5 cylinder Radial Engine

[rdean]

The last couple of days I have been working on the cylinders.


I am not a fan of long bolts that hold both the head and cylinders on to the engine so I modified the cylinder flange so I can bolt them on separately. I will be using only 4 bolts for the cylinder mounting and 4 bolts for the heads. The plans call for 5 long bolts that are not evenly spaced but I think 4 will be fine. You can see where I drilled the holes for the flange and holes for the heads but I have not taped them yet.


The cylinders are ready for the cooling fins but not today.

Thanks for looking
Ray

 

[rdean]

I don't have much luck slotting on the lathe with the cutoff blade to make the cooling fins. I can only get so deep and then it grabs and the excitement and bad language begins.
I have a slitting saw that is 0.060 thick and if I clamp the cylinders in the rotary table on the mill it may work better for me.
I will give it a try.
It was not a piece of cake and it took over 4 hours but they turned out quite nice.


I was so relieved it worked I couldn't help but bolt them on just to see how it would look.

And the other side.


I gave everything a good polish as well.
Now the cylinder head fins don't seem so daunting.

Thanks for looking
Ray

 

[DavidR8]

I aspire to produce work like that!
So nice

 

[Chris Hamel]

Looks impressive

 

[StevSmar]

I couldn't help but bolt them on just to see how it would look.

I would have done the same. And they look beautiful in place!!!

 

[rdean]

Thank you David, Chris, and StevSmar for the kind words.
I am happy with the way they turned out.

Ray

 

[rdean]

The plans call for a Boston Gear G677 internal ring gear that has 48 teeth, 24 pitch, 14.5 pressure angle. I did find that gear for sale at several different places but with a wait time of 4 to 6 weeks and a price of $150 and up. Now I'm not a cheap skate but I just can't my self paying that much for a brass gear that is 2 1/2" in diameter and a 1/4" thick.
I have gear cutter sets in 16dp, mod 1, and mod 0.7 so I should be able to come up with some combination that will work.
The teeth on mod1 cutters are the closest to 24 pitch so this is what I came up with.
Internal ring gear 52 teeth with an outside diameter 2 1/2".
One spur gear 13 teeth so this gives me a 4 to 1 ratio.
Two spur gears 19 teeth each with one behind the 13T gear on a common shaft and one on the crank shaft.
Now this setup is not exactly perfect but it is within 0.020 total small. I will add a little to each of the 19 tooth gears outside diameter to make up the difference.
I will make a test plate where I can install all the gears and see and correct any issues before installing on the engine.



I had a cad drawing of the ring gear and cut it out on the CNC mill. The final pass was with a 0.03125 end mill at a cut depth of 0.200.
It is a beautiful piece of brass and it should work fine.
I hope to cut the other gears tomorrow using the gear cutters on the manual mill.

Thanks for looking
Ray

 

[DavidR8]

Very nice work. When I was reading the post I thought CNC router/mill would be a solution. And boom there it is

 

[Chris Hamel]

Looks great!

 

[rdean]

Thanks Chris

David yes a CNC machine is very useful but I have only used it for the master rod and now the ring gear for this project. All the other work was done on a manual mill and lathe.
Ray