Tag: dirigible

Foreword:

Every once in a while, an artist is asked about their works, and often times, especially when dealing with a sci-fi genre, practicality and physics both come into question.

It is often worst for sci-fi and comic book authors and artists, wherein they defend paradoxes, quantum physics abnormalities, and continuity errors to “that guy”… you know, the guy with the pony tail, pizza stains on his intended-to-be-ironic Captain Planet underoos shirt, stretched to the very boundaries of physics itself… distracting in its apparent potential to succumb to the forces within… That guy keeps me from buying comics in an actual comic book store.

With the steampunk crowd however, one always has time at these events to consider that the person in question… though some may take fantastical art perhaps a bit too seriously, may be in a related profession – and quite likely, knows *something* and maybe even a lot, about what they are talking about.

I tend to say very little when out and about, because I feel I am at peak social adeptness, when I simply listen and nod. In public, I cannot hit *UNDO! UNDO!*, though the phrase often repeats in my mind… and therefore I often think I must disappoint people who meet me, people who probably expect me to be much more outspoken than I am.

It isn’t that I have nothing to say, actually quite the opposite: My opinions and thoughts on any issue are from so many possible angles and dependent on so many possible variables, that were I to chime in with my thoughts on most anything I would need to monopolize the questioners time for hours, perhaps even days – and there would still be a myriad of aspects I never managed to touch upon. My world is not black and white, but eleventy-billion shades of a million hues and and all the greys between.

And, I actually cannot wind down after any meeting with humans, until I have played back every last conversation I took part in word for word in my head a few times over, paranoid that I might have accidentally offended someone, snubbed someone, or just gave some plain out stupid answer instead of what I knew, because the info was buried below 1000 feet of social phobia or because I was cut off before I had a chance to fully expand upon what I was saying… So, in this I have learned to 1) Stick to the basics: “Hello”, “Goodbye”, “What knife?”  2) Don’t assert any degree of expertise at anything if you can help it… especially at conventions. This may be one of many reasons I avoid panels like the plague. So, consider this to be the closest I may ever get to actually holding a panel on anything.

Let me just say that I do every project, any project with a great amount of consideration for the function of my designs; I tend to lend some great deal of time to mapping out construction methods foremost… where beams will intercept with beams, where crankshafts will need to go, weight placement of boilers and other heavy objects, the perceived strength of sails and of lines, how one would get from point a to point b (and other ergonomic factors), and of course how everything is put together. With creatures I build muscle and flesh onto skeletons, and cross-reference lighting in models I create in 3-d on my lab computer. With buildings and contraptions, I merely break out the drafting skills, building solid structures onto a maze of thinly-lined beams and mechanical parts which will never even be seen.

I also take into great consideration things like “Will it work well?” or at least “Is it even possible?”. I am actually, often, quite neurotic about these sorts of things.

On the Practicality of Scale Models and Scale Comparisons:

In the case of airships and physics, I first took to looking at larger objects, such as the Hindenburg for example, it amazed me just *how little* space within that big balloon up top was actually used for lighter-than-air gas, and *how much* was used for passageways, maintenance space, equipment, and metal support structure.

By these things alone, looking at the designs I was making, with no metal supports or storage space within their bags, and tiny boiler/engine size offset by sails to aid in propulsion and steering, I figured I was doing pretty good… very good.

Looking at the scale of a large thing, vs. the scale of a smaller thing was something I was however somewhat unsure of. It seemed to me that scale models would be unreliable; Much like gravity not being scalable: it would also be difficult to scale atmospheric pressure, and especially hard to scale the density of the molecules within the pocket of gas or density of the materials themselves… though much about buoyancy seems to be simply a matter of comparison to the internal and external density.

All of this made me think “I’d better look for some numbers and waste an insane amount of time on things people won’t really care about”.

So, I went a step (or a hundred) further… I did a lot of numbers crunching, hoping to be somewhere in the safe zone for my preferred designs, and hoping that my perception  and memory of what was done in history was not mostly colored by images from “Baron Munchausen” and other fantastical works which could possibly have mixed with historical footage in my mind.

