# Opposed 4 Cylinder Air Engine



## cfellows (Dec 24, 2010)

Since it is going to take me a while to completed these plans, I thought I would trickle out pages as they are completed to this thread. If anyone has any comments or suggestions for improvement, please let me know. This first page is just the general layout and the beginning of materials used for the crankcase and cylinders.

Chuck

Edit: This post and the most current post will have the most recent and complete plans attached as a PDF. 

View attachment Visio-OpposedFourPlans.pdf


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## metalmad (Dec 24, 2010)

Hi Chuck
What a lovely christmas present to wake up to.
Im just going out to see if I can find any inch and a half SHS in the shed ;D
Have a wonderfull Christmas Day 
Pete.


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## Groomengineering (Dec 24, 2010)

Hi Chuck.

I appreciate the amount of effort it takes to draw up a set of plans, and all I can say is thank you. :bow:

And Merry Christmas!

Cheers

Jeff


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## lathe nut (Dec 24, 2010)

Chuck, this is going to be one of those gifts that keep on giving so we will have Christmas all year, Merry Christmas, Lathe Nut


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## cfellows (Dec 24, 2010)

Thanks all. I warn you ahead of time that I'm not a draftsman and don't know much about standards of drawing. I may hit some rough spots trying to document how to build this thing. :-[

Here's the first real drawing page. It's the crankcase and may be the first rough spot. By the way, note that the earlier page I posted indicates a 3/16" front to back offset between the left and right cylinder banks. It's actually .200 because I had to leave some clearance between the connecting rods and the crankshaft webs.

Chuck


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## Blogwitch (Dec 25, 2010)

Chuck,

I love plans like this, and no offence meant, one step up from my C-o-C's. WYSIWYG, what you see is what you get, no rooting about for information.

But please, no bright colours for different parts, I have great difficulty finding the metal in the right colours to match :big:

Keep it up.


John


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## cidrontmg (Dec 25, 2010)

Thank you Chuck, much appreciated. Seasons greetings!
 Thm:


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## stevehuckss396 (Dec 25, 2010)

Thanks Chuck!! Very cool of you to give plans for free.


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## cfellows (Dec 25, 2010)

Thanks, all, for the comments. As far as the free plans go, I'm more interested in a contributing knowledge to the community and perhaps leaving some kind of legacy than earning any income from it.

Here are the cylinder drawings. They seem awfully "busy" but it's the only way I know to present all the information I think people need.

I'm also including a reissue of the first page to include the crankshaft and connecting rods in the General Layout.

Chuck


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## slick95 (Dec 25, 2010)

Chuck,

Thank you for your efforts towards helping all of us improve our knowledge and skills with your drawings and presentation of your engine. I would like to build your engine someday and I will save your plans for the future. I'm a serious airplane nut and your engine is a fine example in both looks and sounds.
Thanks again...Merry Christmas

Jeff


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## cfellows (Dec 25, 2010)

Bogstandard  said:
			
		

> Chuck,
> 
> I love plans like this, and no offence meant, one step up from my C-o-C's. WYSIWYG, what you see is what you get, no rooting about for information.
> 
> ...



So, John, you don't like my brass colored brass parts? :big:


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## Blogwitch (Dec 25, 2010)

Chuck,

The ones I have trouble with is bright blue brass and red steel, pink and purple in anything is classed as unobtainium.

My metal stockist just doesn't carry it. :big:

But other than that, your plans are always good, and easy to follow.


John


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## cfellows (Dec 28, 2010)

Here are the drawings for the end plates that get silver soldered onto the ends of the crankcase.

Chuck


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## cfellows (Dec 28, 2010)

As an after thought, I believe the crankcase could be made from a solid piece of 1.5" square aluminum. This would be done by boring a 1 5/16" hole longways to accommodate the crankshaft. Then, the crankshaft bearing carriers would be made larger, 1 3/8" square to cover the hole. The cylinder holes and the rectangular access hole in the bottom would be bored last. I can make up drawings for this alternative if anyone is interested.

Chuck


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## stevehuckss396 (Dec 28, 2010)

Thanks again chuck!!


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## cfellows (Dec 31, 2010)

You're welcome, Steve! Here's the next installment. I've recreated the PDF file to include pages 1 - 6. This supercedes all previous pages. The last two pages are the front and rear bearing blocks. 

Chuck


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## ozzie46 (Dec 31, 2010)

Thanks Chuck. Much appreciated.

 Ron


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## T70MkIII (Dec 31, 2010)

cfellows  said:
			
		

> As an after thought, I believe the crankcase could be made from a solid piece of 1.5" square aluminum ... I can make up drawings for this alternative if anyone is interested.



