Could dirigibles make a comeback?

Factual Questions
21

Modern airships and blimps are more maneuverable than the old-fashioned Goodyear blimps. The major difference is vectored thrust, i.e. propellers that can swivel up and down. This allows vertical movement. The Zeppelin NT has four vectored propellers, including one on the tail that can point sideways and function like the bow thruster of a ship. Here’s a brief ride report on the Zeppelin NT:

http://www.modern-airships.info/en/zeppelin/zeppelinflight_june_2002.html

Check out other pages on that site too, there are a lot of nice photos.

22

The thing about asking the postal service to carry a lighter-than-air package (or even a weight-neutral one) is that their running costs are (to a certain extent at least) based on mass, not weight; ignoring friction, moving a weightless object laterally (like putting it in a van and driving somewhere still costs.

23

The postal service also doesn’t charge on a linear scale: Typically, the lowest price (at least in the US) is for items of one ounce or less. So a helium balloon, even if you argue that it has negative weight, is still “one ounce or less”, and would cost the same as a first-class letter.

24

I’m holding out for the Linux version but I may have to settle for XP.

25

There were historically three kinds of dirigible: the nonrigid, the semirigid, and the rigid.

The nonrigid dirigible, for which blimp (from “Type B Limp” in trhe British parlance) has become the synonym, is nothing but a giant airfoil-shaped balloon with motor(s) and gondola attached to the underside.

The semirigid was a balloon with a keel, allowing a much larger gondola.

The rigid, on the other hand, was a steel-frame construction with a number of “cells” within it – the cells being airtight membranes that can be inflated with a lighter-than-air gas for buoyancy. The crew on the traditional rigid dirigibles was able to pass between cells on catwalks to travel the length of the ship. In the two great passenger Zeppelins and at least two of the U.S. Navy rigids, the lowest level of the framework was devoted to passenger/crew space, providing an elliptical area of about 800 feet in length and a maximum of about 30 feet in width, over and above a quite large gondola attached to the bottom of the framework.

There are some significant problems raised by the crashes of the 1930 airships – one is that they are not safe in severe weather (Shenandoah and Akron crashes), and the framework requires more flexibility than a typical building (Macon crash). If one can figure out a way to ensure no leakage from the cells, hydrogen is safe – it is only explosive when mixed with air in a specific range of proportions; there is strong evidence that the Hindenburg explosion was sabotage (and it remains the only airliner fire in which a majority of the passengers escaped safely, though many were killed or terribly burned).

There are a number of companies exploring the potential of using airships for heavy cargo movement – something that will travel virtually anywhere at speeds in excess of 100 miles per hour, using very little fuel comparatively in the process, and can carry massive objects, certainly has an economic role worth exploiting. Venture capital has not however been forthcoming in sufficient quantities to enable the building of a modern prototype.

It is worth noting that two of the rigids flew successfully with no problems worth noting from the early 1920s until 1939 – the Navy’s Los Angeles and the Luftschiffebau Zeppelin’s Graf Zeppelin. Shoddy workmanship (in Britain) and attempts to test the limits of the ships (U.S. Navy and explorations) were responsible for most of the horror stories – the Hindenburg, of course, being the glaring exception. (The Hindenburg did fly without incident for a full year, 1936, before the 1937 explosion.)

26

It wasn’t the hydrogen that made the Hindenburg go up like a torch, it was the highly flammable (and explosive) stuff the fabric was coated in to make it airtight. When the cells were breached most of the hydrogen escaped into the air in the first few seconds and was gone.

27

Polycarp can you supply a link to something that provides details for the sabotage theory. The latest theory that I have heard is the fabric coating that Sock Munkey mentions.