I am not going to pretend for a moment that I am infallible, or that I have taken every factor into consideration. Actually I know I haven’t – minor things such as the weight of ballast… which is pretty darned important if you need to dodge an oncoming building or mountaintop.

I have however found that in my results, there was plenty of room for ballast and the weight of the bag (another thing I left out), with even more wiggle room possible if steps were taken to lighten the gondola in construction, in men, or in equipment.

I am not a scientist – I am an engineer, a tinkerer: Much like I routinely do with computer and internet languages and software — I tend unlearn and re-learn quickly as needed for any project; Though I am great at figuring out what I’ll need to know, researching it, and using the new and temporary knowledge to achieve an outcome – there is always the possibility that I have missed some crucial condition along the way. Typically though, I figure my through things by real-world experience, rethinking and re-researching should something blow up (or fail to blow up). Without a MythBusters-sized budget, everything for me on this subject is going to have to come down to calculations which may look better on paper than in actual wood and fabric.

So…Can it Fly?

My chosen gas: Though Hydrogen of course is the lighter of the two reasonable possibilities, I decided to go with Helium at about 9.8 Newtons of lift: the force to lift 1 kg per cubic meter of gas at room temperature and sea level pressure. Helium because, I really do not want to bother with the debate over the safety of Hydrogen when it comes to a hypothetical model. Really, it is a bit ridiculous that I go this far at all – being a painter of fantasy and all.

So, starting at sea level atmospheric pressure, at room temperature, 1kg per cubic meter is my ratio. It really should be nearly 1.1 – but since this is about possibilities, I decided to give myself numerical disadvantages wherever I needed to round a number.

Given that the gondolas I use are about the shape and build of a viking long-ship, let’s go overboard and use the heavy 70-man Viking Gokstad… a huge 76′ 5″ x 17′ ship (23×5 meters)

The Airship Bag, comparing ship to bag in my preferred look, would be an Ellipsoid: 36 meters by 20 meters by 20 meters, or 4/3 * pi * 14400, or 60,319 cubic meters. [edit – HUGELY Important edit paragraph below image]

This would go for most of my paintings anyway; In my painting of “The Rescue” (below), the ship part is a bit larger compared to the bag. This was not a lack of foresight on Abney Park’s part – I actually made the gondola a bit bigger than their design in my painting… a case of aesthetics trumping physics for the sake of fantasy.

But given my standard proportions,  a 36x20x20 bag would be enough bag, or more importantly enough gas to lift 60,319 kg , or 132,981 pounds (over 65 tons) at an air pressure of 29.9 Hg. [see below]

[HUGELY Important edit:] I was thinking today that with all the other numbers being right, the one number bugging me was the volume… and for very good reason: I accidentally used diameter instead of radius. 7520 would be the actual volume of the bag a far cry from 60,319 … which shoots the following pages of content and calculations down completely. The bag should be at least thrice as long as the boat, and almost twice as wide as the boat is long. My mistake does however give me a good proportion for future builds. I.E., even giving the actual 1.1kg instead of the easy 1kg lift per cu meter, I would still need a 73x38x38 meter bag to lift the 23×5 meter boat. Something I will have to keep in mind for future designs – lighter gondola builds, smaller gondolas, bigger bags… Anyway… Read the below as if the bag were this new size of 73x38x38.]

So… Could it carry something the approximate size and weight of a viking longship?

Ship Weight:

The huge and heavy Gokstad ship was made of 6150 kg of oak, 880 kg of spruce and 225 kg of pine.
The ships planks were fastened with 150 kg of iron rivets, the anchor weighed 100 kg and the sail and rigging weighed 1000 kg.

So, the weight of the Gokstad is about 8505 kg total weight, without equipment, men, and rations. Looking good so far.

