AlphaVictory Engine Build

[IronHorse]

Time for a new project. I have had my Lathe & mill for about 3 years now, and I think it is time to design my own engine. I have decided to build an Alpha-type Hot-Air Engine.I was going to call this the "Alpha V" but after my wife saw the drawing, she put up 2 fingers and said "Victory" so the name will stick. I could not find much information on this type of engine, except for some research done at Gazi University in Turkey. http://journals.tubitak.gov.tr/engineering/issues/muh-00-24-2/muh-24-2-2-98073.pdf

I also found this interesting animation on the web.

So I dusted off a old copy of Pro/Engineer and started to put some ideas together.Here is a picture of the model created in Pro/E:

After spending months designing this engine, I really appreciate all the people who make engine plans available on the net. This was a lot of work compared to just following a set of plans. I had to make a lot of assumptions and I Incorporated a lot of ideas I found from many different sources. I do not know if this design will even run, but I sure did learn a bunch of stuff on the way, and if it fails, it will make a nice doorstop! I will try to describe some of these design points along the way.

One of the most satisfying moments came when I finally got the motion analyses to run on the computer. It was like getting a model to run the first time. :big: Here is a short movie of the motion analyses.



Time to cut some metal. I started off with the cold cylinder, nothing too exotic here, just bore and cut some fins on some Ali. There are 2 threaded holes on the top of the cylinder. The large one is for the Regenerator (Economizer) and the other one is a port to release the compression in the cylinders for testing. This port can also be used to pressurize the engine. These type of engines will develop more power if the working gas is pressurized. Using Helium will increase the power even more.

Cutting the fins;

Boring the cylinder;

Milling the flat;

Parting off;

Next will be the hot cylinder.

IronHorse

 

[Deanofid]

That sure is a nice looking cylinder you have turned up there. I think this is an interesting design you've chosen, Ironhorse. This should be a great build!

I've come across a couple of these on Youtube. Possibly a search there would turn up another builder with a brain you could pick. Also, a fellow named Andrew Ross has a similar type, and I've seen pictures of it done up from castings. There are a few webpages about him out there.

Dean

 

[Troutsqueezer]

Very nice rendering there IronHorse. It will be interesting to see it progress.

On a side note: I like your avatar. When I was a kid, Ed Big Daddy Roth was one of my heroes. I built every plastic model he ever came up with and I cut my teeth on drawing each and every one of his creations until I could reproduce them line for line without looking. Rat Fink was always my favorite. I wound up with a minor in art mainly due to Roth and his Kustom Kulture and still pencil draw to this very day, although now I focus on portraits.

-Trout

 

[Longboy]

........I'll have to follow this one. I haven't made any Alphas and this type is scarce on You Tube and is the type developed for commercial usage. Lead the way IronH and if it doesn't pan out you can convert this one to a Gamma. Dave.

 

[BigBore]

Very cool! 8) Thm: 8)

I'll be following this one. I don't have a clue as to how or why it works (yet) but I'm in for sure. Thanks for doing this build. Class has started.......sit down in your seats and pay attention!

Ed

 

[Philjoe5]

Interesting engine Iron Horse. Thanks for posting the pictures and video. Here's to success in your efforts *beer*

Cheers,
Phil

 

[b.lindsey]

Great looking design IronHorse. Since the volume of air shared between the displacer side and power piston side is recycled (heated/cooled) does the lower portion of the displacer piston therefore have to seal with the cylinder wall? Also (and I may be mistaken here) I was thinking that the power piston is usually assisted on its return stroke by atmospheric pressure. If that is true then is the crankcase vented somehow to achieve that? Obviously I need to do more research on these Alpha types...but I am loving what you have done so far!! Looking forward to the build and best wishes for a successful runner.

Bill

 

[IronHorse]

Trout; I have always liked the Rat Fink, sort of the anti-Micky ;D

Dean; I will check out those tonight.

