Search found 114 matches

by derwood
Tue Dec 20, 2016 3:49 pm
Forum: Stirling and "Hot Air" Engine Forum
Topic: Thermal lag plans
Replies: 7
Views: 7750

Re: Thermal lag plans

The gap between the inner and outer tube is the stack. The inner tube is for expansion. The gap between the inner and outer tube needs to be as small as possible without restricting flow.
by derwood
Fri Jul 15, 2016 6:29 pm
Forum: Stirling and "Hot Air" Engine Forum
Topic: Homemade Engine with Generator
Replies: 17
Views: 15361

Re: Homemade Engine with Generator

Nice engine. I don't think it produces 80 watts though.
by derwood
Fri Apr 08, 2016 12:46 pm
Forum: Stirling and "Hot Air" Engine Forum
Topic: large lamina flow build
Replies: 139
Views: 157473

Re: large lamina flow build

It is "all of the above". I think the pulse jet principle best describes it. Inertia.
by derwood
Sun Mar 06, 2016 6:43 pm
Forum: Stirling and "Hot Air" Engine Forum
Topic: large lamina flow build
Replies: 139
Views: 157473

Re: large lamina flow build

the inner tube is open on the hot end. The pointed end is just pointed for airflow purposes. the point is basically hollow. I wont be sharing the new design, I have too much time invested to just give it away.
by derwood
Sat Mar 05, 2016 1:17 pm
Forum: Stirling and "Hot Air" Engine Forum
Topic: large lamina flow build
Replies: 139
Views: 157473

Re: large lamina flow build

crazyguy, the engine design that I shared will work with or without a crank shaft
by derwood
Sat Mar 05, 2016 1:07 pm
Forum: Stirling and "Hot Air" Engine Forum
Topic: large lamina flow build
Replies: 139
Views: 157473

Re: large lamina flow build

no, that's not the problem. there needs to be two cold ends and the inner tube end cant be cooled properly. I have built a new design that works quite well.
by derwood
Mon Feb 29, 2016 10:05 pm
Forum: Stirling and "Hot Air" Engine Forum
Topic: What is the difference between thermal lag and lamina flow engines
Replies: 36
Views: 27580

Re: What is the difference between thermal lag and lamina flow engines

You need to have a bleeder valve to equalize the pressure after the engine heats up. If you use a piston it leaks just enough to equalize. When the engine is heated and not running the pressure needs to be the same as the atmospheric pressure. if the pressure inside the engine is greater it will not...
by derwood
Thu Dec 10, 2015 2:16 pm
Forum: Stirling and "Hot Air" Engine Forum
Topic: Building a Woodstove Fan Stirling Engine
Replies: 9
Views: 10815

Re: Building a Woodstove Fan Stirling Engine

I used a 92mm vw cylinder with a tin can slid over the end of the cylinder. The end of the cylinder that fits into the vw block. I used red silicone and a large hose clamp to seal the can to the cylinder. I used a smaller can for the displacer. I have not been able to find a stock food can that fits...
by derwood
Wed Dec 09, 2015 9:00 pm
Forum: Stirling and "Hot Air" Engine Forum
Topic: Building a Woodstove Fan Stirling Engine
Replies: 9
Views: 10815

Re: Building a Woodstove Fan Stirling Engine

Hey, I have built several stirling engines using vw cylinders. They work great for the cool side of the displacer.
by derwood
Fri Mar 27, 2015 9:50 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: can a laminar flow stirling engine do real work
Replies: 5
Views: 11226

Re: can a laminar flow stirling engine do real work

Find a design that works and make improvements. I asked the same questions and finally just built my own to find out. Yes they can do work but 100 watts is a lot for any home built heat engine. Here are the plans for my engine. Not extremely detailed but good enough to get started. As far as your qu...
by derwood
Tue Jan 20, 2015 9:37 pm
Forum: Stirling and "Hot Air" Engine Forum
Topic: large lamina flow build
Replies: 139
Views: 157473

Re: large lamina flow build

I tested a single cylinder version and it produced 10 watts. Unfortunately it loses power quickly when under a load. I have tried cooling the cylinder but it only helps a little bit. I think the inner tube needs cooling. I am trying to come up with a practical way to cool the inner tube.
by derwood
Thu Jan 15, 2015 5:29 pm
Forum: Stirling and "Hot Air" Engine Forum
Topic: large lamina flow build
Replies: 139
Views: 157473

Re: large lamina flow build

First test run video.
http://youtu.be/wtW9fYVFXOY
by derwood
Mon Jan 12, 2015 3:13 pm
Forum: Stirling and "Hot Air" Engine Forum
Topic: large lamina flow build
Replies: 139
Views: 157473

Re: large lamina flow build

This is the latest configuration. I have not fired it up yet but I am confident that it will run very well. The heat tube and cylinder portion are basically the finished product. A water cooled cylinder can be added later. The crank shaft and case are just a work in progress. The case will eventuall...
by derwood
Sat Dec 27, 2014 1:13 pm
Forum: Stirling and "Hot Air" Engine Forum
Topic: What is mechanizm to balance pressures?
Replies: 13
Views: 6925

Re: What is mechanizm to balance pressures?

Recently I have been trying to pressurize a thermal lag engine and have had similar questions. My engine will not run with an enclosed crank case. The only way I can get it to run is to greatly shorten the stroke. I think the problem is that the crank case pressure gets too high when the piston is a...
by derwood
Tue Dec 23, 2014 3:30 pm
Forum: Stirling and "Hot Air" Engine Forum
Topic: 25 watt Stirling for sale
Replies: 7
Views: 7242

Re: 25 watt Stirling for sale

This is just my opinion. I don't think an engine that size can produce 25 watts without pressure.