Stirlingengineforum.com

I believe that article is from Scientific American. Looks fairly reasonable, but I suspect that it isn't much more than an oversized tin can engine.

There is a book being advertised on http://www.AmericanSterling.com that describes a 5 horsepower engine built in Bangladesh out of scrap. I don't know if it's out just yet, but it might be worth looking into.

-Stefan

FYI: The book "How I Built a 5 HP Stirling Engine" is due out imminently, target date in December. They are taking advance orders.

This engine was not built from "scrap" as far as I could tell from an earlier copy of the manuscript and photos which I had an opportunity to examine.
It was built by native craftsment useing materials and components (ball bearings) with the exception of one particular bearing, in Bangladesh.

It should be an interesting book. Brent H. Van Arsdell has a book, also available on <stirlingengine.com> "Around the World by Stirling Engine"

A Stirling engine is deceivingly simple in appearance but extremely complicated in analysis as to all the aspects of how and why it works as it does.

Having skimmed through all of the prior posts it appears to me that all too many individuals are attempting to reinvent the wheel instead of find web sites to assist them in achieving their goal realistically.

You will find links to all kinds of information "Stirling" at
<notscar.wiki.com>

Happy hunting.

stanhbaker

Recently I came across a website with a reprint of a 1993-94 article about a proposed Stirling engine design for aviation.

It seems that my earlier idea regarding increasing surface area using pins of some sort is not entirely new. This design uses hollow "pencil points" on the "regenerative displacer" to increase surface area by 10 X or more.

http://www.qrmc.com/fourpartstirling.html

Illustrations:

http://www.qrmc.com/fpsfig16.html
http://www.qrmc.com/fpsfig15.html
http://www.qrmc.com/fpsfig19.html
etc.

My own project has been stalled for a while but not abandoned. Mostly I just need to find the time to assemble all the pieces of the current model.

It's nice to see though, that the idea about increasing the surface area using pins fitting into holes is something that has been considered before as far back as 1994, though I don't know if it has ever been tried in actuality.

Looks like the real problem with it is manufacturing the parts Tom. I've had a hard enough time making my "simple" models. I have all kinds of ideas that jump in out out of my head but when I think about what to use or how to cut the materials I get discouraged. The skills required for some stuff goes way over me. A good machinist could probably make stuff like that without breaking a sweat.

I know what you mean,

I've been thinking lately that the best way to increase surface area would be just to make bigger panels, like in a flat solar type design.

More surface area in a small space isn't really all that much of an advantage with solar, as the amount of sun hitting the panel, or alternatively, hitting some sort of concentrator, is more or less the same either way.

It seems easier just to let the sun heat the engine directly using a large flat plate type design that is easy to build rather than trying to squeeze a lot of surface area into a small space and then have to build some sort of big concentrator or reflector system to concentrate the rays anyway.

More surface area in a compact space isn't any advantage unless there is also some way of providing more heat.

I've been thinking a lot lately about the little flat type engines that can run just from the heat from someones hand.

In the winter, a few feet below ground level it stays warm, (50 degrees or so) down below the frost line. I'm wondering if a large "coffee cup" type engine could be built that would run all winter just from the temperature differential between the relatively warm earth and the colder winter air.

Ah, yes... we're back to the half-buried drum idea. (Still love it!)

The only big concern I would have with an outdoor LTD engine is that friction must be maintained at an absolute minimum for these guys to work properly. Keep in mind that low-temp differentials also have very low output for their physical dimensions. In order to do any real work such as charging your 12 volt batteries, you will either have to make it pretty big (working volume wise) or find a way to concentrate that heat (which is exactly what we are trying to avoid using this design).

-Stefan

There has to be a better way of living other then beening a slave to the power grid and to the powers that be. i am new to stirling engine building and have developed and created a 2 1/2 hour dvd to help other beginners new to stirling engines start with a simple tin can model like the SFA tin can stirling engine. It is a How-to instructional video covering start to finish of a soda can model. We hope it helps others and inspire more people to get involved in building stirling engines. http://www.no-ssn-info.com/stirlingengine

Rob42103

Isn't that the same engine as here? For free?
http://www.physics.sfasu.edu/astro/cour ... rling.html

How about this idea, using a combination of springs and magnets?

Hope you keep trying!

Hello Tom. I too have been bitten by the stirling engine bug and am looking for a 12v battery charging solution. take a look at solar evacuated heat pipes as a solar input device. Some people are experimenting with a high surface area graphine heat transfer fluid on youtube.
regards
Wellington

I recently finished a human scale, gamma Stirling engine capable of battery charging. it is about 3' tall, 3" bore, 3.312" stroke. I am in the stage of trying it with different generators and trying different "gear ratios". For transmission, I am using sprockets and chain. It is not yet optimized, but it will produce a small amount of useable power, capable of 12v battery charging. The furnace is 50k btu max and although I am surprised at how the engine will run on embers, in order to produce useable power, I must have a good fire going. It does run well on a good wood fire at about 140 rpm. I have also built a PWM controller to go with it in hopes of more perfectly matching its output to the generator load. The most optimistic calculation of output power is about 60w i.h.p. I will be thrilled if I can get half of that in useable electrical output. It may be closer to 20w.
Although Stirling engines are fascinating and fun to build. For the same effort, one could build a steam engine and boiler, a diesel or some solar panels and produces many times more power.

That's why you make your connecting rods adjustable from the start ;)

manvstaco wrote:That's why you make your connecting rods adjustable from the start ;)

I am not sure about what you are referring to here.