# 3 Cylinder Swash Plate Engne



## Captain Jerry (Sep 2, 2009)

Hi Y'all

This is going to be my next engine build. It bears a resemblance to the Weeble engine but rather than using a wobble plate to translate axial motion to rotary motion, it uses a Swash Plate mechanism. The swash plate is commercial 1/2" bore ball bearing mounted at an angle to the output shaft. The piston rods (arms) are seated on the outer race and the inner race is mounted on a brass core that is set at a 20 degree angle to the output shaft. The rotary slide valve owes it's design concept to the valve in Elmer's 3 cylinder radial but has been redesigned to allow a double ended shaft. It also eliminates the extremely small diameter drive pin in favor of a normal size eccentric.

It is also slightly larger than the Weeble, with a 5/8" bore and a 29/32" stroke for a 3.1 cu.in
 displacement.

Please excuse the bad math. The displacement should be .834 cu.in. (I used diameter instead of radius in the above figure).

Here it is as an Alibre Model in motion.

http://screencast.com/t/h5nnVb1K


Jerry


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## Captain Jerry (Sep 12, 2009)

I am finally getting into the shop to make some parts. The most important part in this engine is the angled bearing seat that gives the wobble plate its nutating motion. I am using a bearing with a .5" bore that is .31 thick. This will let me set a 40 deg. angle. 

The bearing seat was turned from 11/16" brass hex bar. A 1/2" diameter was turned for a length of 3/8" on the end of the bar. The bearing will be held in place with an external snap ring so the snap ring grove was turned and the snap ring installed. I then extended the 1/2" diameter for a distance of .30" from the inner face of the snap ring. From here it was fit and face until the bearing was firmly held in place by the snap ring. 

The part was then reversed in the chuck an faced off with a 70 degree point. The part then was placed in a custom fixture to drill the angled hole for the shaft. If I had a good tilting vise, I would have used it but I don't. The fixture held the part at the correct angle and made it easy to center the part under the bit.  With the part tilted 20 degrees and the 70 degree angled face, the drill bit entered at 90 degrees so skidding was eliminated. A hole was drilled and tapped for a grub screw and that was it. 

Not really. After a day and a half of frustration, mishaps and head slaps, this is how it turned out.












I'm not going to bore you with all the minute details of this build, just the highlights. The bearing inner race mounts on the angled seat and an aluminum ring with three equally spaced piston rods and the control arm is pressed onto the outer race.







More to follow.

Jerry


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## Captain Jerry (Sep 12, 2009)

A few more parts this morning. These are the rotary valve parts. There is nothing unique in the machining except maybe the eccentric which was created by setting one jaw of the scroll chuck one turn late in the chuck. This has been shown elsewhere on this forum by BOGS and others.











I was having difficulty with my local internet connection and images would not upload. The previous post has been edited to include the pics

Jerry


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## Captain Jerry (Sep 13, 2009)

A few more parts. The end plate on the left is the head end. It includes the cylinder mounting holes, the valve ports and the air distribution channels. The three small holes around the center that line up with each of the cylinder mounting holes distribute air to the cylinder heads and return exhaust. The single hole at the six o'clock is air in and connects to the air port on the outside edge. The single hole at about 2 o'clock is the exhaust and connects to a similar port on the outer edge. The six holes in pairs at the outer edges are for standoffs between the two plates.






The cylinders have a 5/8 bore. The started out as brass pipe and it might be considered cheating not starting out from solid bar but since I buy brass scrap by the pound why buy all those chips in the center? The head end is closed with a 1/4" thick disk that is soldered in place.






Cylinders in place, and valve parts on shaft. 






Valve cover in place. In the above picture you can see that the air intake port is opent to the #3 cylinder and using clockwise rotation the cylinder port is just beginning to close.






Moving on to pistons next.


Jerry


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## Captain Jerry (Sep 18, 2009)

The pistons are made. As wear occurs, they will need an adjusting screw across the the slot to maintain fit. That will take a very small screw (2-56) which I don't have on hand so I'll add later.






This thread dose not seem to have much interest so I'm going to shorten up the process. All the critical parts are made. I still intend to add ball bearings to the end plates and o'ring seals in various places but this is a new design and I want to see it assembled before making these additions. Here are the parts.






