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Author here. The beam engine created power from steam, and was a key part of the early Industrial Revolution. The article is a deep dive into the engine: how it works, the history behind it, and the engineering tradeoffs the builders faced. There are quite a few interactive figures that I hope make the concepts easier to see.
This reminds me a lot of the articles at: https://ciechanow.ski/archives/

Not just in terms of presentation, but also quality.

Amazing!

I know right, I clicked on it and thought Bartosz got a new website.
anyone knows what Bartosz is working on these days? miss reading his articles.
Excellent work, glinscott. Thank you for sharing! I am about to send this to all my pals who are parents to schoolkids (um, and also pals who are still, like me, basically a schoolkid :p XD).

Building things up from first principles, and ideally also tactile / visceral examples, is my absolute favourite genre of explanations. Alas, a rarefied genre, because it is so much harder to do well (without doing disservice to the learner's intellect and ability) than expert talking to (presumed) expert. So thanks for contributing to it.

People like George Polya [0], Richard Feynman [1], Grace Hopper [2] are exemplars of this tradition.

[0] https://www.youtube.com/watch?v=h0gbw-Ur_do

[1] https://www.youtube.com/watch?v=EKWGGDXe5MA

[2] https://www.youtube.com/watch?v=ZR0ujwlvbkQ

(And I too try in my own meagre way through my blog and source code, albeit it's all plain text because visual explainers, animated ones that too are ridiculously difficult. So I have some idea of how much of a labour of love your piece is. <Claps hands, Whistles, Doffs hat>.)

Despite all the details, you still left out a lot. Safety valve, pressure gauge(s), regulation of the water pump, water level gauge for the boiler, lubrication (you only have two of the glass/metal can reservoir types for the main axle), and then maybe also the valve gear (the control mechanism for the valves which takes into account where in the cycle the machine is and maybe also how fast it is going, how fast it should be going, and in which direction). And a way to drain water from the bottom of the cylinder + maybe a way to make the steam as dry as possible.

And each of those could be expanded to much more than the page you already made.

Things are almost always a lot more complicated than they seem. It seems so simple -- "water + heat makes steam, steam pushes piston, back and forth motion makes rotary motion" -- but it is really anything but.

> This push on every wall is pressure, and we will measure it in atmospheres, multiples of the ordinary pressure of the air around us.

No, don't do that. Because the pressure of the atmosphere isn't constant. It varies with weather and how high you are.

Instead use Pascal (Pa) or Hectopascal (hPA). I really pays back to use SI units for physical things. Suddenly you have formulas without weird constants, like 1 Pa = 1 N/m^2

It's a sad thing that new articles still propose units that are (since many, many years) outdated: the metric system is from 1793, the SI is from 1960.

BACK then people didn't knew better and used the varying atmosphere as base. But today ?!?!?

I don't have much to contribute to the conversation but I wanted to congratulate you on the work and thank you for sharing.

This is impressive work!

For those in London who want to see one of these in the flesh, as it were, there's one in Tottenham: https://www.mbeam.org/
There’s also the amazing Crossness, which does have occasional steaming days. And if you’re in Manchester the Museum of Science and Industry has a great collection of small and large engines which they run
Cool! If you're in New Zealand, there is a massive, two story Double Woolf beam engine at MOTAT museum in Auckland, along with an array of other steam driven engines that they run from time to time.
This is what finally made the idea behind Watt's condenser click for me.
First off, this is very cool, I love these kind of breakdowns from first principal.

This is sending me :)

> One cup of water becomes roughly 400 litres of steam, enough to fill two bathtubs

Three units of measurement in one sentence, my favorite unit is bathtubs.

Ever hear the phrase "Balls out" when referring to pushing something to the max? Comes form the balls of the centrifugal engine governor. At maximum speed the balls extended all the way outward giving us the term "Running balls out."

https://en.wikipedia.org/wiki/Centrifugal_governor

edit: I once said this phrase at a work meeting and someone objected to my use of a crude term which I then explained much to everyone's surprise. They thought it had something to do with testicles.

Quinn (Blondihacks) on youtube is a model engineer machinist and has, IMO, the most outsider-watchable content on building boilers and steam engines like this.

Highly recommend this primer titled "The Model Engineering Learning Curve" https://www.youtube.com/watch?v=Ps_BQJEMnGA

She's been building a model locomotive for years now, there are over 100 videos: https://www.youtube.com/watch?list=PLY67-4BrEae-xhrvZX33gPk4...

One more: a little engine I'd never encountered before called a wobbler is, apparently, the hello world of machining model engines: https://www.youtube.com/watch?v=HrHDrIms7-0

Wow, that Blondiehacks video opened my eyes to a whole unknown world. Thanks!
One of the unexpected pleasures of having a 3 year old has been learning far more than I ever planned to about steam locomotives. It turns out steam engineering is fascinating, this article emphasized it for me even more. It really amazes me how much ingenuity there is in just connecting the right shapes and joints up so that the right thing happens at the right time, creating perfect cycles, regulators, etc. Seeing it explained in an iterative way like this is fantastic because you can understand what problem is solved by each part. I would love to see a piece like this strictly about locomotives.
High performance "modern" steam engines are fascinating, they're not necessarily simpler than their internal combustion successors, just different. Monotube boilers create superheated steam that pushes 1200°F, which is right around the same temperature as the exhaust gasses in truck's diesel engine pulling a large hill at maximum power. Hot enough to melt aluminum save for the presence of oil jets to cool the piston and a jacket of cooling water surrounding the cylinder. However, since there's no combustion happening in the cylinder of a steam engine, you don't have any cooling water surrounding it--that would be totally counterproductive. So steam engines operate in a thermal regime that is far more extreme than internal combustion engines. Consequently, bores are often cut slightly tapered to account for the temperature gradient across the stroke, in a double acting engine the cylinder bore has a slight hourglass shape, otherwise the thermal expansion would cause the piston to bind at the ends.

