Why no vacuum or hydrogen based airships?

Maybe not for passenger point-to-point travel, but they could have an application as a kind of cruise; I think there would be demand for luxury cruises that let you soar coast-to-coast and admire an entire continent from above in the style and comfort of a first-class cabin.

Plus, of course, cargo. Deliveries that are less time-critical than present air freight, but too bulky for road or train traffic, or in regions where road or rail infrastructure is deficient, could constitute a market for cargo airships. It has been tried, unsuccessfully, by a company that is now setting its sights a bit lower, though still in the lighter-than-air area.

Scylla’s old thread is one of the funniest things I’ve read in awhile. :smiley:

The Hindenburg was carrying 36 passengers on its final voyage,; a 747-8 can carry up to 470. So at first sight, your statement that the 747 carries about a dozen times more passengers is correct. Yet, the comparison is not quite appropriate because it underestimates how the two really compare:

Firstly, the Hindenburg was carrying 97 people in total on its last voyage, 61 of which were crew and 36 passengers. But it was not running at full capacity; according to this site, it had 72 passenger sleeping berths in 1937.

Secondly, not all of the crew members were necessary to run the vessel for technical reasons; a large number of them were staff whose duty it was to turn this into a trip comparable to a luxury ship, e.g. stewards, chefs, etc. You can take up more passengers if you’re less wasteful with giving away space on the vessel to servants. According to the site linked to above, the number of crew that are necessary for technical reasons are 40, which would free up 21 more spots for passengers.

Thirdly, the whole thing turns out even better for the Hindenburg if you look at cargo rather than people, since the slower speed of an airship means you’d have to carry cabins and beds, which increases weight per passenger. The same does not rise for cargo. This message board thread claims the Hindenburg had a payload of 242,200 lbs. The cargo version of the 747-8 has a bit more than 300,000 lbs, so much less of a difference than a factor of 12.

Putting this all together would mean that an airship, if not utilised wastefully, would be much more fuel efficient, calculated per passenger or per pound of payload, than a 747. And if you use the airship wastefully, where the advantage of the airship over the 747 would be reduced, that would occur for purposes such as luxury travel where the fuel efficiency is less of a commercial concern.

That was my thought - while the Hindenburg spectacularly crashed and burned live on Tri-X Panchromatic, and radio, the major number of the other large rigid airships of the 1930’s died from bad weather far from viewing eyes. Airships are just giant sails waiting to be pushed around. A giant gas bag is not amenable to high winds, sudden gusts, lightning or precipitation sticking to the outside and weighing it down - static electricity was just a bonus in New Jersey. Worse, the rigid airships of the 1930’s were of giant stiff girder construction with airbags inside, so were also at risk of structural failure due to gusts too.

I had an idea long ago for a lighter than air sort of railroad.
We have the Trans Canada highway here. I imagined a continuous chain of blimps connected by cables following most or all of that route. The system driven by something similar to an electric chairlift. The infrastructure along the route would be mostly just guiding the cable, not needing to support much weight. Driving stations here and there. Depots to insert and remove payloads.
Using the existing container system, or maybe ones that are designed to be lighter.
Fewer trucks on the road. Electric power. Less on the ground infrastructure than roads or railways. Slightly above weather induced problems on the ground. No bridges required.
Initial investment would be big. But maybe less than adding roads and rails. I think operating expenses would be less long term.

See post #19 where I calculated Hindenberg’s fuel consumption in kg per passenger per 100km, the standard measure for airliners, using apparently authoritative specific data about speed, fuel consumption, and assuming the nominal passenger capacity of 70 (not the smaller number aboard at the time of the disaster and not counting the crew). It comes out to around 6kg/passenger/100km. As I mentioned, for a 747-400 it’s 3.26; you mentioned the later 747-8 for which it’s 2.75.

So for passenger transport, not likely for an airship even with more advanced technology could match a passenger airplane in fuel efficiency especially over a distance where the airship has to carry along full sleeping/dining facilities because of the time involved. Indeed it’s possible passengers would want a slower more luxurious voyage which ships also do for a niche market (even nominal long distance point to point travel like QM2’s trans Atlantic trips, besides pure cruising). But the slower vehicle does have to carry along the extra facilities, and that makes it a a lot harder to save fuel net in long distance transport of passenger.

For goods transport it’s more plausible for a buoyant lift vehicle to beat an airplane in fuel efficiency. The key though is to put the two on a fairly event footing in first cost and labor cost. In the latter respect, besides needing to be fully automated to get the crew size down to airplane size, the buoyant vehicle has to avoid the need for large ground crews, and susceptibility to wind when landing and on the ground. As mentioned, the most promising way to do this seems to be a hybrid where the buoyant lift is less than the gross weight and the aerodynamic lift is used to take off, and in its absence the vehicle comes to earth itself and stays there even when it’s windy.

