Stirlingengineforum.com

I joined this Forum to 'compare notes' with other builders of Stirling cycle engines, having searched hard I have not yet found any. There must be some, but they seem lost amonst the hundreds of Hot Air engines, Tin can engines and Thermo Lag engines (often mistakenly refered to as Laminar flow engines) though the last thing you'll find in one is laminar flow.
My understanding is that a Stirling Cycle engine incorporates a Regenerative matrix between the expansion and the compression heat exchangers, as this was the most significant Patent taken out by The Rev Robert Stirling.
If you are interested in the Stirling Cycle, please make contact.

Geoff Vaizey

what type of engine are you working on specificaly?

Hello Weisermouth84

I have recently completed a 100cc (working volume) 90 deg Alpha Stirling Cycle engine, pressurised on air and propane fired.
There is a picture posted under 'Machined engines' in the members gallery.

What are your interests?

Geoff V

oh wow. Your engine is much more sophisticated than my current project. Are you using stadard atmosphere for your working fluid or are you using something else? Im just getting into sterling engines. Only known about the concept for a few months but im working to complete my first one right now. Im still trying to get an inline (lamina as its refered to) engine running and im running into some difficulty. My main hurdle right now are machining tools and budget but i must say your engine looks really nice. thats a piece to be proud of for sure. What are you using it for?

I'm in the process of installing it in a 5mt motorised catamaran with a shaft drive to a model aircraft prop, hope to get about 7 kg thrust (on air) to start with, working up to 8-9 Kg, I may give it a try on Helium at a later date but for now Air working well.

I have a couple of Thermo lag engines, a 90deg vee twin, now dismantled and a single which reached 2900rpm off load and 2.34watts on load from 20cc, will make time to put some pictures on the Forum.

Geoff V

sounds like youve been in the trade for a while. Sorry I cant bring anything you dont already know to the table. have any suggestions on common problems for a lamina flow? haha i know thats not what you started this thread for but i thought Id ask anyway.

Hi Geoff, which part of the world are you in?

You realize that neither of the Stirling brothers built an engine called a "Stirling Engine", they built Air engines, it was not until the 1930s that Philips in Holland decided they needed a name for the type of engine they were starting to develope (Otto for 4 st petrol engines etc.) At the moment I have 17 motors arround the place here, ranging from a 2 1/4" bore BETA, down to the latest one, a GAMMA motor with a 3/8" bore on the power cylinder. There are one or two motors in my gallery. Ian S C

Hello Doogle

I'm in Cambridge UK.

Geoff V

Ian SC

I really don't want to get into a discussion as to how the Stirling family refered to their engines, non of us know as non of us were there. My point is that it is generally accepted that it is the presence of a regenerator that differenciates between a hot air engine and a Stirling cycle engine. I have no interest in devices that just demonstrate the effects of changing the temperature of a gas in a confined space. My interests are in producing an external combustion engine that outputs enough power to be of use to the human race and can run on fuels other than liquid hydrocarbons which if they don't run out soon may well be in short supply soon or too expensive for most to afford.

If such an engine is possible without serious heat exchangers and a regenerator then all well and good, but as I suspect such an engine would be so large as to be of little practicle use, I wish to continue in my present direction and help others along the way.

So if there are any members with similar aspirations to me, please make contact.

Geoff V

The name "Stirling engine" seems to get used to refer to nearly everything that isn't an IC or steam engine.

Most of my engines use a moving regenerator (the displacer is made of wire wool) which I think is the kind of thing
you're looking for, however I only use low tech construction as I don't have any machine tools. I have a few small power
producing engines that work OK with this design. My latest one is trickle charging a 12V battery, shown in the video below :
http://www.youtube.com/watch?v=U9vPdcW_qTg

The efficiency is still poor though.

In UK a vacuum clearer is called a "Hoover", or in NZ a "Lux", a ball point pen, a"Biro", and so on. To a greater or lesser degree, a small motor with a long displacer (normal ratio length = 3 X dia) has an amount o regeneration. I'm sure that with a larger motor further regeneration would be an advantage.
Geoff, what do you intend to use as fuel, maybe solar, nuclear, you can't use wood or coal, polution, or electricity, very little of that is generated by renewable means. The information about the Stirlings is documented, and you should read about the old motors, that way you dodge some of their mistakes. Ian S C

Dear Junkie

Thank you for making contact, I have seen two other engines where the regenerator matrix is embeded in the displacer and have always liked the idea but for the inevitable increase in the mass of the displacer. It is good to see you producing electricity, not a lot, but more than many.

Geoff V

Ian
Thank you for your lecture regarding the use of Brand names when describing articles and devices. I remember well, when working in Australia in the late sixties, being asked by my secretary if I had any Durex, I was a little shocked until I learnt that, where as in the UK, Durex is a brand of condom, in Australia it is a brand of self adhesive tape. Believing that it is important to minimise misunderstandings I shall continue to try to use the correct generic term when describing my interests and activities.
I also appreciate your recommendations regarding the size of my Library, perhaps you would be kind enough to recommend some additional titles to me? I am sure there are still publications on the subject of Stirling cycle engines that I have yet to read, but I have read all my current collection at least once and can also boast that I am very friendly with one author who's credits include ' The Regenerator and the Stirling cycle engine' 'Air Engines' 'Thermodynamics and Gas Dynamics of the Stirling cycle machine'.
Regarding suitable fuels when liquid hyrdocarbons become difficult to aquire, I suspect that when the 'Lights go out' the Human Race will resort to anything that burns regardless of its effect on the environment. After many years on this Planet I am convinced that the population is quite incapable of correcting the mess we have made and am rather pleased I won't be around the see it.
Now I think I have thanked you for all aspects of your advise todate, so perhaps we can now get back to Stirling engine design.
Geoff V

My main book is "The Stirling Engine Manual" by James G. Rizzo, unfortunately I only have vol., 1, I got Andy Ross's book "Making Stirling Engines" (free down load), a good read, and some ideas worth thinking about.
Although I listed coal as a polutent, it is possible to pulverise it, and burn it as clean, or cleaner than oil. During WW2 in Germany much work went into fueling jet aircraft with powdered coal, the engines worked OK, it was the fuel feed that was the problem. Coal burnt that way would be very good for hot air and Stirling Engines, it works very well in boilers.
Geoff, it will be interesting to see how your boat goes, I would have thought that a propeller in the water might have been more effective. Ian S C