Monday, December 17, 2007

Up Up and Away

Once upon a time, giants roamed the sky. They did so not in the misty past but for several decades of the twentieth century, starting just about at the turn of the century, and ending with the explosion of the Hindenburg in 1937.

Even the Goodyear Blimp has a majestic stateliness to it, sheer bigness that distinguishes it from all heavier-than-air craft. Yet it was dwarfed by the great zeppelins. The Hindenburg over four times as long and twice the diameter - giving it just about 20 times the volume of a Goodyear Blimp - 20 times the bigness. Sometimes size really does matter, and it matters for airships. I am sorry I never got to see a vehicle 800 feet long gliding across the sky, its shadow wrapping the hillsides below.

Dirigibles (technically rigid dirigibles) have a mystique of their own, having simultaneously the worst of reputation and the greatest of fascination. The Hindenburg not only has been remembered as a flying Titanic, it has made all airships Titanics - gigantic gas bags waiting for a lightning bolt. At the same time, dirigibles or zeppelins are endlessly popular in alternate history and kindred branches of Romance - so much so as to be something of a cliché at places like alternatehistory.com.

The airship is the genteel cousin of the aether ship. Unlike the aether ship it uses a real technology - always an advantage in science fiction, though SF airships may bend the physics a bit, and the engineering quite a bit, to have airships carrying massive payloads or heavy armament. (Lighter than air means just that - for all its immense size, the Hindenburg only weighed about as much as a medium jetliner.)

Airships are genteel in other ways as well. Airship travel must have come as close to the pace and grace of train travel as air travel can get. Who would not want to escape from our world, with its technological marvels such as a Greyhound bus with wings, to a world where you relax in the gondola lounge, an inverted Domeliner, as the landscape glides past below, close enough to see the cows on the hillsides.

Even battles between airships are imagined as having something of the pace and flavor of battles between sailing frigates. In fact, airships evoke a more genteel world altogether. On a darker note, not infrequently the airship world is conservative and technologically sluggish, as in Kingsley Amis' The Alteration.

I want to focus not on the gentility of airships, however, but their place on a continuum with aether ships. So maybe I should first do something I failed to do last post: define an aether ship. They are, as I understand them, largely a retro-SF invention, with antecedents in the "scientific romances" of a hundred years ago, but no defined canonical form until I write the next paragraph.

An aether ship is a Victorian or Edwardian spaceship, propelled by a drive that probably though not necessarily interacts with a pervasive cosmic aether. Unlike most later starships, aether ships in general can also travel in an atmosphere and land on a planet (possibly on water) in spite of its great size.

An aether ship in fact is probably about the size and shape of a dirigible, and its behavior in atmospheric flight would be rather similar. It might differ in being roughly a thousand times heavier - the mass of a seagoing ship - but these are technical details that have little to do with the image or magic that airships and aether ships share.

Extented into the past, aether ships become more fantastic, ultimately the airborne galleons of graphic fiction, though even these may have a whiff of proto-science science to them. (Is astrology a fantasy element, or a retro-SF element?) Going in the other direction? One reason that no aether ships are dreadnoughts is that they all become obsolete the year before HMS Dreadnought was launched - in 1905, when a postal clerk in Switzerland demonstrated that the cosmic aether they were supposed to impel themselves through did not exist. After that, aether ships became by degrees ordinary spaceships - a Russian schoolteacher having figured out the basic features of all present day spacecraft and then a bit.

In fact, an aether ship is pretty much how most people still imagine spaceships, and certainly the way Hollywood does, minus the Belle Epoque stylistic elements. Even we hard SF geeks must make a conscious effort not to see our ships as flying on one side like sea craft or aircraft.

Part of the charm of airships is that you can very nearly heave your cake and eat it too - fill the sky with thousand-foot ships, without requiring any fanciful physics, at most a bit of semi-fanciful engineering. After all, if no thousand-foot zeppelins ever flew, the 804-foot Hindenburg did, even if its voyage ended like the Titanic's.