However fuel efficiency is not the only important parameter in goods transport either. If it was, neither airplanes, airships or hybrids could compete with ships for carrying cargo. But everything is not transported by ship* because of the time value of rapid transport of particular items, and a freighter a/c would still cross oceans much faster than an airship or hybrid. The business case for hybrids seems targeted at transporting outsize cargo to remote places on land where a/c with the same capacity wouldn’t have room to land, where their speed in getting there is not important, and ships can’t go either.

*mid to high 90’s% of goods shipped overseas is by ship if counting by weight, but a much more significant % is by plane if counting by value.

There aren’t many blimps out there, but the number is greater than zero. Goodyear uses blimps for aerial footage of sports stadiums, as well as to advertise their own name. Other blimps also fly with advertisements on their sides. There are also military blimps for airborne surveillance/reconnaissance, and other civilian blimps for tourist purposes

The question of why these aren’t filled with hydrogen (or nothing at all) is a valid one.

There’s also the fact that this comparison is between a modern airliner and an 80-year old dirigible. Consider that they probably had porcelain dishes and metal silverware on the Hindenburg. There’s a reason those are made of plastic on modern aircraft. But that’s only part of it, of course. Virtually every part of the ship could be made lighter with modern materials. I’m not saying that this would make airships economical. Just pointing out you need to make apples-to-apples comparisons.

That’s a common misconception. There was no live broadcast of the crash. Herbert Morrison’s famous report (“oh the humanity!”) was recorded on site and broadcast the next day.
http://jeff560.tripod.com/hindenburg.html

–Mark

Time is another resource, I could leave San Francisco with two suitcases full of $100 bills in the morning and have it deposited in my bank in Bermuda by the end of the business day. If I take a blimp, the IRS is going to figure my little dodge out and I’m going to get arrested.

747s can fly above most weather, something blimps can’t do.

The other advantage that airships have over heavier-than-air planes is that they can hover much more easily, using little or no fuel (only as much as is needed to counteract the wind). So if you’ve got an application that requires a lot of hovering, an airship might be a more reasonable choice.

Lockheed is betting on airships, although only as cargo vehicles.

I thought I recalled lighter than air ships that catered to passengers, so I started looking.

http://www.airshipventures.com/
Defunct. According to the website, they flew 20,000 passengers in just over five years.

Since the largest cruise ships are built to carrymore than 5,000 passengers at a time, it looks like the market for passenger airships is a lot more limited than one might believe.

Well of course, if time is of the essence, you’re not going to take an airship, or a boat, or a train, bus or automobile if the journey is over land. That doesn’t mean these other forms of transportation are of no use.

BTW, the world’s longest airship just crashed a few hours ago on a test flight. The company “hopes to be building 10 airships a year by 2021”.

–Mark

A first-class cabin on an airship would resemble a sleeping compartment on a luxury train, not a cabin on an ocean liner. Ditto for all the other passenger facilities. Granted we have luxury train travel, but it’s very much a niche market. It’s true we could do a lot better than the LZ 129 Hindenburg, but as big a zeppelin fan as I am I’m still skeptical there’d be a big enough market for them. If anyone ever tries I’d sure has Hell do whatever I could to score a trip before they went out of business.

This post cannot be left unacknowledged.

Very nice.

The Graf Zeppelin had something called Blau gas. I tried reading about that on Wikipedia, but it went over my non-scientific head. Can somebody explain that to me?

The Hindenburg was just the most visible and publicly seen, even recorded ridged airship disaster and it more or less nailed down the coffin lid on public confidence in that mode of travel. Before it was the R 101 British airship disaster, the American navy’s Akron and Macon disasters, and the Shenandoah wreck, the R-23 wreck… many more I’m sure I forget.
There have been more wrecked airships than successful ones (like the Los Angeles and Graf Zeppelin) come to think of it.
Ridged airships are simply too big for their structural strength when the worst of weather comes in and the variations in air pressure during storms sent them on a roller coaster ride to hell.

Boat, train, auto or bus can travel through stormy weather … and the latter three can just simply stop and park. An airship not so easy, even with a trained crew on the ground, we’ll still need a hanger. I’m thinking a thunderstorm squall line, not exactly uncommon.

I mean a really BIG hanger too …

Airships had a ground crew of nearly a hundred men to grab the mooring lines and pull the great airship to the mooring mast. How you going to pay those sons of bitches all minimum wage or better today? They wouldn’t even go out in nasty weather to look up into rain, maybe get dumped on with hundreds of gallons of released water ballast. Why would they even do that if you could pay them, when they can pull in up to $75,000 a year in child benefits, welfare, housing subsidies, and green stamps, all for sitting at home doing nothing at all? YOU go out and pull on your damned zeppelin! :slight_smile:

I’m sure a modern dirigible would use a geodesic design for its framework instead of the square girder-and-joist plan the Hindenburg used.

Speaking of Buckminster Fuller, he proposed that if you only made it big enough- like city sized- a geodesic dome would float just from the air inside being warmer than the outside: https://en.wikipedia.org/wiki/Cloud_Nine_(tensegrity_sphere)