# Attkinson engine & the Pendergrast design..



## johnmcc69 (May 5, 2020)

a lot of interest of this crazy little engine lately.
 I have a copy of his hand drawn plans & build notes that were purchased years ago & have redrawn them in CAD for my own benefit of learning my CAD software, this was 6 or 7 years ago. 

I have not built the engine but am wondering if others have? To the Pendergrast plans?

 I see a lot of frustrations of building this from the Gingery book, I do have the book & can feel your pain...


 D.Sage & Gordon (members here, & others as well..)  have put in many hours building beautiful engines & have had problems making this one run.

 An associate of mine has tried contacting the Pendergrast family to release these drawings but has had no luck.

 I would be interested in hearing from anyone who has had any contact with them, or any other history of "BP Machine".

 This is a really nice engine, & apparently, some of them run.

 I don't want to reinvent the wheel here & totally understand copyright "stuff" & have freely shared drawings here, but maybe a collective effort could make a "runner". 

 Again, thanks to Dave, Gordon, & others for sharing their time, perserverince, & lost hairs on this.

 John


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## Richard Hed (May 20, 2020)

johnmcc69 said:


> a lot of interest of this crazy little engine lately.
> I have a copy of his hand drawn plans & build notes that were purchased years ago & have redrawn them in CAD for my own benefit of learning my CAD software, this was 6 or 7 years ago.
> 
> I have not built the engine but am wondering if others have? To the Pendergrast plans?
> ...


Can you tell us more?  I have no idea; what this is.  Sounds interesting tho'


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## Charles Lamont (May 20, 2020)

The name is most likely to be Prendergast, if that helps .


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## stragenmitsuko (Jun 6, 2020)

I think , looking at the shape of the connecting arms and the governor on the crank shaft
this might very wel be a running example of the prendergrast design .


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## Richard Hed (Jun 6, 2020)

Whoa, that's absurd!  I'd like to build that.  It makes me laugh.  THat is a spark plug, isn't it?


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## dsage (Jun 6, 2020)

I asked the Youtube poster (in the video comments) which set set of plans he used. We'll see what happens.
I suppose various authors borrowed heavily from each other and I've never seen the Pendergrast (sp?) drawings but it looks a lot like the Gingery if it weren't for the governor.
Which brings up something I never thought about for the Gingery. How to control the speed other than to make a throttle for it (which it does not have). I guess just by limiting the fuel at the needle.
Interesting.
Thanks for digging that video up. I thought I'd found them all in my efforts to get to the bottom of the Gingery woes.


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## stragenmitsuko (Jun 6, 2020)

he did make a throttle , look at the wood screw in the intake


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## johnmcc69 (Jun 6, 2020)

Thank you Stragenmitsuko for digging that up. It does look like the PENDERGRAST design.

 It will be interesting to see what kind of reply Dave will get.


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## Charles Lamont (Jun 7, 2020)

Aha. Apparently there are numerous different spellings.


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## Richard Hed (Jun 7, 2020)

Charles Lamont said:


> Aha. Apparently there are numerous different spellings.


Altho', when I pay attention, I am a very goo speller.  In the 1850's and before, Mercans spelt things any way they sounded.  But during the 1850s, Daniel Webster wrote his Spelling Primer.  after that, things had to be spelled with certain rules--the silly rules we have now.  Look at how the constitution was written in the old days--all nouns were capitalized on the first letter.  That is also how th e Germans write nouns today.  At one time (Shakespeere spelt his name at least 25 diffeent ways), General Jackson (later prez.) argued with someone (he was quite contentious, after all) that his opponent couldn't even spell (some word) 25 different ways!  That's pretty funny in my Haughty Opinion.  My point is that I believe Daniel Webster ultimately did a grave disservice to Merica.  BTW, General Grant (my Hero) is thot to be a notorious speller today.  But he certainly was NOT by his times standard--He only became famous a few years after Webster's disasterous book. 