In real history, the airship was not so much killed as it never quite gained enough lift. The future of airships looked pretty bright after the First World War. German zeppelins had bombed London, only a nuisance value at the time though a grim foretaste of total war. More substantively they were the eyes of the High Seas Fleet. Britain and the US were both interested in naval airships for long range reconnaissance - an application that, if pursued, would find solutions for most of the technical requirements of transatlantic commercial airship service. In Britain the program fell victim to interservice rivalry (the Royal Navy was interested in airships, but the RAF was not) and postwar retrenchment.

In the US the program muddled along for some years, and the US Navy built a few big airships, but the first - USS Shenandoah, 680 feet long and only 35 tons - was lost to a needless breakup in a storm in 1925, and the even larger USS Akron, 785 feet long and 100 tons, was lost at sea with almost her entire crew. The crash was survivable, as crashes of helium airships frequently were, since even if they break up the gasbag sections tend to drift rather than plummet to earth - but the crew had not been issued life jackets. Lost with her was Real Admiral Moffett, the Navy's leading champion of airships, a further blow to the program. When her sister ship USS Macon also crashed at sea in 1935, all but two of the crew survived. Of the big US airships, only the ex-German zeppelin USS Los Angeles ended its career in one piece.

Loss of four out of its five airships in peacetime operation is enough to explain why the US gave up on dirigibles. All of the losses seem to have been avoidable. Taken together they raise the question of whether any structure as large and lightweight as a dirigible could be built strong enough, with 1920s and 1930s technology, to stand up to violent weather. On the other side, the Zeppelin company operated commercial service safely for years, suggesting that airships could be safe in the hands of those who respected their limits.

So let us suppose that airship development in the 1920s had seen better luck, institutional and operational. By the 1930s major navies all have a squadron or two of airships, and commercial airships are entering transatlantic service. (As as a new generation of great ocean liners did, and on land the streamliners, in spite of the Depression.)

The skies will not be filled with airships, any more than the seas are filled with battlecruisers or ocean liners. Even at their height, only a couple of dozen might be in service worldwide, but they would make their mark as the embodiment of luxury travel. A fair comparison to the role of more successful airships might be flying boats, another technology that flowered in this era. Only a handful of Pan Am's China Clippers were built, and they only flew in commercial service for short time, but they were and are an air travel legend.

In World War II they would serve for the most in unsung but critical roles, as Atlantic convoy escorts and Pacific long range patrol craft. Is there any justification for an early radar apparatus that is too large for a plane, but not too heavy for a zeppelin? If so, airships in the Pacific might have served in an AWACS-like role.

Like giant flying boats, the great airships would not long outlast the war. The transatlantic airliner would muscle them aside, and the postwar generation - technical marvels utilizing wartime progress in airframe structures and materials - would end up in a few years as specialized cargo carriers, or as scrap, though smaller blimp types might remain in more widespread use than in our world.

The abiding temptation of airship fantasies, in my modest opinion, is asking too much of them - filling the sky with zeppelins doing the impossible, instead of accepting them as rare giants of the sky, purple argosies dropping down with costly bales.

Their time would still have come and gone, but what a wonderful way to fly.

11 comments:

Kedamono said...

Oh I wish... Airships may have a come back. They have a lower carbon footprint, and, as you've pointed out, are bit safer than an airplane when it comes to crashing... for the most part.

There are people out there trying to design the next generation of airship, Aeroscraft for one. DARPA is looking at another design as well, the P-791

But, as you have noted, it's not a proper alternate history unless it has airships. :-)

Rick said...

Those are cool! But what are those antigravity-pod lookalike landing gears on the DARPA ship? (Which looks like a trimaran blimp.)

It strikes me that in the scenario I outlined, a few big airships might survive the postwar decimation for use in heavy lift, as at construction sites. The load capacity of the great airships is comparable to transport planes, but a *lot* more, I imagine, than any helicopter can lift. (The S-64 Skycrane can lift 10 tons; I think a Russian helo can lift more, but the Hindenburg could lift 107 tons, comparable to a 747.

I imagine fine positioning of loads would be the biggest challenge - an airship can lift a lot more than a helo, but it is a lot less maneuverable!

Carla said...

I seem to remember hearing a radio programme on a company developing airships for use in airlifting large or awkward loads into inaccesible places. They may take a while to get there, but they don't need airstrips.

You may like to know that I've awarded you a Roar for Powerful Words, complete with free psychedelic lion :-)

Jim Baerg said...

