My first LTD Stirling Engine - a few questions
Posted: Mon Feb 04, 2008 5:56 pm
Hello All, a new member here, have been lurking for a few weeks and just recently registered. Discovered LTD Stirling engines on Youtube and had to have or build one. After watching videos until my eyes were blurry, I decided to try and build one from scratch. I am reasonable handy and have the luxury of a small lathe so I began accumulating 'stuff' to assembly the engine. I had no plans and just built what 'felt right'. Following is a description of what I used and then some questions..... and yes, it does run if you fiddle with it long enough. ;-)
Top and Bottom plates = Hard Drive platters approx 3.75" dia probably stainless steel
Flywheel = another of the Hard Drive platters also 3.75"
Displacer = 1/4" balsa
Vertical Cylinder = a slice from an old acrylic vase approx 3" id x .75" H
Power Cylinder = copper nipple smooth bore 5/8" ID
Power Piston = JB Weld molded in the copper nipple then sides turned down slightly leaving 2 sealing 'rings'
Stroke of displacer = .5"
Stroke of Power Piston = .375"
Crankshaft supported with ball bearings
Gland = brass fitting turned down with vertical hole 5/8" high
Displacer rod = chrome slider rod from old CD drive
System turns pretty freely, power piston action is smooth and pretty good compression. Had to fiddle with the displacer rod to get it run smoothly.
Initial tests didn't work at all. No sign of any attempt to run using a single tea candle. So, I slept on it overnight and thought thru the system. Decided to increase the displacer stroke to maximum (.5"). Still nothing so I added more heat and put some ice on the top and 'Eureka', it started to run. Slowly but running. It would run until the ice melted then stop.
So, a few questions. I assume the use of the HD platters was not the most efficient. I think they are stainless steel with an oxide coating and aren't transferring heat well and that is partly why it takes so much heat to run? Swept volume ratios? Stroke differences, do I need more power stroke?
Sorry for so many questions being a new guy but I am excited I actually go this first one to run I want to build another BETTER one. Not too interested in kits, would rather do it myself, but I am not reluctant to take accept some knowledgeable help along the way.
I live in Nothern California so if any of you are near Sacramento, let me know. Would love to share experiences.
Don
Top and Bottom plates = Hard Drive platters approx 3.75" dia probably stainless steel
Flywheel = another of the Hard Drive platters also 3.75"
Displacer = 1/4" balsa
Vertical Cylinder = a slice from an old acrylic vase approx 3" id x .75" H
Power Cylinder = copper nipple smooth bore 5/8" ID
Power Piston = JB Weld molded in the copper nipple then sides turned down slightly leaving 2 sealing 'rings'
Stroke of displacer = .5"
Stroke of Power Piston = .375"
Crankshaft supported with ball bearings
Gland = brass fitting turned down with vertical hole 5/8" high
Displacer rod = chrome slider rod from old CD drive
System turns pretty freely, power piston action is smooth and pretty good compression. Had to fiddle with the displacer rod to get it run smoothly.
Initial tests didn't work at all. No sign of any attempt to run using a single tea candle. So, I slept on it overnight and thought thru the system. Decided to increase the displacer stroke to maximum (.5"). Still nothing so I added more heat and put some ice on the top and 'Eureka', it started to run. Slowly but running. It would run until the ice melted then stop.
So, a few questions. I assume the use of the HD platters was not the most efficient. I think they are stainless steel with an oxide coating and aren't transferring heat well and that is partly why it takes so much heat to run? Swept volume ratios? Stroke differences, do I need more power stroke?
Sorry for so many questions being a new guy but I am excited I actually go this first one to run I want to build another BETTER one. Not too interested in kits, would rather do it myself, but I am not reluctant to take accept some knowledgeable help along the way.
I live in Nothern California so if any of you are near Sacramento, let me know. Would love to share experiences.
Don