21st Century Zeppelin? (Paging Broomstick's Husband)

Factual Questions
1

For some years now I’ve been hearing reports of the possibility of actually constructing new rigid dirigibles for use on heavy-lift cargo flights and such things. But nobody gets any more detailed than “X company announced it’s looking into the possibility…”

When I saw Broomstick’s post quoted above, it reminded me of this.

Questions:

  1. Are any companies seriously pursuing this beyond the speculation stage?
  2. If so, what uses are planned for the new dirigibles? Do they include passenger flights?
  3. What about the structural stability problems that affected the Shenandoah, R101, Akron, and Macon?
2

There’s at least one company of which I know for sure it has serious plans in the drawer, Berlin-basedCargolifter. Apparently, they’re building up their fleet.

3

Oh, and there’s another one (also German) that focuses on passenger flights: Zeppelin NT (“New Technology”). Interstingly, it’s a direct successor of the company that operated the big transatlantic Zeppelins until the Lakehurst disaster.

4

Also, the UK’s Advanced Technologies Group is manufacturing blimps (also known as Lighter Than Air, or LTA, systems) that can they claim be used for civilian/military cargo transport, surveillance and even low cost alternatives to telecom satellites.

5

Well…there must dirigibles build, since I saw one several time from my window, cruising over Paris. No clue what it’s used for, though.

And a descendant of the Zeppelin family (IIRC) created a company which operates a (modern) zeppelin (in Austria, I believe). It’s only for tourism purpose, though. They would cruise above some important touristic site.

6

I believe the one used by Paris is a blimp, rather than a rigid airship.

There is a company called “American Blimp Corporation” which manufactures blimps such as the ones you occasionally see rented out as floating billboards. They’ve been in business for several years now, having realized there was a market for LTA if they could make them cheap enough and require a smaller ground crew. IIRC, their base model is “only” in the vicinity of a million or two dollars, and requires a ground crew of six.

A company called “The Lightship Group” rents blimps manufactured by American Blimp Corporation, mostly for advertising / event filming purposes.

Paris first started using their blimp during the bicentennial celebration of the French Revolution, which also coincided with some other major event. They thought it would give the police a much-needed surveillance capability, while not being as noisy and obtrusive as helicopters.

American Blimp: http://www.americanblimp.com/
Lightship Group: http://www.lightships.com/index2.html

This link lists some of the airship companies you might be interested in: http://hotairship.com/database/index.html

7

Well, the husband is sleeping off today’s activities so for the moment you’re stuck with just lil’ ol’ me.

As best I recall, these are the good points and bad points of LTA flight (that’s both ridgid and non-ridgid varieties)

Among the good points - much more fuel efficient since you’re using power just to go forward, not to hold you up in the air.

Do not require pavement - just a good mooring mast. Much cheaper to build than actual airports or roads.

Bad points - the sheer quantity of lifting gas required. Even if it’s cheap per cubic meter, you need so much that it represents a considerable expense. Now, you can use equipment to reclaim the majority of the gas, but that’s an additional expense and complication. And you always lose some over the course of time.

You need ground crews. Sometimes, you need a LOT of ground crew.

You need pilots trained to operate these things, which don’t fly quite like heavier-than-air craft.

And, like all aircraft, LTA’s are at the mercy of the weather to a degree ground vehicles never are.

In “developed” countries, with their infrastructure of airports, roads, and so forth, and the high price of human labor (those ground crews, remember) there is little incentive to develop this technology (although if petrochemicals ever become REALLY scarce this may change).

However, in locations such as Africa, where there is considerably less infrastructure and human labor is available and cheap, this becomes much more attractive as a transportation technology beyond novelty rides for tourists.

Last I heard, Zepplin NT is looking into cargo-carrying for Africa, among other places. I haven’t heard of passenger carrying, although there’s no reason it couldn’t happen. LTA’s are, however, slower than airplanes. For some cargo, such as what goes by frieght train, cost may be more important than speed, but peopel tend to want to go fast. Passenger carrying may be more likely in the third world if it’s cheaper than airplanes and trains are not as attractive an alternative in the location.

I don’t see why LTA’s would be inherently more dangerous than heavier-than-air flight, it’s just that there have been some spectacular disasters that linger in the public mind without the [Carl Sagan voice] millions and millions [/Carl Sagan voice] of safely flown miles the airlines have to offset the occassional spectacular screw-up.

8

Oh! the humanity!

