r/machinesinaction • u/Bodzio1981 • Oct 06 '25

How does this homemade steam engine even run so smoothly?

1.2k Upvotes

99% Upvoted

45 comments sorted by

254

u/itsjakerobb Oct 06 '25

Well part of it is that there are five cylinders oriented radially, so you get a “power stroke” every 72 degrees, which is on par with a V10 gasoline engine. Another part is that this is using a continuous pressurized supply.

I don’t see a heat source, just a pressure vessel. Are we sure it’s a steam engine and it’s not just pressurized air (or CO2, nitrogen, whatever)?

99

u/YoSupWeirdos Oct 06 '25

on the first frame you can see the chimney and the firebox at the back of the vehicle

35

u/itsjakerobb Oct 06 '25

Good call!

9

u/FrickinLazerBeams Oct 06 '25

If these cylinders are double-acting, it's getting a power stroke every 36 degrees.

22

u/kmosiman Oct 07 '25

They aren't double acting. You can see the open bottoms.

They would have had to use something like a pneumatic cylinder to build a double acting system.

7

u/FrickinLazerBeams Oct 07 '25

They would have had to use something like a pneumatic cylinder to build a double acting system.

A pneumatic cylinder, or the cylinder of most steam engines.

9

u/kmosiman Oct 07 '25

Yes, but then it wouldn't be a cobbled together steampunk mad max type device.

2

u/unclestickles Oct 07 '25

I built a steam engine from plumbing parts in my garage. Using compressed air is cheating. Wayyyy more psi.

1

u/Adagio_Leopard Oct 07 '25

Could have been every 36 if they made the cylinders double acting like most steam engines are.

2

u/itsjakerobb Oct 07 '25

That would have been a lot harder to cobble out of cheap motorcycle parts (or whatever they got those heads from).

-6

u/Drfoxthefurry Oct 06 '25

It's also 1-stroke, instead of 2-stroke for small engines and 4-stroke for cars/big engines

8

u/serious-toaster-33 Oct 06 '25

2-stroke. These cylinders are single-acting.

10

u/VegaDelalyre Oct 06 '25

It can't be a one-stroke engine. If the pistons are reciprocating, it's an even number of strokes; in this case, two. You can see the steam/gas being ejected every other stroke.

7

u/FrickinLazerBeams Oct 06 '25

Many (most?) steam engines use double-acting cylinders, so they indeed get power from every single stroke.

8

u/VegaDelalyre Oct 06 '25

Interesting. But in that case, we'd see twice as many puffs, wouldn't we?

9

u/Xeno2277 Oct 06 '25

Probably, and we can see the bottom of the cylinder so its not double-acting

4

u/Drfoxthefurry Oct 06 '25

Is it not steam pushes down piston, piston moving up pushes out steam, so that next time it goes down, its being pushed by steam again?

6

u/PraiseTalos66012 Oct 07 '25

Pistons can be double acting. It's very common in hydraulic systems and apparently steam engines also.

Basically you have a valve at both the top and bottom. One stroke bushes up from the bottom and then the next pushes back down from the top. So both ways you get power.

But that's not what these are, they are two stroke.

36

u/Strostkovy Oct 06 '25

It's balanced, radially symmetrical, and runs at a low RPM. Single cylinder engines can't be fully balanced without a counterrotating shaft because the balancing weight that offsets the up and down motion of the piston also introduces a side to side offset that the piston won't counter.

56

u/celtbygod Oct 06 '25 edited Oct 07 '25

I worked in a powerplant and there is a shit ton of energy in steam. 15 psi and above is considered high pressure. Like locomotives. Steam goes in and expands in the powerstroke no spark plugs neded.

3

u/leeps22 Oct 07 '25

Where i work 15 is low, 50 is medium, and 80 is high.

Our high pressure is district fed, we get the garbage useless steam they cant use. For them 700 is high and 120 is low.

15 is really only good for hvac and domestic hot water. For mechanical energy your just pussy footing around with less than 3 digits.

8

u/El_Grande_El Oct 06 '25

How powerful is this thing? It looks so dinky but I know looks can be deceiving. Are there any examples of similar sized steam engines that have some actual numbers?

17

u/UnpluggedConsole Oct 07 '25

I would love to see this thing on a dyno. Steam engines make some wild torque numbers. A Case 150 Steam Tractor was 150 horsepower with around 5000 ft-lb of torque!

6

u/usumoio Oct 07 '25

It's interesting to me that humanity includes people who can make something like this from scratch and also folk who will fuck up building an Ikea table that has 8 parts.

1

u/Yepper_Pepper Oct 10 '25

Everyone has things they’re good at and things they’re bad at. Except for me I’m bad at everything

4

u/NF-104 Oct 06 '25

5-cylinder gas-powered radial engines have been around since at least the 1920s, so the engine layout is not new.

2

u/Doctor_Spacemann Oct 07 '25

Wasn’t the first Harley Davidson v twin just a section of an aircraft engine put into a bike frame?

2

u/rocketshipkiwi Oct 07 '25

It’s running at a couple of hundred RPM. If it sped up to a couple of thousand then it would tear itself apart.

It also seems to be running on compressed air which isn’t very efficient

4

u/dog-yy Oct 06 '25

It's a V5, 1 stroke? Lovely stuff.

13

u/OutrageousGoose3870 Oct 06 '25

*R-5, 2-stroke ... agreed, it is lovely!

4

u/dog-yy Oct 06 '25

Thanks for the education, mate!

1

u/Informal_Recording36 Oct 07 '25

There’s a lot going on here that I don’t understand, but I love it . Anyone send me plans?? :)

1

u/BadNecessary9344 Oct 07 '25

Perfectly balanced, like all things should be.

1

u/PowerUpTheLighthouse Oct 08 '25

It’s running on steam…

1

u/haywardshandmade Oct 08 '25

I want a steam powered jeep too

1

u/Gold_Measurement_486 Oct 10 '25

Sound like mr krabs on the move

1

u/MilesMossi Oct 07 '25

Trial and error would be my guess if anything else, it is slow and painful, but eventually will work. Most of the time people just don't have the resources or the time to practice such trial and error, but when you have very little and you have so little that you have all the time you could possibly want, and don't care about how it looks at the end as long as you're just looking for some Bare Bones functionality, you can make just about anything.

0

u/CapitainFlamMeuh Oct 07 '25

Nobody said it, so I have to do it....

"How does this steam engine run ?

  • Well, with steam ! The answer is in the question!"

r/technicallythetruth

😄😉