Attkinson engine & the Pendergrast design..

[dsage]

John:

Can you check "Detail A" the assembly of the carburetor pieces On the assembly drawing sheet.
You show the end of the air intake tube with the narrow ridge inserting into the carb body.
The recess in the body to accept the tube is 0.2" deep. The ridge you show inserted is only .093 wide
The other end of the air tube has the 0.2" wide ridge which would be matched to the body recess.
BUT
Turning the tube around would move the Needle valve farther from the carb body.
I'm not sure what the correct orientation should be.


BTW. Fantastic and very professional drawings.

Thanks

 

[stragenmitsuko]

Great job , thanx a million for sharing .

Pat

 

[johnmcc69]

Richard, Dave, & Pat Thank you for the comments.

Dave, you are correct. The .200 Lg. end should be in the carb body, this is mentioned in the build notes under "Part #20". No other information was supplied concerning the "OS Jet Assembly" that is to assemble to the .156 Dia. through hole.

John

 

[dsage]

That's good. Thanks.
Another thing they don't mention is where the fuel goes in. I assume in the side of the mysterious needle valve. LIke some others I've seen.

Has anyone found the OS Part #21111006 (for engine #10 FSR-S) needle valve?

I haven't been able to locate even a picture of it. I probably won't buy one but just want to see it.

 

[Gordon]

Needle valve
https://rcshop.net/en/motors/nitro/spare-parts/needle-valve-assy-10fp-s-21111006/

 

[dsage]

Thanks Gordon.

 

[GKNIPP]

John, you will receive no flak from me. Thank you so much for putting the link on here. You did an excellent job on them.
YES, I did receive permission to share these drawings from Brooks Pendegras at the N.A.M.E.S. show some years back. You folks will much appreciate the work John put in on these as the originals were basically pencil sketches. To this day I have not built this engine but it is on my to do list.
Thank you again John.

 

[Ken Brunskill]

OK.
Here is a link to the files I created:

https://drive.google.com/drive/folders/13jC5HWuBakT9M-XBz8e1oYulAwKTAXRj?usp=sharing
It seems Greg might have run into some trouble trying to arrange the files to be shared. I've contacted him & he did truly want to post them. I've put them here on my drive to be shared. I may receive some "Flak" for sharing them, but it seems Greg was granted "Permission" from the original designer, A. Brooks Pendergrast, so I'm putting them up. If there are any issues involved in doing this, I will take them down immediately.

A lot of time was spent in doing these drawings, & I made every effort to preserve the original design intent. I recreated the CAD models from the original hand sketched drawings. The only "Liberty" I took with them was in changing some of the dimensions to more of a "standard" layout, (Some parts were dimensioned from both sides of the parts, some had some missing dimensions...) I recreated the build notes as well from his hand typed documents (I HATE typing), so there could very be well errors, I made no attempt at fixing spelling & grammatical errors. I did decide not to use all cap's though...what you have is exactly what he provided in his original info.

There is a small BOM included with the build notes & I have included what I feel to be a more complete BOM. The file name is "MBM.PDF" & it lists all the parts & what drawing they can be found on.

Lastly, all credit goes to A. Brooks Pendergrast for the design & thanks to him for agreeing to share his design. Thanks to Greg for giving me the opportunity in recreating the drawings. Standard disclaimers apply, use at your own risk & no claims are made that this design is a successful one.

John

John,

I would like to offer to create a Set of Solidworks 3D models from your pdf's. Will only do so with your permission. Willing to do this because I am learning this software, and practice only improves one's skills. It will take a while as I am building a couple of models myself and am helping a friend with his build in my shop.
Do not know which software you used to create the pdf's it appears that it had 3D capability. Would be interesting to see how to integrate you file into a Solidworks file and vice-versa.

 

[Steamchick]

Thanks John, A lot of effort there. Much appreciated by many, I'm sure.
K2

 

[johnmcc69]

No problem Ken, help yourself. I created the drawings & models in Pro-Engineer 3D CAD software.
If you are only starting out in 3D CAD modeling, you might want to try redrawing something a little less complicated like one of Elmers engines (Same theory applies to beginners in machining). These are fun little engines to model up & may not frustrate you as much as something more complicated. I still draw Elmers engines for fun, his plans are clear & there is a nice variety of engine styles to choose from. If you do choose to start with the Attkinson, start with the simple parts, baseplate, piston, pins, shafts, make some assemblies, some simple drawings. Don't let yourself get frustrated.