Here it is assembled. 






Now on to the testing.

Jerry


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## Kermit (Sep 18, 2009)

I think you're wrong about the level of interest in this build Jerry.

I for one, have never seen a "swash plate" anything before, so understandably, I have nothing to add to this post. But I do want to understand it when you are done building. Please, continue to explain as you go along.

Please!  

Much respect,
Kermit


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## Majorstrain (Sep 18, 2009)

Nice work Jerry,

Please do continue the progress pics, I've been occupied outside the shed and have just caught up on reading your thread.

Looking forward to seeing it running.

Cheers,
Phil


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## joe d (Sep 18, 2009)

Same here, Jerry:

Don't have any knowledge of swash-plate technology, so I'm following to learn. Please keep posting...

Cheers, Joe


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## Brian Rupnow (Sep 18, 2009)

Jerry---You are doing fantastic work, and we are all watching and learning!! I'm not getting a lot of APPARENT interest in my pump series either, but people are looking at the posts, you can tell by the "thread counter". I find that some threads get a lot of opinions and comments made on them, while others don't seem to get a lot of interest---but---people are interested---they're just not commenting. Keep up the great work.---Brian.


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## zeeprogrammer (Sep 18, 2009)

Yeah...what Brian said. The counter counters your comment .
And I too have been watching this build with interest.
Please keep it going.


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## Cedge (Sep 18, 2009)

Jerry
I too am watching your progress with great interest. The Swash Plate engine is one I'm hoping to tackle in the future, so you're plowing ground that some of us might be digging in, down the road. Having done a couple of build logs, don't let the lack of questions or critique convince you there is a lack of interest. In most cases you are the only one who really knows where you are going, so most of us don't know what to ask let alone how to assist.

These guys are as supportive as any you'll ever encounter, so keep posting and we'll do our part by reading and cheering you along.

Steve


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## Maryak (Sep 19, 2009)

Jerry,

When you as far from convention as you are with your designs you are pretty much on your own. I like many others enjoy your posts but what to say that is constructive and relevant.............. I'm lost. *Please *keep on keeping on and we will keep on trying to follow where no man has gone before.

Best Regards
Bob


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## dsquire (Sep 19, 2009)

Jerry

I too am watching the progress and enjoying and learning as you go. I may be silent on the sidelines but I would like if you carried on with the posts and the build. I know this is going to be an impressive engine when finished. :bow:

Cheers 

Don


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## Captain Jerry (Sep 19, 2009)

Hi Y'all

Thanks for the kind responses. I hope I didn't sound like too much of a primadonna but the other day my wife commented that I sometimes suffer from the delusion that she is listening to me. It got me thinking!!

The posts will continue but I had to take a day off from the project to bury a horse. 

Best to all
Jerry


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## zeeprogrammer (Sep 19, 2009)

You didn't sound at all like a primadonna...but I know what you mean. Sometimes you wonder if people are interested. But it's a great forum...great people.

Sorry about the horse. Family? (And that's not supposed to be funny. I lost my dog last year...it was hard.)


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## Captain Jerry (Sep 19, 2009)

About the horse, it was difficult for all of us but mostly for my grand daughter. It was the jumper that carried her through many events and championships on the local and national level and helped her win an equestrian scholarship at the Univ of Tenn. Katie had only been at school for 3 weeks in her first year. Bez was 23 yrs old and had been retired for a couple of years.

Katie has gone back to school and things are settling down around here.

Jerry


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## deere_x475guy (Sep 19, 2009)

Jerry I too have been silently watching in the background with interst. Keep up the posting...and thanks for taking the time to do it...


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## 1Kenny (Sep 19, 2009)

Same with me too, Jerry. I've been watching and learning in awe.

Kenny


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## Captain Jerry (Sep 21, 2009)

Hi Y'all

The engine runs. There is much to do to get it to run well. I just couldn't wait to put the air to it. I was mostly concerned about the valve. On paper ( or CAD screen ) it looked good but until it was actually built and tested, I wasn't sure how well it would work. I am probably premature releasing this video since the engine is in extremely rough condition. There are no seals or packing around the shaft, air leaks everywhere. There are no gaskets on the cylinder heads and the valve cover. There are no bearings anywhere, just bare steel shaft turning in reamed 1/4" aluminum holes.  There are many parts that will need to be re-made, either because of re-design or machining errors. There is no proper support or base to hold everything in alignment. The valve timing has not been tweaked. Just eyeballed at about 90 deg.

