Search found 9 matches

by playludesc
Fri Mar 23, 2018 9:25 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: Large LTD Diaphragm Gamma Stirling Questions
Replies: 19
Views: 5356

Re: Large LTD Diaphragm Gamma Stirling Questions

Yeah, I'll be pressure testing it with air for sure. Need to figure out when my 2mm thick aluminum caps are gonna start bulging/when my o-rings are going to fail. But my guess is my plan for sealing the connecting rods will be the first point of failure.
by playludesc
Thu Mar 22, 2018 11:48 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: Large LTD Diaphragm Gamma Stirling Questions
Replies: 19
Views: 5356

Re: Large LTD Diaphragm Gamma Stirling Questions

Thanks for the heads up, bumpkin! Just so you know, I'm not just modeling this for the fun of it--I plan to 3D print most of the parts excluding the hot and cold caps and hardware. I also plan to try and pressurize the engine with helium if I can figure out a good seal for the connecting rods. I hav...
by playludesc
Tue Mar 20, 2018 10:24 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: Large LTD Diaphragm Gamma Stirling Questions
Replies: 19
Views: 5356

Re: Large LTD Diaphragm Gamma Stirling Questions

I spent some time thinking about it last night, and I'm pretty sure that a flatter design would be better than the one shown above. The reason being that in my current design, with such a large displacer stroke, the volume of air compared to the area of contact it has with the hot and cold caps is m...
by playludesc
Tue Mar 20, 2018 10:11 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: Large LTD Diaphragm Gamma Stirling Questions
Replies: 19
Views: 5356

Re: LTD displacer to power piston ratios

I would suggest a ratio of 60:1 to 61:1. If you do not read the Senft book on this topic before trying to design your own engine, then you are either a genius or a fool. Thanks for those numbers! I wanted to get the Senft book, but the budget wasn't there to spend $45 on it. Can you help me clarify...
by playludesc
Tue Mar 20, 2018 10:05 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: Large LTD Diaphragm Gamma Stirling Questions
Replies: 19
Views: 5356

Re: Large LTD Diaphragm Gamma Stirling Questions

Ah, here is the image again. I forgot how much I hate photobucket.

Not shown: the ring around the outside of the displacer will be filled with aluminum wool.

Image
by playludesc
Mon Mar 19, 2018 4:58 pm
Forum: Stirling and "Hot Air" Engine Forum
Topic: Large LTD Diaphragm Gamma Stirling Questions
Replies: 19
Views: 5356

Re: Large LTD Diaphragm Gamma Stirling Questions

I've spent some of my free time the past couple weeks modelling the first prototype. I finished the displacer and it's cylinder and went to calculate how large I'll need to make the power piston and it's cylinder. Therein lies my newest problem: the swept volume of the displacer is almost two liters...
by playludesc
Tue Mar 06, 2018 11:06 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: Large LTD Diaphragm Gamma Stirling Questions
Replies: 19
Views: 5356

Re: Large LTD Diaphragm Gamma Stirling Questions

Thank you for the reading list Alfista! My original thought was for it to be a kinetic sculpture of sorts, but if I can get any appreciable power out of it, I'd love to put it to use. In the summer I'm thinking I could get as good as a 30-40°F temperature differential and maybe more in the winter if...
by playludesc
Tue Mar 06, 2018 10:59 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: Large LTD Diaphragm Gamma Stirling Questions
Replies: 19
Views: 5356

Re: Large LTD Diaphragm Gamma Stirling Questions

Ian S C wrote:In a pressurized engine, both sides of the motor is pressurized.
Do you mean that the space the power piston moves into on it's power stroke must be pressurized if the working gas is pressurized?
by playludesc
Sun Mar 04, 2018 12:36 pm
Forum: Stirling and "Hot Air" Engine Forum
Topic: Large LTD Diaphragm Gamma Stirling Questions
Replies: 19
Views: 5356

Large LTD Diaphragm Gamma Stirling Questions

So I have an idea to eventually make a large, LTD Gamma type and bury it in my front yard. My hope is to use a design similar to the commonly homemade LTD toys. The general idea is that in the summer, the sun will heat the hot cap and the cold cap will be cooled by the soil. In the winter, the forme...