hckrnws

Wow, getting a drone to survive the massive electromagnetic fields (and plasma!) around lightning strikes is quite an accomplishment. Prior art in the area used rockets trailing a similar light wire to trigger lightning - used by Dr Uman's team at University of Florida (https://ufdc.ufl.edu/UFE0047331/00001).

And the prior art before that involved a kite and a key

I'm sorry but Figure 1 Lightning Protection Drone....all I see when I look at that is a abomination of antenna....like 5 or 6 roof antennas crammed into a single point in space time.

Not that it don't look super cook in its own way. But I just reminds me of antennas

This is really cool, but I'm super skeptical of their proposed use case for protecting cities.

Aren't lightning conditions often preceded by strong winds and poor weather conditions? Not a great time to be flying drones. And the approach seems more complicated than simply installing lightning rods.

I'd sooner envision people using the technique to get a kick out of throwing lightning around like they're Zeus.

I've flown my Mavics in rain and strong wind before - certainly stronger than anything I'd associate with lightning. Most of the lightning storms I've seen haven't been especially windy, but it might vary elsewhere. And that's a consumer drone with negligible weatherproofing.

I assume if there's a business case, they'll eventually automate this with drone swarms that wait in cabinets on building rooftops.

FWIW, where I live there are often intense thunderstorms during the spring and summer, and they are usually accompanied by windstorms, sometimes generating tornadoes.

AFAIK the electric buildup starts even before the meteorological shenanigans.

> flying drones into optimal positions beneath thunderclouds to actively trigger lightning strikes, and then guiding the discharge safely away from vulnerable areas

From a military standpoint, I wonder what it would take to discharge into a vulnerable area...

You could put the wire in the vulnerable area - perhaps using the same drone? But I don't think it would be any use. A lightning strike releases about 1 GJ of energy, mostly into the sky. So the effect at the target would probably be no more than a few kg of explosives which you could have delivered using the wire anyway.

Fire it at a transformer, take out power in an entire region and blame God. A perfect tool for the CIA.

Plausible deniability?

People tend to get mad when you bomb them, but if no one noticed the drone in the storm it's just a natural strike...

> I wonder what it would take to discharge into a vulnerable area

HAARP /s

We've come a long way from Benjamin Franklin flying a kite into lightning. https://en.wikipedia.org/wiki/Kite_experiment

This [1] article claims that the electricity from 115 strikes could power the entire US grid for a year, but it's surely napkin math. Awesome tech, though!

[1] https://www.treehugger.com/how-much-energy-is-in-lightning-8...

Apparently a single lightning strike contains the equivalent of about 40 gallons of gasoline. It’s very powerful but not that significant on the scale of a whole city.

In fact a quick back of the napkin math suggests it would only power a city of a million people for half a second.

https://en.m.wikipedia.org/wiki/Harvesting_lightning_energy

I wonder what the average property damage is per strike. And if forcing lightning reduces or changes storm power. Maybe for preventative reasons you put them outside of towns and such.

That article seems very very wrong. I think they missed the difference between GW and GWh.

https://www.youtube.com/watch?v=fs28lEq9smw

Hah quite the oversight! To put a spin on an old saying, a little math is a dangerous thing.

that article does not make that claim

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I wonder if we managed to harness and store this electricity from the lightning into some kind of large battery. If a drone can successfully fly and connect with the lighting, this seems like a possibility.

Edit: I read past the line where they mentioned this was in the plans.

The lightning "strike" mentioned in the article was probably not a direct hit. Nothing can really survive >30kA of current. I recall concerns from Boeing engineers when they switched to carbon fiber fuselages, that a strike would be far more serious than before, with Aluminum fuselages.

https://www.weather.gov/safety/lightning-power

https://aviation.stackexchange.com/questions/35493/are-carbo...

> I recall concerns from Boeing engineers when they switched to carbon fiber fuselages, that a strike would be far more serious than before, with Aluminum fuselages.

It's a serious problem for carbon-fiber wind turbine blades. Fiberglas is an insulator, and doesn't have lighting problems. Aluminum is a good conductor, and doesn't have lighting problems as long as there's a good a path to ground through the hub. But carbon fiber is a resistor, so conducting a lightning strike generates heat. Some copper or aluminum wire has to go into the turbine blades to bypass this.

There's 2 kinds of CG and there's long-line-induced EM.

Ordinary -CG is 30 kA / 30 C / energy of 1 t of TNT. +CG is 10x that.

Direct hits are survived all the time by lightning rods for the past 275 years.

Long, unshielded lines of any sort can induce massive transient voltage transients (low current) that need to be protected with appropriate TVS circuits that will wear more in storm-prone areas. EMI from nearby lightning in unshielded computing systems with antennas or even without antennas can also be a factor.

That is impressive, specially the drone surviving! I expect something along the lines of disposable drones, which would like still be cost effective at saving 100-200b yen a year! It’ll be fascinating seeing this deployed!

That's a freefly Alta X in the photos which is a $20k drone commonly used in cinematography.

So.. how long do we have before situational personal lightning bolt is a thing?

Apparently they already have the ability to create lightning bolts in the lab for testing. Maybe they can license that.

> we conducted artificial lightning tests on drones equipped with the lightning protection cage. The results showed that the system withstood artificial strikes of up to 150 kA—five times greater than the average natural lightning strike—without any malfunction or damage, covering over 98% of naturally occurring lightning conditions.

The future is now: Check out Lightning On Demand, https://lod.org/ (Tesla tower approach & scientific motivations) & https://youtu.be/lix-vr_AF38?si=w78LyF9tlxGJB8Ay (capacitor driven Lorentz plasma cannon demo)

Next step, use the energy?

Yes, thanks for repeating the content from the article.

"In addition, we aim to not only trigger and control lightning, but also to harness its energy. Future efforts will focus on developing technologies for capturing and storing lightning energy for potential use (Figure 7)."

isn't conventional wisdom that this is "impossible" because you cannot charge batteries that fast?

If the energy is going into batteries. It doesn’t necessarily have to.

Also, technology continues to improve, and this isn’t a “next year” thing.

Maybe a bank of (extremely) huge capacitors that get charged up very quickly, and are then connected to a battery pack to charge it more slowly?

Keeping control of those charges seems like a huge challenge, as they literally contain the electrical energy of a lightning bolt. I guess for physically plausible capacitors you'd also need to step the voltage way down (by six or eight orders of magnitude!?) before it reaches the capacitors. Are there physically-plausible transformers or other devices that could do that?

Or something that somehow captures the lightning as (lots and lots of) mechanical or thermal energy and then gradually converts that back into electricity?

Stick the caps in series?

Like most things, you’d probably end up heating water somehow and using that energy.