Blimps

[jks9199]

Something I've been puzzling over for a bit...

Lighter than air craft -- blimps, zeppelins, whatever...

They seem like a great answer to several needs today, at least off the top of my head. I suspect they'd be pretty fuel efficient, they aren't limited to waterways or train tracks, and you'd think they could have some decent freight transport capability with careful design. Sure, they wouldn't be as fast as a plane -- but how often do we really need to travel that fast? And if they flew more directly, with fewer layovers... Hey, I'd rather spend 8 or 10 hours in travel than 2 or 3 hours to a hub, layover for a couple of hours, and another 2 or 3 hours to my original destination... which I may have literally flown over in getting to the hub!

So why doesn't there seem to be any serious development? They seem to have been left as advertising gimmicks...

 

[mrhnau]

Something I've been puzzling over for a bit...

Lighter than air craft -- blimps, zeppelins, whatever...

They seem like a great answer to several needs today, at least off the top of my head. I suspect they'd be pretty fuel efficient, they aren't limited to waterways or train tracks, and you'd think they could have some decent freight transport capability with careful design. Sure, they wouldn't be as fast as a plane -- but how often do we really need to travel that fast? And if they flew more directly, with fewer layovers... Hey, I'd rather spend 8 or 10 hours in travel than 2 or 3 hours to a hub, layover for a couple of hours, and another 2 or 3 hours to my original destination... which I may have literally flown over in getting to the hub!

So why doesn't there seem to be any serious development? They seem to have been left as advertising gimmicks...

Interesting. I imagine the Hindenburg might have something to do with that

You would still have the same problem, needing layovers, unless you only have one or two dedicated routes, and thats all you do. I'm sure there would be a group of people interested in that, but it might not be large enough to afford the kind of infrastructure needed. Can't use normal airports I imagine, with them being so huge and slow.

Transport of goods might be an interesting endeavor, but I doubt it would be quicker than trucking or trains. Might be cheaper, but time is often money...

 

[Empty Hands]

Interesting. I imagine the Hindenburg might have something to do with that

The Hindenburg was filled with hydrogen gas, which is explosive. All zeppelins after that time, including the few around today, were filled with helium gas, which is not explosive.

As to why you would fill a giant balloon with an enormous amount of explosive gas and then fly around in it, you will have to ask someone else.

 

[Mr G]

I bet blimps are strongly affected by the weather. They have to be hard to control. Just a little bit of wind and off she goes.

Some American helicopter company tried to combine four helicopters tied to a huge zeppelin. I think it was called the Heli-Stat. It crashed.

 

[Big Don]

As to why you would fill a giant balloon with an enormous amount of explosive gas and then fly around in it, you will have to ask someone else.

Seemed like a good idea at the time...

I think blimp travel would be a really neat way to travel for just the scenery. Getting there could be way more than half the fun...

 

[Steel Tiger]

I'm a big fan of the dirigible balloon as well but they do have some serious drawbacks. The reason the German ones were so big was their construction. The rigid construction was heavy which limited lifting capacity. The Hindenburg, for instance had a usable lift of 112 tonnes.

They leaked gas, but modern materials would minimise that problem.

They are badly effected by strong winds. Both the German and the few American dirigibles had plenty of horsepower driving them, usually three to six 250hp engines. Even so, the German transAtlantic flights had great discrepancies between east-west and west-east, four or five hours on average.

In good conditions they could do 80kmh, but could fly for much longer periods than a plane.

They need enormous facilities. You could fit three A380s into the hanger for a zeppelin like Hindenburg or Graf Zeppelin.

Incidentally, the Germans used hydrogen because, at the time, the US were the only producers of Helium on a large scale and the gas was classified as a strategic resource, so could not be sold to countries other than allies like Britain.


There was a modern dirigible project called Cargolifter around 2000. This was based around a semi-rigid dirigible capable of lifting 160 tonnes. The company went bankrupt however.

Just by way of comparison - Airbus' A380
73m long
freighter model can carry 150 tonnes of cargo
Airspeed is mach 0.85

 

[Big Don]

By comparison, the Hindenburg was 245 m (804 ft) long and 41 m (135 ft) in diameter, longer than three Boeing 747s placed end-to-end. Only 79 feet shorter than the Titanic.

 

[exile]

I reckon a trip between NY and Columbus by blimp couldn't arrive any later or more off-schedule than the same trip as provided by the incompetents who seem to be operating US Airways....

 

[Grenadier]

By comparison, the Hindenburg was 245 m (804 ft) long and 41 m (135 ft) in diameter, longer than three Boeing 747s placed end-to-end. Only 79 feet shorter than the Titanic.

And suffered a fate on the same order of magnitude similar as the Titanic!

The problem with blimps, is that they're going to be helium-filled. One big problem, is that no matter how well you construct your blimp, you'll always be leaking helium. If you try to make your blimp that much more leak-resistant, you're going to add a significant amount of weight, reducing the capacity of your blimp.

Helium diffuses out of the materials pretty quickly (at least twice, probably more, as fast as air does), and is not retained by our atmosphere. Thus, once you use the helium, it's gone, departed from this world, and diffused into outer space.

There aren't that many sources of natural helium left in this world. Most of the helium gas comes from Amarillo, Texas, where natural gas fields essentially trap the gas. It took millenia of radioactive decay to form alpha particles (highly energized He2+ ions), that eventually formed the bulk of that helium, and replenishing that helium takes a long time, if at all, since significant radioactive decay doesn't happen overnight.

Helium demand, not surprisingly, has been skyrocketing in the recent years, especially over the last decade. Production plants haven't been optimized in the rest of the world (there are several in the Middle East that are still in their "almost ready" phase), and consumption has really jacked up the prices of helium.

To put it this way, we use liquid helium to keep our superconducting NMR magnets at 4 degrees K, and go through about 100 liters every 6 weeks. Back in 2002, we were paying less than 4 bucks / liter, but now, that same company hits us for 8 bucks a liter.

It's also seen in the gas cylinders, as well. A 300 cubic foot cylinder of ultra high purity helium gas used to cost about $125-150, depending on what the sales folks had for breakfast. Now, that same cylinder costs $320.

So... How do we replace all of that helium? I honestly don't know... If someone can come up with a way, then he's going to easily, unanimously win the Nobel Prize in Chemistry. Some folks say "well, wait until nuclear fusion becomes widespread! You'll get helium as a by-product!"

To put it this way, if someone can make nuclear fusion a commonplace reality, then he's going to be even more famous than the theoretical guy I listed above.

 

[exile]

What about using neon instead? It's not particularly rare, in the universe at large, anyway. A good deal heavier than helium, but still lighter than air, and totally inert. Even the halogens leave it coldly uninterested...

 

[cdunn]

What about using neon instead? It's not particularly rare, in the universe at large, anyway. A good deal heavier than helium, but still lighter than air, and totally inert. Even the halogens leave it coldly uninterested...

Because it's 'a good deal heavier than helium'. At STP, 22.4 L (1 mole) of dry air weighs about 29 g. 22.4 L of helium weighs 4 g, meaning 22.4 L of helium can lift about 25 g of mass. 22.4 L of neon, though, weighs about 20 g, so it can only lift about 9 g. So, you have to have have 2.8 times the volume of neon to lift the same mass as you could with the helium. And an even three times as much neon as hydrogen.

Therefore, to replicate the lift of the Hindenburg in Neon, you'd need a bag roughly the size of the Empire State Building... without being any more massive than the Hindenburg bag.