This little blog series is based on a talk I gave on August 18, 2012, at Pi-Con in Enfield, Connecticut. About a dozen people showed up, which was very gratifying, and I think all of us had a good time.
Airships are the signature technology of steampunk and alternate-history stories. If you look up in the sky and see an airship (that doesn't say "GOODYEAR" on the side), you may have slipped into another reality.
Now, I happen to be a fan of steampunk and alternate histories in general, but I'm also an airship buff. Which means I sometimes get frantic when stories get them wrong. (Actually I get frantic when stories get anything wrong. I spend a lot of time being frantic.)
Flying isn't easy, at least for humans. Flying machines have to do three things. They need lift, they need propulsion, and they need control. Without lift it's not a flying machine, just a car. Without propulsion it just sits there, and without control it's an unguided missile.
Lift is the most obvious, and the one which got the most attention. If nothing is countering the pull of gravity, you're stuck on the ground. There are two ways to generate lift: thrust and buoyancy. With thrust, you generate a push down that counters the pull of gravity. Rockets do it by sheer brute force, but airplanes and helicopters use a more elegant method based on the Bernoulli Effect, in which forward motion creates a difference in pressure between the top and bottom of the wing (or rotor), which generates lift. If you prefer, you can think of this as "suction" rather than thrust.
The second problem is propulsion. Inventors tried all sorts of methods: flapping wings, sails, oars, and hand-cranked propellors. Ultimately the solution had to wait for the development of motors light enough to go aboard flying machines.
The final problem is control, which turned out to be a lot harder than anybody realized. Airships were still grappling with control issues as late as the 1930s, and airplanes simply weren't possible at all until the Wright Brothers figured out that you can't steer an airplane the way you steer a boat.
Buoyant flight came first. The Montgolfier Brothers managed it in 1783 by taking advantage of the difference in density between hot and cold air to create the hot-air balloon. The discovery of lighter-than-air gases like hydrogen, methane, and helium led to the "gas balloons" which were the dominant form of flying machine during the 19th century.
Balloons have been unjustly neglected in steampunk. They were the apex of aerospace technology for nearly a century. Even as late as 1895, when H.G. Wells was writing The Time Machine, he used the balloon as an example of a machine which could travel in three dimensions.
Balloons solved the lift problem, but they ignored both propulsion and control. If you go up in a balloon, you're going wherever the wind decides to take you. You can land if it turns out you're going the wrong way, but that's about your only recourse.
This limited the applications of balloons. They couldn't carry passengers because nobody wanted to buy a ticket to travel in a random direction. Their military applications were important: tethered observation balloons became a key technology. It's worth remembering that some of the first fighter planes in World War I were deployed as "balloon busters" to shoot down enemy observation balloons. Even today unmanned aerostats have a role in military reconnaissance.
I've always been disappointed by how few steampunk writers have made use of balloons in fiction. When Jules Verne wrote his first "Voyage Extraordinare" in 1863, it was Five Weeks in a Balloon, about an aerial expedition across Africa.
If you want daring action sequences, consider the use of balloons to carry messages and refugees out of Paris during the Franco-Prussian War of 1871 -- lifting off in the dark of night, flying at the mercy of the winds over enemy lines with the whole Prussian Army taking pot-shots, and trying to reach friendly territory before the lifting gas leaks away. That really happened. Parisians must have felt like they were living in a Verne novel.
Even today balloons still test the limits of human flight: just two months ago Felix Baumgartner set a world record for parachute jumping, leaping out of a balloon. Steampunk needs more balloons.
Next time: the first powered airships!
Comments