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I need to limit the development of the internal combustion engine so that it is only available in small numbers to few individuals and does not progress technically, or at least only progresses slowly. I want something that can power a large airship, but perhaps only just.

The background is a world that supports human life but is not the Earth. There is roughly 1g gravity and plenty of water but little land. The atmosphere is very thick and the only populated areas are large plateau islands raised high up where the atmosphere is more bearable. The story will revolve around the development of airships in this world but I want them to be developed in small numbers by some eccentric rather than as a state based or wide spread option. The level of technology is roughly 1800’s but does not have to follow our time line (some things may be invented early other things being late if it can be justified).

Other details can be manipulated to suit. I thought that the internal combustion engine would be one of the key constraints for a working airship but bonus if anyone can suggest a better choke point to limit airships instead of the internal combustion engine.

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  • $\begingroup$ When you say "the atmosphere is thick" I can't help but think of pea-soup or possibly oobleck. I'm pretty sure that's not what you mean - and it might make quite a difference to the answer if you can clarify somewhat. $\endgroup$ Commented Aug 11, 2022 at 21:07
  • $\begingroup$ I imagine a very shallow sea or salt marsh covering most of the planet covered by the lowest part of the atmosphere which is very cloudy, misty and humid at a higher pressure than on Earth. Higher up on the island plateaus there will be less cloud and the air will be thinner - a lot like our atmosphere. However I have not totally clarified the situation so if it really helps feel free to tweek it a bit. $\endgroup$
    – Slarty
    Commented Aug 11, 2022 at 21:57
  • $\begingroup$ @Slarty I propose a banal idea, the area the eccentric came from just had more resources and/or was just more ahead technologically than the rest of the world in the first place. The area already had the surplus required to experiment when most parts of the world didn't. On a tangent , I will point out(feel compelled to)that basically all of technology corporations market today was either funded by government programs or collectively developed(github, etc), almost all of Netflix's code is open source for example. Corporations tend to be quite conservative when it comes to actually innovating. $\endgroup$ Commented Aug 11, 2022 at 22:35
  • $\begingroup$ @Broken ECLSS unit I suppose that would help, but I almost want to have this inventor be a little like captain Nemo with the Nautilus, good as that story was my problem with it was he had far too much technological development and needed to make too many break throughs to make it believable. I want the inventor to come up with something that allows him alone to make the airship workable. I thought the internal combustion engine piece might do the trick but I'm not sure. It needs to be something specific rather than there were just a few more resources here or there (although that might help). $\endgroup$
    – Slarty
    Commented Aug 11, 2022 at 22:53
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    $\begingroup$ Why internal combustion in the first place? External combustion has inherent limitations that would seem to fit your needs anyway. en.wikipedia.org/wiki/Henri_Giffard $\endgroup$ Commented Aug 13, 2022 at 21:29

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Limited/Unavailable Fossil Fuels

If this planet isn't like Earth and hasn't undergone it's own version of the carboniferous era there may be few if any fossil fuel reserves to depend on. In this case, fuel would be rare and expensive, either because there simply isn't much to go around, or because they're using biofuel instead, which they have to grow and process manually. If internal combustion engines were too expensive to operate for all but the wealthiest, this would also hamper research and development of the technology (limited interest) and increase the cost of the engines themselves (limited production, no economies of scale).

This could also impact cultural perceptions. ICEs might be looked upon as toys for the rich, an amusing but mostly useless dead-end technology. None of the great minds of the day would expect them to amount to anything, so they focus on technologies they consider more promising instead.

External combustion engines (steam engines, stirling engines) would also be held back but not to the same degree, since they can use any fuel that would burn, making them much more cost effective (they're also better suited to combined heat and power installations).

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  • $\begingroup$ Diesel ignition can run on vegetable or animal oils, but that gives its own set of supply restrictions -- "Why are fuel prices so high this year?" "The candlefish run was almost non-existent." Diesels, however (especially early low-tech ones) are heavy and likely underpowered, and take a long time to start (heating a glow pug with a torch). $\endgroup$
    – Zeiss Ikon
    Commented Aug 12, 2022 at 15:41
  • $\begingroup$ In addition, some animal and vegetable oils "gel" at low temperatures, like those you might encounter at high altitude. This is part of why biodiesel powered aircraft are still at the test-bed stage, even though their turbines would have little issue running on the fuel (turbines can run on virtually any flammable fluid). $\endgroup$ Commented Aug 13, 2022 at 1:02
  • $\begingroup$ Many ICEs can run or be modified to run on wood gas which can use wide array of combustible biomass. $\endgroup$
    – jpa
    Commented Aug 14, 2022 at 16:28
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    $\begingroup$ @ShawnO'Neil Generally, you'd expect piston engines to come before turbines, especially gas turbines. Materials that can take high RPM and concomitant G loads at high temperature are far more advanced than the cast iron needed to build an early-tech hot bulb semi-diesel. $\endgroup$
    – Zeiss Ikon
    Commented Aug 14, 2022 at 21:40
  • $\begingroup$ @ZeissIkon I wasn't trying to imply that they would use turbines in this fictional scenario, but rather pointing out that in the real world the gel point of biodiesel is a bigger hurdle to its implementation than getting an engine to burn it. $\endgroup$ Commented Aug 16, 2022 at 1:48
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Wind

/ if anyone can suggest a better choke point to limit airships/

You already did.

/The atmosphere is very thick /

The kinetic energy formula is 1/2mv2. If you have triple the atmospheric pressure, a given volume of atmosphere has triple the mass and so triple the energy. Wind on earth already packs a wallop! Combine that with the increased thermal mass of your massive atmosphere and you have serious weather which means serious wind.