Bill; I wondered about the lack of Atmospheric pressure too, but it is a closed system, so not too sure yet.

 

[Longboy]

Great looking design IronHorse. Since the volume of air shared between the displacer side and power piston side is recycled (heated/cooled) does the lower portion of the displacer piston therefore have to seal with the cylinder wall? Also (and I may be mistaken here) I was thinking that the power piston is usually assisted on its return stroke by atmospheric pressure. If that is true then is the crankcase vented somehow to achieve that? Obviously I need to do more research on these Alpha types...but I am loving what you have done so far!! Looking forward to the build and best wishes for a successful runner.

Bill

There is no displacer in an Alpha Stirling. Both sides have a conventional piston that seal with the cyl. wall. On the cold cyl. side the temperature drop in operation lowers atmospheric pressure to below ambient and therefore surrounding atmos. pressure contributes to piston returning up its bore. Since the Alpha Stirling principles are in play above the piston crowns, a sealed crankcase would be at ambient outside atmos. pressure anyway but a vent at this point may help intermediate pulsing by leaking pistons moving up & down in bore. Dave.

 

[Ed T]

This guy has some very interesting stuff about ALPHA Stirlings www.stirling-fette.de/english.htm - Cached. I have not been able to access the site w/o going through GOOGLE. If you put the link into google, it should be one of the top listings.

 

[Diy89]

Sweet cylinder, this is going to be a nice runner.

 

[kvom]

A lucite cover plate for the crankcase would be a nice touch.

 

[IronHorse]

Kvom:

I had that idea too early on. I was going to use a watch crystal for the "Window". I may still do it on phase II.


IronHorse

 

[robertvi]

Nice to see you will be able to seal the whole crankcase to allow pressurization. I read in James Senft's introductory book about Stirlings that a pressurised engine achieved a higher power density than a diesel

 

[cfellows]

This is the first style of Stirling (is it a stirling?) I ever saw a drawing of. I've not seen one in operation. Looking forward to watching your progress.

Chuck

 

[IronHorse]

The Hot Cylinder:

This was a new experience for me; cutting Stainless steel. I was going to make this out of CRS, but then I figured that since I am using a graphite piston and no oil is used, I might have a rusting problem on the inside of the cylinder. I decided to use some 303 Stainless for this part. My new indexable cutters worked good, but the chips that come off are really hot .

Boring out the cylinder;

Drilling the mounting holes; This was a little nasty operation. I was probably drilling at the wrong speed or something, but the drill bit looked like is was beat with a hammer after drilling a couple of these holes.

I had an idea to make a crude type of heat exchanger on the hot cylinder. I have read that you should make the cylinder walls as thin as possible, but I did not want to go less then 0.05" wall thickness. This heat exchanger will allow a local thinning at the heat source and also increase the surface area. I probably should have made more, closer cuts, but I will test this version first. I did not want the cuts completely around the cylinder, so I offset the part in the four jaw.

Parting off. I actually cut through the entire width, instead of resorting to a hacksaw. I think at times my neighbors thought I was skinning a live cat

At the same time I used my RT to cut out a thermal spacer from some 1/8" Phenolic.

.

Next Up: Crankcase

IronHorse

 

[b.lindsey]

Nice progress IronHorse...looks like you conquered the stainless as well, and with a very nice finish too!

Bill

 

[kcmillin]

Beautiful work.
How did you get such a nice finish on the cylinder? Its takes me alot of sandpaper and a few burnt fingers to get something that nice.

very impressive.

Kel

 

[Deanofid]

It's coming along nicely, Ironhorse.
I recently got a supply of ceramic sheet for the insulators on my own current stirling build. I've read that it is more effective than other materials. It's 1/16" thick, and can be stacked a few layers thick if needed. I have a small excess. If you'd like some to use for this engine, you're welcome to it.

Dean

 

[Philjoe5]

Looking good IH. That's a neat trick for making a thermal spacer.

Cheers,
Phil