole system" uses less power than a lightbulb .... unless they are referring to the smart phone controller ..

So what you say about rotor turning due to drag has occurred to me. I'd say that since this system is electrical, it could be turned on at high airspeeds / high rpm. When you're taking off and climbing, you like drag because there's lift associated with it. But suppose you're already at flight altitude and cruising and/or you're just trying to go faster -- so you're trimmed out with minimal AoA -- that's when you'd like to flip the switch and turn the ionization on, in order to reduce the drag and improve efficiency/range and airspeed.

I wouldn't worry about wind vs no wind, since it's all about relative airspeed. We can't turn off the wind, but we can try to mitigate its effects and more laminar airflow would help do that. With their high wing-loading, gyros do better against crosswinds than most other aircraft (I can't think of any aircraft that does better)

See above. Voltage is not the same as power. High voltage with low current can be low power. The voltage is what ionizes the air flow, so high voltage works better.

 

[Martin W.]

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Thanks sanman .... I suspected the plasma was maybe generated by high voltage .

Probably similar to static electricity which makes me think we could make those tufts of wool stand straight up with static alone ....... my mind wanders ....

I am not a skeptic per say .... until some new entity comes along claiming new technology that will be available soon .... as far as I am concerned it would be a very low cost and easy experiment to install that aerodynamic gadget on a big truck and monitor fuel flow going down the highway .... plasma on .... plasma off .... etc.

But they have not.

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[Tyger]

I'm a skeptic as far as practicality. At aircraft speeds that's an incredibly large amount of air molecules flying past the ionization elements.

The third video has the ionizing elements on the "wing" surface, but at what seems like very low airspeeds.
In the second video, it appears that the ionizing element is in front of the (wing-shaped?) surface that is holding the tell-tale yarns.

 

[Vance]

Some things to consider:

--- a gyrocopter rotor turns because of drag (upflow of air) thru the blades



.

Please help me understand how a rotor in autorotation turns because of drag Martin.

 

[Tyger]

Ya, that's a bit like saying wings have lift because of the (induced) drag. Thay may be true in some sense, but isn't turbulence behind a wing more like parasite drag? But, whatever adjective you want to give it, if you can reduce that by improving laminar flow, overall drag will become less without losing any lift.

 

[Jean Claude]

I'm a skeptic as far as practicality. At aircraft speeds that's an incredibly large amount of air molecules flying past the ionization elements.

To think about :