For a fun rabbit hole to dive down, check out Doble steam car technology or the Besler airplane engine.

One of my treasured toys - probably from a few years older than your 3 year old though - was a rocking cylinder steam engine my father gave me. It was a present from his father as part of a steam powered boat they built together probably in the late 1940s.

Something similar to this: https://en.wikipedia.org/wiki/Oscillating_cylinder_steam_eng...

And you can still get them reasonably inexpensively: https://www.aliexpress.com/item/1005007964198565.html

I bought one for a friend's 5 year old a while back and became BEST UNCLE EVER!

The run well on compressed air (like an electric car tyre inflator or small air compressor), or for a bit more high temperature danger they run great attached to the steam wand of an espresso machine. When I was a kid dad built me a steam boiler out of a steal aerosol can and some copper tubing with a folded brass sheetmetal alcohol burner. That's not a 5 year old friendly thing though, from memory I'd have been maybe 10 or 12 when he started letting my light alcohol on fire in that garage or backyard. (Modern parenting may disapprove...)

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Love this article!

One nit: All three animations that show the governor and the flywheel have the governor turning the wrong way, causing the gears that join them to do physically impossible things.

How did you do the figures? Iterative design with Three.js and an agent? What did that process look like?
Ancient Greeks had a steam engine. They called it a Hero's engine. They used it as a toy.

They couldn't use it as anything else than a toy. The reason they couldn't because they didn't have the metallurgy and the machining to create pistons, valves, etc.

There's an important lesson that can be applied to every technology, I think: technological progress is always iterated, never revolutionized. If your novelty - a programming language, a framework, a methodology, whatever - doesn't stand on the shoulders of the giants, then you have simply nothing to apply this novelty to.

> The reason they couldn't because they didn't have the metallurgy and the machining to create pistons, valves, etc.

It was a turbine. You don’t use pistons in a turbine. They lacked knowledge of turbine blades, the metallurgy to make pressure vessels, and the tools to make parts with the tolerances needed to spin at high RPM and withstand high temperatures.

Nice replacement since B Ciechanowski joined OpenAI, we don't get those high quality articles anymore.
Ha. The title lead me to believe this was about Erlang. But this is great too.
Yes, I also got briefly very confused about the top comment.
The first steam engines were vacuum engines, fill a cylinder full of steam and as it condenses it sucks the piston down, Watt's improvement and patent was on a separated condenser unit so you did not have to reheat the whole cylinder each time. This doubled the efficiency, that is, reduced the amount of coal you had to burn by half. But Watt would not sell manufacturing rights to his patent he sold operating licenses, If you had an engine that utilized Watts patent idea you owed him half the price of the coal you did not have to burn by using it. Consequently there were a lot of "pirate" engines, the most common method of working around Watts patent was to claim that your condenser was integrated into(as opposed to separated from) the cylinder some how.
Yes, great details! Not sure if you've read it, but "Richard L. Hills, Power from Steam: A History of the Stationary Steam Engine (1989)." is a truly wonderful overview, that really digs deep into the business. It has many letters directly from Watt, including the problems they had getting these huge engines built (before any decent roads!).
why are you badly summarizing the post?

It wasn't a vacuum engine, as per post the water just cooled the cylinder. And it wasn't half of the coal, it was a third.

The interactive article is so good!

(Sorry I am pasting my old comment.)

Some Model Engineering related resources:

Engineering drawings of small model engines used in model aircraft making. These designs are intended for manufacturing and practical operation, rather than merely for display, and can be used to build fully functional engines.

https://www.modelengineeringwebsite.com/Beam_Engine_drawings...

https://modelengineeringwebsite.com/Classic_ME_beam_engine.h...

https://outerzone.co.uk/plans.asp?cat=Engines&Xcardsperpage=...

https://modelenginenews.org/midge/index.html

https://modelengineeringwebsite.com/Midget_gas_engine_1.html

https://www.adriansmodelaeroengines.com/catalog/product.php?...

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Whenever I see an explanation of an old technology, I don't wonder "How do that work" but rather "How did they even build this"

How did they make vacuum and be sure it was indeed a vacuum ?

How did they melted that metal alloy into the right shape ?

How did they built those precise mirrors ?

How many times did they fail before succeeding ?

How did they lubricate and seal properly all components ?

I know I could explain 80% of those inventions easily by studying them for a few days each. I know I would never be able to build 1% of those machines myself, I'd constantly run into technical issues and it'd take me years for each

If you enjoyed this and haven’t been, you need to plan a trip to Paris to spend a day at Musée des Arts et Métiers.
This is SO cool!

How do you make those animations?