# Head cold from Hell and maybe a Stirling engine



## Brian Rupnow (Jan 18, 2018)

I'm sick.--Sicker than a friggin' dog, suffering from a head cold!! Small wonder though--All my kids have had it, my grandkids have had it, my wifes had it, and the guys at work have had it. I thought I was going to be lucky and have it pass me by, but no such luck. My head feels like a giant bucket of snot!!  Now that I have shared that disgusting fact with you----I'm thinking of maybe building a Stirling cycle engine. I've always stayed away from Stirling engines, because they barely have enough power to get out of their own way. Today I watched a couple of YouTube videos by Tubal Cain, where he does a reasonably good job of explaining the operating principle of these engines. I would prefer to build a simple all metal engine with a power piston and a displacer piston, similar to the one in tubal Cain's video. I'm not really after the polished brass and glass test tube variety, which are works of art.--Nor am I after the "two tin cans and a piece of wire" variety. The one in Tubals video looks about right to me---Plain Jane, but all metal. I will have to see where I can get plans of that.---Brian
https://www.youtube.com/watch?time_continue=1&v=DkfXd8634WY


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## Brian Rupnow (Jan 18, 2018)

I just spent a good portion of my afternoon watching all four videos of Tubal Cain building a Stirling engine from scratch. He makes it look easy, but he is quite emphatic about warning that there are no plans, no dimensions, and no blueprints available. All I was able to glean dimension wise, was that the bore of both power piston and diffuser piston was about 3/4", the crankshaft  and diffuser piston rods were  3/16" diameter, and the connecting rods were 1/16" x 1/4" brass bar, the piston pin was either 1/16" or 1/8" diameter, and the flywheel was 3 1/4" o.d. the stroke on the diffuser side looked to be about 1/4" greater than the stroke of the power piston. The stroke of the power piston looked to be about 1 1/4". the diffuser piston was a loose fit into the diffuser cylinder to let hot air to bypass the piston and the power piston had to be a very very good fit into the power cylinder. Although his engines used castings for the two main components, I see no reason why they couldn't be whittled from aluminum barstock.
https://www.youtube.com/watch?time_continue=1&v=DkfXd8634WY


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## Brian Rupnow (Jan 18, 2018)

The displacer piston has about 1/16" radial clearance from the cylinder walls and the displacer cylinder is connected to the power cylinder by a 1/4" diameter passage. It seems only logical to me that the power piston at top dead center must not travel past this 1/4" passage.


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## Brian Rupnow (Jan 18, 2018)

After carefully watching and listening to all of the associated videos, I have learned that the displacer cylinder may in fact be 7/8" diameter. Apparently its not critical, as long as it is about 1/8" larger than the displacer piston. The displacer piston is actually the outer aluminum shell of an industrial paint or ink marker with the felt removed from the inside and a custom aluminum "bung"  Loctited into the open end. At top dead center and at bottom dead center, the displacer piston should be about 1/16" clear of the inside ends of the cylinder. The power piston is machined from mild steel. The angular offset between the crankshaft throw on the power piston and the displacer piston is 90 degrees.  It seems that "displacer" and "diffusor" are basically the same thing.


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## fcheslop (Jan 18, 2018)

This may give you some more info
i normally build with 1mm clearance for the displacer and use a ratio of 1.6:1 upto 2:1 
http://ridders.nu/Webpaginas/pagina_ervaringen_tips_stirlings/ervaringenstirlings_frameset.htm
I reworked Rudys tractors engine and she has a little bit more power
Mainly reducing dead space


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## Tom Jamboretz (Jan 18, 2018)

Perhaps this link would have plans that may be of help. Also IC engine plans.http://www.jerry-howell.com/Duplex.html     TJ


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## Hopper (Jan 19, 2018)

Be careful.  Stirling engines can be very addictive! And quite hard to get running sometimes.
Here's a link to detailed plans for Dr Senfts "Moriya", a well proven working model. It's a table fan but the basic design can easily be laid down flat with a flywheel to make a more conventional engine.
Link: http://courses.washington.edu/me355b/Fan_Project_Description.pdf

A common mod is to make the displacer cylinder ("hot end") from stainless steel so the heat does not conduct well up to the "cool end", as it is the temperature differential between these two ends that makes the whole shebang work. 

Have fun! (and hope you get well soon)


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## Journeyman (Jan 19, 2018)

Brian, I can recommend the various books by James G. Rizzo about Stirling and other hot air engines. plenty of plans and info on sizes etc. I think his first book was "Modelling Stirling and Hot Air Engines" published in 1985 so may be a bit hard to find copies now. Made my first engine from one of his designs, some details of my effort *** HERE *** all made from scrap, there is a PDF plan on the website.

John


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## Brian Rupnow (Jan 19, 2018)

I dosed myself up with antihistamines and managed to stagger in to my office across town today, and at the end of the day watched all four of Tubal Cain's Stirling engine  videos again. No offence to Tubal Cain, but the work in those videos seemed--Ahem---Pretty damned crude. At least "crude" in comparison to a lot of the work I've done on my own engines. However, the engines ran.--and they ran pretty darned good. It's a shame that a few more reference dimensions weren't given, but with what information was given it seems like it won't be difficult to extrapolate all of the unknowns. Of course if I try and build my own version of what Tubal has done, I won't be casting the parts. They will be cut from bar stock. The only thing I won't have absolute control over is the displacer piston, as it has to be made from a purchased aluminum bodied ink marker. Even if I don't make this engine, it will be a nice little design exercise. I probably will make it, if only because I have never made a Stirling before, it doesn't have a lot of complex parts, and it seems to be a fairly "forgiving" design.


