Power for model steam engine..

[The Artful Bodger]

Obviously I am intrigued by Brian's model of the 'Rocket' and have been considering how a supply of pressurised gas could be had to move such a model.

So how about this idea? Make a pressure vessel suitable size for the job, fit it with a reliable safety valve and a regulated output for the model. Pop some dry ice in and watch the fun!

NOTE: I did say a reliable safety release.

[RB211]

What's wrong with a boiler and water?

[The Artful Bodger]

I found an example !!

https://youtu.be/yw53O0gdBH8

[David Powell]

There is nothing that compares with the challenge, and satisfaction, of designing, building, driving, repairing, or completing live steam preferably coal fired models. I have been in the hobby since 1963.
I have a house full of models, a workshop arranged specifically to serve this hobby, a lot of good friends and a lifetime of memories.
What more could a fellow want?
Regards David Powell.

[J Tiers]

Obviously I am intrigued by Brian's model of the 'Rocket' and have been considering how a supply of pressurised gas could be had to move such a model.

So how about this idea? Make a pressure vessel suitable size for the job, fit it with a reliable safety valve and a regulated output for the model. Pop some dry ice in and watch the fun!

NOTE: I did say a reliable safety release.

It has a history, as an idea.

My father had things powered that way when he was a kid. The "boiler" was just an aluminum bottle with a screw top and an outlet tube for a rubber hose. There was a relief valve in it, nothing fancy, not nearly as complicated as a boiler relief valve. I remember it being around the house and asking about it when I was small.

I believe his powered a boat model, which I never saw, and possibly something else as well, which I do not recall.

[Ringo]

what about 12gram CO2 cartridge? the ones for BB guns

https://www.midwayusa.com/product/1375632954

https://www.walmart.com/ip/Crosman-1...idges/19426365

[rwilliams]

Hi,

Take a look at compressed air mine locomotives, for example.

https://www.youtube.com/watch?v=vzGS4j1YQPs

Bob

[aostling]

I found an example !!

https://youtu.be/yw53O0gdBH8

That is cool, in both senses of the word!

[old mart]

It is common for builders of steam models to carry out early testing using their shop compressed air. Be careful of exotic gas sources as some are corrosive.

[mklotz]

It is common for builders of steam models to carry out early testing using their shop compressed air. Be careful of exotic gas sources as some are corrosive.

For small engines, an airbrush compressor makes a small, light, convenient substitute for a boiler.

[BCRider]

Further to the idea of the 12gm CO2 there are other larger tanks for CO2 used by paintball players.

Downside to the 12gm and paintball CO2 sources is the very nigh pressure. You'd want a regulator as part of the makeup otherwise you're feeding many hundreds of PSI to your "steam" engine where in fact you only want a few psi for most models. Well, either a regulator or a very fine adjusting needle valve to dole out the gas at a suitable rate and allow the engine to self regulate. But just don't stall or block the flow or the downstream pressure will go up rapidly.

The dry ice idea works because it gases off slowly and provided the pressure is not held back will pretty well self regulate by running the engine faster to where the pressure to supply volume evens out. The Lego engine is a good example of this. As the dry ice cooled off the air in the plastic bottle the sublimation rate slowed down and the engine slowed to a crawl. Mind you there again if the engine is blocked from flowing the gas again there is a potential over pressure possible. And that's where a safety valve would be needed.

So all in all a pretty slick idea. Just not sure it isn't more of a PITA to pick up and store dry ice as your "fuel". I'd think it's easier to just go with a compressed air source or steam.

[Dan Dubeau]

Anybody ever repurpose a cappuccino machine? We were given one years ago, and it's basically a little sealed boiler that forces steam through the a small cup full of coffee grinds. Would be pretty easy to replace the diecast cup with a plate and fitting for a tube. I have no idea if it would even work. Wouldn't run for very long, but could possibly power a small engine?

[loose nut]

Look up boiler less steam engines. These had a pressure vessel, in place of the boiler, to hold a steam "charge" and would be filled of off a stationary boiler. Used in areas that didn't allow open flame or sources of ignition. Same idea for compressed air.

[PStechPaul]

I have seen some articles about using a microwave magnetron to vaporize small quantities of water into steam to power an engine. Of course you would need a source of electrical power for the magnetron, so this would just be a novel electric motor that does not use magnetism to produce mechanical energy. There are some claims that such an arrangement can be connected to an alternator and thus be self-powered, but I would challenge that assertion. The only way I could see such a system produce net output power only from water would be if a tiny bit of fusion would be produced on the deuterium or tritium in the water. Nevertheless, it seems like an interesting project.

http://amasci.com/freenrg/magputt.html

https://arstechnica.com/science/2020/05/microwave-thruster-makes-for-clean-burning-jet/

https://www.physicsforums.com/threads/steam-generation-with-microwaves.371527/

I do wonder if perhaps an engine could be made where a small amount of water could be injected into a cylinder which has a hot electrical heating element, so the water would be quickly vaporized to produce a charge of steam for power. Again, this would just be a novelty, as it would be necessary to provide electric power to the heater, and a simple electric motor would be much more efficient. Perhaps the hot element could be heated directly from burning fuel or an exothermic chemical reaction. Maybe even heat from a thermonuclear source?

[old mart]

I'm pretty sure that "flash" boilers were used for steam powered vehicles which injected a high pressure spray of water onto a heated area to give instant steam pressure without having to wait for large quantities of water to come to the boil.