Low Temp Difference Stirling

[TaigTIN]

Hi all, I've noticed that not so many people make stirling engines, the ones that can run from the warmth of your hand. My question is, are these types of stirlings harder than lets say an Elmer's wobbler type engine? This is my 1st project ever, only like 2 months into this hobby. I can make my engine run on a hot cup of coffee, and that's it. My next challenge is to make it run from heat from your hand. So would a wobbler make a better 1st project? I mean this stirling hates friction and tolerances are soo tight. I resorted to ball bearings for main shaft since no other combination of metals worked in reducing friction. Anyway, sorry for the long post, but if anyone here has successfully made an LTD Stirling, and had it run from warm hands, I appreciate any input...

Martin...

 

[b.lindsey]

Martin,

LTD Sterlings are generally tougher to get running for the reasons you mention, friction, precision tolerances, etc. My half size mizer from Jerry Howells plans runs well though not from the heat of my hand. The main reason is I never took the time to balance it to that degree of accuracy, though if I did I do believe it will run that way....I have had it running on a 4 watt night light bulb, just runs slowly. If you already have a successful LTD Sterling then you should be fine on any of Elmer's engines, or similar projects.

Bill

 

[Blogwitch]

Martin,

I am sure you would gain a lot of info in your pursuit of a low temp Sterling if you have a read of Jan Ridders' offerings. He goes into deep discussion about his trials and tribulations and how he solved a few of them.

http://heetgasmodelbouw.ridders.nu/Webpaginas/pagina_ltd_stirling_met_cds/cd_dstirling_frameset.htm

Select 'English' at the top of the article.


Bogs

 

[mklotz]

An LTD Stirling will unquestionably be more difficult to build than any of Elmer's wobblers. Like Bill, I've built Jerry Howell's half-size miser and, like Bill's, it will run on very weak heat sources (or a plate of ice cubes) but not on the heat from one's hand.

Since you're a novice (I hate the term "newbie"), consider building a wobbler or two first, then a conventional Stirling or two, then try your hand at an LTDS. If ever there was a situation where the cliche "walk before you run" applies, it's building miniature Stirling engines.

 

[TaigTIN]

Wow, so if I can make and LTD Stirling even though it runs only on hot cup of coffee, seems like you're all saying Elmers engines are easier to build !

The only reason I started on an LTD Stirling as a 1st build is because since I'm new to hobby and I spent quite a bit on a Taig lathe, Scroll saw and grinder, it didn't leave me with funds for an air compressor. But thanks to your kind responses, I can now feel a bit more confident on taking on Elmer's style of engines.

Also, I liked the idea of bringing my stirling to work and have it running on my desk....want to see people's reactions, especially when I put it on a tray of ice and boggle ppl on how even ice has energy...

Martin

 

[black85vette]

A cup of hot coffee wows them pretty good! If you got it to run at all you did a good job.

 

[Longboy]

I made 3 coffee cup engines and I am just too cool of a guy *beer* to get any of them to run from my hand. When you learn the secret tell me! ;D

 

[mklotz]

Also, I liked the idea of bringing my stirling to work and have it running on my desk....want to see people's reactions, especially when I put it on a tray of ice and boggle ppl on how even ice has energy...

They'll be even more impressed if you tell them it's running off the energy in the air in the room - which is actually a little closer to the truth.

Another good trick is to have them put their fingers on the 'hot' plate of the displacer. The engine will speed up and you can tell them it's sucking energy out of their body - which is true.

 

[Mainer]

I built the full-size Miser, and after I first built it, it would, if the moon was in the right phase and I held my tongue just so, run on the palm of my hand after a bit of coaxing. It would run more reliably on my wife's hand, her hands tend to be warmer than mine. Now, after it's been mostly sitting around for about ten years, I can't get it to run on my hand anymore. It still does fine on a cup of hot water though.

A friend of mine built one, and his runs fairly reliably on one's hand.

 

[TaigTIN]

Any chance of getting the plans for the miser?...I'd like to give it a shot


Martin

 

[RonGinger]

Miser is a Jerry Howell design and the plans are on his website http://www.model-engine-plans.com/

 

[Tin Falcon]

If you are looking for free plans Jan Ridders will e-mail plans by request. Jan's plans are metric.
Jerry's I believe are imperial.
Tin

 

[njl]

Martin,

If you can't afford a compressor, you can use one of those pump up plant sprayers to run small wobbler type engines. When I was a kid I used to borrow my fathers from his green house and use it to power my Mamod steam tractor when I had run out of meths!

Nick

 

[Deanofid]

you can use one of those pump up plant sprayers to run small wobbler

What a good idea, Nick. Quiet, too.

Years ago, I used a tire pump. Just turned a little spud to fit in the valve stem clamp on the pump hose that reduced it to 3/16" to fit rubber tubing. It will run a small D valve engine, too, long as you care to pump it.

Dean

 

[Tin Falcon]

you can improvise on an air compressor. air brush compressor old refireration compressor bicycle pump. or even blow in the thing if the engine is built well enough . if you built a ldt stirling that runs you can build an engine that runs on lung power.
Tin

 

[Kaleb]

you can improvise on an air compressor. air brush compressor old refireration compressor bicycle pump. or even blow in the thing if the engine is built well enough . if you built a ldt stirling that runs you can build an engine that runs on lung power.
Tin

Or build a boiler! Live steam is a wonderful thing, and you won't regret it! Be sure to do it properly, though. I'm sure you could get all the advice you need here!

 

[TaigTIN]

I've also read somewhere that an aquarium pump works also....and the're like $20.....or I saw an airbrush compressor for like $50 on craigslist. For a little more, an airbrush compressor sounds like it would b enough..

Martin

 

[mklotz]

For $40 you can get an airbrush compressor from Harbor Freight...

http://www.harborfreight.com/air-to...si-oilless-airbrush-compressor-kit-92403.html

I have an older model from HF and it can run any of the many Elmer Verburg engines I've built, including the multi-cylinder ones. It will also run my horrendously lossy elbow engine.

Even if you eventually graduate to a larger compressor, these small airbrush compressors are great for impromptu tabletop demonstrations or shows where air is not supplied and you want to keep down the amount of stuff you have to transport.

 

[TaigTIN]

Thank you mklots, I live about 5 mi from a Harbor Freight....I'll have to pick one up.