- May grabbed himself a wee dram, courtesy of a Scotsman.

Really useful engine

This desktop distraction could be the answer to…

3y ago
199.7K

This short (thankfully) video shows the operation of a gift item I’ve received: a model (ie toy) Stirling engine.

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0:58

The most exciting thing you've seen all day? Thought not.

The Stirling engine operates by expanding and cooling a gas (in this case plain air) in a closed system using an external heat source, making it an external combustion engine. The basic principles were patented as long ago as 1816 by Scotsman the Reverend Dr Robert Stirling, who was an advocate of the middle-eastern carpentry and curtain-rending cult but also a part-time inventor. I am not aware that any of his sermons have been passed down to us, but his engine idea has gained considerable traction over the years.

How does it work? I was going to tell you, but to be honest the explanations on Wikipedia, howstuffworks and elsewhere are pretty good, so what’s the point? That’s like getting a dog and then biting the postman’s leg yourself.

Stirling engines lend themselves to ‘stationary applications’, because they tend to be quite heavy for their power output. They have been used in submarines. They are quiet, mechanically simple (no valves, for example, or ignition system) and can run on any heat source: fossil fuels, peat, solar, fart gas, anything.

'…fart gas, anything.'

They haven’t had much use in cars, despite some encouraging experiments by NASA and the like. But with the rise of the hybrid, the Stirling engine makes a good case for itself. It can run at a constant speed, as a generator, and consume sustainable fuels. Although its power-to-weight is poor, its thermal efficiency is high at 40 per cent or more, compared with a typical 32 per cent for a petrol engine (Toyota’s Atkinson-cycle petrol lump is outstanding at 38 per cent).

Really, though, this is just an excuse for me to show off my toy engine and experiment with my desktop phone-camera mount. Sorry about the shaky fingers near the start, but I tried the meths before I put some in the burner.

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Comments (274)

  • The Stirling engine page on Wikipedia has some great images, too, Mr. May.

      3 years ago
  • NASA AMC Stirling powered car project

      3 years ago
  • Best thing i have I seen since James mays the reassembler

      3 years ago
  • Here’s a humdinger.

      3 years ago
    • Nice one, I saw it last night also. It got me thinking that a combination Wankel /Stirling engine cycle might be possible. But also, if the original question that James has posed is to try to achieve an efficient method to recharge an electric...

      Read more
        3 years ago
    • Perhaps, if smaller turbines could, some day, approach the efficiency of larger units.

        3 years ago
  • I wonder if it would work with a convex glass and a sunny day?

      3 years ago
    • They will work in a heliostat, as will bread ovens.

        3 years ago
    • yes, can confirm that one, I've build a solar oven for 12 pounds , material cost. the addition of extra mirrors will heat it enough to bake bread. Also will boil water for tea.

        3 years ago
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