PIP 3 Cylinder Radial

littlelocos · Aug 11, 2024

LuvToFish said:
Thanks. I’m at a point where I’ve drilled down most of the way but stopped short until I figure out a way to gauge the land thickness. I’m considering making a slot gauge with the width of the land. @littlelocos Any thoughts?

It's been a while since I made mine. All holes were tapped manually in the mill using a sleeve-style tap guide (like the ones held in a lathe tail-stock.) I usually follow the procedure of tapered, plug, and bottoming with the taps. The valve cages were initially set up dry, but leaked. This was rectified with a drop of wicking Loctite.

littlelocos · Aug 11, 2024

petertha said:
More what I'm wondering about is the gas flow through diffuser. Is it entering through the lower (yellow shade) array of holes, into the pie chambers & then flung out to the induction tubes? What does the (pink shade) opening do?

The idea was to allow some of the mixture to pass thru the diffuser at the drive pin as well. The diffuser was needed as I had trouble with fuel distribution between the cylinders. It helps to make sure each one gets its fair share of the mix.

littlelocos · Aug 11, 2024

michael-au said:
The hall effect sensor is installed, connected the electronic ignition to test that it works, all good fires the spark plug ok

View attachment 158710 View attachment 158711

This is some REALY NICE LOOKING work. Wow!

littlelocos · Aug 11, 2024

petertha said:
Is been a long time since I looked at these plans. It just re-occurred to me the carb is front-ish on the nose case. So presumably the mist charge can lubricate cam gear train, back through bottom rod assembly, through that the rotating vane diffuser/booster? part up to the heads. But I can't quite figure out how that diffuser/booster wheel works. There is an aperture slot on the upper area & a series of holes on the bottom? Any explanation in that regard? (The full parts diagram is shown in post#1)

Yes, the idea is that the fuel/air/oil mix takes care of the timing gears, cam, crank, cylinders, etc. as it passes thru the crankcase rather than relying on blow-by or exhausted oil as is typical for commercially available four stroke model airplane engines.

petertha · Aug 11, 2024

michael-au said:
The hall effect sensor is installed, connected the electronic ignition to test that it works, all good fires the spark plug ok

Nice spark ignition system, Michael. Sorry for all the questions but this has been on my brain recently. Maybe I missed but what specific CDI unit did you select & what hall sensor was used? I assume the orange part with set screw is your magnet rotor? Is the distributer conductor strip gap-less for CDI-IN (as opposed to some kind of contact spring) About how much air gap between the cylinder terminals? From your initial intro picture post-1 looks like a shop made park plugs. Did you end up using these for your recent successful test or ended up with commercial plugs?

LuvToFish · Aug 11, 2024

littlelocos said:
It's been a while since I made mine. All holes were tapped manually in the mill using a sleeve-style tap guide (like the ones held in a lathe tail-stock.) I usually follow the procedure of tapered, plug, and bottoming with the taps. The valve cages were initially set up dry, but leaked. This was rectified with a drop of wicking Loctite.

Thanks. I did a bit of back and forth drilling and manually tapping the last bits in the cage holes. I’ve got all six pretty close but not flush with the cylinder cavity. I removed and reinstalled the cylinders from the fixture multiple times in order to ensure I wasn’t drilling to deep. It’s really hard to gauge the depth by eye when installed on the fixture. If anything I’m a bit shallow at this point but I’m thinking it should be fine. Here’s a pic of my progress. I’m now ready to perform a thorough cleaning and loctite them in. Next op is drilling the ports to finish off the cylinders.

michael-au · Aug 12, 2024

petertha said:
Nice spark ignition system, Michael. Sorry for all the questions but this has been on my brain recently. Maybe I missed but what specific CDI unit did you select & what hall sensor was used? I assume the orange part with set screw is your magnet rotor? Is the distributer conductor strip gap-less for CDI-IN (as opposed to some kind of contact spring) About how much air gap between the cylinder terminals? From your initial intro picture post-1 looks like a shop made park plugs. Did you end up using these for your recent successful test or ended up with commercial plugs?