I ahve to admit, when I see horrible spellings I am put off, I have to consciously consider my own thots on that, that is, it is not the spelling that is important but the meaning.  Can the poor spelling person put two ideas together and come up with a third or fourth idea?  That's important , not spelling, not punctuation (except if you read Churchill's writing one has a difficult time understanding him because he doesn't use any commas).

Also, we might pay attention to how our mother country spells things.  Spelt, learnt, and many other words that sound much more like how they are spelt.


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## GKNIPP (Jun 18, 2020)

John converted these to CAD drawings  for me.  I have a set of them but have not built it yet.  They were originally hand sketched by Brooks Pendegrast and I got them from him at a NAMES Show in Wyandotte, MI some years back.  I received Mr. Pendegrasts permission to share them.


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## L98fiero (Jun 18, 2020)

GKNIPP said:


> John converted these to CAD drawings  for me.  I have a set of them but have not built it yet.  They were originally hand sketched by Brooks Pendegrast and I got them from him at a NAMES Show in Wyandotte, MI some years back.  I received Mr. Pendegrasts permission to share them.


I'd be interested in a set of the plans. It will be a while before I get to it but they look to be interesting and challenging.


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## dsage (Jun 18, 2020)

If you are sure they are not protected by copywrite I'd be interested in a set. If for nothing more than to see what was done differently to make it work compared to the Gingery engine.
What CAD package were they created in?


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## Gordon (Jun 18, 2020)

If he gave permission to share the sketches I would certainly like to get a copy of the sketches.


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## GKNIPP (Jun 21, 2020)

Absolutely, I will share the beautiful CAD drawings John did.  They are much clearer and dimensioned better.   I had asked him when I bought the original hand sketched prints if he would allow me to share them and he gave me his blessing.  If I remember correctly he was getting out of the business at that time.   ( Here is the assembly views and finished dimensions as an example of the improved drawings by John.)



If someone would tell me how I could put them in the downloads section, it would save me having to send to everyone.  There are (24) 8.5x11 sheets of detailed drawings.


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## stragenmitsuko (Jun 21, 2020)

Sweet , I'll be building one for sure . 

Greg if I'm not mistaking you can put all the files in a single zip and then just add it to post like you did with the drawing above . 
More experianced  users correct me if i'm wrong please .

pat


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## Richard Hed (Jun 21, 2020)

stragenmitsuko said:


> Sweet , I'll be building one for sure .
> 
> Greg if I'm not mistaking you can put all the files in a single zip and then just add it to post like you did with the drawing above .
> More experianced  users correct me if i'm wrong please .
> ...


I have a lot of files in bitmap form (*.bmp) but they are not allowed.  but JPEGs are allowed.  when I get some time, I will convert some bitmaps to JPEGs and put some stuff up, but most liekly in the future as I managed to get a summer time harvest job.


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## dsage (Jun 22, 2020)

I'm confused:
Who is offering the drawings??
There are two of you responding here. Richard Hed and GKNIPP.
In any case there is no need to convert the drawings. Just ZIP them into one file and attach them in a message or upload them  to the Uploads section.


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## Richard Hed (Jun 22, 2020)

dsage said:


> I'm confused:
> Who is offering the drawings??
> There are two of you responding here. Richard Hed and GKNIPP.
> In any case there is no need to convert the drawings. Just ZIP them into one file and attach them in a message or upload them  to the Uploads section.


I have some drawings -- the Corliss Cole Ray drawings that I have in bitmap.  They are not the same as Gknipp's.  This forum will not accept bitmaps.  I was going to convert them to JPEGs but now you have given me a much better solution.  Thanx.


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## dsage (Jun 23, 2020)

Richard Hed:
Thanks for your offer - but does this Corliss Ray engine run??
We were interested in the Pendegrast design drawings because it has been shown to run.
Now you're throwing in another version and getting things confusing (for me anyway). 