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## fcheslop (Jan 20, 2018)

They are forgiving sometimes The main reason for failure is friction and air leaks 
Homeware sections in shops can provide good materials for the hot caps and displacors 
You can tell the Stirling builders they are the ones with a vernier  measuring ladle handles 
Another good source if you can find an electrical contractor using stainless conduit and the bigger engines stainless exhaust pipe although Im sure you already know that
cheers


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## Sleddog (Jan 20, 2018)

Brian Rupnow said:


> It's a shame that a few more reference dimensions weren't given.



Drop him a PM asking for them.


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## Brian Rupnow (Jan 20, 2018)

Sleddog said:


> Drop him a PM asking for them.



No, he mentions 2 or 3 times throughout the videos that he "has no plans" and that he doesn't "sell blueprints" and that he "makes it up as he goes along". I get the idea that he doesn't want to give out that information and I can respect that. His instructional videos on both the build and the theory behind the working principles are very well done. He does however, at the end of the final video give blanket blessing to anyone who wants to "copy his work".


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## Brian Rupnow (Jan 20, 2018)

Tubal mentioned that his flywheel was made from lead and was 3 1/4" diameter with a 3/16" center-hole. One of his engines had a spoked flywheel and one on a similar Stirling had the more simplified flywheel I have shown. No width is mentioned, but best guess is about 5/8" overall thickness. My flywheel will be 3 1/4" diameter x 5/8" wide made from cheap old mild steel.


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## Brian Rupnow (Jan 20, 2018)

Tubal had the advantage of casting his crankshaft supports as part of the main base. I don't have that option, as I am building from barstock, so my bearing stands will be 3/8" thick aluminum (maybe brass for some bling) bolted in place with #10 shcs from under the base. I will also counterbore my bearing stands for two 3/16" ball bearings. These ball bearings will have the seals removed and all traces of factory grease washed out with laquer thinners to give the absolute minimum of rolling friction. That 1" wide x 3/16" slot in the other end of the base is going to be for an alignment key for components which will be built up from the base..


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## Brian Rupnow (Jan 20, 2018)

And---Oh My!!!--What if we were to use the top end with the diffuser and power cylinder and mounting plate from the Moriya fan which is proven to work well---. The finned "cold end" will dissipate heat better than the solid casting used by Tubal Cain, and gets around the issue of me not being able to cast the displacer cylinder into the body like he did.--Also sets up the possibility of a cooling fan.---The power piston is the same diameter on both the Tubal Cain engine and the Moriya fan, but the Moriya displacer piston is slightly larger in diameter than the tubal Cain engine. (0.91" as opposed to about .780" dia.)


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## Brian Rupnow (Jan 20, 2018)

My cold is getting better. It's still there, but its going. I will try my favourite medicine soon---Gargle with whiskey for three minutes, then swallow. Repeat as necessary. I have worked most of today on this design, and although it is slowly taking on a bit more machining content than I initially wanted, I like the design. This is a very nice "middle of the road" example of an engine. It is not all polished brass and varnished base, but it's a step up from what I initially had in mind. I'm in no rush to start machining, so will keep working away at this 3D model until I have everything as I want it.


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## Brian Rupnow (Jan 20, 2018)

Makes a nice size package!!


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## Brian Rupnow (Jan 21, 2018)

So there we have it---Pretty as a new pup!!! I can't say I'm really enthusiastic about the studs called for in the Moriya fan drawings, but I will probably change them up to socket head capscrews when I actually get to building it. The entire top end including both diffuser and power cylinders and pistons are taken directly from the Moriya fan drawings, and if you take a look on YouTube there are literally dozens of videos showing Moriya fans a operating.  The offset on both power piston crank-throw and diffuser piston crank throw match that of Moriya's. The distance from the bottom of the cylinders to the centerline of the crankshaft again matches the Moriya fan.  The main base, flywheel, and crankshaft are more along the lines of what Tubal Cain shows in his videos. The only "exotic" material on the entire engine is that brownish colored piece of insulation between the hot end of the diffuser cylinder and the 1/2' plate it bolts to--It is called up as being asbestos, but I will try and source an insulating material that is a bit more health conscious.


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## Brian Rupnow (Jan 21, 2018)

The good news is that after scrounging around in my "left over pieces" bin, I've found enough material to build everything for this model. The bad news is that my printer just ran out of ink.


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## Brian Rupnow (Jan 21, 2018)

I wouldn't want you guys to think my life is dull or boring in any way---But it is winter. I had nothing to do today, so I started making parts. Todays work yielded the engine base. The eagle eyed among you may notice that the base looks a bit thicker than it does in the solid model. It is. I had a piece of 2" x 1" material, and decided not to spend any time making it 3/4" thick. This will ultimately work to my advantage because it gives a little more room to slide a can of Sterno under the hot end of the displacer cylinder. Today is my 29th wedding anniversary so me and good wife are off to a fancy restaurant for dinner.


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## Brian Rupnow (Jan 21, 2018)

What an ignorant wee piggy that gusset plate is turning out to be!! The piece of stock I have to make that from is just slightly larger than the finished part will be. My largest drill is 1" and the radius on the gusset is 1". There is really no good way to hold it in the mill vice to use my boring head. It looks like it will be a faceplate job. I will have to think about this one some more, and see if I have some scrap to make the brown colored fixture from.


