# 8 Cylinder Radial Engine C-O2 My Design



## AssassinXCV (Apr 27, 2012)

I couldn't find any 5 cylinder radial engine designs that were free, and also the lack of tools right now (4 jaw chuck for square bar cylinders) I decided to design my own from scratch. The proportions of my design just didnt look good, so i decided to try something out of the ordinary; an 8 cylinder radial engine.

There are some of these engines out there, but are not as common as the 3,5,6,7,9, or 15 cylinder radial engines, and that's what I like about it. Using some of my spare time at my university, and the machine shop that we've used for some of our classes, I can start making parts until the end of the semester, before i get my own mill.

Pictures so far:

The crank case is made out of 6061 B221 Aluminum.

Mounted in a rotary table, using a 1" carbide insert face mill i started the task of milling the octagonal shape.






I swapped out the 1" carbide insert face mill with a 1 1/4" face mill; just to give me some more leeway when parting. First side complete.





Second side complete.






Third side complete.






Some more views.














Will finish on Tuesday.


Ian


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## Maryak (Apr 28, 2012)

Hi Ian,

Your off to a good start and Goodonya for having a go at your own design :bow:

Unless it's a 2 stroke, I understand from a recent thread, you will have problems with an even number of cylinders.

I'm sure those of us who know more about this than me, ( most of us), will chime in.

Best Regards
Bob


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## vcutajar (Apr 28, 2012)

I suspect this is going to be an interesting build. Will be following you as you progress with the build.

Vince


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## AssassinXCV (Apr 28, 2012)

Maryak  said:
			
		

> Hi Ian,
> 
> Your off to a good start and Goodonya for having a go at your own design :bow:
> 
> ...



Yes, it is a two stroke. I will have a single cam attached direct drive on the crankshaft, which will open the valve all the way when the piston reaches the top, but also continue supplying air on the way down. When one piston gets it's full blast of air, the piston before it is still getting some air pressure, but it is reducing.

Thank you for your interest,

Ian


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## AssassinXCV (Apr 30, 2012)

Update:

Completed the Outside shape of crank case today. Took a final pass over each side to make sure they are symmetrical. Measures 2.408 minor diameter, just off the 2.410 I planned.














Ian


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## AssassinXCV (May 1, 2012)

More Pictures!

Boring out the main hole in the crank case.

Center Drilling





Used 1/2" Drill then 1.25" drill





LOTS OF CHIPS 





1.5" Boring Bar





1.875" Hole diameter






Ian


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## AssassinXCV (May 3, 2012)

Time to drill the bores in the case for connecting rod access to the cylinders:

Marked and center drilled:





Using a 5/8" drill to bore out the holes in the case:





First two done:





Last one:





Looking pretty good:





Next I will drill and tap four holes on each side to mount the cylinders to the case.


Ian


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## AssassinXCV (May 4, 2012)

Cylinder Mounting Holes:

Marked one side where the holes will be drilled:
	

	
	
		
		

		
		
	


	




Center Drilled all the holes:





Using a 0.1015" drill I drill the holes for tapping. I used a 0.1015" instead of a 0.9095 drill to give a stress free tapping in the soft aluminum.(Tap-Drill chart at school stated either 39-0.9095" or 38-0.1015") :













Ian


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## AssassinXCV (May 6, 2012)

Started work on the cylinders. They will take some time on my mini lathe, but they'll get done.

First one of the eight.










Ian


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## AssassinXCV (May 6, 2012)

First Cylinder 75% complete, But it's as much as i can do now for each cylinder until i get a mill.
Things to do: - I need make the bases square and drill the mounting holes; also drill and tap for the cylinder head.
          - Drill the exhaust ports around the angled edge of the cylinder. That's just above the top of the piston at BDC; similar to 
           Kerzel's V-Twin.

The cylinder bore is exact 0.500in. perfect for the 1/2" piston.

Freshly parted off on the lathe:





Cleaned and dried:





On the case. As you can see, the base will need to be milled square, or else it will collide with others due to the overhang:





Ian


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## Rayanth (May 9, 2012)

Assassin,

Sorry for the late arrival to the party - there ARE some free 5-cylinder radial plans out there. I have done and redone (and just finished doing again) the Edwards Radial 5 build-up in Inventor, just to have something to do on the late nights that I'm not at work. I believe Robert Sigler had most copies of the plans pulled from random websites, but they are still available via at least one source - the Yahoo Group R and R Engines (radial and round or something).

I have a copy of latest revision if you're interested.

Presently looking for something more challenging to CAD up. maybe a 14 or 18 cylinder radial... or a V8/V12 or something.

- Ryan


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## AssassinXCV (May 10, 2012)

Rayanth  said:
			
		

> Assassin,
> 
> Sorry for the late arrival to the party - there ARE some free 5-cylinder radial plans out there. I have done and redone (and just finished doing again) the Edwards Radial 5 build-up in Inventor, just to have something to do on the late nights that I'm not at work. I believe Robert Sigler had most copies of the plans pulled from random websites, but they are still available via at least one source - the Yahoo Group R and R Engines (radial and round or something).
> 
> ...



I have seen that (Forest Edwards Radial 5) before in my searches, but I don't have the machinery to build one as complicated as that. I've had my eyes on the Rudy Radial 5, but that one was pretty pricey; though I've heard it does come with tips and techniques and such.

Thank you,

Ian


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## Rayanth (May 11, 2012)

Well, I will surely be following your work here with interest =)

Keep it up!

- Ryan


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