Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines
The Regular Stuff: Chat, Buy, Sell, Off Topic, etc. => General Discussion - Model & Toy Steam Engines – Stirling Cycle – Flame Lickers – Small Antique Originals => Topic started by: Steamburns on April 22, 2025, 02:26:25 pm
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If you know of a better burner option for these HB's let me know. I know keith appleton uses blowtorch nozzles. I feel if I got the heat source better, it might be able to run it.
I am not really familiar with that boiler line, though suspect that specific model to be a bit small for that engine. In general, from an engineering standpoint you are looking at an approximate equation like:
Boiler water capacity
_____________________________ =/> Swept Cylinder Volume @ speed + System Steam/Temperature Volume Loss
Flue heating surface area x (BTU input - BTU system heat loss)
Or to say it in plain language:
(the Water Capacity of the boiler) divided by (the flue heating surface area) times (the BTU input minus the BTU system heat loss) must be equal to or greater than (the Swept Cylinder Volume at desired speed + Volume of System Steam/Temperature Loss)
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Here's something I've been thinking about for some time. Consider it an unproven idea but one which hold promise:
If you are good at machining curved aluminum, and don't mind a custom aesthetic to the outside of your boiler, I have seen where someone (Paula?) has made a curved block which wraps around the bottom of an Empire boiler. The block has a hole drilled in it to snugly mount an electric cartridge heater, and the block serves as the heat transfer mechanism.
This approach could be scaled up to size of your boiler, using more than one of these cartridge heaters made for household water heaters: https://www.amazon.com/DERNORD-Immersion-Cartridge-Heating-Replacement/dp/B074K98XR7?th=1
Please note these heaters come in 120 and 240 volts as needed and are 500 watts each.
Just an idea. Maybe you can find some inspiration in it.
Best of luck!
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Please do not think I'm being critical in a casual manor, but since you are asking for input, I will give a critic of what I see.
That boiler looks to me to be just a little bit undersize for a Stuart #9, as it appears that the cylinder is a significant fraction of the boiler's diameter, and that boiler isn't any too much longer than the cylinder either. That #9 is going to eat through one heck of a lot of steam with each stroke even if not under any load!
It appears that the inside of the cylinder is showing rather heavy machining marks from being bored, and I would think that a careful honing job would be very beneficial there.
Need I mention that all of that uninsulated steam line is a real efficiency killer, while at the same time having a governor in line might be cause of a further restriction unless really properly built and adjusted (ie: fully open) at zero throw-out?!?!
Possibly the exhaust is overly restricted using smallish piping from the cylinder's exhaust, through the oil separator and into the condenser/water tank and onto the exhaust vent from there.
I cannot judge the efficiency of the fire heating the boiler, but to get all you can out of that unit, it will need the most efficient heating you can manage.
Engine has no issue running, I got the entire engine smooth as butter and can rotate on just 5 psi, however within about 2 or 3 minutes, 75 PSI is completed depleted depending on how fast I run the engine. Even on a low idle, the steam depletes. The governor remains fully open unless I run it at balls out.
If you know of a better burner option for these HB's let me know. I know keith appleton uses blowtorch nozzles. I feel if I got the heat source better, it might be able to run it.
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Please do not think I'm being critical in a casual manor, but since you are asking for input, I will give a critic of what I see.
That boiler looks to me to be just a little bit undersize for a Stuart #9, as it appears that the cylinder is a significant fraction of the boiler's diameter, and that boiler isn't any too much longer than the cylinder either. That #9 is going to eat through one heck of a lot of steam with each stroke even if not under any load!
It appears that the inside of the cylinder is showing rather heavy machining marks from being bored, and I would think that a careful honing job would be very beneficial there.
Need I mention that all of that uninsulated steam line is a real efficiency killer, while at the same time having a governor in line might be cause of a further restriction unless really properly built and adjusted (ie: fully open) at zero throw-out?!?!
Possibly the exhaust is overly restricted using smallish piping from the cylinder's exhaust, through the oil separator and into the condenser/water tank and onto the exhaust vent from there.
I cannot judge the efficiency of the fire heating the boiler, but to get all you can out of that unit, it will need the most efficient heating you can manage.
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More progress updates:
Spent a ton of time on the No. 9 engine needing new gaskets. Unfortunately whomever machined this No. 9 did it in a wonky way.
A port screw on the point cylinder head goes through a steam inlet into the cylinder, thus leaking steam everywhere.
I fixed it through trial and error about 4 times until steam tight.
I also got all the binding freed up and put new cylinder piston rings in the cylinder as well as gland packing and figuring out the binding in the crankshaft. Many hours and weeks on that one.
Anyways, here is the current progress on this No. 9 plant.
One major issue I’m having is the HB4 boiler will get to 75psi and run out steam pretty fast with this engine. Not sure what’s going on.
With a bonus photo at the bottom of the machinists error.[attachimg=1][attachimg=2][attachimg=3]
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Spent 11 hours tonight on this… not nearly complete but have the basis done.
[attachimg=1][attachimg=2][attachimg=3]
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Well boy do I have a project on my hands!
Will keep you updated:
[attachimg=1][attachimg=2]
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Beautiful engine! Oak looks great! Good luck!
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The very beginning stages:
Oak plinth, stained & sealed.
Oak absorbs the stain very nicely! Looks lovely Jubbly ![attachimg=1][attachimg=2]
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Hi Folks!
I am starting another steam plant for Charlie over the coming weeks. This will include a Stuart No. 9 with a Stuart HB6 boiler & feed water pump, from Stuart. Not sure how long shipment is going to take on this one.
The 504 boiler does not provide enough steam to keep the No. 9 running very long, perhaps only 3-4 minutes.
It’s a behemoth of an engine. I performed its first steam test today, and will be repacking glands. Once I know more about dimensions of the boiler I’ll be ordering the wood and all the plumbing required.
Engine runs very well and is insanely powerful. This plant will feature some items from SPS, PMR, Stuart, and custom built items from myself.
Will keep you updated in this thread as they come along.
[attachimg=1][attachimg=2]
https://www.youtube.com/watch?v=SOl8yFtepOg