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## Goldflash (Jan 22, 2018)

Brian 
I think you have made a basic mistake with your design 
The Hot air engine works on the expansion and contraction of gas due to heating and cooling 
I Think You have the Cooling Fins on the wrong side of the Plate which has the port going to the power pistons. 
I use Berocca Viatmin Tubes for the Displacer Pistons ( 1 inch Diameter ) or fabricate from alluminium Tube . Hot end caps I form from Copper Sheet and Hi Temp Braze to End of Hot Cylinder 
Use ball bearings with no oil just WD 40 for Lube 
Piston Rod bush make 4 x Diameter Long for any type of Gas Seal . Cast Iron is best ( self Lubricating ) 
Piston Rod is normally 1/8 " drill rod polished to mirror finish to reduce friction 
Power piston is cast Iron and run about 1/16 wall thickness 
Friction and Gas seal is Everything 
All cylinders are Spigot and Socket and use Thread Tape rolled into a twine to Seal . and a bit of Silicon sealer to hold in place 
Use WD 40 to lubricate 
These things wear out quickly as most do not use a cross head piston to take side load of piston rod and Leak air / gas 
I use a cross head piston on my designs to prevent this


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## Hopper (Jan 22, 2018)

It works both ways, ie fins north of plate or fins south of plate -- see the Moriya plans I posted a link to earlier. I prefer the way Brian has done it, and Moriya, because the plate then acts as a heat sink to stop heat form the hot end traveling straight into the finned area of the cool end. But plenty of other engines work the other way. The exact port location is not critical because it is the pressure going through the port that pushes the power piston down its bore and pressure is virtually constant through the whole system, depending on where the displacer piston is at and how much air is in contact with the heat source vs in contact with the cooling muff.

One advantage of having the cooling fins on the other side of the plate, as in the engine in your (Goldflash) pic is the connecting rods can be longer, giving less conrod angle, giving greater mechanical advantage and less inclination for sideways forces to jam the piston or guide rod. But again, plenty of engine made the other way work just fine too. So its six of one and half a dozen of the other.


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## Hopper (Jan 22, 2018)

Brian Rupnow said:


> What an ignorant wee piggy that gusset plate is turning out to be!! The piece of stock I have to make that from is just slightly larger than the finished part will be. My largest drill is 1" and the radius on the gusset is 1". There is really no good way to hold it in the mill vice to use my boring head. It looks like it will be a faceplate job. I will have to think about this one some more, and see if I have some scrap to make the brown colored fixture from.



Or you could clamp the job to the faceplate using a clamp and bolt, the standard type used to clamp a job down to the milling machine table.


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## fcheslop (Jan 22, 2018)

For the hot caps I use stainless steel or glass as they are poor heat conductors and like to machine a heat dam into the hot cap when possible. It seems to make for a longer running engine
kind regards


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## Barnbikes (Jan 22, 2018)

Brian 
Not to fill up your project post but here is a picture of the engine my dad picked up a while ago.

Like how they used wood as the center of the flywheel.


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## Brian Rupnow (Jan 22, 2018)

And here's an update on whats happening today. I trimmed my over-thick piece of material for the gusset down to 0.742" (that is the width my once sharpened 3/4" endmill cuts to.) The layout lines on the piece show the cut lines. The base is finished, setting in the background, with two likely candidates for the fixture which will be made to mount the gusset plate onto the faceplate for boring. There is no work at my across town office tomorrow, so I should be able to finish the gusset and maybe the last piece of frame plate that the cylinders mount to.


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## Brian Rupnow (Jan 23, 2018)

And for those of you who like to see set-up pictures---Here we have the 2" diameter hole bored thru the gusset plate. I used my longer boring bar to clear the bolts which are holding the gusset fixture to the faceplate.


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## Brian Rupnow (Jan 23, 2018)

All of the aluminum frame pieces are finished. Even though there was a fair bit of extra work carving the radius in the gusset, I like it.  Faceplate work is something I do very little of, so it was kind of fun.


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## Brian Rupnow (Jan 23, 2018)

I scrounged around in my brass drawer, looking for enough brass to make the bearing stands from. All I had that was big enough to get two pieces out of was the last of an aluminum bronze bar I've been using up. Damn, that's miserable stuff!! It's as hard to machine as mild steel. I'm glad that these two stands will be the end of it. I can't even remembered why I had it, but I will make it a point to not buy any more.


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## Herbiev (Jan 23, 2018)

Looking good Brian. Looks like the whiskey did the trick


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## Brian Rupnow (Jan 25, 2018)

Here we have a couple of rather poorly lit pictures of the bearing stands. One picture is an "in process" shot of the stands being reamed "in line" and one shows them assembled with a pair of very tiny 3/16" ball bearings from the r.c. hobby shop. I will take the side seals off the bearings and wash them out with laquer thinners to remove any grease. I still have to round of the tops of the stands.


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## Brian Rupnow (Jan 25, 2018)

Not a great deal of progress today, but some. I rounded off the tops of the bronze crankshaft stands and they are finished. I took the seals out of the miniature ball bearings and washed all the grease out of them.--This sounds rather counter productive, but it is what is recommended for Stirling engines, as it cuts down on the rolling friction.


