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?Chinese? Stirling Beam Engine

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Stilldrillin:
Hi Peter! Welcome to the forum / collective.  :wave:

Stirling engines are all "alchemy", but soo satisfying when they finally run reliably......  :clap:

Good luck with yours. It will soon be sorted...... :thumbup:

David D

bogstandard:
Peter,

This was my first and only foray into building a sterling engine, this is a low temperature version.



After this vid was done, I duly did a fumble and dropped it onto the floor and bent the very thin crank, so it is gathering dust on a shelf awaiting rebuild  :doh:

Friction is the killer with these limited power engines, and lubrication isn't the answer, that usually stops them dead by causing too much friction.
On the type you have built, a think some sort of lubrication is allowed, maybe graphite powder. But smooth precision fits are the way to get them running at full wack.

It seems like Dr Sterling is due a lot of recognition, as designs on his engines are used on the space shuttle for refrigeration purposes, and the Japanese are looking at ways of using them in cars, they already have a solar powered prototype driving about. Third world countries are now using larger solar powered versions of them for water pumping and power generation. So not only is it a very old design you are mkaing, it is also maybe the saving of the planet by not relying on fossil fuels.

Keep at it, you will succeed in the end.

John

NickG:
John,

As you said, oil is a definite no no on the low temperature differential versions. I found with my meths heated water cooled one, a drop of thin oil on the displacer rod and one on the power pistons just helps seal it. You're dead right though, sometimes I've added another drop of oil whilst running and physically seen the engine slow down!

I know you've had success with flame gulper type engines, in your opinion which is more difficult to get to run? I've often thought due to a flame gulper sucking in very hot gases in rather than just air heated by a flame in a stirling engine, there must be a greater scope to gain a bigger temperature differential in the gulper therefore more of an under pressure and more power? - although there is only 1 power stroke. Also, I gather that if the hot gases are quenched too quickly the underpressure is too short lived and atmospheric air forces its way in before the valve closes.

Nick

klank:
John, Nick, David, Spin, Bernd and everyone - so kind of you all to take the trouble to post. Thank you all for the encouragement and good wishes.

State of play now:- I did the "blow in the hole" water test - no leaks apart from a bit around the displacer rod as expected.
I dis-assembled the "motion" and thoroughly cleaned everything.
The two con. rods connect to the crankshaft big end via two discs of brass, mounted eccentric/drilled and tapped on the thickness to receive the threaded ends of the rods. I polished their faces (they run close together side-by-side) but left them dry of lubricant - I think their flat faces would "drag" together if lubed too much.
The "bare" crank/discs revolves very freely in its plain brass bearings - one drop of clock oil on each.
One drop of oil on the displacer rod.
On linking up the displacer con. rod with piston attached and displacer cylinder sealed onto the block, sharp flick on flywheel - about 20 revs. No feel of binding anywhere.
The power piston drops like silk in the finned cylinder - I ran it in with a little powdered graphite. I made sure its gudgeon pin assembly inside the piston was free and sealed the screwed bit which projects through the piston crown.
Connected this up to the beam and the beam con. dod to the other disc. Same flick on flywheel - still about 20 revs.
All seems free.
Heated up the displacer cylinder end gently for a minute, flicked the wheel - 20 revs. I tried flicking the other way (just in case I'd got it wrong) and only 5 or 6 revs.
Eventually had the tube glowing on the end - same result!!!
One strange thing - when flicking the flywheel under heat, whilst it ran, there was a continuous singing/ringing sound as of a fairly small high pitched brass bell! (A bit like the sort on a Hotel desk if you know what I mean). Very odd.
?Resonance? of something?
The noise dies away if I flick it over as the tube cools.
The b***er still won't run. :doh:

John - that is a lovely little engine - so delicate. Is it like the one for which free plans were given in the ME a few months ago? Where do you get the plastic displacer materials? It is beautiful.

At our (local) club exhibition (Taunton) at the beginning of May, I was talking to someone who had a collection of Stirling engines running - he said Phillips had developed a commercial Stirling "type" engine which could deliver 900 b.h.p.!!!

bogstandard:
That definitely sounds like something is catching as the engine warms up, or a pulse vibration that is telling you that the main bits are working as they should.
 
Get the engine hot, and super gently turn it over slowly by the flywheel and see if you can 'feel' anything catching or going stiff.
 
Really the only area on the engine that would cause that sort of resonating ringing are the cooling fins. the ones on the hot cap would be the main suspects. Either something is catching in there, or the air, as it is pulsing, is causing them to resonate at a certain frequency. If you want to stop the noise, try sticking a tiny ball of crumpled up bacofoil between each fin.

Jan Ridders is the man to get plans from. He is a very knowlegeable man, and we have had some good discussions about his engines. In fact he has started to use one of my ideas for vertical wicks on flame lickers because of the success I had with one of his designs.

http://heetgasmodelbouw.ridders.nu/tekening_overzicht/tekeningen_overzicht.htm

Plastic tubing is easily obtainable from fleabay, if you want the address, I will root it out for you. I made the eggcup clear cylinder out of a garden light unit that I no longer wanted.

http://www.homemodelenginemachinist.com/index.php?PHPSESSID=a90213aca8b938f0d06e41e921b100dc&topic=1424.0



John

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