The more the merrier I guess. Upload them and we'll take a look.
Thanks


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## Gordon (Jun 23, 2020)

Richard Hed said:


> I have some drawings -- the Corliss Cole Ray drawings that I have in bitmap.  They are not the same as Gknipp's.  This forum will not accept bitmaps.  I was going to convert them to JPEGs but now you have given me a much better solution.  Thanx.


Is the Corliss Cole Ray engine also an Atkinson Differential engine or some other engine entirely?


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## dsage (Jun 23, 2020)

Gordon:
Good question. We might be being (trolled) led down a garden path here  
Whatever.


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## Richard Hed (Jun 23, 2020)

dsage said:


> Richard Hed:
> Thanks for your offer - but does this Corliss Ray engine run??
> We were interested in the Pendegrast design drawings because it has been shown to run.
> Now you're throwing in another version and getting things confusing (for me anyway).
> ...


They run, but the two I have do not.  I bought one from an old and dieing machinist 40 years ago.  He had said it was complete but it was not, needs about 15-20% more work done on it.  The other one I bought as a kit around the same time.  I have gotten less far in that time than the old machinist had.  But now, I am goint to start work on both of them soon (soon--like the next year or two).  If you want to see a working model you can view


or    (this is the first time I ever saw this one)

Here's a double:


This is the famous "Coles/Ray Corliss"  which is the one I have with some modified parts.

The model with the "L" shaped aluminum base is the Coles/Ray Corliss.  I had more links in this last night wh;en I posted it, and the short sentenaces were changed around and the links are gone.


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## Richard Hed (Jun 23, 2020)

Gordon said:


> Is the Corliss Cole Ray engine also an Atkinson Differential engine or some other engine entirely?


Corliss is an engine invented about 1848 (not sure) in which the valves are taught to shut off sooner if the engine is speeding too much, that is, if it is not using the power generated.  It is nothing like the Atkinson at all.  It is far more complex.  the reason why it is called the Cole Ray is becau;se "Coles" foundered the kit and Ray made the drawings for it.  I have a copy of the original Ray's -- they are absolutely AWEFUL in today's standards, but for 1946 they are a grand work of ART.  See abouve in my reply and you can visit some Corliss engines and even see the Ray model.  (Don't thimk this is a Coles)

OH crap, I am working 6/12s now and haven't time to put them in a zip.  Will do so when I have time.


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## Gordon (Jun 24, 2020)

Richard Hed said:


> They run, but the two I have do not.  I bought one from an old and dieing machinist 40 years ago.  He had said it was complete but it was not, needs about 15-20% more work done on it.  The other one I bought as a kit around the same time.  I have gotten less far in that time than the old machinist had.  But now, I am goint to start work on both of them soon (soon--like the next year or two).  If you want to see a working model you can view
> 
> 
> or    (this is the first time I ever saw this one)
> ...



Your videos are not showing up. Just a black box.


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## Richard Hed (Jun 24, 2020)

Gordon said:


> Your videos are not showing up. Just a black box.


They are utube links.  There were four or five and now therew are less and mixed up.  Don't know how this happened.  Anyway, just look up "Coles/Ray Corliss" or some combination of those words on the Utube and you'l find lots of them.


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## dsage (Jun 24, 2020)

Richard Hed:
Nice engine but
WHY ARE YOU WASTING OUR TIME HERE.
This thread is about the Atkinson differential engine and in particular the Pendegrast design.

I'll say no more. 

NOW Lets get back to the Atkinson differential discussion PLEASE.


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## GKNIPP (Jun 29, 2020)

Folks, I'm sorry, however I have not forgotten about any of you.  I'm trying to get help zipping the Atkinson drawings so I can share with all of you.
Thank you so much for your patience and understanding.

Greg


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## Cogsy (Jun 30, 2020)

GKNIPP said:


> I'm trying to get help zipping the Atkinson drawings so I can share with all of you.



If you're using Windows it's very simple. Have all the drawings in a single folder then right-click on that folder and from the drop-down that opens up hover over the 'Send To' option and another small drop-down will show several options. One of those options will be 'Compressed (zip) folder' - select that one and it will created a zipped folder with all your drawings in it, and will leave your original drawings exactly as they were on your PC.