I used the plugs I made and the gap is around .023in or .58mm that ma need adjusting not sure yet
CDI was from Roy Sholl, he has stoped producing them but has passed it on to Dan Williams, dlwssignition @ gmail . com
Roys web page is still up if you want to look at it https://www.cncengines.com/
The blue part has the magnets and the orange part is the rotor, it has a thin strip of brass on it
The rotor is very close to the contacts in the distributor
Hell sensors I got from some where on the internet, I have had them for a while so I can't remember the site I got them from

michael-au · Aug 15, 2024

Have been waiting for some Cerrobend to be delivered, it arrived this week
It has a low melting point 70deg
I got a birko that is used to boil water and a small stainless steel cup
The cerrobend is put in to the cup and then the cup is put into the boiling water and this melts the metal, then it can be poured into the brass tube and then bent with out deforming

This is the birko and the SS cup

This is the cerrobend

The setup in the lathe for bending the tube, the lathe is being used as a vice just to hold the fixture

3 Exhaust Pipes bent to shape
After bending the tubes are put back into the boiling water and the cerrobend just melts out

Setup for holding the tubes for cutting

All tubes were cut to length with a dremal, the cutting wheel on the dermal was run down nails on either end so all tubes were cut to the same dimensions

Still have to do the Inlet tubes, these will be a bit more tricky as they have two bends that need to be at a precise distance with a sideways twist so the fit onto the header and slide into a hole in the crankcase

Peter Twissell · Aug 16, 2024

When you bend the intake tubes, may I suggest that you modify your bending tool (the plate with a hole in it).
I would suggest adding a fixture to locate the end of the pipe after the first bend is made and trimmed to length.

michael-au · Aug 16, 2024

Peter Twissell said:
When you bend the intake tubes, may I suggest that you modify your bending tool (the plate with a hole in it).
I would suggest adding a fixture to locate the end of the pipe after the first bend is made and trimmed to length.

Thank you for the suggestion, I will defiantly look into that

michael-au · Aug 16, 2024

Made a fixture to hold the exhaust and inlet plates to a 1/4". hole at a 15° angle

Exhaust pipes were silver soldered and polished

Installed on the engine

Peter Twissell · Aug 16, 2024

Looking good!
When I make the fixtures for bending pipes for my engines, I make the first bend, trim to length, solder the flange on, then make the fixture so that the flange bolts into place to align the pipe for the second bend.

LuvToFish · Aug 16, 2024

michael-au said:
Made a fixture to hold the exhaust and inlet plates to a 1/4". hole at a 15° angle

View attachment 159098

View attachment 159099
Exhaust pipes were silver soldered and polished

View attachment 159100
View attachment 159101
Installed on the engine

View attachment 159102

As usual, amazing work Michael!

michael-au · Aug 30, 2024

Finished the inlet pipes
This is the. fixture I used to bend the pipes

When I had the pipes to the correct length I made this jig to cut them so they are all the same

michael-au · Aug 30, 2024

I did try to start it, unfortunately it would not keep running it would fire
It took a while to get the timing right (ignition), it's looking like a fuel problem, so I have. made a new Bake plate and put the carby inlet in the back, so it goes straight into the diffuser

My feeling with this setup is that the carby is now a bit low in relation to the fuel tank
I will make a new inlet manifold so that the carby is facing out to the side, I think this will solve the problem with the fuel

But I won't be able to work on it again for a few weeks as I have had surgery (Thursday 29-8)on my left hand (carpal tunnel and trigger finger release), right had has been done and is all good

Thank you for following and I will put more up when I can get back to it

LuvToFish · Aug 30, 2024

Glad to hear your on the mend! I love the ingenuity that went into the tubing fixtures. Interesting that you were having a fuel issue with the carb mounted in the standard location. Could it be a problem with the carb? A vacuum leak somewhere? The intent of Don’s design is for the fuel mixture to lubricate the bearings from front to back as it’s sucked into the defuser for delivery to the intake headers. Will the relocation prevent proper lubrication?

danallen · Aug 30, 2024

When I was having trouble starting my newly completed Edwards radial the problem ended up being my homemade spark plugs. The material that I used was supposed to be "just like Corian" but it wasn't. My plugs shorted out internally.

LuvToFish · Sep 8, 2024

I made a little progress on my pip radial engine. Just finished the crankcase and mock fitted the cylinders in place.

michael-au · Sep 8, 2024

LuvToFish said:
I made a little progress on my pip radial engine. Just finished the crankcase and mock fitted the cylinders in place.
View attachment 159573

Great work looks really good, you have the hardest parts done

littlelocos · Sep 8, 2024

Awesome job! Very nice finish, super-clean!

PIP 3 Cylinder Radial

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