Crew and Equipment:

Now, let’s outfit it like a viking ship… because sky vikings are scary and awesome. Add 70 men at about 80 kg each (5600kg). Let’s give them 400 kg of equipment and melee weapons, 1000 kg of food, 1500 kg of water and 1000kg of miscellaneous cargo (3900kg total) … just in case they go 2 weeks without spotting land. We could cary a lot less than this if we touch down to hunt, gather, melt show, or drink from streams.

18005 kg. ship, men, and cargo… already, if we eventually want cannons on this thing, I am going to have to trim down the number of men, and lower the equipment rations. I can also trim down weight by using lighter wood, less of it, and using wood doweling in place of iron spikes… but for now, and because I don’t really have figures on lighter woods or lighter construction, let’s go with the tough route and keep this number.

Propulsion, Steering,  and Rigging:

I’ll make 3 times the amount of sails and rigging needed for rigging an ocean-bound ship, since I seem to like sails, and there is a big bag in the way of the wind, and we need steerable sails on all sides for control. (add 2000 kg)

Boiler/Engine: about 825kg for a small boiler with enough energy for the engine with enough energy for the props, going at a small ships steam engine capable of producing 125 horsepower. Not a primitive and heavy design like the Side Lever, but not advanced and light like the Direct Action… Not as tall and awkward as the Walking Beam, or even the Steeple, still towards the more primitive end, like a Siamese.

Differentials/shaft/exchange machinery + Props: about 354 kg.

Fuel: For a 2 week trip (336 hours), averaging 75 horsepower, at 2.5 pounds of coal per horsepower per hour, about 63,000 pounds (28576kg)…it is looking like fuel is going to be the big killer for any long trips, no matter the size or the cargo, or horsepower. Really, I think I went a little overkill on the horsepower, so it’ll likely be both.

24784 total weight + 28576 fuel

53,360 total weight to a 60,319 kg lift factor… Wonderful!

… or… wait…

… we are only at sea level so far…

I guess we are fine if we want to just skim the surface of the water at low tide for 2 weeks in a nice temperate zone.

Above Sea Level:

“Gross lift DECREASES as pressure decreases but it INCREASES as temperature decreases. Thus, as a gas balloon rises in the atmosphere, the decreasing pressure and temperature oppose each other. The decreasing temperature increases lift while the decreasing pressure decreases lift. Atmospheric pressure changes are more significant than temperature changes. Overall, lift decreases as altitude increases.” (http://www.gasballooning.net/Physics%20of%20Lifting%20Gases.htm)

I suppose with my love for cold mountain ranges and antarctic climates in paintings, I am actually better off with the cold environment, doubly so if the temperature within the bag is regulated. Therefore, I am not going to worry too much about temperature, and my primary concern is altitude:

To make things harder, let’s go about 5,000 feet above sea level… which is a pretty good amount if we are traveling between coastal towns, to and from islands, across the ocean, etc… actually, it could get us around anyplace East of the Dakotas as long as we stay away from the Appalachian Mountains or somehow chart between the higher points (I haven’t tried mapping this out, there may not be any passage lower than 5,000 feet through the eastern range for all i know… but I am pretty sure there should be).

72ºF+459 brings our temperature to the Rankine temperature of 531 degrees… this is really a bit pointless to do, because I am going to use a constant and equal temperature. This takes away the advantage of a lowering temperature, or traveling into a lower temperature, and leaves it as a constant (531/531=1), wherein the temperature within the bag is the same as that outside of the bag, and the 531/531 (1) is left there as a bookmark.

So, for 5,000 feet above sea level, the pressure is now 25Hg. This comes out to: 60319*1*(531/531)*(25.00/29.92) = 60319*0.83556149732620320855614973262032 kg = 50400.234 kg

50400.234 kg… less lift than we need, but only by about 3,000 kg. So, we reduce the crew and rations by half. Done; And with 1800 kg left over… we have plenty to spare.

But What if I Don’t Want to Hang Around the Midwest?

A good point. Really, who would? Most of the big Steampunk happenings are on the West or East coast. It would be a shame if we couldn’t get there.

