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Design a steampunk airship

Airship diagram

Aimee needs help designing a steampunk airship. Any takers? (Roland?)

http://www.strangevehicles.com/content/item/102694.html

For story reasons too complicated to get into here, I'd like to have most or all of the living quarters down in a gondola suspended below the balloon. So more like the semirigid or nonrigid airships in the diagram above, although I'm not actually set on it not having a rigid frame.

The Hindenburg had capacity for 72 passengers and 40 crew members. It was 250 meters long and 40 meters in diameter and used hydrogen gas to stay afloat.

I'm thinking of using hydrogen gas in my story too despite (or perhaps because of) the fire Hydrogenase airshippotential. How big do you think my airship would have to be to need about 8 to 15 crew members while having capacity for about 15 passengers (hotel-like setting, not just seats) with an equal-sized cargo space?

I'd like to create the hydrogen in situ using Chlamydomonas reinhardtii algae, similar to Vincent Callebaut's dream, but built like a ship rather than a city. What kind of lightweight medium would you grow algae on in an airship setup?

Airship design
R34 Airship

Here are a couple of other diagrams that floated my boat. (Click on any image to find the source of the pretty pictures.) Now I'm ready for your ideas --- go!



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I wouldn't use hydrogen for a large dirigible like you're proposing. That would be too flammable as evidenced by the horrific destruction of the Hindenburg in 1937. (My mother recounted to me her hearing news reports of the disaster.)

I would use helium instead.

As far as Chlamydomonas reinhardtii algae is concerned, according to this abstract "The best producer of hydrogen is eukaryotes algae which contain the enzyme hydrogenase. The enzyme produces hydrogen as a waste product during metabolism. The goal of researchers working with algae is to take part of the enzyme which produces hydrogen and insert it into the plant’s photosynthesis framework, thereby coaxing the algae to produce significant amounts of hydrogen by-product." (From the International Journal of Hydrogen Energy found at: https://umexpert.um.edu.my/file/publication/00003241_82524.pdf) According to Wikipedia it's found in soil and water and I'm not sure how you would get enough soil and/or water on the ship to provide the necessary amount of hydrogen you would need to lift the ship off the ground. The Hindenberg had 7,062,000 cubic feet of hydrogen. That's a LOT of gas. (Maybe you can get a few politicians to be passengers? Their ramblings might give you enough gas! ha ha).

Just because you're writing a steampunk novel, doesn't mean that they didn't have technology that was as sophisticated as ours, it just went along a different path and I would think that they would've found a way to create enough helium for their needs. Even the Victorians had the ability to make helium.

Nevertheless, I am looking forward to seeing your novel. Will you be self-publishing or just doing fan fiction? BTW, I've betaed fan fiction.

Comment by Nayan Wed Jan 4 11:09:22 2017

I love the idea. :-)

For inspiration I know just the place: Girl Genius. Steampunk, airships, mad science. (Start at the first page and prepare to get severely distracted. :-) )

While airships seem primitive, they were actually state-of-the-art when they were introduced. The first Zeppelin, LZ1 (first flight 1900) had an aluminium frame long before this became common in airplanes. Airships pioneered lightweight engines, construction materials and techniques.

If you ever have the opportunity, a visit to the Zeppelin Museum in Friedrichshafen (Germany) is well worth it. In the museum you can walk through a partial full-scale replica of the Hindenburg. It's very impressive and looks modern even today. Mainly because almost everything is made out of aluminium.

And since you're filling your airship with flammable hydrogen, you might as well use flammable but lighter than aluminium magnesium alloys.

A very cool concept I seem to recall from a William Gibson novel was an airship “filled” with vacuum. That would give the best obtainable buoyancy. The trick is finding an enclosure that's light and doesn't implode!

But with a conventional airship, to carry 30 people and freight you're probably looking at something between (at least) an LZ-120 (710,000 cu ft) and LZ-126) (2,764,460 cu ft) depending on required cargo capacity and range. Blimps and semi-rigid airships are probably not big enough. And the internals of a rigid frame airship are a good setting for a story. I seem to recall an action/spy movie set in an airship.

But I very much doubt it could literally be steam-driven; steam engines require huge amount of water, and are also very heavy. German Zeppelins often used Maybach engines like this VL 2. It can produce 570 hp at a weight of 2,530 lb. That is 0.22 hp/lb. That's of course just the engine without a gondola and drivetrain. But even doubling the weight still gives around 0.11 hp/lb.

One of the most modern steam locomotives ever built, Tornado, weighs 105 long tons (235,200 lb) and produces 2000 kW (2681 hp). That's just 0.011 hp/lb. So the power/weight ratio of a steam engine is like a factor of ten worse than an internal combustion engine. And as an engineer, the idea of firing a steam engine under a huge bag of hydrogen gives me the willies!

If the airship is filled with hydrogen, it would be logical to use fuel cells to produce electricity to drive electric motors. Electric motors are very efficient, compact and can have very good power/weight ratios, up to 5 hp/lb.

From what I've seen, growing algae requires significant amount of water. That weight penalty probably makes it unpractical to generate hydrogen in-situ.

Of course since this is fiction you can mostly ignore technical realities when it suits you. :-)

Hope this helps!

Comment by Roland_Smith Wed Jan 4 14:25:16 2017
Roland --- That's extremely helpful! I'm not actually using any steam technology --- I just figured "steampunk" was a useful shorthand to send folks in the right mental direction. Instead, the idea is that technology stopped right about where it is now with various complicated restraints. So fuel cells and electric motors it is! Thanks for the leads...
Comment by anna Wed Jan 4 19:44:08 2017

"Of course since this is fiction you can mostly ignore technical realities when it suits you." Roland

No.No.No. NO!!! Science fiction is about SCIENCE and TECHNOLOGY which means you can't be making this stuff up! If you really wish to ignore technical realities it is not longer "science fiction" but fantasy. Nothing wrong with fantasy but please! Don't call it science fiction.

Comment by Nayan Wed Jan 4 21:09:44 2017
What about the films of Hiyao Miyasaki? Naausica especially has some wonderful ones, and Howl's Moving Castle too.
Comment by Monique Bourque Wed Jan 4 22:06:27 2017

(Is that a cool title or what? Dibs on the "weirdest comment title" award.)

@Anna: A zeppelin built with todays technology would almost certainly use carbon fiber composites for the frame and gondola because of its high streng/weight and stiffness/weight ratio. I'm not sure what to use for the gas bags. rip-stop nylon with a rubber or metalized coating?. Hydrogen being a very small molecule easily permeates through a lot of stuff.

I would think that the danger of a hydrogen filled airship could be reduced by filling the space between the gas bags and the outer shell with nitrogen instead of air; Hydrogen gas is only really dangerous in the presence of oxygen.

Further I would imagine that controls are servo-powered and partially automated (e.g. keeping trim, autopilot) etc.

The outside skin could consist of printed flexible solar cells to generate electricity when flying above the clouds.

@Nayan: A lot of good science fiction ignores technical realities in the name of "wouldn't it be cool if...". For example, the accelleration in the cannon used in Jules Vernes' From the eath to the moon (approx. 3,000 g's) would be well above survivable limits to put it mildly. And Larry Niven's Ringworld contains several concepts that are probably not possible given our current knowledge; scrith, General Products hulls, boosterspice and hyperdrive to name a few. Still, I would not qualify those as fantasy.

Comment by Roland_Smith Thu Jan 5 14:12:15 2017