I'd like to echo my thanks for your clear and well set out plans, Chuck. 

Not having any kind of engineering or drafting background I have struggled with basic published plans. Yours are pitched perfectly for the novice like me.

I would be grateful if you get the opportunity to draw your aluminium crankcase alternative.

Thanks, and Happy New Year!


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## lathe nut (Dec 31, 2010)

Thanks, Thanks and more Thanks, Happy New Year, Lathe Nut


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## kjk (Dec 31, 2010)

It's a great engine Chuck - thanks for posting the plans.


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## cfellows (Jan 7, 2011)

Here's the next installment. This document includes the crankshaft assembly. This uploaded document contains all the pages so far, 1 - 7.

Chuck


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## cfellows (Jan 7, 2011)

Yet another update. Here I've included the drawings for the valve block. Next I'll include the valve tube and the air connection block that attaches to the rear end of the valve block.

Chuck


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## cfellows (Jan 9, 2011)

I've now added the valve tube and air supply block. Things are getting a little complicated now. Please let me know if you seen any errors or something that is confusing.

Thx...
Chuck


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## LockNut (Jan 9, 2011)

Chuck, wonderful job on the engine, I could listen to run all day  ;D . And a Big Thank You for the plans that the uneducated can follow.

LockNut


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## lugnut (Jan 10, 2011)

Great plans Chuck, the only thing I see that you might of left out, is maybe the holes in the valve block for the air supply tube & block that attaches to the back end of the valve block with 2, 2-56 socket head cap screws. But is obvious they need to be there so maybe it's not that important.
Waiting for the gears plans so I can make a gear cutter to make them. I love this little engine.
Mel


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## cfellows (Jan 11, 2011)

Thanks, all, for the positive comments. Mel, I may get the gear drawings done later today. In the meantime, the gears are 24 DP, the smaller gear is 15 teeth and the larger gear is 30 teeth. You could also do 32 DP gears, the small one would be 20 teeth and the larger one would 40 teeth.

Chuck


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## kustomkb (Jan 11, 2011)

It's a great engine Chuck! Thanks for sharing the plans.


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## cfellows (Jan 12, 2011)

I've updated the plans to include the timing gears. I'm including the most recent drawing in both the first post of this thread and the most current. All others will be deleted.

Thx...
Chuck


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## gmichael (Jan 20, 2011)

great project. thanks for the plans.  Mike


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## cfellows (Jan 20, 2011)

Thanks, all. I'm working on the drawings for the air supply manifold and tubes. 

Chuck


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## rleete (Jan 20, 2011)

Are these gears the same as the Liney engine? They sell gear sets, for those not wanting to make their own.


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## cfellows (Jan 20, 2011)

rleete  said:
			
		

> Are these gears the same as the Liney engine? They sell gear sets, for those not wanting to make their own.



Sorry, I don't know what size gears the liney uses. I would be really surpised if the Liney gears will work since my engine is 30% larger than the Liney engine.


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## cfellows (Jan 20, 2011)

Here are an updated set of drawings. These include the diagrams for the air supply manifolds. They were inserted as page 10, pushing the timing gears out to page 11. I'm going to be surprised if I don't get some questions about these... 

Chuck


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## kustomkb (Jan 20, 2011)

Thanks for the latest installment Chuck!

I've been having fun playing with your design in the computer as can be seen in the PDF below.



View attachment Chuck Fellows Opposed 4.PDF


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## cfellows (Jan 20, 2011)

KustomKB  said:
			
		

> Thanks for the latest installment Chuck!
> 
> I've been having fun playing with your design in the computer as can be seen in the PDF below.



Looks good. What software are you using?

Chuck


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## Shopguy (Jan 20, 2011)

Chuck
Thanks for posting these drawings certainly an project to be considered. Beautiful work :bow:
Ernie J


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## kustomkb (Jan 20, 2011)

> Looks good. What software are you using?



Thanks Chuck, I have Solidworks at work. I tried moving a few things around just for the extra practice. If you click on the image in the PDF and drag, it can be viewed in 3-D. Drawing something in the computer is one thing but coming up with the design is entirely another. I showed your design and helical gear cutting to my buddy at work and he said "wow, that guys pretty smart eh?" I agreed.

Cheers


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## cfellows (Jan 20, 2011)

KustomKB  said:
			
		

> Thanks Chuck, I have Solidworks at work. I tried moving a few things around just for the extra practice. If you click on the image in the PDF and drag, it can be viewed in 3-D. Drawing something in the computer is one thing but coming up with the design is entirely another. I showed your design and helical gear cutting to my buddy at work and he said "wow, that guys pretty smart eh?" I agreed.
> 
> Cheers



Thanks for the kind words. Not sure how smart I am, but sometimes I get a desire to make something and I just can't let it go until I figure it out. Then, once I figure it out and make it, I often lose interest. For example, I haven't made another helical gear since I made the fixture and the original set of gears. On the other hand, if I need any helical gears, now know how to do it!


