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Comment by dahjkol | Hacker News Reader

I wonder if blimps or zeppelin is the future for "green" aviation

The future is probably to only allow the middle-class and the well-off people to fly again, the tickets costing 5 or 10 pounds from London to the likes of Prague or Malaga that used to be so popular among the young and the low and low-middle-classes will probably be a thing of the past.

The same goes for personal cars, the governments are all too happy to give money directly to the high-middle-classes so that they could buy EVs costing north of 40,000 euros while imposing very high taxes (when not banning them altogether) for 10 to 15-year old SH cars favoured by the low and low-middle classes (because that's all that they can afford).

The Financial Times has had a really interesting article [1] on this a couple of days ago from the perspective of those high-middle class people, some of them are worried that the low and low-middle-class people will revolt once put in front of these new realities (like the Gilets Jaunes have done in France), but imo they will most probably do nothing of the sort.

[1] https://archive.is/H03ng

If tickets will be that cheap, why wouldn't poor people travel, too?

Edit: Nevermind, misread.

I think he said the opposite, tickets won’t be that cheap anymore.

They are that cheap now and relatively poor people travel.

I suspect that the only way for long-distance, heavy-lift aviation (and military aviation) to continue operating in a political/economic climate that demands CO2 reduction/elimination will be via biodiesel. Batteries ain't gonna do it. Zeppelins might be way forward for freight traffic where slow doesn't (often) matter as much, but for large scale passenger transport (again: assuming it's to survive) I don't see anything approaching the specific-energy embodied in diesel. Fischer-Tropsch (sp?) is well understood and can be made to work with pretty-much any feedstock.

What about hydrogen?

I've been advocating Hydrogen for energy storage/transport for decades, but I don't think it works for planes. Specific energy (energy per kg) is against it, I'm afraid. It's not the H2 that weighs much, but it's such a sneaky/leaky gas that containment vessels end up weighing quite a lot. (Maybe there have been improvements in the past decade or so - it's been about that long since I looked.) Hydride storage can't deliver the H2 fast enough for aircraft (again, unless there've been some advances) and we'll not even speak of the flammability issue ;)

Many large companies in the aviation industry are investing hard on it though. For example: https://www.airbus.com/innovation/zero-emission/hydrogen/zer...

I think electric airplanes are still the more probable future. My understanding of the current problem is that the weight to energy ratio in electric batteries is still too high for useful flights. But this ratio is improving year by year, and very soon we will be near the number where electric aircrafts will be competitive with fossil fuel ones on some types of flights.

The energy density of kerosene absolutely destroys Amy battery tech we have and kerosene is used up, therefore making the aircraft lighter over time, further increasing range.

Mainstream commercial electric aviation is probably a half a century away (provided we don't actually discover something even better that supercedes it).

As far as I'm aware, there is no significant effort on battery-powered airliners in the industry. The only significant bets are on hydrogen and biofuels.

Since the Hindenburg disaster, hydrogen zeppelins have gone out of style. Probably rightly so. What non-flammable levitating gas we are left with is helium. Never mind that helium appears to be going up in price, it has twice the density of hydrogen and hence, is far less efficient. So i think zeppelins are basically dead, except for short, recreational flights.

I could see a use for hydrogen filled drone zeppelins carrying cargo. Cargo typically doesn't need to travel as quickly as people do and we can take risks with cargo that we wouldn't take with people.

Also, I have a feeling that hydrogen got a disproportionally bad reputation after Hindenburg. After all, people do travel in devices that are loaded with gasoline and jet fuel, so it's not like it isn't possible to safely handle flammable material.

I don't know about you but i just have a nightmarish vision in my head of thousands of self - propelled incendiary devices flying around and setting cities and countrysides ablaze. Shudder. No thanks.

And your comparison of zeppelins to cars and planes is flawed. The former consists chiefly of an extremely flammable gas. Protecting it is a thin layer of canvas (which can also burn). The latter contain a relatively small container of liquid which is protected by layers of solid metal and foam and all kinds of valves.

They are actually too inefficient.

https://blogs.scientificamerican.com/guest-blog/helium-hokum...

I would love to see some real investment into them once again, for energy efficiency they can't be beat

There's a UK company which is hoping to launch regular airship services for short routes within the next 5 years: https://www.theguardian.com/world/2021/may/26/airships-for-c...

Are they competitive with cars/trains though. In the article linked by the sibling it says the Airlander can reach speeds of 50 knots. That is probably fine for a cruise-ship type experience, but for actually going anywhere a well designed train network seems like it would be much more effective?

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