# Gamma Stirling



## eskimobob (Nov 2, 2009)

It might be a bit late to start a thread on this I guess because I have done a lot of the work already. 

I've been interested in Stirling and Hot Air engines for a long time and in about 2002, my wife bought me a Stirling Engine kit for my birthday. It turned out to be a box of barstock (cut near to size) and a set of drawings. At the time I had only hand tools and no chance of getting a lathe or drill press so I put the box away for the future.

Fortunately I now have the space and over the last couple of years have bought and been getting familiar with some machines (Myford 'M' Type, Drill Press and an old stripped down Denford Triac which I have rebuilt).

I have recently been making some progress on the Stirling engine. The part with the most machine operations so far has been the cooling block. It took me an age to drill the 102 x 4.1mm holes. 
Anyway, this being my first proper engine, I want to give it a bit of a shine so I read with interest the tutorial on polishing which rcplanebuilder has done. Having bought a small mop bit for my Dremel (not actually a dremel but almost identical) and some metal polish (can't get MET-ALL in the UK so bought PEEK instead) I set to it last night and am pleased with the results. Here's a before and after pic.







I'll add some more photos as I get on with bits but here's an Alibre representation of what it might look like assembled.


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## tmuir (Nov 2, 2009)

Wow!

I haven't seen that style of cooling block before, very different and very cool looking.
You've got a great finish on it too.


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## zeeprogrammer (Nov 2, 2009)

I was reading the post from bottom up and first saw the rendering of the engine.
When I saw the cooling blocks I thought it was another rendering.
Was I surprised...and impressed. Very nice.

(It's not that I read the posts that way. I use the 'recent posts' and start looking at posts where I left off. That means I see the bottom of a post first...and its pictures...and have to scroll up to the beginning of the post to start reading.) ;D


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## black85vette (Nov 2, 2009)

Interesting cooling block and nice job on it. Where is the kit from?


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## mklotz (Nov 2, 2009)

I hate to bring this up but metal will be a better heat radiator with a matte, rather than a high shine, finish.


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## BobWarfield (Nov 2, 2009)

Hence radiators are black, Marv.

But you being the math/physics whiz, how much of a difference does it make?

A few percent?

Hate to give up that bling for a few percent!

Nice job!

Best,

BW


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## vlmarshall (Nov 2, 2009)

Machinery's Handbook, under "Properties of materials", lists the heat transmission of iron as: New, .5662 Btu/hour , and Polished, .0920 Btu/hour.

It's not Aluminum... but it gives you an idea of what polishing a surface will do.

Still... that's a unique cooling block, I hope it works for you. ;D


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## Deanofid (Nov 2, 2009)

It's really pretty, Eskimobob! Hopefully, with all those holes, you'll have a good amount of cooling. Great finish!

Dean


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## eskimobob (Nov 3, 2009)

Thanks for the kind comments guys  - Regarding reduced cooling effect, I never gave it a thought :big:

I got a bit more done on the flywheels last night. Drilled the cosmetic holes and tapped the shaft screw thread.






Plan to bling them up a bit too when I get time.


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