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Since my ability to progress in the fabrication of this prototype is temporarily limited by the Covid 19 disruption I have decided to attempt to refine the design of the piston/displacer/regenerator. I chose Approtehcies design for it's low tech simplicity and the steel wool regenerator piston is ce...

The aluminum displacer core will not be sealed. So temp induced pressure changes will not develop. In addition the top will be insulated with ceramic fiber mat. Theoretically the air flow through the regenerator material should be sufficient to prevent the underlying displacer core sides from overhe...

Thanks Trev,

Initially I plan to use the coarsest steel wool available to minimize shredding and experimenting with high temp binders as this is the least expensive option. If this fails I plan to try stainless steel "scrubby" material.

Is this the material you are describing?

I agree. Components, materials, and special tools are arriving daily. However being part of a local virus response team has diverted my attention temporarily. Luckily I received Principals and Applications of Stirling Engines a few days ago and am reading through it as time and my comprehensive abil...

If your calculations and the tables used for them are accurate the layer of steel wool surrounding the displacer piston core will be approximately 1/8 to 1/4 inch thick. That will be significantly different than the amount of steel wool used in Approtechies engine. Luckily I am going to be able to t...

0.28 grams seems pretty light.
A penny weighs 2.5 grams.
Are you sure your calculations are correct?

I too considered the SP design but decided the equipment and skills required to fabricate it put it out of the DIY range for most people. I have the skills and equipment to make one...but most people do not. Having owned a prototyping business in the past I also estimated it's per kW cost to be awfu...

I have begun receiving the "off the shelf parts" for the single cylinder test/development engine. As expected they are revealing flaws in my first design. I had originally planned on using stainless steel "Bain Marie" pots. Unfortunately the supplier who assured me that they were...

Thank you for posting this PDF. It is especially timely in my case. It is a quick read and not as technical as I expected. If possible can you post a version with working links to the animations. If you cannot do this but have a version with working links I am willing to help do so. Thanks again! Dana

As much as I hate to make changes to any working design early on I am considering replacing the aluminum bottle which forms the central core of approtechie's displacer with an aluminum cylinder to eliminate the dead space the neck area creates. It seems like a "no-brainer" but of course I ...

Trevor,

I'm not sure I understand what you mean by the upper and mid range areas.
Are you referring to the movement range of the diaphragm?

Trevor... Thanks! I appreciate and encourage such suggestions. I can't take credit for using truck brake diaphragms. It was approtechie's idea. I have considered using Kevlar reinforced Viton sheeting to fabricate diaphragms if truck brake diaphragms are not sufficiently durable. You are of course c...

Not obvious in the images previously shared is that the displacer is actuated by a "box" or "groove" cam. I have not seen examples of this type of displacer actuator being used in a Stirling engine previously. If anyone has please post a link or provide what information you can s...

I too was saddened by Inresol's demise. More sad than most since I had purchased two of their gensets for integration into a larger project. More sad about the delay of the larger project than the financial loss as that can be "chalked up" to very expensive education expenses. Mainly what ...

If anyone wants the SketchUp files for this to better view this please just PM me. SketchUp basic is a free to use program from Google which will not only allow you to zoom and rotate the above views but also reveal internal features (such as the aluminum bottle and expanded aluminum inside the rege...