"a few big airships might survive the postwar decimation for use in heavy lift, as at construction sites"

Or carrying cargo over sparsely populated land areas where rail & road construction isn't worth the expense.

It's occurred to me that hydrogen airships could be made reasonably safe. Zeppelins had a series of spherical hydrogen bags inside the outer skin with air surrounding the bags & inside the skin. If that air was replaced with the (fairly cool) exhaust from a stirling engine or fuel cell, the fire hazard would be greatly reduced since there would not be enough oxygen for combustion.

Hydrogen & helium are the gases with the greatest life, but methane & ammonia are also usable though they have a bit less than half the lift. I can't see any reason to use methane except in some sort of emergency when the hydrogen has been lost & you're right by a natural gas well or pipeline.

However, ammonia has the interesting property that it will condense to a liquid at about 10 atmospheres pressure at 25 C (or lower pressure at lower temperatures). So pumping ammonia between a gas bag & a tank like those used for storing propane would adjust the amount of lift for the airship.

I have a horrible pun I could use now, but I'll instead keep this mostly serious.

Anonymous said...

Airships, modern ones anyway, can use computers and swiveling ducted-fans to allow them to be as manuverable as heliocopters. Older ones (pre-1970's), are about as manuvorable as a pre-fly-by-wire flying wing. Both need to correct for wind conditions faster than human responses allow. Modern materials, safety techniques, and lifting strategies may well lead to a revivale of airships. I hope so. As far as early radar on airships; the actual radar equipment wasn't that big, but the size of the airplane restricted the size of the antenna. An airship would let you mount a much larger antenna as well as protect them. Early antennas were relitively fragile. Unmanned radar blimps are used in the real world as radar pickets. I imagine that huge, manned airships carrying large radar arrays would be viable for your world. Think of a lighter-than-air AWACS. If you think about it I'm sure you can come up with several uses for airships that are currently preformed by airplanes. Of course, a 1,000 ft long cigar shaped airship done up in the livery of the White Star Line gliding over the mountains would be the sight of a lifetime.
Ferrell Rosser

Kedamono said...

The P-791 is a Hybrid Airship design using four hovercraft pods that let it cruise on the ground or operate in "suck down" mode and hold it in place.

This is based on technology pioneered by the World SkyCat Corporation, that sadly I believe is now defunct. I wonder who got their SkyKitten demo model?

Rick said...

Carla - Thanks for the honor, though once again I don't what sites to single out for the pass-along!

Jim - My slow mind can't come up with the pun, but presumably it has to do with, well, gas. :)

Ferrell - large blimps were in fact used as radar pickets though the 1950s, something I hadn't really known. So something like a WW II AWACS seems fairly plausible.


All of this, though, leads to another interesting challenge of world building. It seems to me that it is not so hard to get an alt-1930s with great dirigibles or 8-engine flying boats, but harder to justify a world with both. They are alternate solutions to long-range flight - the more progress is made by one, the less demand for the other.

Yes, this can be finessed - Country A opts for dirigibles, Country B for flying boats - but the effect will still be present to some substantial degree. Worldbuilding is often about choices.

Grif said...

Wouldn't it be interesting if someone did a steampunk space-travel story using rockets? Ron Miller did one where a version of the British Interplanetary Society 1930s moonship was launched in the 19th Century by a Ruritania-like country, and someone else imagined, on his blog, a 1900 moon expedition led by Robert Falcon Scott...are we sure that the Victorians couldn't have built rocketships?
Grif

Jim Baerg said...

Rick Re: the pun

If you build an air ship that uses ammonia for adjusting lift. The prototype should be called 'Ammonia Bird' & naturally it's hanger would be 'The Gilded Cage'. ;^)

Anonymous said...

Well, speed over carrying capacity, or area covered vs. time-on-station. Airships vs. Flying boats. you're right, some countrys would choose airplanes and some airships for a peticular mission. At the 1930's level of technology, both are equally valid choises. Everything is a choise, give and take, so you can always have a justification for airships over seaplanes (or visa versa)in your world. Choose the one you want.
Ferrell Rosser

Carla said...

I saw this and thought of you....
Best wishes for the New Year!