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## Brian Rupnow (Jan 26, 2018)

I have almost reached the point in this engine build where everything "generic" in nature is finished, except the flywheel and crank throws. The crank throws will be made from aluminum. Tubal Cain made the flywheel on his Stirling engine from cast lead. I was going to machine my flywheel from mild steel, but mild steel just doesn't have that visual "pop" that I like so much. So--Today I stopped in to Barrie welding and checked out their shorts rack for a suitable piece of brass or bronze. I found this one for $18, and I will use it for the outer rim of the flywheel and machine a center from aluminum. Once this bit is done, everything that follows will be pure Stirling engine, courtesy of Moriya fans.--Plagiarism at it's very finest.


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## Brian Rupnow (Jan 26, 2018)

Todays offering to the machining gods--A pair of crankshaft "throws". Tomorrow, if I'm lucky, I'll finish the two piece flywheel and maybe the connecting rod journals. After that it will be hard and heavy into dedicated Stirling parts.


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## Brian Rupnow (Jan 27, 2018)

It's a flywheel!!! If I had five 5/8" holes drilled in the web and a couple of finishing passes on the sides, it would be a beautiful thing. I don't get silly and try to shrink the rim on. I completely finish the bronze ring first, leaving about 0.010" on each side and on the o.d for final clean-up passes after assembly. I machine the aluminum for a "damned close" into the bronze ring, taking the last few passes on the aluminum at .0005" until the bronze ring will just begin to slide over the aluminum. Then its get the #638 Loctite out, slather a bit on, slide the ring into place, and leave it set until tomorrow for finishing.


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## Brian Rupnow (Jan 28, 2018)

So there we have it.--a beautiful thing. Everything that is not directly related to Stirling engine parts is finished. This week I hope to start on the parts that will make this a Stirling engine.


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## Brian Rupnow (Jan 28, 2018)

Today I got confirmation that the baby Jesus still loves me. I was tapping #6-32 holes through the aluminum "crank throws" for grub screws to hold them in position on the crankshaft. The tapered tap was pretty "oinky" going in, but lots of oil and a very gentle hand got both pieces tapped. Since the center hole is only 3/16" in diameter, I had to run a bottoming tap through after the tapered tap to have a complete thread. The bottoming tap snapped off with a piece about the size of a babys fingernail still above the surface. I immediately thought "Oh Oh--I'm going to have to remake this piece". I went out to my garage and brought in an assortment of pliers, and VERY gently grabbed the little piece of tap still visible and VERY GENTLY worked it back and forth----And it came out!!!  That happens so rarely for me (the fact that it actually came out) that I thought it was worth posting about!!


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## Ghosty (Jan 28, 2018)

Brian, time to get some new #6 taps

Cheers
Andrew


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## Brian Rupnow (Jan 29, 2018)

This was a piece of "had it anyways" brass that is in process today. Normally I would buy a piece closer in diameter to the finished part here, but when you're dealing with "had it anyways" material the rules are different. This is destined to become the "power cylinder" on my engine.


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## Brian Rupnow (Jan 29, 2018)

I was a bit unimpressed with how "unfreely" the flywheel spun on my engine with the bearings degreased. Then I loosened the bolts off on one of the bearing stands, and WOW!!!
[ame]https://www.youtube.com/watch?v=lUDu-TNftR0[/ame]


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## Brian Rupnow (Jan 30, 2018)

And that is the last of the shiny bits for this engine. The power cylinder is on spec., and honed internally to knock down any and all ridges. I used a 3 stone brake cylinder hone, light oil, and my variable speed electric drill to hone it with. I still have the buffs and waxes left over from my hot-rodding days, an old Eastwood polishing kit. It certainly brings brass and bronze to life with a minimum of effort. I didn't notice until after I had taken the picture that there is still some layout dye tight where the cylinder transitions into a flange.


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## Brian Rupnow (Jan 30, 2018)

Oh Yeahhhh---


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## Brian Rupnow (Jan 30, 2018)

I'm very pleased with the way the "cold end" cylinder turned out. The slots between the fins are .094" wide, which happens to be the width of my HSS parting off tool. I cut the slots with power cross-feed--One hand on the "disengage" lever and one hand holding a can of spray on WD40. It was a bit nerve racking, but everything went well. Tomorrow before I take the 4 jaw chuck off, I will make the square cover that attaches to one end of this part.


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## ShopShoe (Jan 31, 2018)

Brian,

That cylinder is a work of art! 

I'm always happly to start my day reading your posts.

--ShopShoe


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## Brian Rupnow (Jan 31, 2018)

Thanks Shopshoe--You are the kind of person that I post for. I love it when folks step up and say hi. I know my counter shows lots of lookers, but I really like it when I hear from people watching.---Brian


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## werowance (Jan 31, 2018)

I'm also watching.  one of my first things to look at in the morning as well.  thanks for sharing your project with us.


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## Brian Rupnow (Jan 31, 2018)

This morning I managed to make the cover plate for the cold end cylinder closest to the flywheel. The cover and the cylinder are just held up there by faith and some pushed into place bolts, so I can take a picture. Now I have to go across town to my customer and help put on a dog and pony show for his customer.


