Double points if you hit it with something incendiary so that the hydrogen ignites.

While I agree that yes, there will definitely be people who shoot at them, same as shoot at DJI drones, there is no reason to disparage an entire group of people into a caricature.

Why not? We’re surrounded by this behavior it’s not simply a caricature.

Please stop posting regional flamebait and whatever else this is. Please see https://news.ycombinator.com/item?id=37298978 also.

https://news.ycombinator.com/newsguidelines.html

This example could quite literally be my nextdoor neighbor. He was ranting and raving to me the other night about the deep state, george soros, how hard he was going to "pray for me" after learning I got vaccinated, etc... If a big white balloon was flying around inspecting power lines I can guarantee he would say something like this and might shoot it. People all over the country would. I think it is inappropriate (and arguably dangerous) to try and pretend that this issue does not exist. Not flamebait. This form of mental illness is its' own pandemic at this point.

Exactly our first inspections are in remote areas so it should be less of a problem. But, even with those small leaks it's not that much of a problem because the airship itself does not empty that fast!

Concerning your question on range: We will easily fly an entire day without refueling (and more), basically an entire day means 200 miles.

Would a bullet not be hot enough to ignite the hydrogen? I know the Goodyear blimp takes fire regularly when moving between cities. Like you said the small leaks aren’t a big deal but bullets are hot.

Actually to create a fire you need the 3 things: Fuel: in our case H2 Heat: in our case hot bullet Oxidizer: in our case there will be only H2 is the enveloppe (O2 won't have the time to enter the envelope along with the bullet). So a fire should not start.

We are not at that stage yet, but we can't wait to test it!

Let me know if you want to come to Florida and test it haha. It’d be fun to do like up a couple test envelopes and see what happens with a few different rounds.

Regular rifle bullets are not nearly hot enough to ignite gaseous hydrogen. Only something like tracer or incendiary ammunition would be a concern for fire.

A broken light bulb or a spark on the ceiling are enough to ignite Hydrogen; and that is why facilities that process it must have ventilation.

"A covered Hydrogen filling station must have electricity for ventilation." Agree or disagree?

And what about microwave energy beaming? Can microwave wireless energy transfer cause a hole in an airship? What about freak lightning storms while inspecting high energy power lines in a balloon filled with flammable and explosive gas?

It looks like it may be possible to store Hydrogen in Sodium Bicarbonate.

There are aerospace-grade hydrogen tanks that aren't supposed to explode in a crash landing, but what about midair collision and war?

There are people working on drones that hover in midair (that do not add flight and ground risk) that efficiently use the air currents too.

I'm afraid [this airship firm] hasn't done a sufficient level of testing to determine how easily the product can become a war liability, and I don't think FAA should clear Hydrogen airships for energy infrastructure inspection.

Could an airship or similar (maybe over an ocean) capture atmospheric helium?

There is a shortage of Helium (and 3He and 4He for fusion), which the sun makes out of Hydrogen with heat and radiation from fusion and fission.

There is no significant amount of atmospheric helium. It's not something that can captured.

Our helium supplies come from natural gas wells. In some areas the natural gas contains enough helium to be worth separating and storing.

Basically no. Its very small, not very reactive, and I guess also has a tendency to escape the atmosphere and trail off into the void.

They are in France so the FAA doesn’t apply, but you think the FAA shouldn’t approve hydrogen airships because in the event of war, attackers will not go for cities or nuclear power plants or military bases or national scale gas storage or highway bridges but will instead target hydrogen lifted blimps in remote areas?

If a small drone explodes and takes down an electricity pylon in nowheresville in the middle of a war, I reckon most people would be very grateful that’s all that happened and willing to fund drones just to draw fire from more important areas and nothing else.

Sparks such as from damaged electronics are hot by the way, hence their ability to ignite flammable gases (unlike, evidently, bullets).

Why are you worried about microwaves, or a flaming gas bag during a war? Rockets seem to supersede those concerns entirely. Or the much more valuable infrastructure targets that would also be vulnerable if a craft like this was vulnerable.

Re freak storm; then it catches fire, like many other things that get struck by lightning.

Bullets cause cylinders under pressure to explode.

It is feasible that microwave power beaming or similar could affect the wind or the airship directly.

Drones are very inexpensive. Ukraine's latest are probably sufficient to cause operational failure for airships.

It is appropriate to be concerned about flaming gas bags positioned over critical energy infrastructure.

We don't know how to fly a flaming gas bag out of the way when there is a Hydrogen fire.

> Bullets cause cylinders under pressure to explode.

They don't actually - they cause pressurised containers (propane for example) to outgas but they don't cause an explosion or even ignition.