If you're using a MAC or some version of Linux then I have no idea.


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## Gordon (Jun 30, 2020)

GKNIPP said:


> Folks, I'm sorry, however I have not forgotten about any of you.  I'm trying to get help zipping the Atkinson drawings so I can share with all of you.
> Thank you so much for your patience and understanding.
> 
> Greg


Perhaps you could send the individual files to someone like Cogsy (global moderator and staff member)and they could zip and/or convert the files and they could then post them.


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## awake (Jun 30, 2020)

Cogsy said:


> If you're using Windows it's very simple. Have all the drawings in a single folder then right-click on that folder and from the drop-down that opens up hover over the 'Send To' option and another small drop-down will show several options. One of those options will be 'Compressed (zip) folder' - select that one and it will created a zipped folder with all your drawings in it, and will leave your original drawings exactly as they were on your PC.
> 
> If you're using a MAC or some version of Linux then I have no idea.



Depends on the Linux distro, but on Ubuntu you can right-click and compress files - don't have to go through "Send to"; it is right there on the pop-up menu.


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## stragenmitsuko (Jul 10, 2020)

I found another beautifull build of this little engine on yt . 
Not the pendergrast , the builder says it's a gingery .
But still , a nice runner , altough I think it misfires on occasion . 
Sounds a bit like a hit'n miss .


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## Steamchick (Jul 11, 2020)

I guess you hadn't noticed the hit-and-miss device to govern speed, mounted on the front. (The "square box thing with a valve operator/inhibitor and spring).
The governor fly weights are probably on the shaft on the reverse of the engine in this view?

but I may be wrong?


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## Gordon (Jul 11, 2020)

Steamchick said:


> I guess you hadn't noticed the hit-and-miss device to govern speed, mounted on the front. (The "square box thing with a valve operator/inhibitor and spring).
> The governor fly weights are probably on the shaft on the reverse of the engine in this view?
> 
> but I may be wrong?


The Gingery design does not have a governor. The parts on the front are the intake valve/carburetor and exhaust valve/muffler.


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## Steamchick (Jul 11, 2020)

Thanks, I was watching the intermittent operation of one of the valves then...
Thanks for the info. - I'm glad to learn.
K


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## stragenmitsuko (Jul 11, 2020)

Yes the valves are vacuum operated , so each time the intake valve opens there ought to be a power stroke . But that doesn't always seem to happen so I thought it was misfiring from time to time .
Anyway , it's a runner wich is an achievement in itself .


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## Steamchick (Jul 11, 2020)

The model is lovely to watch and see running. But like many "patent avoiding alternatives" never really got going - probably just not a commercial success after the "patent" blockade ended? I'll have to read the history on wicked-feet.


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## Gordon (Aug 25, 2020)

GKNIPP said:


> Folks, I'm sorry, however I have not forgotten about any of you.  I'm trying to get help zipping the Atkinson drawings so I can share with all of you.
> Thank you so much for your patience and understanding.
> 
> Greg


Have you made any progress on distributing these drawings? I certainly would like to see them and so would several others.


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## dsage (Aug 25, 2020)

Are you running Windows 10?
If so Zipping is easy.
Select all the files, then RIGHT click and you should see an option in the list to ZIP.
Select that and a choose a place to put the zip file that you can find later and you're done.
Easy Peezy


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## Makin chips (Jan 4, 2021)

Has any progress been made on making tha Atkinson CAD drawing available? Thanks in advance.


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## dsage (Jan 4, 2021)

stragenmitsuko said:


> I found another beautifull build of this little engine on yt .
> Not the pendergrast , the builder says it's a gingery .
> But still , a nice runner , altough I think it misfires on occasion .
> Sounds a bit like a hit'n miss .




Somehow I missed  post #32 with the video. I was encouraged by his comments concerning his having to modify the intake port. I also came to that conclusion and made it a slot instead of a hole. Of course there are lots of ways to make that work. Maybe I'll get back to working on mine.