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## Brian Rupnow (Jan 31, 2018)

Tomorrow should be---Ahhh---interesting. I plan on building the "hot end" displacer cylinder. Instructions say that it will work best if machined from a solid 1 1/2" square cold rolled steel bar. I bought the bar this afternoon and cut it to a length adequate to make the part, give 1/2" clearance to the chuck jaws, and 1 1/4" that is gripped in the chuck jaws. All work is to be accomplished in one "chucking" without removing and repositioning the part from the chuck. I'm not sure my machining skills are up to it. We are getting into some pretty darn thin walls and end in the finished piece. I'll let you know how it goes---


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## Brian Rupnow (Feb 1, 2018)

The hot end cylinder is probably going to be the most difficult part to machine on this entire project. As a consequence, I will post a step by step set of pictures. Picture number one shows the piece of material cut to length in my bandsaw and stood on end in my milling vice to center-drill one end. Picture 2 shows it in the 4 jaw chuck of my lathe being "centered". The nose of that long rod in the tailstock chuck is seated in the center drilled hole, and my dedicated dial indicator bearing against the side of this indicator rod which allows me to dial in the 4 jaw until the center drilled mark is exactly centered in the lathe. Picture 3 shows the end of the part after three 0.010" clean-up passes were taken to square up the previously saw-cut end. there is a lot of "stick-out" from the jaws of the chuck, so only light cuts were taken.


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## Brian Rupnow (Feb 1, 2018)

Now, with a tailstock dead center in place, I use my 0.120" wide carbide tipped cut off tool to plunge about .425" deep from the corner of the square stock, just behind what will become the 3/16" wide flange. I took a total of 3 passes side by side to allow me enough room to get a carbide tipped turning tool into the slot to begin turning operations on the rest of the length of material. The plan is to turn the o.d. of the cylinder down to a point where it is about .125" oversize from finished diameter.


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## Brian Rupnow (Feb 1, 2018)

And here we have the full length of the cylinder plus about 3/8" more, turned down to 1 1/4" o.d.---about 1/8" oversize from the finished diameter.


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## Brian Rupnow (Feb 1, 2018)

Up to this point, it has pretty straightforward machining. Nothing really exacting. Now I'm at the point where the bear shat in the buckwheat!! I have to drill and bore a hole 1 1/16" in diameter and not a hair longer than 2.00". The end thickness of this part is only 1/32" thick, and an over-length drilling is going to be really bad ju-ju. I will start with the 15/32" drill shown and work my way up in increments to 1" which is my largest Silver and Demming drill bit. Then I will bore the last 1/16" with one of my brazed carbide tools.


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## Brian Rupnow (Feb 1, 2018)

We have a hole--Exactly 1.062" diameter and exactly 2.00" deep. It was a lot more difficult than I thought it was going to be. I drilled and drilled, and then I bored and bored, and then I drilled some more and--Oh, you know how it goes. I didn't want to go larger nor deeper. I ended up right on spec, but its a lot more work than just drilling a hole through. My next step will be a scary one. I have to turn the o.d. down to 1.112" diameter, leaving only a 0.025" thick wall. This will be the part that determines whether I have made a hot end cylinder today, or just saved the flange.


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## Brian Rupnow (Feb 1, 2018)

We have a hot end cylinder. There is about 7 hours of work in that little sucker, but it turned out nice. After the hole was completely finished I turned down the o.d. in .005" depth of cut passes to the finished size of 1.112" diameter. When I parted it off there was a high pucker factor, and I didn't want to part it completely off in case it pulled out the end which is only 0.030" thick. I cut the last 1/4" off with my hacksaw, then dressed the remaining little stub with my belt sander.


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## Brian Rupnow (Feb 1, 2018)

It fits!!!--Right at the very last moment, after I had center drilled the hole locations, I remembered that I wanted to use shcs. instead of studs like it shows in the solid model. I called Brafasco, my local nut and bolt store to see if they had any #10-24 shcs. x 3" long, and they had 30 in stock.----So---I drilled the four holes undersize and tapped them. Now I have to figure out where I can buy some 3/16" Teflon for the insulator between the hot end and the frame. The Moriya plans call for asbestos sheet, but I won't be doing that. Hoping I can find a source locally.


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## TonyM (Feb 2, 2018)

Another build well on the way Brian. I am just amazed how much you manage to achieve as well as your other work and a cold from hell on top.


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## Brian Rupnow (Feb 2, 2018)

Hi Tony--The cold is better now. One thing about being semi retired, it leaves a great deal of time to play in my shop.--and it's winter here. 30 cm of snow and -20 temperatures, so I'm not inclined to go and play outside.---Brian


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## Brian Rupnow (Feb 2, 2018)

I went out this morning and picked up a scrap of Phenolic bout 3" x 1/4" x 10 for $2 from a local supplier in Barrie to use as an insulator between the hot-end and the rest of the engine.


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## Brian Rupnow (Feb 2, 2018)

Here is an interesting shot. Due to the tight tolerances on the cold and hot ends of the displacer cylinders, it is absolutely critical that the ends of the cylinders be perfectly square to the long axis. When I made the cold end cylinder, the end facing away from the chuck was squared off in the same operation as the bore. The other end however was cut off with a parting off tool, and I never trust parting off tools to give a good square result . As suggested in the Moriya plans, I attached the cylinder to a piece of round stock that was turned for a tight fit in the bore, and squared the end of the cylinder off.


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## Brian Rupnow (Feb 2, 2018)

I didn't do a whole lot today, spent half of it running errands around town and going to the toolshop to buy 1/8" endmills. I did manage to finish a piston. I departed from the Moriya fan drawings because they had the piston and the piston pivot made from two separate pieces bolted together. I couldn't see any benefit to this, so I made the piston a one piece unit with 4 "lightening" holes. I turned the piston to .002" oversize, then finished it up with 280 grit emery cloth strips, and once I got it down far enough to start into the bore of the cylinder I lapped it in with #600 grit carborundum paste.


