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.

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Machining A Horizontal Stirling Engine

Satisfy your need to view some quality machining by looking through this Stirling engine worklog. We’ve seen these engines used a few other times in creating electricity from solar energy, powering a car, and even built from aluminum cans. [David Morrow] built this rendition to push the limits of his machining skills. We’d say he succeeded. The finished piece should run with the help of a heat source such as a candle. There’s no video of this engine, but we’ve embedded a clip of a similar device after the break in order to give you an idea of how this would work.

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12kW Solar Collector

Though not much info is readly available about it on the web, [Joe Carruth] is trying to build publicity (and venture capital) for his home-built solar electric generator. At its essence, it is a Stirling dish system with an adjustable composite mirror surface. This means that instead of having to rotate the entire contraption in order to follow the Sun, [Joe] only has to make  the mirror segments pivot. A Stirling steam engine at the tip converts the energy into the movement used to generate electricity. Solar power plants (or ‘farms’) that are emerging are beginning to consider the advantages of using more efficient Stirling dishes rather than less efficient solar panels. If anyone has an idea as to how [Joe] can automate sun tracking for the mirrors, please post it in the comments. A couple more videos on the topic (in general) are available below: Continue reading “12kW Solar Collector”

Dean Kamen’s Stirling Engine Car

kamen_car

[Dean Kamen]’s company, the people behind the Segway, have created a hybrid car that uses a Stirling engine instead of a standard internal combustion engine. Stirling engines are closed cycle, meaning heat is applied to the outside of the cylinder walls. They are generally more efficient than standard car engines, but haven’t been used much outside of industrial applications. We suspect that the drivetrain arrangement is similar to the Chevy Volt where the engine is used to charge batteries which are in turn driving an electric motor. This is different from modern hybrids that can have either electric motor or gas engine driving the wheels. The article is unfortunately full of classic [Kamen] hyperbole and minimal detail. He calls the Stirling engine “an insurance policy” for the electric car since it can recharge the battery. That’s right, folks. If you run out of juice, you can put gas in the car. I doubt many Prius owners will fall out of their chair over that. Being a Stirling engine, we’d be more impressed if you could charge the thing by rubbing warm toast on it.

[via Make]