Another Edwards built.

[petertha]

Cool. Is this 4340 or comparable? Are the slots to allow rotation of the cam relative to the ring gear or something? If so, how are they attached? The slots seem big relative to the fastener heads or shanks on the plans so obviously I'm not understanding.

ps - I am almost complete a radial cam timing spreadsheet. I want to check a few more things before posting but I think we have been making this more complicated than designer intended. He labels TDC on the cam so I think the vertical line of the ring gear bolt circle screw positions are intended to be utilized for clocking alignment. He has the INT/EXH phasing & overlap integrated into the tabular profile relative to those datum's so I think you just need a means to ensure that alignment.

 

[Glorfindel]

Cool. Is this 4340 or comparable? Are the slots to allow rotation of the cam relative to the ring gear or something? If so, how are they attached? The slots seem big relative to the fastener heads or shanks on the plans so obviously I'm not understanding.

ps - I am almost complete a radial cam timing spreadsheet. I want to check a few more things before posting but I think we have been making this more complicated than designer intended. He labels TDC on the cam so I think the vertical line of the ring gear bolt circle screw positions are intended to be utilized for clocking alignment. He has the INT/EXH phasing & overlap integrated into the tabular profile relative to those datum's so I think you just need a means to ensure that alignment.

I tought it was 1020, but now, i think it's 4140.
I will simply do a Rockwell test today.

About the slots beeing to big, you are right!! Dumb me lol!!! I putted 0.086 radius instead of diameter lol!!!

I want to adjust the cam with the slothed holes first.

Then my gear will have 3 pre drilled holes and when everything will be timed, i will drill in the camring trough the 3 holes and put a pin to lock everything in place.

I hope it make sense, sorry for my bad english.

 

[petertha]

Yes, if I understand correctly, the slots will provide some degree of adjustment between the ring gear and cam plate. What I like about that is the crankshaft gear is fixed and 2 idler gears also can be fixed between each other beforehand which makes life easier during timing operation.

However, with the slots, depending on where you place them, you may have lost the TDC alignment which was provided by the vertical bolt holes (highlighted yellow in my picture markup). The way I saw the cam being aligned is set piston to TDC & simply put a machinist square on these holes. I think this would be simpler & more accurate timing than measuring start of lift or max lift, particularly because this engine has different intake & exhaust duration & non-symmetrical overlap about TDC. I feel that Edwards made this simple for builders by positioning the ring gear retention holes relative to TDC.

Lastly what is the plan on the cam lobes, are you hardening?

 

[tornitore45]

I completely missed the indication of TDC on the cam drawing.
That makes the phasing super easy.
I plan to place a set screw, between the lobes tracks, to temporarily fix the ring gear to the cam.
With the idler pinions already brazed together and the set screw loose I bring Cylinder 1 to TDC. The ring gear will rotate freely inside the cam hub. At tghis point set the cam as the drawing shows and tighten the set screw.
When the engine is disassembled I will drill the corresponding holes in the ring gear. Still the two 18 T pinions must be marked because they have only 6 correct meshing positions.
Hardening the cams is a tall order for one that only has a propane torch, is quite massive to bring to temperature.

 

[Glorfindel]

I removed the sloted holes. Didnt have a 1/16 end mill handy.

As far as hardening, we got a complete heat threatment laboratory, so no problem here.

I guess i will put it up to 45-50HRC

 

[Glorfindel]

Finaly done the Camring

 

[tornitore45]

Beautiful job! From the tool marks it looks like rotary table work on the round features, or may be the light and the polishing you did.

 

[Glorfindel]

Beautiful job! From the tool marks it looks like rotary table work on the round features, or may be the light and the polishing you did.

Thx.

I did it one side at time, on the dmu 50. We can choose different "patterns" for pocketing.

I will take more pics of my setups for the next parts. For this one, I putted a small chuck plus a V block in a vise clamped on the table lol!!

I will take a pic of that tomorrow.

 

[Glorfindel]

That's the setup i was talking about ;-)

 

[Glorfindel]

First side done.

 

[tornitore45]

I think we can have a small dance party on that rotary table.

 

[petertha]

You sure have some nice machines in your home shop basement -haha

I don't quite get the master rod final machining steps. Are you undercutting it with that rotating tool (pic-1) so it completely parts off from (pic-2) stage where it still has excess material underneath? Or is that operation related to the opening clearance where the link rods pivot within?

 

[Glorfindel]

You sure have some nice machines in your home shop basement -haha

I don't quite get the master rod final machining steps. Are you undercutting it with that rotating tool (pic-1) so it completely parts off from (pic-2) stage where it still has excess material underneath? Or is that operation related to the opening clearance where the link rods pivot within?

You are right, I used that cutter to do the clearance for the link rods.

I also made a little jig to do the other side.

 

[Glorfindel]

I forgot to take a pic of the jig. I'll do it tomorrow.

 

[Glorfindel]

This is the setup.

 

[josodl1953]

It looks a bit different from the original Edwards design. Is there a particular reason for this? Did you use the original 72 degree increments for the link rod holes or corrected angles?

Jos

 

[Glorfindel]

It looks a bit different from the original Edwards design. Is there a particular reason for this? Did you use the original 72 degree increments for the link rod holes or corrected angles?

Jos

Yes, it's the original geometry. I only removed some material around the holes.

 

[Glorfindel]

Idler gears. Wire edm.

 

[josodl1953]

About this off-center carb cover, this is to prevent fuel accumulating in the intake manifold. As you may know, hydraulic lock can be a problem in the lower cyliners of radial engines. Fuel( or oil in the real ones) can accumulate in the lower cylinders causing a hydraulic lock when both valves are closed. That is why the lower intake pipes protrude in the inside of the manifold, all to prevent liquid fuel entering those cylinders.

Jos

 

[Glorfindel]

About this off-center carb cover, this is to prevent fuel accumulating in the intake manifold. As you may know, hydraulic lock can be a problem in the lower cyliners of radial engines. Fuel( or oil in the real ones) can accumulate in the lower cylinders causing a hydraulic lock when both valves are closed. That is why the lower intake pipes protrude in the inside of the manifold, all to prevent liquid fuel entering those cylinders.

Jos

Yes, thats what i figured out.

He putted the carbs lower than the bottom tubes to avoid that.