So, if we wanted to get over the tip of the Rockies, we need to calculate for 15,000 feet above sea level (pressure of 17Hg): 60319*1*(531/531)*(17.00/29.92) = 60319*0.568181 kg = 34,272.1591 kg

53,360 kg, but only 34,272.1591 of lift.. not so good. This again is for the full crew of 70 vikings though.

Almost a 20,000 kg difference – one would need to drop half the fuel, and again drop half the crew… 70 men are however only needed if they are sky-vikings, but for explorers… it probably ony takes 5 men to run this sort of ship – and 15 is actually pretty good if you want workers, soldiers, cooks, or passengers in there. As long as it takes less than a week to get across the Rockies – you’re doing okay. And, since a lot of that range is actually 7,000 feet in the foothills to 11,000 through the mountains – you could probably get by on 2/3rds fuel – giving you about 10 days to make it to Californy-i-a.

Conclusion: Sorry sky-vikings, you have to stick to the coast or the Midwest if you want to use your airship. Everyone else is good to go though.

Cannons? Combat? Weapons?:

Oh! I almost forgot:

I know I have painted cannons into mine. I like them. They go boom. We like the ships what go boom… but it isn’t entirely practical.

If you want cannons, well, I’d recommend cannons that are not going to rip your ship apart with the force of their firing.

16 lb cannons would weigh over 1000kg each with a small amount of ammunition, but more importantly, I wouldn’t want to fire one from a suspended ship anymore than I would want to sit on a rope swing firing a bazooka. Okay.. actually that sounds like a fun experiment… but I am not normal.

Also to be considered: You need 2 men (or more) per cannon… fuses, gunpowder, cannonballs, cleaning and re-positioning… it is intensive work, especially on a swaying ship. More men, more weight.

More importantly, what would you be firing at? If anything is below you, gravity already gives you a great advantage, the same goes for explosives. You could just drop bricks, or cows, or savage chickens if you are feeling really mean; It makes more sense though to just drop bombs – more damage, less weight in the hold. Oh.. and stay out of range of their guns. Use a telescope/periscope to see what you are aiming for, because unless your target is very big – if you can see it, you are already too close.

If you are wanting to defend yourself against things that fly, well, I’d recommend something with a great amount of range, and a rapid fire rate. 50mm is about as big as I would bother going with cannons, which makes them “guns”, or if you are smart – go with a rifled barrel instead.

For the most part, I would not want to get into a scuff with anything that had a chance of hitting me, and would not recommend fighting with anything from an Airship if your weapons aren’t better range weapons than theirs. The most important thing about Airship combat: Don’t do it if it can be avoided. When that fails, airship to airship combat is a job for rockets, sharpshooters, and otherwise: an unholy rain of bullets. I think Cherie priest had it right with the use of Gatling guns… highly advantageous, especially if you are not sure who is the better shot (or who has the better luck).

The likelihood of “them” sending an airship at you, without having some great advantage: slim to none. Expect to defend yourself against faster, better armored, more maneuverable craft – perhaps metal-shelled vacuum airships (highly unlikely), or even steam-powered planes (also unlikely)… but what of lighter-than-air mines? rockets? perhaps even rocket-lifted gliders? I just thought these things up, and chances are that “they” are thinking even harder… so keep that Gatling gun handy… and steer clear of “them” whenever possible. If you can, leave the fighting to the steam tanks, gun trains, ground forces.

A Visual Comparison:

Conclusion:

It seems, in this case, steampunk aesthetics can often rely on a heavily fantasy-driven model. The more realistic I go in design, the less fantastical they are, and the closer to actual existing constructs the look will become – on into dieselpunk, and on further into actual historical or modern-day models.

A lot of times in art, aesthetics take precedence over function. When it all comes down, it is the look of the piece that draws the viewer in, and how good it will look on a wall is what matters to most art buyers – it is the difference between being a concept artist or an architect, and an actual fine artist.

I hope you enjoyed the rundown and the walk-through, and thank you for reading.

Please take the time to look through my store or my gallery if any of these images interested you (or if they didn’t… I have a lot more than just airships in my collection, and a lot more airships than just these shown)