Heat sources for model Stirling engines

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Heat sources for model Stirling engines

Postby Autolycus » Fri Sep 21, 2012 1:54 am

Hi all,
I have a few basic Stirling models from various sources, including the obligatory coffee-cup variety and one that runs from a liquid-fuel burner with a wick.
The thing is, I detest the idea of igniting such a smelly device under the engine's glass "cylinder" bulb, then watching as soot gradually obscures and reduces the effective heat transfer from such a source. I have successfully installed a 220vac lamp holder under the Cylinder bulb instead.
From an aesthetic viewpoint, this works very well. The compact spot bulb is of the 50-watt, 2" diameter type, as used in various concealed domestic lighting applications (you've guessed it, I've forgotten the exact type & model number whilst writing this...), and doesn't look out of place from the "front" of the clear plastic Display Case (made by Trumpeter & bought from a plastic model kit shop off Nathan Road in Hong Kong...), that it all sits under. The spotlight bulb is secured in an angled holder/base, so may be directed upwards and "rearwards" - from the viewing perspective - thus illuminating the engine without dazzling the watcher.
There is, however, just one teensy-weensy problem. This 50-watt, mini-spotlight bulb is just not hot enough to generate sufficient radiant heat to expand the air in the cylinder bulb and get this whole thing spinning...! When the spotlight is switched on, with the plastic case removed, "flicking" the flywheel gently does impart an initial attempt at rotation - which almost immediately fades away. Applying the business end of a small hair-dryer does have the desired effect, with the motor whizzing into life, so we know everything works as advertised - but a noisy, bulky, electric hair dryer is not an option for this application...
And that is where you come in.
Does anyone out there in the specialized world of Stirling-type engines know of a company that either makes Really tiny, 100-watt or even 150-watt spotlight bulbs - of any voltage - and which are powered by either a.c. or d.c. current? Alternatively, has anyone else found a supplier of compact, ceramic, electric Heating Pads that will sit unobtrusively and silently underneath one's cylinder(s), gently coaxing such simple Stirlings into circulation?
We all appreciate that thermal insulation, adequate ventilation and appropriate electrical installation will be priorities in such an endeavor, but we are determined to have a silent, smoke-free, sensitively-lit Stirling model engine up & running - in its own transparent enclosure - soon...!
So, now it's over to the mages & sages of the Stirling world, for your words of wisdom... Please? :?:
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Joined: Fri Sep 21, 2012 12:53 am
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Re: Heat sources for model Stirling engines

Postby Brent » Mon Sep 24, 2012 10:25 am

If you want an very elegant solution I would get a "thin film heater and regulate it with a rheostat.

Here's a Google image search so you know what they look like. Or search Google images for thin film heaters.

http://www.google.com/search?q=thin+fil ... 68&bih=612

I've also had good luck with 10 watt christmas light mounted very close.

Brent Van Arsdell
Brent Van Arsdell
American Stirling Company
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Re: Heat sources for model Stirling engines

Postby Autolycus » Mon Sep 24, 2012 8:02 pm

Hi Brent,

Many thanks for the info - I'll do a google search for both options and let you know which is the most effective solution.

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Joined: Fri Sep 21, 2012 12:53 am
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Last Name: Herbert

Re: Heat sources for model Stirling engines

Postby jelo » Thu Nov 15, 2012 2:11 pm

Yes be sure to check out the thin film heater with a rheostat as it is suitable for your intended purpose.
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