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## dsage (Jan 4, 2021)

Gordon:
I believe you mentioned once that your Atkinson build borrowed something from the Pendergrast design? Did you have some sort of Pendergrast drawings to work from for the changes to the Gingery.?


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## Steamchick (Jan 5, 2021)

Richard Hed said:


> Altho', when I pay attention, I am a very goo speller.  In the 1850's and before, Mercans spelt things any way they sounded.  But during the 1850s, Daniel Webster wrote his Spelling Primer.  after that, things had to be spelled with certain rules--the silly rules we have now.  Look at how the constitution was written in the old days--all nouns were capitalized on the first letter.  That is also how th e Germans write nouns today.  At one time (Shakespeere spelt his name at least 25 diffeent ways), General Jackson (later prez.) argued with someone (he was quite contentious, after all) that his opponent couldn't even spell (some word) 25 different ways!  That's pretty funny in my Haughty Opinion.  My point is that I believe Daniel Webster ultimately did a grave disservice to Merica.  BTW, General Grant (my Hero) is thot to be a notorious speller today.  But he certainly was NOT by his times standard--He only became famous a few years after Webster's disasterous book.
> 
> I ahve to admit, when I see horrible spellings I am put off, I have to consciously consider my own thots on that, that is, it is not the spelling that is important but the meaning.  Can the poor spelling person put two ideas together and come up with a third or fourth idea?  That's important , not spelling, not punctuation (except if you read Churchill's writing one has a difficult time understanding him because he doesn't use any commas).
> 
> Also, we might pay attention to how our mother country spells things.  Spelt, learnt, and many other words that sound much more like how they are spelt.


Please remember that "English, as she is spoke" is a derivation of languages, from more than 2500 years ago: Celtic, Gaelic, Greek; 2000 years ago: Roman-latin, 1500 years ago; Saxon, Danish, Norsk (Viking); 1000 years ago: French, 500 years ago: Spanish; then just a few hundred years ago: Various Indian and Chines dialects, (from the East India Company and various Chinese business interests); German (Victorian and Hanovarian royalty), and 20th century influxes from the African, Asian and Caribbean and Eastern Europeans that have emigrated to Blighty for a better life...
"American" mostly derives from the "Mayflower-era" languages and accents that melded while on board ships for 3 to 6 months of passage to the New World. Then later influxes of the millions of Irish, Eastern European/Russian Jewry, Spanish, African and Caribbean and Chinese workforces who all went there for a better life... during the 18th and 19th Centuries, followed by everyone from everywhere in the 20th Century, as well as the various Native American languages that were there for a few thousand years before Columbus...
I recommend Churchill's "History of the English Speaking People". (Up to 1938). It condenses a library of books into a small-enough set of brief volumes to make History manageable. And he is very readable!
K2


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## Richard Hed (Jan 5, 2021)

Steamchick said:


> Please remember that "English, as she is spoke" is a derivation of languages, from more than 2500 years ago: Celtic, Gaelic, Greek; 2000 years ago: Roman-latin, 1500 years ago; Saxon, Danish, Norsk (Viking); 1000 years ago: French, 500 years ago: Spanish; then just a few hundred years ago: Various Indian and Chines dialects, (from the East India Company and various Chinese business interests); German (Victorian and Hanovarian royalty), and 20th century influxes from the African, Asian and Caribbean and Eastern Europeans that have emigrated to Blighty for a better life...
> "American" mostly derives from the "Mayflower-era" languages and accents that melded while on board ships for 3 to 6 months of passage to the New World. Then later influxes of the millions of Irish, Eastern European/Russian Jewry, Spanish, African and Caribbean and Chinese workforces who all went there for a better life... during the 18th and 19th Centuries, followed by everyone from everywhere in the 20th Century, as well as the various Native American languages that were there for a few thousand years before Columbus...
> I recommend Churchill's "History of the English Speaking People". (Up to 1938). It condenses a library of books into a small-enough set of brief volumes to make History manageable. And he is very readable!
> K2


Thanx, I've read ALL of Churchill's stuff in books, but not his newspaper or magazine writings. I even got to book 5 of that horrendously large encyclopedic sized biography of 8 large volumes=the ONLY person to ever check these books out of the library.


