Moriya Stirling Fan - Double size

[David Morrow]

The short version of a long story is that after having built one Moriya ( a variant, really ), I wanted to repeat the experience without building the same thing. So double size it is. I'll post the pic's here and a brief description. For a bit more detail, you can have a look at the build page here :
http://www.ldrider.ca/cnc/moriya-double/moriya-double-1.htm

The material for this thing, at least the material for the base and the displacer cylinder are awfully big for my little Sherline CNC mill and Myford S7 lathe.

I cut the 1" thick slab of aluminum down to size first on the band saw.

Next, I printed and glued the cad drawing to the work piece. For more complex jobs this really helps ensure everything gets done and in the right order.

The bulk of the displacer hole gets cut out with a hole saw. This takes all of 2-3 minutes on the drill press and means much easy job for the light mill.

Being so thick, I don't like to commit to milling down 1 inch as part of a single operation. So, I break it up into smaller jobs of about .250" - .350" at a time.

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I got a bit ahead of myself in the beginning. A sneak preview... but it's a secret so do tell and don't ask.

 

[David Morrow]

Base is cut out and partially drilled. First sub-assembly mounted.

 

[GailInNM]

Looks good David.
Moriya is one of my favorite engines.
Gail in NM

 

[David Morrow]

A bit of progress over the past couple of days.

One big lump of aluminum reduced to a smaller lump of aluminum.

That was exhausting...

 

[David Morrow]

For a variety of reasons, I made the cold end cap square but I don't know if I like it yet. I can rework it so that it's round but I'll wait until the rest of the fan is mostly finished to see how it all fits in esthetically.

Power cylinder is now started. It'll be about 2" O.D. x 4" long

 

[lazylathe]

That looks great David!

Will be an excellent Stirling fan once completed!!
Nice and big and purposeful!!! ;D

Andrew

 

[kustomkb]

Very nice work!

I have the Moriya book too. One day...

Thanks for the inspiration.

 

[David Morrow]

Due to the large diameter of the brass needed to properly scale up the power cylinder, I minimized it and made a retainer to secure it to the base instead.

 

[David Morrow]

I decided that the square cap on the cold end just didn't quite work esthetically so I turned it down on the lathe.

 

[David Morrow]

Crank brackets cut but with a bit of finishing work remaining. My eyes continue to have difficulty trying to get a handle on the relative proportion of some of the parts but I have no doubt that they are correct.

 

[David Morrow]

After a whole lot of time making the displacer connecting rod, I decided that it was going to be too heavy. I made another one but this one is not only much lighter, but it's a better visual match to the power piston connecting rod.

 

[Lesmo]

Hi David

I really like this one, it’s nice and solid, it will be a treat to watch when it’s running. I will be following along. By the way I love the fan flywheel, really smooth and curvy.

Regards Les

 

[David Morrow]

Well, it's Fall again and the bike is in the garage for the Winter so it's back to the basement.

Here are the crankshaft lobes. I'm afraid that they may be a bit heavy so I may have to reduce the diameter, mill some lightening holes or mill something decorative in them to get rid of some weight. That will have to wait until the job is otherwise complete to see how it runs.

 

[David Morrow]

Bearing retainers for the crankshaft; a nice evening project :

 

[David Morrow]

I made the fan blade web last night ( blades and hub to follow ).

One quirky little element that I added was a mini fan to help keep the displacer cylinder cool. I don't know if it will work or not but it should add some visual and mechanical interest to the project. Here is the drive pulley up close and a full frontal shot of the project to date.

 

[David Morrow]

The blade assembly felt like it was a little heavy with just three blades attached and I was a bit concerned about adding two more. So, I redesigned the web for three blades ( which also made the web lighter. )

 

[David Morrow]

One part of this project that I was a bit unsure of was making the legs. As it turned out, it was easier that I figured. I made a jig from plywood and MDF, made some careful measurements, and put my shoulder into it. So, now we have legs. I also made a platform that will help to secure the legs but also serve to ( hopefully ) deflect some of the heat away from the cold end as well as serve as a place for yet another platform below that to place the alcohol lamp.

 

[David Morrow]

Here's an idea of size; this new fan compared to a regular sized Moriya ( variant ) on the right. And a bottle of IPA for those who prefer that sort of comparison ( my preference ).

 

[David Morrow]

Power cylinder crank arm and connecting rod now complete and installed.

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[David Morrow]

The hot cap is now mostly made; I used a piece of steel tubing which was fortunately ready made with an I.D. just a few thou' sort of what my finished dimension was going to be - a huge bonus in lathe time. And the O.D. was just over .250" over the finished dimension. The next step will be to silver solder the end plate on. I will likely use a piece of very thin copper or brass for its very high thermal conductivity.

And, I milled the retainer to hold the cylinder to the base.

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