View Full Version : LTD sterling engine pics

11-09-2007, 11:36 AM
Just finished up my sterling engine:

movie of it running off my dell laptop powersupply waste heat:


tony ennis
11-09-2007, 11:45 AM
Very nice.

11-09-2007, 12:19 PM
that looks and works great! I have to make one, fairly sure i have the plans in either one of the projects in metal books or Steam and Sterling. whats the displacement piston made out of and what did you use for the lower cylinder?

11-09-2007, 12:34 PM
Displacement piston is pink foam from Home depot. Had to machine it to thickness. Tried using a hot nichrome wire with electricity from a train transformer... Worked okay but had a potato chip warp more than I liked.

After a few failed attempts with the hot wire I finally settled on using a flycutter in the mill. I double sticky taped down the foam and fly cut equal amounts from both sides to minimize warp. Hard part was figuring how to get the tape off. finally figured out to use alcohol to melt the tape off which worked very well.

Final displacer is flat to about .010"

The regenerators were fun too. I made an aluminum punch and die to punch out the 1 1/4" foam disks using my drill press as a press (cut to thickness with the hot wire). Worked very well.

Lower cylinder is acrylic from the local plastic house. I blind threaded 4-40 to hold the hot/cold plates on. Acrylic is really brittle and several of the threads stripped and I had to make a few "helicoil" inserts to repair them. I'd probably drill thru and use nylon bolts if I did it again.

11-09-2007, 06:46 PM
Two thumbs up for sure! Nice work hitnmiss.

Thomas Staubo
11-10-2007, 07:42 PM
Nice engine you built there.
BTW, it's spelled 'Stirling (http://en.wikipedia.org/wiki/Stirling_engine)', not 'sterling' ;)

How did you manage to make that spiral groove, it looks like an end mill was used, but how?

PS. On the Wikipedia link (above), there's an image of an interesting variant of the Stirling engine, with a rhombic drive. Anyone built/seen a model like that?


Alistair Hosie
11-11-2007, 11:03 AM
You did a great job pal well done watching it is fascinating.Alistair

11-12-2007, 08:20 AM
Spiral was cut with my CNC mill. Kinda cool to watch, people seem to stare at it.

despite numerous written suggestions to not oil anything due to added viscous friction I couldn't help myself and added a little thin oil to the displacer guide. After running it for a while I got to wondering about the oil. Last night I tore thing apart and cleaned the oil out with solvent. Now the engine runs much better. It will run off my hand quite briskly and starts up very quickly (about 5 seconds of warm up)