Here is the power cylinder assembly. This is an Airpot cylinder. I will epoxy it to the brass base. I still have to drill and tap the brass so I can mount it to the top plate. I am going to change my plans to make the Airpot piston work.
Well, I have the foam ready to work. It is 9/16" thick and a little bigger than the cylinder. I still cant figure out a good way to hold this with out smashing the crap out of it or ruining it when I remove it (tape) ? Any Ideas? I've got plenty of extra to "practice" on:O)
How about sandwiching it between two pieces of something: plywood, plastic, etc? You could make the top and bottom plates a little smaller so they don't need to be turned down, and then just use sand paper so that only light pressure is needed, and hence not much torque.
I finished the displacer piston's and the rod that gets epoxied into it today. I'll get a picture when I epoxy them together tomorrow. I also started on the piece that will get epoxied into the piston and hold the con rod. I'm going to use silicon to for the gasket on the displacer cylinder. I'll show that to.
I have had good luck using a 3-M ROLOC disc and arbor in a drill press. As you are taking it down to final thickness, keep flipping it over and it will turn out very flat with uniform thickness. There is also a low risk of catastrophic failure (flying across the room like a frisbee) if you hold it flat against the drill press table at all times.
Well, I've got more done. Having more puter problems. I cant fix my pictures:O( I have the rod for the displacer done and the gland almost done. I just have to finish a couple more parts, Glue a couple of parts together, and start assembly:O)
I haven't followed any plans exactly, but have followed the principles and rough dimensions of Dr. James Senft's N-92 and P-19 engine designs (but then all LTD heat engines are derivative of his design).
Here is a quick picture. Kinda bad quality, but you'll get the idea.
When I drilled the foam, something wasn't aligned right. The hole is about .025 over sized. I'll probably go ahead and use them as is. To glue them up I'll chuck the rod in my drill press chuck to hold it upright until the epoxy dries. The aluminum shaft will get glued into the piston. There is a small hole in the end for the con rod.