Stirling Cycle engines like their cousins the Steam Engine and Internal Combustion Engines are heat engines in that they use heat to produce working power. They are different in that they do not directly burn fuel to produce that working power. The Stirling engine usually is a two piston arrangement, or more correctly one piston and one displacer. The engine usually consists of a pair of cylinders, one small and one large which are interconnected. The power piston is in the small cylinder and is mechanically linked to the displacer in the large cylinder. The engine works by first heating the air trapped within the power cylinder expanding it forcing the power piston out. The trapped air transfers into the displacer cylinder where it is cooled and contracts, as it contracts the displacer piston and power piston are sucked back in. The air transfers back into the heated chamber where the process starts again. Note that the key is not the heat, the key is the temperature differential between the two cylinders, you can chill the displacer side of the engine and have it work just as well as if you heated the power side. For more detail see Operation Simply Explained In the last century stirling cycle engines predominantly found fame as quiet pumping engines for houses. With a small amount of coal they could keep water pumping all day. More recently the world has been turning to stirling cycle for a more efficient way to power generators and cars. There are some engines in commercial production at present capable of doing this. Of course like the electric car, the stirling car will be a slow accelerating beast.

Ericsson Hot Air Engine

All of the pictures on this page are of an Ericsson Hot Air Engine, the last being a diagram of the engine innards. The Ericsson engine is a Stirling Engine meaning it does not burn fuel to operate.…

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Heinrici Hot Air Engine
This article is based on an email conversation with This email address is being protected from spambots. You need JavaScript enabled to view it.">Brad Soward who was answering a series of questions sent to me from This email address is being protected from spambots. You need JavaScript enabled to view it.">Andrew Alkemade. The words are Andrew's and Brad's. The photos of Andrew's engine are his, and the photos of the engine at Brad's place are mine. Andrew and Brad have both given their permission to reproduce their discussion in the interest of helping other Heinrici restorers.

Andew's words and pictures are © Copyright 2003 Andrew Alkemade
Brad's words are © Copyright 2003 Brad Soward
My pictures are © Copyright 2003 Paul Pavlinovich

Andrew's request for assistance...

Hope you can help.

I have a Heinrici motor that was passed down by my father and his father.  The motor was used in a mineral water bottling operation that the Alkemade family ran around WW1.

The motor I have is a later model with a 2" bore and central displacer. (see photos).

I am very interested in talking with anyone that has one as mine has a problem which I would dearly like to fix.

As it was missing its original stand it had never been used to my knowledge until a few weeks ago when I finally got around to building one and got hold of an old kero blow lamp as a heat source.

After a 5 mins or so after a far bit of oil and assistance it finally started to run by itself. It lasted about 5 mins and started to slow down then it stopped.

I found that the arm that works the central piston had come loose from it shaft. Looks as if the locating pin had sheared some time ago and the rust has started to let go. Tried to fix it by drilling out the pin but that was less than perfect.  It worked for a while and was particularly good one very cold night.  The first time it ran it was lucky to do 150 RPM but on that night was probably closer to 300.

Since then the pin has worked loose again and the timing has slipped significantly to a point where it will barely run. Before I dismantle it to rebuild the shaft and create further problems for myself I have few questions if you can point me to someone who can help.
  1. Heat source is the kero blow lamp a suitable heat source or is it likely to be too hot and do damage.  How important is the water cooling if running it for short periods
  2. Timing. Should the central arm work exactly in parallel with the external arm attached to the fly wheel or at some other orientation. Does anyone have a description of the timing between the mail piston and the central one.
  3. Oil..should normal engine oil be placed in the "petroleum" cylinder and is there any special operation of the internal rod. I presume it provides lubricant to the central piston and the main piston.
  4. If I dismantle the main piston is there any special tricks I need to be aware of.
  5. Are you aware of anyone close to Melbourne that has one on going condition that might be able to help.…

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How Stirling Engines Operate / Work
I used to have my own article here, but due to some inconsistancies I decided to rewrite it. At about the same time I came across this article by Mike Palmer This email address is being protected from spambots. You need JavaScript enabled to view it. on the Stirling section of his Station Road Steam site. Mike kindly agreed to allow me to republish the article here - thanks mate. Mike's company Station Road Steam produces a Stirling engine kit called the Super Vee which is the engine used in these pictures. You can check out the Super Vee and Mikes other products at Mike's site.
The article and pictures are all © Copyright to Mike Palmer and may not be reused without his explicit permission.

A fixed volume of air is heated. As it gets warmer, its pressure increases. By allowing the air to act on the underside of a piston, the engine can do work. Having pushed the piston to the top of its stroke, the air is then cooled, reducing its pressure and allowing atmospheric pressure to push the piston back down. Repeat rapidly and you have a hot air engine!…

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Kyko Stirling Fan

The pictures of this interesting stirling engine powered fan utilising a kerosene burner were sent to me by This email address is being protected from spambots. You need JavaScript enabled to view it. who wrote:
> Dear Sir:
>  I have a kerosene powered fan (KYKO the only markings) that in 1960 was being used by a doctor in the jungle of French speaking Cameroun. It had previously been used by an 82 yr. old British merchant who had spent many years in the Cameroun. It is in good working order and I brought it home with me to the US in 1979. It is an interesting piece and takes up a prominent place in my living room. I have decided to do research about it and am convinced from pictures and history found that I do have an original KYKO fan. I am looking for someone who could tell me more about it and give me an idea of what it is worth, or how to find out what it is worth. With your permission I could email a picture. Any help would be appreciated.
>  Sincerely,
>  John Rowe

If you're able to help John with information or a value then please contact him on the address within the article. Please let me know as well and I'll update this page.…

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The Stirling Cycle engine is also known as external combustion, Carnot Cycle, and several other names. This article should help your understanding of why this is so. Essentially all of these devices utilise the same basic principles.

It is thought that the first true hot air engines were devised by Sir George Caley around 1807, but the first successful engine which could perform useful work was the Stirling Cycle engine devised by the Reverend Robert Stirling in 1816.…

Read more: Stirling Cycle History, Past, Present & Future