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## cfellows (Jan 23, 2011)

Yet another installment. Here I've included the air supply tube drawings and added some more detail to the manifold drawing.

Chuck


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## cfellows (Jan 24, 2011)

Almost forgot the pistons and rods. I had put the engine back together already and had to disassemble it again to get the measurements.  :-[

Anyway, this installment includes the rods and pistons.


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## cfellows (Jan 24, 2011)

I added some more detail to the crankshaft drawing. I discovered today, when I was reassembling the engine, that the process of getting the 3 piece crankshaft assembled in perfect alignment is helped by milling flats on the connecting rod journals where the setscrews tighten down in the middle crank disk. The trick is to be sure and get the milled flats exactly parallel with a line drawn between the centers of the crankshaft and the connecting rod journal. This also keeps the connecting rod journal from getting boogered by the tip of the setscrew.

Chuck


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## T70MkIII (Jan 25, 2011)

Thanks very much for continuing to add to your plans, Chuck.


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## kustomkb (Jan 27, 2011)

Thanks again for the drawings Chuck.

Here is a little animation I came up with;

[ame]http://www.youtube.com/watch?v=JpAx64VbT9Y[/ame]





View attachment Chuck Fellows Opposed 4 CF.PDF


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## T70MkIII (Jan 28, 2011)

Really nice animation, Kevin.


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## cfellows (Jan 28, 2011)

Nice work, Kevin. With animation like that, all you need to do is add sound and there's no need to build the engine! 

CHuck


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## Maryak (Jan 28, 2011)

Gee Kevin,

I really like that. :bow: :bow:

What program made it possible for you to exercise your artistic talent so well. ???

Best Regards
Bob


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## crueby (Jan 31, 2011)

In looking through the plans, one thing I dont understand: why is the timing gear set up to reduce the spin of the valve tube to 1/2 the speed of the main crankshaft? Doesn't this result in the pistons firing every other revolution? If not, why not? If so, why? I'm confused (obviously!)


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## kustomkb (Jan 31, 2011)

Cheers! 

Chuck, That's funny, I was thinking about adding your sound...

Bob, once all the parts are drawn and "mated" in Solidworks and you have dragged the components into an exploded view configuration, the animation process is fairly automated.


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## cfellows (Jan 31, 2011)

crueby  said:
			
		

> In looking through the plans, one thing I dont understand: why is the timing gear set up to reduce the spin of the valve tube to 1/2 the speed of the main crankshaft? Doesn't this result in the pistons firing every other revolution? If not, why not? If so, why? I'm confused (obviously!)



The engine is set up to run and sound like a 4 stroke IC engine.

Chuck


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## lathe nut (Jan 31, 2011)

You are all very impressive, WOW Lathe Nut


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## Gordo (Feb 4, 2011)

Great plans and project, can't wait to get started!!!!
Gordo


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## cfellows (Feb 5, 2011)

Thanks, all, for the comments. As a reward, here is another installment. I've inserted drawings for the exhaust manifold and slave valve assembly right after the cylinder drawings. 

I believe this concludes everything for the engine. Unless there is a large demand, I'm not going to provide drawings for the stand. Most people will probably want to build their own custom stand anyway.

I've now uploaded the PDF file to the downloads section as well as the first posting in this thread. If anyone has any questions or notices something missing, let me know.

Chuck 

View attachment Visio-OpposedFourPlans.pdf


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## arnoldb (Feb 6, 2011)

> Thanks, all, for the comments. As a reward, here is another installment.



 :bow: :bow: Thank you Chuck. I didn't leave any comments, so this is not a reward, its a blooming brilliant gift, definitely going on my short-to-medium term build list to show the appreciation you're due for your effort.

Kind regards, Arnold


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## T70MkIII (Feb 7, 2011)

Thanks very much indeed, Chuck :bow:


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## AssassinXCV (Jun 6, 2011)

That design inspired me to design my own version: Changes = different measurements, and slight appearance changes.

All credit goes to you, other than the small changes i made. 













Thanks for the inspiration,

Ian


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## cfellows (Jun 6, 2011)

Nice looking drawing. Are you going with the same bore and stroke? I had my 4 cylinder out in the garage running it yesterday. Sure do like the sound.

Hope you will share the build with us.

Chuck


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