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## stragenmitsuko (Jan 22, 2021)

Makin chips said:


> Has any progress been made on making tha Atkinson CAD drawing available? Thanks in advance.



Same here .


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## Richard Hed (Jan 23, 2021)

This Atkinson is so ridiculous of an engine (and it's relatively efficient too, I understand) that I want to start one, so I started searching for any drawings at all.  There are MANY builds on utub and many mentions of Gingery model.  But finding drawings is so far a bust.  I'll keep looking however.


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## Steamchick (Jan 23, 2021)

Hi Richard: GKNip seems to be the man trying to publish his drawings on this feed? (see page 1). Maybe you should ask him directly?
K2


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## Gordon (Jan 23, 2021)

Richard Hed said:


> This Atkinson is so ridiculous of an engine (and it's relatively efficient too, I understand) that I want to start one, so I started searching for any drawings at all.  There are MANY builds on utub and many mentions of Gingery model.  But finding drawings is so far a bust.  I'll keep looking however.


amazon.com/Building-Atkinson-Differential-Vincent-Gingery/dp/1878087231/ref=sr_1_1?dchild=1&keywords=atkinson+differential&qid=1611425844&s=books&sr=1-1


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## dsage (Jan 23, 2021)

Careful what you wish for.


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## stragenmitsuko (Jan 23, 2021)

Steamchick said:


> Hi Richard: GKNip seems to be the man trying to publish his drawings on this feed? (see page 1). Maybe you should ask him directly?
> K2


Did send a private message , twice . Never got a reply


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## Richard Hed (Jan 23, 2021)

Gordon said:


> amazon.com/Building-Atkinson-Differential-Vincent-Gingery/dp/1878087231/ref=sr_1_1?dchild=1&keywords=atkinson+differential&qid=1611425844&s=books&sr=1-1


I never buy from gog or magog (amuzonk) if I can help it.  I found the book at a cheaper price than gog on abebooks.com.  My son told me however, that gog and magog own Abe.  Don't know if that is true.

Steam:  GKnipp is the one who was going to send us the drawings from his friend but never got around to it.  I hope he is OK as I thimpfk his drawings are probably a better build than the Gingery.  But not sure.

GKnipp got his drawings from Brooks Pendegrast but we haven't heard from him since June of 2020.  Hope he stayed out of the covid .


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## GKNIPP (Jan 24, 2021)

PM sent.  I apologize for being away so long.  I am going to attempt to make a copy of these plans and send them to stragenmitsuko upon his approval.
You guys will love these

Greg


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## Gordon (Jan 24, 2021)

I am confused as to what we are waiting for and what is it? Apparently Greg received sketches from Brooks Pendergast with permission to share them. Then the drawings were rendered in CAD but only Greg has received these drawings. What does he have and will he ever release them? 

Sorry for the impatient post but so far we have seen nothing but smoke and mirrors. Do drawings exist?


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## Richard Hed (Jan 24, 2021)

Gordon said:


> I am confused as to what we are waiting for and what is it? Apparently Greg received sketches from Brooks Pendergast with permission to share them. Then the drawings were rendered in CAD but only Greg has received these drawings. What does he have and will he ever release them?
> 
> Sorry for the impatient post but so far we have seen nothing but smoke and mirrors. Do drawings exist?


Relax, you've been waiting 6 months, He is back and working on it.  Says he needs to send them.  Don't know if he knows how to zip or what files are uploadable.  Yes, I've been waiting too and a bundle of other guys as well.  I do, however, like hyourself, wonder if I will live to see them.  LOL


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## stragenmitsuko (Jan 27, 2021)

I'de be happy to help out , but I didn't receive a private message .


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## Richard Hed (Jan 27, 2021)

stragenmitsuko said:


> I'de be happy to help out , but I didn't receive a private message .


