Model Engine Maker

Help! => Specific Engine Help => Topic started by: Robert Hornby on February 18, 2022, 02:37:03 AM

Title: Cup of Tea Engine
Post by: Robert Hornby on February 18, 2022, 02:37:03 AM
Some 25 or so years ago I made a cup of tea engine and subsequently sold it (that is another story). I wish to build another one but cannot find the original plans, so I am making it from memory. Please help with the ratio of displacer volume compared with power cylinder displaced volume, or is it not too important? By the displacer volume I mean the volume of the cylinder minus the volume of the displacer.
Robert
Title: Re: Cup of Tea Engine
Post by: Hugh Currin on February 18, 2022, 03:56:51 AM
Robert:

I believe the displacer to power cylinder volume is dependent on the temperature differential being exploited. The Low Temp Differential engines have a large displacer compared to power volume.

I'd suggest you look at some of  Jan Ridders designs  (http://www.ridders.nu/Webpaginas/pagina_overzicht_stirlingmodellen/stirlingoverzicht_frameset.htm). He may even have a design you could use directly. I've found him very responsive in sending drawings.

I'm making (turned into a very long term project) of a version of his "Egg Cup Stirling". The build log is on this site somewhere.

Let us know what you find. Thanks.
Title: Re: Cup of Tea Engine
Post by: PJPickard on February 18, 2022, 01:20:02 PM
There is this too:
http://animatedengines.com/ltdstirling.html
James Senft has designed many Stirling cycle engines
Title: Re: Cup of Tea Engine
Post by: Jo on February 18, 2022, 02:17:13 PM
Please help with the ratio of displacer volume compared with power cylinder displaced volume, or is it not too important? By the displacer volume I mean the volume of the cylinder minus the volume of the displacer.

Low delta Temperature engines, like the "cuppa model engines", typically have a displacer cylinder differential swept volume of about one hundred times greater than the power cylinder.

Jo
Title: Re: Cup of Tea Engine
Post by: Robert Hornby on February 19, 2022, 10:30:41 AM
Thank you very much for your inputs they help tremendously.
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