All that having been said, here it is.






My video skill are a little rough too.

Jerry


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## dsquire (Sep 21, 2009)

Captain Jerry :bow: :bow: :bow:

For an engine that isn't finished and is missing all those parts and pieces I'd say it runs pretty darn good. Now with a bit of your TLC and patience fine tuning it, you will have a real gem on your hands. Keep up the good work.

Cheers 

Don


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## zeeprogrammer (Sep 21, 2009)

You just started this a couple of weeks ago!
Nicely done. An unusual engine that will get a lot of attention.
Thanks for posting it.


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## joe d (Sep 21, 2009)

Jerry

Congratulations :bow: You've got "Proof of Concept", the rest is decorational!  Thanks for this one, I really had no idea how the swashplate worked.

Cheers, Joe


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## ozzie46 (Sep 21, 2009)

Congrats on a job well done. It runs and that is a major accomplishment on a new design, first run.  :bow: :bow: :bow:

 Ron


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## Captain Jerry (Oct 4, 2009)

I'm still working on this. Its getting a lot better and I am learning a lot. I really wanted this engine to run smoothly at low rpm and to be reliably self starting. To this end, I designed a different type of valve and so far I am very happy with it. This valve isolates the intake and exhaust from the rotating shaft which allows proper sealing. It exceeds my expectation. Simple O-ring seals are effective and after lapping the valve surfaces and a little running in, it show very little pressure loss or leaks. The engine now runs on very low pressure (2 - 3 psi) and is reliable self starting at low or high speed. At some point in the future I will experiment further with valve timing and overlap but for now the overlap is set at about 15 degrees and the eccentric preceeds the piston by 90 degrees.

I have not setup any torque test yet but applying finger pressure to the rotating shaft makes me think it is substantial. 

The picture below shows the engine sitting in front of the little Unimat with which it was built. I think that this is about as big an engine as I can build on the Unimat so if all goes well my new 9x20 will arrive tomorrow. This will allow me to complete the engine with a proper mounting and to experiment with reversing valve design.

The video shows the engine running slowly but the frame rate may not show that very well but it can be made to run smoothly at less than 60 rpm on 1 or 2 psi. It shows self starting at all positions of the shaft and at 30 - 40 psi it is very fast and smooth.

The pics also show all the scars and scabs of design and dimension changes so before going any further, I'M STARTING OVER. Every part will be remade so when I start over, I will attempt to document each step and to present dimensioned drawings.

Here's the pics and vid.

Jerry


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## zeeprogrammer (Oct 5, 2009)

Very nice Jerry.
1-2psi is very impressive to me.


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## Brian Rupnow (Oct 5, 2009)

Mighty fine stuff, Jerry!!!


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## ozzie46 (Oct 5, 2009)

Very Nice 

 Ron


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## Cedge (Oct 5, 2009)

Nice work Jerry!! Looking forward to the build log.

Steve


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## arnoldb (Oct 5, 2009)

Good going Jerry Thm: - looking forward to the build log!

Regards, Arnold


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## ariz (Oct 6, 2009)

compliments for a well made and nice running engine!

and if you have built it with that little lathe, your work has to be still more appreciated :bow:


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## rake60 (Oct 6, 2009)

Beautiful runner Jerry! :bow:

Rick


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## Captain Jerry (Oct 7, 2009)

There will be a small delay in this post as I move to a different world. 

REAL LATHE!!

On Monday, I picked up a lightly used HF 9x20 and spent all day yesterday getting to know it. For you guys that are used to real machines, this might seem silly, but having been limited to a Unimat SL1000 this is a real eye opener! I bought the lathe from a guy that has lots of other goodies in his shop and needed to unload this machine to make room. 

He was interested when I told him I was building steam engines and I will try to get him to join this group and show some of his work. He builds [size=14pt]JET ENGINES[size=10pt].

Anyway, I'm going to take a couple of days to translate my methods and thinking from Unimat to 9x20. I've been reading all the 9x20 mod sites that I can find but I'm not going to get bogged down in modifing this machine until I get used to it.