In the mean time, I've done a small bit of searching for some drawings of any sort for this build, oddly, I have found some other types of engines that are very intrigueing but impossible to find drawings for too.  One is that Coombes Engine.  Anybody have plans for the Coombes Engine?  Can anyone tell me what book in the Gingery series is the Atkinson Engine?


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## Gordon (Jan 27, 2021)

Richard Hed said:


> In the mean time, I've done a small bit of searching for some drawings of any sort for this build, oddly, I have found some other types of engines that are very intrigueing but impossible to find drawings for too.  One is that Coombes Engine.  Anybody have plans for the Coombes Engine?  Can anyone tell me what book in the Gingery series is the Atkinson Engine?








						Gingery Book Store
					

Gingery Book Store features books written expecially for Inventors, Tinkerers, Machinists and Experimenters



					www.gingerybookstore.com


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## Richard Hed (Jan 27, 2021)

Gordon said:


> Gingery Book Store
> 
> 
> Gingery Book Store features books written expecially for Inventors, Tinkerers, Machinists and Experimenters
> ...


Thanx Gordon,
But "sold out", both the "cycle" and "differntial".  I went to other online bookstores and the prices were from 23$ to 158$.  Absurd (PLUS shipping!)


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## johnmcc69 (Jan 27, 2021)

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






						ATTKINSON 2021 - Google Drive
					






					drive.google.com
				




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


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## Richard Hed (Jan 27, 2021)

johnmcc69 said:


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


And I thank all of you for your efforts.  BTW, I looking for the Gingery book on his Atkinson Differential when I discovered there was also an "Atkinson Cycle" which is a different build.  I lookt up the stuff on Wiki and found he had created a THIRD type engine which Wiki explained was like a 2 cycle engine.  So I went to Abe books, Alibris and you guys' all time favorite gog and magog, and I found a single "Differential" for sale, the minimum price of 23$ PLUS shipping!  There were others there as well:  IN THE 158$ category!  Well, the Gingery website is offering them for 12$ or under!  So I went there with the intent of buying one of each but when I ordered, they BOTH were out of stock.  So dissapointed, I went outside to have a smoke and guess what I found?  Have hyou guessed?  It was a Gingery "Differential"  that I had order a week ago and forgot about sitting on my porch.  So HALLELUYA!  What a pleasant surprize.  I do that, ordeer a book and know it's coming but by the time it reaches me I have forgotten what book I order.  Ha ha.  I learned this mantra:  "O'wah tahnas siam" many years ago and I feel like an elated fool.  LOL

PS, does anyone know where Brooks P. is?  The way he is being spoken of, I thimpfk maybe he has passt on to the great steam engine.


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## dsage (Jan 29, 2021)

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


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## stragenmitsuko (Jan 29, 2021)

Great job , thanx a million for sharing . 

Pat


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## johnmcc69 (Jan 29, 2021)

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


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## dsage (Jan 29, 2021)

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.


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## Gordon (Jan 29, 2021)

Needle valve








						Home :: MOTORS :: Nitro :: Spare parts :: NEEDLE VALVE ASS'Y 10FP-S - 21111006
					

Online-Shopping for Radio Controlled Hobby Products. Shop RCShop.net for a great selection of RC cars, drones, helis, planes, and more!




					rcshop.net


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## dsage (Jan 29, 2021)

Thanks Gordon.


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## GKNIPP (Jan 30, 2021)

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.


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## Ken Brunskill (Mar 1, 2021)

johnmcc69 said:


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


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.


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## Steamchick (Mar 1, 2021)

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


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## johnmcc69 (Mar 1, 2021)

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


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## Steamchick (Mar 1, 2021)

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


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## wespete66 (Mar 10, 2021)

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.






						Gingery Book Store
					

Gingery Book Store features books written expecially for Inventors, Tinkerers, Machinists and Experimenters



					www.gingerybookstore.com


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## Steamchick (Mar 11, 2021)

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


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## Richard Hed (Mar 11, 2021)

Steamchick said:


> 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?
> ...