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## Brian Rupnow (Feb 3, 2018)

Time for an update. This morning I completed the connecting rods for both the power piston and for the displacer piston. All I really have left to do now is to make the displacer piston and guide bushing for it and cut out/install the phenolic insulator between the hot end and the frame plate. In the video you will notice that I suffered a fit of tangle-mouth and said that all I had to do now was make the displacer cylinder. I meant to say "displacer piston".




[ame]https://www.youtube.com/watch?v=tCqg6uvvc2U&feature=youtu.be[/ame]


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## Brian Rupnow (Feb 4, 2018)

This was the morning to make gaskets and machine the phenolic insulator that goes between the hot cylinder and the machine frame. It machines very well, but its stinky dusty damned stuff. I wore a simple particulate mask and had the window open (brrr) while I machined it. Seems to have turned out well.


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## Brian Rupnow (Feb 4, 2018)




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## Brian Rupnow (Feb 5, 2018)

This morning I picked up the thin wall stainless steel tubing for the displacer piston, and machined the two ends from aluminum. Next step will be final assembly of the displacer and then assembly with the rest of the engine.


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## Brian Rupnow (Feb 5, 2018)

Everything is back together, and I have tried the first run. No joy yet. The engine wants to run, but there is a bit too much friction where the displacer piston rod passes thru it's guide bushing. The displacer piston is not rubbing on the inside of the cylinder. With the crankshaft throw disconnected from the piston rod, it is difficult to push in and out with my fingers. Everything is too hot to mess with right now. I have to think on this a bit---In the Moriya fan where the cylinder sets vertically, the weight of the displacer piston would not be putting any side pressure on the guide bushing, but I don't think that is whats happening here. If that were the case, my engine should run freely if I stand it on end. I may have to take the hot side of the engine apart and work some magic on the rod to bushing fit with some 600 grit compound.


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## Brian Rupnow (Feb 5, 2018)

Disassembly shows that yes, the piston rod is definitely binding in the bushing. I can remedy that with some 600 grit compound. More damning though, is that the pressed in piston cap opposite the rod is lose, and those things have to be air tight. I had pressed it and Loctited it, but the heat burned away the Loctite and the press fit was too light. I will think on this a bit and see if I can expand the existing cap mechanically or make a new one which would be a tighter fit.


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## Brian Rupnow (Feb 5, 2018)

This shows me pressure rolling the end of the displacer cylinder to decrease the inside diameter a bit to get a stronger lock on the cap which had came loose previously.


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## Brian Rupnow (Feb 5, 2018)

And there we have it my friends---FIRST RUN!!! I still have some tuning to do and some proper pivot pins to make, but Lord, Lord, I got a runner.
[ame]https://www.youtube.com/watch?v=q380skpC-AA&feature=youtu.be[/ame]


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## ZebDog (Feb 5, 2018)

I have been watching this build congrats on your first running stirling


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## Sleddog (Feb 5, 2018)

Way to go Brian. Congratulations on the runner.


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## Brian Rupnow (Feb 5, 2018)

Sleddog said:


> Way to go Brian. Congratulations on the runner.


Thanks Sleddog--I've spent the rest of the afternoon trying to refine things a bit. There are an absolutely amazing number of places that an engine like this can "bind".


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## Brian Rupnow (Feb 5, 2018)

And a second run after I have spent the afternoon taking out any "binds" I could find in the engine. It's just as I thought when I started--these engines don't have enough power to get out of their own way. The biggest challenge seems to be keeping them running once they have found their "sweet spot".
[ame]https://www.youtube.com/watch?v=g9a5bSxOGaQ&feature=youtu.be[/ame]


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## fcheslop (Feb 6, 2018)

Congratulations on a runner
Be careful these engines can become as addictive as they are frustrating
kind regards
frazer


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## ShopShoe (Feb 6, 2018)

Congratulations Brian.

It's great to get a runner that quickly. Your time from conception through design to build and run have lessened considerably since I started following your various projects.

I have had a stirling on my future build list for quite a while and you inspire me not to give up on that.

--ShopShoe


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## Brian Rupnow (Feb 6, 2018)

Okay--Perhaps a mini personal milestone has been reached. I have built a Stirling engine. It runs. It runs great, but it doesn't run long before the cold end heats up and with the loss of heat differential between the hot and cold engines it slows down and quits. I am not terribly impressed!! (Maybe a little bit impressed). I have no really good way to make the hot end any hotter, but I can make the cold end stay colder!!! If I make a new cold end cylinder with no fins and put a water jacket around it, using the same type of seal that I used on the Rockerblock water reservoir, then circulate cooling water through the jacket, the cold end should stay cold.