Question for those of you with 9x20 class machines. This has the standard toolpost which wants 1/2 " bits and I want to stick with HSS. Short of going to a QCTP, do you recommend 1/2" square HSS blanks or some kind of holder for 1/4" bits?

Off to the shop. I'm pumped!

Jerry


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## lathe nut (Oct 7, 2009)

Jerry & Brian and the other fellow that post what you make I want to say that I am another one who looks and a lot of the times does not comment until a project is done, I start my day with the cup of coffee in the morning reading the post and pics and end the day with the same, I love this group and what it has to offer everyone who wants to learn you fellow put lot of hours on there projects and share with us what you have done and the way you go about doing it, the play by play is what needed for at least me, I am not good at all of that yet but am the king of copy and paste, maybe this winter projects, again worth repeating, your are being notice and appreciated, Lathe Nut


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## rake60 (Oct 7, 2009)

Jerry you will find that 9 X 20 to be a very capable little machine.
If the previous owner had not replaced the 2 bolt compound clamp
with a 4 bolt modification, you will want to do that first.
It is a simple mod to make. Here is my thread on it from our very
early days.
http://www.homemodelenginemachinist.com/index.php?topic=805.msg5261#msg5261

The tool post is actually made to hold a 10MM tool bit.
A 3/8" bit with a .020" shim under it will put the tip almost
dead nuts center.

Rick


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## Captain Jerry (Oct 7, 2009)

Rick:

Thanks for the response. I have ordered material for the 4 bolt clamp and a couple of belts, but I am puzzled by the tool holder. I did not get any tool bits from the previous owner so when I got it set up I searched around my box of bits and by laying a 1/16" parting tool on it's side, and stacking two 1/4" bit on top, the tip of the topmost bit was on center. That is a total of .5625 in. A 3/8" bit would need a 1/8" shim. What am I missing? Do I have an oddball tool post?

By the way, you are right about this machine being a heavy beast. I had to get my wife to help me get it off of the pickup truck and up the ramp to my shop. (I'm 71, she's 69)

Jerry


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## rake60 (Oct 8, 2009)

Your wife is only 69 and you had to help her unload the lathe? 

When I brought mine home I had my 25 year old son here to help
unload it. We got it to the basement, set it on the bench and I marked out
where the mounting holes should drilled. When I told him that we needed to
lift it off the bench so I could drill the holes, then lift it back onto the bench...
His reply was "You gotta be ****** kidding me!"
My memory fails me at the moment as to what that missing word was.
 Rof}

You may not be missing anything on the tool post center.
The standard Sieg 9 X 20 is made to center a 10MM tool however
every vendor selling that lathe makes adjustments to make it
"Their Own" machine. The only way to find the absolute center is
to chuck up a scrap piece of stock and face it to center.
Half the diameter of the nub left in the center is the amount of 
shim required for that tool bit size. 

Rick


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## Captain Jerry (Nov 13, 2009)

Hi "Y'all

The continuation of this saga appears in a new thread, "3 Cylinder Spider". This was a first effort at a new design and the revisions are numerous. The valve remains the same and the mechanism is mostly the same but the treatment is very different.

Thanks for you interest in my offbeat creations.

Jerry


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## BobWarfield (Nov 14, 2009)

Very cool little engine!

I've always been fascinated by swashplates. Apparently they were used in torpedos because they fit the slender profile and produce a lot of power.

Cheers,

BW


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## Tin Falcon (Nov 14, 2009)

actually the early torpedoes had compressed air engines
Tin


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## Maryak (Nov 14, 2009)

The English 21" torpedo was powered by a diesel engine, the compressed air in these torpedoes supplied the oxygen for the engine. When a practice warhead was fitted, (i.e. one filled with water instead of explosive), the exhaust from the diesel was used to pump out the water allowing the torpedo to float at the end of its' run and be recovered. Oddly enough these test shots were mostly recovered by a TRV, (Torpedo Recovery Vessel), from the test range.







Best Regards
Bob


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## BobWarfield (Nov 15, 2009)

Google "torpedo swashplate", lots of info:

http://en.wikipedia.org/wiki/Swashplate_engine

Cheers,

BW


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