[sub]Sorry, but it was bound to happen sometime in this thread, so why not now[/sub].

9

Well…Thanks, Yabob. I often wondered what was this thing and why it was there, but never thought I would find the answer on an american board.
Now, I’ve another question. What’s the difference between a blimp and a dirigible (my dictionnary translate blimp by “survey dirigible”, which didn’t help, and I didn’t find any hint on the site you gave a link to)?

10

A dirigible is any LTA craft that can be steered.

A blimp is a non-rigid LTA craft.

So a blimp is a kind of dirigible. We use the term “zeppelin” for a rigid dirigible because of a) the inventor, and b) the most famous one in history (before the Hindenberg explosion) was the Graf Zeppelin, the first flying machine to circumnavigate the globe and visit the poles. And because “rigid dirigible” sounds stupid when you say it out loud.

11

IIRC, the Zepplin NT folks were looking into using the new Zepplins as “cruise ships” for the very wealthy. The idea being that you shell out lots and lots of money for a month long trip that offers lots of senic viewing.

12

Thanks, Ukulele…

13

This is dubious. At cruise speeds a jet airliner does not expend a great percentage of its fuel generating lift, and by some standards is commendably fuel efficient: A full 747 can deliver something like 80 passenger-miles per gallon. And it does this at an impressive speed, something that paying customers tend to appreciate.

In favor of the 747 is that it flies fast and high where the air is thin and cold; this means drag is low, jet engines are efficient, and weather is rarely a problem. The dirigible must necessarily fly slowly and at a comparitively low altitude, where weather is often a problem.

The achilles heel of airships is their size. They have to be large to carry enough passengers/cargo to be of interest. They have to be lightl to get off the ground. This means they can’t be especially strong, and so will inherently have problems dealing with the kinds of forces that normal weather conditions (e.g. thunderstorms) can exert on large objects.

14

At cruise speeds a modern jetliner may, indeed, be a decently efficient form of travel but they don’t travel the whole trip at “cruise speed”. Jetliners are notoriously inefficient while low and slow, and low and slow they have to be twice on each and every flight - takeoff and landing.

And, even at cruise, a significant portion of the force expended does go into holding that puppy off the ground. Something is exerting of force in the neighborhood of 300,000 lbs in order to resist the pull of gravity - if it was, you wouldn’t be in level flight but descending (perhaps extremely rapidly). Airplanes must keep moving forward and it is this forward motion that generates the lift that holds them up. Now, jetliners are designed and operated at certain set speeds which reduce the drag and maximize the use of thrust, thereby achieving efficiencies. LTA’s, however, can (in calm conditions) hover indefiniately over one spot at a given altitude without any energy expenditure at all. No jet can match that. Even a helicoptor can’t, for while it can hover it does so only with a constant energy burn.

Also, LTA’s are NOT restricted to low altitudes due to an inherent quality of the manner of flight - helium is bouyant at all altitudes. It is nothing at all unusual for a helium balloon to travel at jet altitudes using the same lifting mechanism. The early LTA’s were limited in altitude for the exact same reason the early airplanes were - go too high and the pilot couldn’t take it. There is nothing to prevent an LTA from having a presurized cabin for the comfort of humans aboard.

The only real drawback to them as cargo-carriers is their slow speed - but in a region of the world where roads are rare to nonexistant, airstrips likewise scarce and hard to build, and railroads have never been built they have possible advantages.

And, yes, there are undoubtably folks willing to pay for a ride in such a machine (yours truly included, if I can fit it into the budget). Tourism is just as likely a way to make money as any other.

15

They are indeed inefficient when low and slow, which is why they spend rather little of their time there. The good overall efficiency of a 747 includes the necessary takeoff and landing.

Yet the energy expended to provide lift is, at cruise speeds, not enough to make a 747 inefficient. And note that lift equal to the weight of the plane (which may be 800,000 lbs or more) must be provided both in descent as well as in cruise.

Quite true – if the goal is standing still or moving slowly, nothing will match the efficiency of an LTA.

There’s a problem here. A balloon can reach high altitudes only if it is large enough that its helium (or hydrogen, I suppose) can expand as the air density decreases. A rigid or semi-rigid LTA will not allow much expansion – it will have to vent gas as it ascends or risk damage from the expanding gas. Loss of gas means loss of lifting ability (and replacing the lost gas will cost money).

I can see them as interesting tourist curiosities (I, too, would like a ride). As a practical means of moving passengers and/or frieght, I’m not so sure.