You can shoot clean through a propane tank with a 50 cal bullet and not even see (from a distance) the effect .. unless the air temp and humidty is enough to condense water about the outgassing.

Go and check out some "let's shoot a propane tank" videos - no explosions UNLESS someone rigs an ignition source (lit flare, etc).

You've been getting your 'facts' from Hollywood.

Then how did an aluminum aircraft contacting a building cause enough of a spark to cause an on-impact jet fuel explosion?

Indeed we easily could find some pre-existing videos of pressurized cylinders exploding and there being flames. I don't think you're going to convince me that flammable pressurized canisters do cannot cause thrust when punctured.

Does there have to be another existing fire for punctured [propane] tanks to rocket upward like in the movies?

Does a drone RPG carry a light? Really.

As I said, bullets don't cause pressurised propane cannisters to explode.

> aluminum aircraft contacting a building cause enough of a spark

Read the accident report - static electricity, not a bullet, not a pressurised propane container.

> Does there have to be another existing fire for punctured [propane] tanks to rocket upward like in the movies?

Usually a pulley system or another Hollywood trick.

> Does a drone RPG carry a light?

No. Also, not a bullet, it's a Rocket Propelled Grenade.

Just to clarify, here's a slow motion video of a bullet fired into an unsecured pressurised propane tank (small) with a lit flare next to it.

https://youtu.be/ptend5StNB8?t=62

You can see the tank outgassing and falling off the 44 gallon drum (doesn't "rocket into the air"), the gas eventually (in slow motion it takes a while) lights up from the lit flare and there's a dramatic fireball (burning gas) but no explosion as such - after all is over and done with the propane tank will look a little singed, have two holes in it, but won't look "exploded".

There are other videos with no flares .. much the same happens save there are no fireballs, the gas just expels and expands out into the atmosphere.

So the scenarios should include:

- static electricity

- lightning

- flame

- puncture

- midair collision

- acts of war

- solar flares; Carrington events

- combinations thereof; static + puncture

- chance presence of combustible gases and particulates; [grain dust,] + spark/static

Something like that's got to be fuzzed like a flying slot machine.

Your focus is on the wrong thing. The hypothetical gas bag is not the vulnerability - an enemy having direct access to your energy infrastructure is your vulnerability in this scenario.

And, frankly, flaming gas bag is not a serious threat. It would be neat to see, but a small undirected hydrogen fueled fire without access to any other fuel source is not scary. I'd be more concerned about the body of the deflated vessel causing a short than anything

"Procedure(s) for removing a [flaming] dirigible from high energy power lines, hangar masts, and other energy infrastructure" would be a good start

What a weird set of concerns.

Civilian aircraft aren't generally expected to be able to withstand midair collision or war. Why would this drone be any different?

Most aircraft today contain some kind of power storage that can ignite dangerously; 100LL or Jet-A in the case of airplanes and helicopters and some drones, lithium-ion batteries in the case of many drones and upcoming eVTOLs (and for aux power in many modern airplanes as well).

Regulatory frameworks and engineering practices are absolutely able to be used to consider the risks of fires in energy storage systems.

If positioned in a fixed location over critical energy infrastructure , this drone is on another level.

Rockets that contain hydrogen have self-destruct, and NASA doesn't want to load a rocket with Hydrogen while astronauts are onboard on the ground; though rocket fuel hydrogen is chilled and pressurized with lots of energy.

The true cost of guarding a hydrogen blimp that's guarding the critical infrastructure? Is it as much as guarding an upriver reactor cask that's under ordinance spec?

Compared to grid scale battery farms for energy storage, would Gravitational Potential Energy and/or CAES Compressed Air Energy Storage (which are less lossy, anyway) be less of a liability if in the flight path of a slow to fixed hydrogen airship?

Aerospace-grade [hydrogen, jet fuel,] tanks are probably more impact resistant than any airship ever?

Which critical energy facilities have procedures for handling a hydrogen airship in their airspace with and without a wind event?

Gravitational Potential Energy in old mines is enough energy storage for domestic US needs FWIU, but supercapacitors or ultracapacitors may be necessary to handle renewable load spikes when the sun shines across the grid.

I know a bunch of folks that will take that as a challenge…

> Driving around in more rural Georgia, it's not uncommon to see street signs riddled with gunshot holes.

My first thought as well. You'd likely need to make it a federal felony to shoot one and have an ad campaign to make it well known or I can't see these lasting 6 months in a rural setting.

That's not just a southern thing. I see the same all over the country.

The implication is that it's not a federal felony to fire a weapon at a flying aircraft? I know that there are different laws in different countries, but I can't imagine that would be legal, even in the United States!

Unfortunately it is also exceedingly likely that the folks who shoot at road signs as their particular outrage against government are most likely to think that surveillance drones are there to spy on them, and not inspect infrastructure. I don't think regulations or laws matter to those folks.

