Search found 26 matches

by danalinscott
Mon Apr 13, 2020 9:47 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: Developing a 1000w generator based on approtechies' design
Replies: 32
Views: 36567

Re: Developing a 1000w generator based on approtechies' design

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...
by danalinscott
Sat Apr 11, 2020 7:05 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: Developing a 1000w generator based on approtechies' design
Replies: 32
Views: 36567

Re: Developing a 1000w generator based on approtechies' design

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...
by danalinscott
Wed Apr 08, 2020 5:06 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: Developing a 1000w generator based on approtechies' design
Replies: 32
Views: 36567

Re: Developing a 1000w generator based on approtechies' design

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?
by danalinscott
Sun Mar 29, 2020 1:26 pm
Forum: Stirling and "Hot Air" Engine Forum
Topic: Developing a 1000w generator based on approtechies' design
Replies: 32
Views: 36567

Re: Developing a 1000w generator based on approtechies' design

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...
by danalinscott
Mon Mar 09, 2020 7:15 pm
Forum: Stirling and "Hot Air" Engine Forum
Topic: Developing a 1000w generator based on approtechies' design
Replies: 32
Views: 36567

Re: Developing a 1000w generator based on approtechies' design

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...
by danalinscott
Mon Mar 09, 2020 3:18 pm
Forum: Stirling and "Hot Air" Engine Forum
Topic: Developing a 1000w generator based on approtechies' design
Replies: 32
Views: 36567

Re: Developing a 1000w generator based on approtechies' design

0.28 grams seems pretty light.
A penny weighs 2.5 grams.
Are you sure your calculations are correct?
by danalinscott
Mon Mar 09, 2020 11:35 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: Is anyone working on LTD SunPulse-style engines?
Replies: 5
Views: 8155

Re: Is anyone working on LTD SunPulse-style engines?

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...
by danalinscott
Sun Mar 08, 2020 9:14 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: Developing a 1000w generator based on approtechies' design
Replies: 32
Views: 36567

Re: Developing a 1000w generator based on approtechies' design

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...
by danalinscott
Sun Mar 08, 2020 8:59 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: The Right Theory of the Real Stirling Engine.
Replies: 23
Views: 16111

Re: The Right Theory of the Real Stirling Engine.

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
by danalinscott
Sun Mar 01, 2020 8:43 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: Developing a 1000w generator based on approtechies' design
Replies: 32
Views: 36567

Re: Developing a 1000w generator based on approtechies' design

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 ...
by danalinscott
Sat Feb 29, 2020 8:38 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: Developing a 1000w generator based on approtechies' design
Replies: 32
Views: 36567

Re: Developing a 1000w generator based on approtechies' design

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?
by danalinscott
Fri Feb 21, 2020 10:41 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: Developing a 1000w generator based on approtechies' design
Replies: 32
Views: 36567

Re: Developing a 1000w generator based on approtechies' design

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...
by danalinscott
Thu Feb 20, 2020 10:29 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: Developing a 1000w generator based on approtechies' design
Replies: 32
Views: 36567

Re: Developing a 1000w generator based on approtechies' design

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...
by danalinscott
Tue Feb 18, 2020 10:08 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: Developing a 1000w generator based on approtechies' design
Replies: 32
Views: 36567

Re: Developing a 1000w generator based on approtechies' design

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 ...
by danalinscott
Mon Feb 17, 2020 3:19 pm
Forum: Stirling and "Hot Air" Engine Forum
Topic: Developing a 1000w generator based on approtechies' design
Replies: 32
Views: 36567

Re: Developing a 1000w generator based on approtechies' design

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...