Airships would be blown about. Now maybe kiteships could be a thing...

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  • $\begingroup$ Well +1 for mentioning kite ships. I like the idea, although that might have to form the basis of another question. The real issue is to allow a small scale eccentric inventor to develop the thing whilst limiting interest from governments and companies until much later. Also having invented it I don't want the technology getting rapidly developed into something much better quickly. $\endgroup$
    – Slarty
    Commented Aug 11, 2022 at 22:02
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Internal combustion engines do exist, but they're "atmospheric" engines that don't compress the fuel-air mixture before ignition, and are thus large, complicated contraptions with low power output. Available steam engines are similarly poorly suited to lighter than air aircraft.

Your eccentric has developed a multi-stroke, compressed charge cycle that delivers a consistent, controlled mix of fuel and air to the cylinder, and an electrical ignition system fast and reliable enough to match it. In the real world, this took Nikolaus Otto 14 years of development and collaboration with others, that almost didn't happen due to conflicts with Gottlieb Daimler, and spark ignition wasn't invented for most of a decade later. Your eccentric and his associates have just hit the combination of good ideas while avoiding the bad ones that put them a couple decades ahead of everyone else. This is entirely believable, considering how much time and effort people spent on dead end designs in real life.

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Material Availability

Iron ore and other metallic elements are heavy, and unlikely to be found on mountain tops where your people are. Mining ore also requires large areas for open pit mines and such, and mountaintop land is scarce and expensive. Maybe getting iron and nickel requires dangerous expeditions down into the deep atmosphere.

Fuel shouldn't be the issue, as you can build an internal combustion engine that burns hydrogen, natural gas, methane, alcohol, all kinds of stuff. But if you don't have enough critical materials it either limits how many engines you can make, or you have to use substandard materials that result in heavy, low output engines.

If you need lots of iron and steel in your society, pick another element unique to ICE engines, and make that scarce or lower quality. Copper, aluminum, magnesium, ceramics, gasket material like asbestos, whatever.

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  • $\begingroup$ if there is enough land to feed them on the mountain tops mines are easy. there many types of mining besides open pit mines. $\endgroup$
    – John
    Commented Aug 24, 2022 at 2:18
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I think the easiest way to constrain the internal combustion engine (ICE) is to limit how much fuel is available. If the quantity of fuel is in high demand and not readily available, the ICE would be curtailed. Wood can work to lift an airship by burning it to create hot air, but it becomes very difficult to use it within an internal combustion engine (there are ways, but it wouldn't be very easily done). By limiting what can be used inside the ICE, you've thus delayed the development/availability of it. It's more of a practicality reason than anything else.

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Make external combustion engines a lot better.

I mean, they're already pretty great! And also pretty much dominating the scene through most of the 1800s, so you might not really need to change that much at all.

On Earth, the first combustion engines were designed to use gunpowder. That might provide a good place to fork off into an alternate history -- either everyone just keeps running with that, or it scares everyone badly enough that they drop the idea.

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Perhaps your peoples' material science has not advanced far enough and the engines do not hold up well physically. Bearings don't last, castings crack, etc. Could fail catastrophically at a critical moment or simply wear out too soon, especially under heavy use.

This would also make the whole business more expensive. "Another new engine? !#@$!!! "

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Trade secrets. Technology is a jealously guarded secret. I suggest you find and read Deathworld 2 by Harry Harrison, where the protagonist has to survive on a low-technology world, and there are various countries who have secrets of technology. One knows how to extract oil from the ground and produce gasoline; another knows how to make steam-engine cars; another knows how to make electricity, etc. The cars have various tricks to make them harder to reverse-engineer.

https://en.wikipedia.org/wiki/Deathworld#Deathworld_2

Limited materials In our world we make engines out of iron; what if on this world metal is very hard to come by, and iron is just not available? You might have a technology mostly based on wood and fabrics, with a very small amount of metal. This wouldn't be ideal for airships.

Combining the two, suppose someone invents a way to make a ceramic engine and nobody else knows how it's done. They know what ceramic is but there are a few tricks they don't know.

P.S. It just makes sense that steam engines would be invented before internal combustion engines.

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No Blaugas

Airships already have a problem with internal combustion engines: As the liquid fuel gets burned, the airship gets lighter and tends to rise, requiring the valving of expensive lifting gas to keep the ship under control and in flying trim.

Historically, Zeppelins solved this expensive problem by using blau gas as a fuel, since it has about the same density as air.

This give you two sets of possible controls:

  • Make your lifting gas more expensive, thereby making the required valving so much more undesirable.

  • Keep approximately-air-density fuels unavailable or tremendously expensive. Perhaps your world's equivalent of Hermann Blau simply didn't think of it. Or maybe industrial accidents years before stopped development. Or maybe rival fuel firms influenced regulators to keep it unavailable. Or perhaps the fuel requires a particular imported additive to avoid poisoning the local sleet-frogs.

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  • $\begingroup$ An interesting point. Perhaps there is scope with gas in others ways as well. I had also considered some form of lifting gas contamination problem making airships almost unworkable followed by a secret discovery of a better way of making (discovered by the eccentric inventor) that enabled him alone to make airships well. $\endgroup$
    – Slarty
    Commented Aug 12, 2022 at 14:17
  • $\begingroup$ Blaugas is essentially a variant of the classic diesel and gasoline, it's just different fractions of petrol. I'd be pretty surprised if they could produce fuels but no blaugas. $\endgroup$
    – toolforger
    Commented Aug 12, 2022 at 17:46
  • $\begingroup$ @toolforger yes, which is why this answer also suggests ways to make it rare or undeveloped. $\endgroup$
    – user535733
    Commented Aug 12, 2022 at 18:49

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