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Trackless Locomotive

Posted by zimirken 
Re: Trackless Locomotive
July 19, 2022 10:15AM
Your really making great progress!

I went back to re-read your notes on your engine. Your comment that it doesn't run for very long. This might be attributed to your short stroke relative to diameter. Then to have 2 cylinders to eat all that steam is something to think about. The rpm is high in order to produce the power. The negative is that it has a high water rate (steam rate). Not a bad thing and just something to be aware of. Your plans for forced circulation will generate steam to meet your demand...my opinion. Please prove me right.

After evaluating my 10 HP Stanley Engine, I lean more towards a longer stroke relative to cylinder diameter.

Your atmospheric steam test is great! I particularly appreciate the sight glass on the circulation line. smiling smiley It appears you're making good steam with your system and the centrifugal pump. Keep going with the separator drum.

I attached an example of a separator drum on a natural circulation system, Tony Grzyb. Hope this gives relative size and shape along with location to the heat source. I believe you have proven on another system that you can go smaller on the separator drum than what is pictured. You own the design, go with your instinct.


Re: Trackless Locomotive
December 21, 2023 02:24PM
I'm back into steam engines, although at a rather inconvenient time of year for things that are sensitive to freezing. As I'm getting older my hobby obsessions last longer, but I still tend to rotate every few months. In any case, I've got a few new ideas.

I last posted about the circulation coils and firebox for them that I made. Part of the reason I stalled out is because I just couldn't come up with a steam drum at the time. Well, tomorrow I'm going to look at and pick up one of these for $20:


They seem to be some sort of pressurized oil reservoirs. They have a big sight glass built in and they look like they're designed to take hydraulic system pressures. They also seem to have npt threads on both the top and the bottom. I'll finally get to ditch the sketchy aluminum water heater that doesn't have nearly enough heating surface.

Even if they don't work out, I found that a local steel mill sells 4" sch40 steel pipe for ~$25 a foot. If I have to, I'll buy some of that and machine flanges held on with tie rods like a tie rod hydraulic cylinder. I still have my CNC at work, and we just upgraded it with the ability to broach internal keyways, so no more pinch collars for shafts!

Next, I never liked that I ended up putting a janky displacement lubricator on my engine made out of threaded pipe fittings. I recently read about one person's unique method of lubricating their scale locomotive. They have a cylinder with a piston and rod coming out, like a regular pneumatic cylinder. The back of the cylinder is connected to the steam line of the engine, and the front of the cylinder is also connected to the steam line through a needle valve. The front cylinder is also connected to some sort of valved opening that allows you to fill the front part of the cylinder with oil.

With this system, when pressure is applied to the engine, the cylinder will slowly be pressed forward due to the surface area difference from the piston rod sticking out. This will slowly push oil through the needle valve and into the steam line. The needle valve controls how fast the oil exits the cylinder, and the piston rod serves as a visual indicator of how much oil is left. When there's no pressure going to the engine, there's no oil flowing either. The best part is that this also works with compressed air, unlike a displacement lubricator. If you wanted to get fancy, you could add a sensor to detect near empty even. I plan on experimenting with this idea later.

Finally, the last modification I want to do is switch from the soft rubber pneumatic tires to thin hard tires (like push mower wheels but a bit bigger). This should reduce a good bit of horsepower required to move around. I'll likely end up rebuilding my locomotive to both accommodate the new boiler, and new wheels. Luckily it's just a simple wooden frame.

At some point I want to try to build a steam powered circulation pump to see if I could reduce the running electrical demand. But that's farther in the future.
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20220312_093658.jpg 628.3 KB open | download zimirken 03/16/2022 Read message
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DSC_0014.JPG 362.9 KB open | download Rolly 04/02/2022 Read message
My new Code boiler-2.jpg 35.3 KB open | download Rolly 04/02/2022 Read message
LED gauge.jpg 39.6 KB open | download Rolly 04/02/2022 Read message
water level gauge face.JPG 842.8 KB open | download Rolly 04/02/2022 Read message
Valve Simulation2.pdf 304.9 KB open | download Rick.H 06/29/2022 Read message
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pump.JPG 294.3 KB open | download Rolly 06/30/2022 Read message
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Image (4) reduce.jpg 957.1 KB open | download Rick.H 07/10/2022 Read message
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