16-Cylinder Stirling Engine Gets a Tune Up

Tiny catapults, kinetic sculptures, a Newton’s Cradle — all kinds of nifty toys can adorn the desk of the executive in your life. On the high end of the scale, a 16-cylinder butane-powered Stirling engine makes a nice statement, but when it comes equipped with a propeller that looks ready for finger-chopping, some mods might be in order before bestowing the gift.

We don’t knock [JohnnyQ90] for buying a rotary Stirling engine from one of the usual sources rather than building, of course. With his micro Tesla turbine and various nitro-powered tools, he’s proven that he has the machining chops to scratch-build one of these engines. And it wasn’t just the digit dicing potential of the OEM engine that inspired him. There was a little too much slop in the bearings for his liking, so he machined a new bearing block and shaft extension. With a 3D-printed shroud, a small computer fan, and snappy brass nose cone, the engine started looking more like a small jet engine. And the addition of a pulley and a small generator gave the engine something interesting to do. What’s more, the increased airflow over the cold end of the engine boosted performance.

Need the basics of Stirling engines? Here’s a quick look at the 200-year history of these remarkable devices.

32 thoughts on “16-Cylinder Stirling Engine Gets a Tune Up

        1. I recall there used to be more information on the internet of USSR radio-isotope stations powered with gas filled, then due to leaking from lack of maintenance, air filled external combustion engines. Last time I checked I couldn’t find the links.

  1. I’m trying to find some of those butane tanks shown in the video. Does anyone have a source for them? I have one that I use but it’s starting to die and I’d really like a backup.

          1. Yeah, I’ve thought about using those but due to how mine is constructed, I’d have to cut something off and to me that screams of weakening the cylinder.

  2. I wonder if with some modifications to lighten it as much as practical, and adding the bearings to the output shaft, it could propel a model airplane, with a proper propeller?

    Some kind of housing around the center to hold oil and spray or splash it onto the linkages would help it last longer.

      1. I think once you start a sterling you can pressurize it to produce more poop from it. I vaguely recall videos of a very old commercial unit sourced second hand from a school. Used to generate power, it looked very similar to any small portable gas generator made in the 60’s.

  3. Wow, that is really neat for $269. With 8 cylinders, that is one of the more complex Sterling engines I’ve seen outside of NASA designs. Most or more simple designs.

    I wonder what the energy output is compared to the energy input?

    I wonder if using a hydrogen-helium gas for the internal heat exchange pressure change medium will do to improve performance as I assume this unit is operating on air only which isn’t as efficient.

    I was just thinking today that using UPLC or HPLC fittings or other Air Force Texan like air rifle higher pressure fittings may help with designing higher pressure systems since increasing the pressure is another way to increase performance.

    Finally, as noted above… friction reduction is always a bonus. Therefore cylinder linings and maybe cylinders with sapphire maybe cut with lasers and ground to perfection can aid in performance.

    Awesome just looking at! Like the tractors shows where I first observed the sterling engines and other external combustion engines… I think especially with solar troughs if not the dish type focus systems… these external combustion systems have potential that is being overlooked especially in regards to creating lower clearance jobs for the general public to stay busy.

    Some want a border fence with Mexico… I say a solar concentrating trough power plant with desalination units that can also operate as radar!

      1. Other than the plastic looking like an inside cut… I’d think a reamer would be used. Boring bar works though. Makes me wonder about the cylinders and other components that can use a perfect optimized fit for performance ratio and where gas sealed if not using air in the actual working gas area… what is being used and improved on with better optimized tolerances to get more power at higher pressures… even with a pressurized outer section that can aid in heat exchange also… maybe make contact with the cylinders while re-enforcing the pressurized system and sealing more to prevent leaks which would aid in heat exchange too say if using pure hydrogen with maybe an outer helium shell. I might be tired thinking about this.

  4. He put too much effort into making this nice to just leave that terminal strip dangling by the wires like that! I’m thinking maybe he could replace it with the black-plastic kind, since those usually have screw holes, and mount it to the wood. Normally those do leave their terminals more exposed than the kind he used but there are ones with a clear plastic cover that snaps on the top. That would be about right I think.

  5. I also think this is more art than performance since the increased friction of more cylinders versus one may be a source of loss in torque. Especially, I’d want a flywheel added and especially a vacuum sealed flywheel super capacitor also with magnetic clutch too… why not. It’s not a gas turbine… though cool look of one.

    1. I forgot to edit and elaborate on one larger cylinder versus more smaller cylinders with the same volume of working gas. Maybe heat exchange is the issue… though would be interesting to see graphs of the physics metrics in regards to performance. Then add in materials used to make. Heat transfer to weight and at higher pressures. Titanium or highest strength to weight ratio performance aluminum? Carbon fiber wrapping also with an expansion layer in between for thermal transfer and if different materials… buffer for expansion and contractions differences at high pressures.

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