They are two different engines.  Two differnet methods of operation


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## Mike Ginn (Mar 11, 2021)

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


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## dsage (Mar 11, 2021)

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.


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## DKGrimm (Mar 12, 2021)

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.


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## Steamchick (Mar 12, 2021)

Excellent article!
K2


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## dsage (Mar 12, 2021)

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


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## Gordon (Mar 14, 2021)

DKGrimm said:


> 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.


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## DKGrimm (Mar 15, 2021)

Gordon, I see that you're right; the Colorado club site no longer has the article I followed.  And it's absolutely true for this AD engine that ring seating is critical.  I did find a copy of that procedure.  My copy was made in 2007, but I've seen an earlier copy from as far back as 2003.  I'll attach the here, assuming ownership and copyrights and all that stuff is not an issue.


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## Steamchick (Mar 16, 2021)

There are loads of videos and articles if you browse the web. 
I have seen many: e.g. *Making Piston Rings *- Video Results 
Enjoy!
K2


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## dsage (Mar 21, 2021)

johnmcc69 said:


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


John:
As I always do I redraw all drawings that I receive.
I might have missed something but it appears you have left out ONE of the most important dimensions in the drawings - the location of the spark plug hole.
Please elaborate.

Thanks


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## johnmcc69 (Mar 21, 2021)

Dave, see drawing #5, sheet-2, front view. The location is shown as .31 ("X") & on cylinder CL.

 The hole SIZE, which is not shown, is M10x1.  (to elaborate...) 

 John


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## dsage (Mar 21, 2021)

Sorry. I didn't notice that pdf had two pages. Changes made.
Thanks

Now for another related question.
I did an animation of the engines motion works and I have doubled check all the dimensions that I think affect it.
It appears that the right hand piston almost travels past the spark plug hole. There's just a small opening left. The left piston is fully past the hole plus a bit to the left.
Have you ever observed this? I was expecting both piston tops to stop right in front of the hole.


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## dsage (Mar 22, 2021)

Here is what I get from my animation. I will add that the pistons tops are both nicely in front of the exhaust hole when they travel to the right so I don't think the cylinder is misplaced. Again, I'm just trying to be sure I have everything in order and would appreciate feedback on what you observe in your model (or on your engine if you have made one).
Thanks


Pistons location with respect to SPARK PLUG hole:








Piston location with respect to EXHAUST hole:


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## Gordon (Mar 22, 2021)

dsage said:


> Here is what I get from my animation. I will add that the pistons tops are both nicely in front of the exhaust hole when they travel to the right so I don't think the cylinder is misplaced. Again, I'm just trying to be sure I have everything in order and would appreciate feedback on what you observe in your model (or on your engine if you have made one).
> Thanks
> 
> 
> ...


Perhaps the timing is intended to be slightly past TDC so that the RH piston has cleared the hole and the LH piston has not yet covered the hole. Moving the hole would make firing at TDC mandatory. Just a thought.


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## dsage (Mar 22, 2021)

Thanks Gordon. I posted the same question to gg... who just completed his on the Atkinson thread and has it running. He showed some nice pictures of the pistons about as I came up with. Apparently a 6mm drill fits in through the 10mm sparkplug hole over top of the piston.
 So for whatever reason mechanically it seems to be correct.

You could be right. Maybe firing after TDC slightly will allow the RH piston to be on it's way down. Maybe with the wacky mechanism it can't tolerate having to fight the combustion early as is normally the case.
Something to keep in mind. Good thinking.

I'll consider my RE-drawings correct and continue on. I hate to start over on this engine but I'd still like to have one of these so I'm considering it. Probably a next winter project.
Thanks


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## johnmcc69 (Mar 22, 2021)

Dave, I checked my CAD model & it is exactly how you have it with the piston partially blocking the spark plug hole.

 John


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## dsage (Mar 22, 2021)

Excellent. Thanks. I'll continue.


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