Keep us posted on your progress & I'll try to help in any way I can.

John

 

[Steamchick]

Thanks John. I studied this engine last year to develop the pressure cycle diagram. For a few lads on this site.
I have made a little marine 2-stroke, a few steam engines, boilers, and various fittings. But not sure if I'll attempt the basic Atkinson or one of his later engines. Just a couple of water pumps (2 steam, 2 manual), a boiler and re-furbish a twin oscillator on the list to be resolved first. Oh, and a small single glow engine to make... plus decorating, etc.
Life!
But thanks for the drawings, I'll stick to pencil and paper. (3 drawing boards and lots of pencils!).
K2

 

[wespete66]

an FYI.. Some have mentioned the difficulty in getting hold of the book. It seems that the Gingery Book Store is up and going again as of March 1. I've just rec'd my copy of the differential engine book from them!
Also, many thanks to those who share their own files.

https://www.gingerybookstore.com/

 

[Steamchick]

Just been on the Gingery site: There are 2 books:
"Building the Atkinson Engine" and
"Building the Atkinson Cycle Engine"....
But which is the better and latest? They look from the pictures to cover the same engine?
Do you need both to make this engine?
Ta,
K2

 

[Richard Hed]

Just been on the Gingery site: There are 2 books:
"Building the Atkinson Engine" and
"Building the Atkinson Cycle Engine"....
But which is the better and latest? They look from the pictures to cover the same engine?
Do you need both to make this engine?
Ta,
K2

They are two different engines. Two differnet methods of operation

 

[Mike Ginn]

Hi K2
I have both books. The differential engine is based on US Patent number 336505 which you can Google. This engine has 2 pistons running in the same cylinder. The cycle engine has 1 piston. The books are very similar and apart from the design they cover the casting process. You probably don't need the books if you follow Ken Brunskill's (excellent) design/drawings. I am in the process of scaling these 0.75 in metric in dxf format.
Mike

 

[dsage]

The difference is. The Cycle engine actually runs (I built one). I saw a GINGERY differential running once but the guy said he had to change something from the plans to get it to go. He couldn't recall what. Hmmm.
Feel free to build the GINGERY differential and document it here. A few of us would like to see a successful build.

 

[DKGrimm]

Just logged in as a newbie to this forum, and read some of the Atkinson Differential posts. This is a sore topic for me right now because I have had my Gingery version running well in the past. Not so much at the moment because of my own neglect, but that's a different subject.

I'm attaching a copy of an article I wrote and submitted to a model engine magazine, rejected because this engine was not popular enough for the reader base. It comments on a lot of the topics discussed here. See what you think.

 

[Steamchick]

Excellent article!
K2

 

[dsage]

Thanks very much for your article. It confirms my suspicions that "something just isn't right" with the Gingery design. Apparently more than a few things. I'm glad you got it going.
It's unfortunate that you did not noticed the other two topics here on HMEM to do with building the Gingery in particular. You can look for them by searching "Atkinson". I would have worked from your notes when I made a whole bunch of changes and started building my Gingery (which has thus far failed). Also Gordon might have benefited from your efforts.

Enough said here. This is the thread on the Pendergrast designed engine build which (as you mentioned in your article) you were enamored by. I've actually seen Ed Irwin's Pendergrast run at NAMES. Turns out he lives not far from me. I have since made contact with him. And I'm watchin intently yet another thread on here also building the Pendergrast engine.
I'm not sure which way to turn now. I may have made too many changes to mine. I'm running into most of the problems you mention.

Thanks

 

[Gordon]

Just logged in as a newbie to this forum, and read some of the Atkinson Differential posts. This is a sore topic for me right now because I have had my Gingery version running well in the past. Not so much at the moment because of my own neglect, but that's a different subject.

I'm attaching a copy of an article I wrote and submitted to a model engine magazine, rejected because this engine was not popular enough for the reader base. It comments on a lot of the topics discussed here. See what you think.

I am curious about the method for making rings you referenced from the Colorado Model Engineering Society. I don't see anything there.Perhaps because you have to be a member. Rings are a pretty important part of getting this engine to run.