| Gallery, Projects and General > Project Logs |
| Brass Stirling (#3) |
| << < (5/5) |
| cidrontmg:
No bling yet, but some more pictures. Iīve done a burner, and modified some bits. And I think Iīll do still some mods. Itīs running better all the time, but I believe itīs not yet as good as it might be with little(?) additional mods. The burner, not looking much as yet, but working, and no leaks. One end cap is the same ex-displacer cylinder cover that I had to make new. This is how it looks at this stage. Something that is no longer visible. The displacer must have a vent hole. Here, 1 mm dia. It is otherwise rather dangerous (to the engine). It is an airtight chamber, which gets very hot. Without a vent hole, it will build quite a pressure inside, and maybe pop one end cap away. And destroy the test tube. If you build something similar, keep in mind... The tube that connects the cylinders. It is brass, and the displacer end is threaded 5/32X40, and screwed directly to the cylinder (with thread sealer). The other end has a normal tubing joint. The "back curve" is needed for the locking nut to move somewhat. The displacer rod sealing seems to be a critical point in these engines. Once again there was an audible leak in there, so I made a Teflon bushing. Now it is quite tight. I cut two half moons off the crank disk, to balance things somewhat. In this type of engine, there are reciprocating masses moving at 90o to each other, so balancing the crank so that it is "neutral" (=will stop at a random position) will not balance all of the engine. To my surprise, this mod was pretty effective. The engine vibrates very little. I still will need to attend to the power piston big end. Thereīs a ball bearing there, but the structure is too heavy. It sits on top of the power piston, so any extra weight there is power wasted. More when thereīs more. :wave: |
| madjackghengis:
Hi Olli, it looks like youre getting that stirling together very nicely. I always enjoy when an old piece, discarded, can be re-used, it feels like sort of organ donation engine to engine. I went back to get a better look at all the parts and pieces on your power piston, I got to thinking if you wanted, you could set up a spriing under the piston which comes close to counter balancing the static weight, and with that for rebound, you would get most of all that power back, you'd just keep the mass and the associated inertial loads and factors such as its most natural rpm. You've got so much mass involved in the direct movement of the power piston it probably wouldn't be as effective trying to substantially reduce the weight directly on the piston rod, although it could do fine with a plain bearing on a pin, given it doesn't rotate much in angular movement. Don't mean to criticize, just some thoughts from looking long and serious at that design, planning on building one of similar nature at some point soon. I think it's looking very sharp with the polishing up, and the matching burner done up. I enjoy the extraordinary number of moving levers and pieces. :headbang: well done, mad jack |
| arnoldb:
Nice one Olli; runs like a charm :thumbup: :beer:, Arnold |
| picclock:
Hi Ollie Very nice to see it running, it certainly looks the part in the video. Glad to see that my predictions (and prejudices) with the PTFE (Teflon) piston expansion were unfounded. Hope the rest of the year turns out as successfully for you. Best Regards picclock |
| Navigation |
| Message Index |
| Previous page |