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## Brian Rupnow (Feb 6, 2018)

Just for the heck of it, I set the engine up this morning with the cylinders vertically aligned as they were in the Moriya fan, which I copied. The engine started up and ran like a trooper. Then after it had ran for about 4 minutes, the cold end heated up and it gradually slowed down and quit, as the hot and cold end temperatures equalized. to me, this only confirms the need for some type of cooling system on the cold cylinder.
[ame]https://www.youtube.com/watch?v=WAN8n9cw0YA&feature=youtu.be[/ame]


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## fcheslop (Feb 6, 2018)

Hi Brian, A stainless steel hot cap with a heat dam machined into it would help
Also that seems a mighty big flame you are using this wont help . The flame should have a sweet spot near the very end if its further up I would check how much clearance you got between the displacor and the end of the hot cap.Also check the power cylinders gap as dead space and air leaks kill these engines as does any binding how ever small
Moriya runs for a good hour or so on the original meths burner 
The insulating plate Im not sure how good that stuff is I used some of that insulating glass plate they use on oil heated injection moulding tools it goes between the tool and the platen sandanyo plate Iv known it as
Never the less youve a runner congratulations and happy fiddling with it.
kind regards


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## Brian Rupnow (Feb 6, 2018)

I could hear a noise when turning the engine over by hand, the noise occurring when the displacer piston was at its end of stroke farthest from the crankshaft. I just pulled the displacer cylinder apart, and sure enough, the piston cap was loose again. Time for a little experiment to see if I can silver solder the stainless I have. If so I will make a new end cap from thin mild steel and silver solder it on.


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## Brian Rupnow (Feb 6, 2018)

I've taken this as far as I can without adding auxiliary cooling to the cold end. I made a new piston cap out of mild steel and it easily soldered to the stainless steel piston tube. The engine starts fine. It runs for about 3 minutes, then gradually slows down and stops. At the end of that 3 minutes the cold end of the displacer cylinder is to hot to lay your finger against. I wonder a bit about the weight of the flywheel being too great, but again, going by the Tubal Cain videos, he casts his flywheels from lead, so my creation of aluminum center with bronze outer rim should be ballpark close. I'm very happy that my engine runs, and that it ran so easily without a ton of messing around with it. I would like it to set and run like that for two hours. If I am bored next week, I may make a water cooled version just to see what happens.


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## Brian Rupnow (Feb 6, 2018)




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## Foozer (Feb 6, 2018)

A little generator to power an LED [is it 'a led' or 'an led'?] is seen in the future . . .


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## fcheslop (Feb 6, 2018)

Good luck with the water cooled version
Youre displacer keeps blowing apart due to to much heat 
You could drill a small hole near the diplacer rod it wont have any effect on the running. Its often shown on other engine drawings
This engine was also my first Stirling engine and can confirm either horizontally or vertically they are sweet runners
cheers


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## Brian Rupnow (Feb 6, 2018)

No, the displacer piston "blew apart" because the aluminum cap wasn't a hard enough press fit into the s.s. tube. I made a new mild steel cap and silver soldered it in place, so it won't be blowing apart again. Does your engine which you make reference to have the big fan blade like the original Moriya plans? Does it run continuously without stopping? If it has the big fan, can you flip the fan with the engine cold and have it rotate more than one revolution?---Brian


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## fcheslop (Feb 6, 2018)

I no longer have Moriya it now belongs to Mr Stilldrilling I think he is on the forum
My Moria had an alloy flywheel and when turning it over you should feel slight resistance at one position or if you try to spin her you should see the engine bounce. I also fitted bronze bushes replacing the ball bearings to slow it down a bit
David is on MEM he would probably tell you about when a fan is fitted as he finished it by fitting one. I never got round to it
Still think youre flame is to hot and this is heating up the whole engine very quickly.My Moria would run for at least 1 hour when the fuel ran out
Another problem area on these engines is the displacer rubbing in the hot cap .Just worth keeping an eye out for it
Iv sent David a p,m on another forum to see if he has any video of her on utube
cheers


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## fcheslop (Feb 6, 2018)

Found this video of my old engine by David after he fitted the fan
https://youtu.be/gipPEklfEj8


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## Brian Rupnow (Feb 6, 2018)

Time for some "outhouse forensics" now. The Moriya fan Stirling is an exceptional design because #1--The fan is blowing (or sucking) air directly over the fins of the cold end to keep it cool in relationship to the "hot end", without blowing over the hot end to remove any heat. You can see this in a dozen different YouTube clips---the flame under the hot end doesn't even flicker.---and ---#2-the weight of the displacer piston is somewhat irrelevant, as it is operating in the vertical plane, so there is very little force on the guide bushing due to gravity. In the YouTube posts by Tubal Cain, he uses an aluminum casing off a felt pen with an extremely thin wall, which weighs less than half of the displacer piston in the Moriya. By doing this, he makes the gravity effect on the bushing as negligible as possible to provide friction free running. Instead of fins on his "hot end" he casts a very thick aluminum wall around the hot end which will act as a heat sink, which allows the engine to run much longer before the temperatures at hot and cold end equalize to stop the engine. Additionally, since he has less friction, he gets away with a smaller flame at his heat source. The only heat source I have available right now is my propane torch, but I hope to buy some solid fuel tablets or an alcohol burner later this week. Although I have no doubt that the water cooling I have designed would get the job done, I may instead go the same route as Tubal did and re-purpose an aluminum felt pen casing for my displacer cylinder. This would be about the same amount of work as a water cooling set up, with less mess. I'm learning as I go here, so be patient.


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## fcheslop (Feb 6, 2018)

Hi Brian, although I can see youre reasoning the crux of the matter may well be friction as the engine simply should not need a large flame to get it running
I ran Moriya horizontally and vertically with no ill effect on  performance and at that time it had a flywheel so there was no cooling from the fan
If you remove the blanking plug from the cross drilling from displacer to power piston the engine should turn with no friction or binding at any point .
My displacer was simply made by drilling into an alloy slug and a light press fitted cap and was probably a lot heavier than it should have been.
Air leaks are also a killer of these engines and its easy to find them by dunking the engine in water and turning it over
They are frustrating little beggars to make
cheers
frazer


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## Barnbikes (Feb 6, 2018)

Have to agree with to much flame. Most hot air engines/fans run on an alcohol lamp. Also you might want some more gap between your fins for cooling.