You are right! As we are in Europe we fill like this will be less of an issue than in the US.

Nevertheless, we will soon test what happened when we shout our flying HyLighters.

For a different perspective; I suspect they'd be fine in the US. Signs and drones are different. The former is petty vandalism, so is the latter sometimes but others you might feel pretty justified in removing the little spy camera from your space.

But a blimp, high up and clearly doing something? Nah, it'd be fine.

There are open questions around the limits of airspace below the FAA ceiling and property lines. There's been multiple cases in the US of people intentionally shooting down drones operating above their property, including in urban areas, and it has not yet been heard by the Supreme Court. Common Law held that property owners controlled their property from the Earth to the Heavens, which is inclusive of airspace. The current law in the US says that property owners control their airspace within their "reasonable control".

I am not a lawyer, but is is a very open question if you're flying low enough someone can visually sight you and shoot you down over their property, whether or not that this is a violation of the law /for unmanned vehicles/. Drones in particular have become a serious nuisance and many property owners have taken actions against them in the US triggering court cases, most of which haven't yet reached their conclusion.

EDIT to add that the rules here even vary by state in the US, in some states you own 83 feet over your property of airspace, in others it could be as much as 400 feet (above 400 feet is controlled airspace under the jurisdiction of the FAA). Generally speaking, shooting any aircraft, jamming any radio signal, or shining laser pointers on any aircraft is already federally illegal in the US and violates FAA/FCC regulations, but it's not clear that these regulations are actually constitutional and enforceable, or that it cannot be an act of self-defense to shoot down a low-flying aircraft intruding on your property.

> Unfortunately it is also exceedingly likely that the folks who shoot at road signs as their particular outrage against government are most likely to think that surveillance drones are there to spy on them, and not inspect infrastructure.

I think you're conflating issues. At least where I grew up, people didn't shoot road signs out of anger at the government. They did it out of boredom. Sometimes as a competition with friends, sometimes alone. I never partook myself.

This seems like a uniquely american problem.

Please don't post nationalistic flamebait (regardless of nation). We've had to ask you this more than once before.

https://news.ycombinator.com/newsguidelines.html

Please don't overestimate the amplitude of said 'nationalistic flamebait'. I have felt this way about your 'feedback' before.

Note: The rate limiting you have imposed on my user meant that I had to wait several hours to post this reply.

Sorry, but that's like responding to "please don't drop a lit match in a dry forest" with "but it was just a little match".

We rate limit accounts when they post too many low-quality comments and/or get involved in flamewars. Unfortunately your account has a history of doing that, so we've rate limited it. If you build up a track record of using HN as intended, you'd be welcome to email [email protected] and we'll be happy to take a look and hopefully remove the rate limit.

Testing if I can reply. Content to be added.

That's good, but following the rules most of the time doesn't make it ok to break them the rest of the time. We have to moderate based on the worst things people post, not the best things.

> We have to moderate based on the worst things people post, not the best things.

Do you though? Shouldn't it be a balance?

I'm still not exactly sure why I can only post about 5 comments/24h.

You got a reply.

It is surprisingly difficult to get pure hydrogen to burn. The DOE safety sheet [0] lists an upper flammability limit of 74% which matches my experience pretty well. In other words: gunshots would most likely just cause leakage.

[0] https://www1.eere.energy.gov/hydrogenandfuelcells/pdfs/h2_sa...

But what about after they leak? Wouldn't the hydrogen then mix with air and get below 74%?

If this is set up similar to other LTA airships (simplified, its bags of air contained by the outer skin with a structure supported by a very light airframe), then a wayward bullet might pierce one or two of these cells - which a certain number of these are allowed to deflate before problems begin. Also, most shot-sign mischief is carried out by shotgun and the max vertical distance it can travel is considerably less than 1000ft.

thank you for the insight, that's very interesting

Fuel, Oxygen, Spark.

You need all three.

It is more complicated. You also need fuel/oxygen ratios that allow for sustained burning, else any fire extinguishes quickly. And heat. There are many fuels that just don't burn unless you heat them up and control their burning to heat the incoming fuel.

Yeah, I wasn't thinking full Hindenberg, just damage would be expensive enough…

Shooting the thing and watching it come down might be fun enough for some.

I have witnessed man's desire to shoot anything that flies. It was at a shooting range in the military, my group (ie eight soldiers) each had a full clip and were supposed to do target practice. Suddenly two unsuspicious ducks passed, flying at 2 meters from the ground, at a very low speed. Everybody without exception emptied their clip on these birds (all 100-ish bullets missed fortunately, so good for the Dutch army).

Imagine the bonus is a ball of fire in the sky for the winning shot!