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## fcheslop (Feb 7, 2018)

Another notable point is that you are running the engine horizontally so it should run longer than when its vertical .
You can see a very simple burner running a 2inch bore engine in this video
https://youtu.be/DTqcLoUxCAg
The burner is just one of those small jam jars with a bit of stove rope for the wick .The rope is the size for sealing the glass into the door around 6mm
kind regards


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## Brian Rupnow (Feb 7, 2018)

Woke up this morning with a great idea.--(No, not that kind of idea I'm 71)--I don't have a small fan to blow cooling air over the cold end cylinder on my Stirling, but I do have a great big old air compressor with enough hose to reach my office/test bench. After good wife gets up I will do some really minimalist fixturing and play a stream of air across the cold end fins while running the engine to see what happens.


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## Brian Rupnow (Feb 7, 2018)

I'm just down here playing on my cad station until Momma gets out of bed----I'm going to take her to work at 10:00 and then go over to Canadian tire and buy some "Meth Gell" which seems to be jellied methylated spirits in a small container to use as emergency heat source when camping.


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## Brian Rupnow (Feb 7, 2018)

I must have done something to really anger the machine gods this morning. I picked up a can of jellied methylated spirits with the wick in the can, and set out to see if the engine would run with a lower heat source than the propane torch. The engine tried really hard to run, but never quite made it, neither in horizontal nor vertical position.---So as I am furiously spinning the flywheel by hand and muttering "Run you bastard" under my breath, I hear a crunch and everything stops. Close examination shows me that the 1/8" diameter piston displacer rod is bent. How in heck did that happen?--Pulled the displacer cylinder apart to investigate, and see that the OTHER end has pulled out of the displacer piston. Gahhhhh---What happens next!!! Okay--Quickest easiest thing to do right now is to get some weight out of that stainless displacer cylinder. It's wall is currently 0.045" thick. If I can mount it on a mandrel and take that wall down to 0.025" thick in the lathe, and work a little voodoo on that end that pulled out so it stays together, and make a new piston rod that should get me back to square 1.


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## Brian Rupnow (Feb 7, 2018)

In one of these pictures you can see the displacer piston in the lathe, on a mandrel. I removed .020" radially so the wall has gone from .045" down to .025" thick for weight savings. The piston was attached to the mandrel with Loctite. Believe me when I say it took seven men and a bulldog to get the mandrel out after the lathe operation. The  end which had came off was aluminum, and was undamaged. I loctited the outside diameter, pressed it into place with my arbor press, then went around the circumference every 45 degrees and gave the barrel a good whack with a centerpunch and hammer to securely lock it in place with a mechanical lock.


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## Brian Rupnow (Feb 7, 2018)

AWRIGHT!!! We have huge success!!! After reassembling the engine with a lightened displacer piston and a new piston rod, I still couldn't get it to run--even with the Propane torch. After multiple attempts and no joy, I thought "What have I got to lose" and squirted a bit of light oil on those ball bearings that I had so carefully removed the seals and grease from.--It took right off and ran like a Prince on the Propane torch. I watched it run for 10 minutes, playing a stream of air from my compressor on the cold end, then took away the propane torch and substituted a cam of jellied meth spirits. It ran another ten minutes . Then I got tired of holding my air nozzle on the displacer and quit doing that, and it ran for another ten minutes. I finally had to take the can of meth away to make it stop.
[ame]https://www.youtube.com/watch?v=jpFPORCCEXk[/ame]


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## Brian Rupnow (Feb 7, 2018)

The engine has just passed the half hour test, running in "horizontal mode" as I had hoped for. It doesn't appear to require a cooling fan nor a water jacket. It is running from the heat from a can of "methylated spirits". At this point I am ready to declare the engine completely finished and successful. If anyone wants a complete set of updated mechanical drawings in pdf format, contact me and send $25 Canadian to my Paypal account at [email protected] There are 30 drawings, including assembly drawings and bills of material
[ame]https://www.youtube.com/watch?v=Pc8sli9XXto&feature=youtu.be[/ame]


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## Brian Rupnow (Feb 8, 2018)




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## Brian Rupnow (Feb 9, 2018)

When I was ultimately successful in a half hour horizontal run with only the methylated spirits for heat I noticed one thing and commented on it in the video. The engine would speed up and then slow down as it ran. It never quit, but the speed changes were interesting. Now after running the engine another 3 or 4 half hour runs, it is running much faster and not intermittently slowing down. I am assuming there were different "high friction" points in the linkages and bearings, that were not readily apparent to me, but were significant to this one flea power engine. The more it runs, the more these "high interference spots" get worn down until they disappear.


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## Brian Rupnow (Feb 10, 2018)

During the time I was building this engine and posting my progress, someone suggested that it should run with the heat from a "tea candle". I thought--"Oh sure. Maybe one of those test tube and graphite Stirlings would run on a tea candle, but not this one. It's simply too heavy for that."---Well, this morning  it proved me wrong. I can hardly believe this myself.
[ame]https://www.youtube.com/watch?v=fsvoGoJUIXA&feature=youtu.be[/ame]


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