PIP 3 Cylinder Radial

[michael-au]

Made a new inlet manifold today, it now goes straight into the diffuser

Can't do to much still waiting for my hand to heal, but its all good




so now the fuel tank is to low, I packed it up on to some foam and did get it to run for a short time as it runs out of fuel
I now need to seal up where the inlet pipes go into the crank case this would be where there is an air leak and make a plug to seal up where the carb use to be
Its a bit hard doing this one handed so it will have to wait a for a while now
At least I know it will run when sorted out

 

[michael-au]

Ok got it to run for bit longer very finicky on the needle valve not sure if its the carby or the needle valve, anyway I know it runs

My thoughts on making this engine if you make as a glow engine there is only one change I would make that is with the front bearing, I personally would not put it on the inside of the crankcase, I would put it on the outside so the prop driver can run against it when pushing on the prop nut to start it

This would not be hard to do, instead of machining the recess on the inside you would machine it on the outside of the crankcase

The problem I found is that the crank is pushed back in to the case and the intern pushes the diffuser back on to the backplate

If you decide to go with spark ignition I would change the front bearing as I just mentioned and also the rear bearing I would leave it as a sealed bearing, make the defuser with out any cutouts in it and mount the carby on the rear of the engine, I would still put the hole for the carby up the front and make a plug with an o-ring for it this would serve as an oil port

Final thoughts, I am happy how it came out, I learnt a lot in making fixtures and setups. I think its a nice look engine

Thank you to Littlelocos for information and designing the engine



made new parts for the stand to lift the fuel tank up






Diffuser with out cutouts

 

[Peter Twissell]

Nice!
My workshop also has the spatters of oil on the walls which record the first runs of several engines.
(Not to mention the one on the roof which records the first test of an oil pump!)

 

[LuvToFish]

@littlelocos, @michael-au. I’ve just started work on the crankshaft and had a question on the instructions for milling the crank web sides. The instructions state: ”Crankshaft Sequence #7 – Crank Web: Returning to the mill, mount the Crankshaft between crankpin centers, re-strapping the leg of the lathe dog as done previously. Set the rotary table to +60° and cut the flat forming one side of the crank web with an end mill. The space between the side of the crank web and the crankpin journal should be reduced to 0.312". Reset to -60° and repeat for the other side.”

I’m confused by what is meant by “the space between the side of the crank web and the crank pin”? Where is the measurement taken exactly? TIA.

 

[michael-au]

@littlelocos, @michael-au. I’ve just started work on the crankshaft and had a question on the instructions for milling the crank web sides. The instructions state: ”Crankshaft Sequence #7 – Crank Web: Returning to the mill, mount the Crankshaft between crankpin centers, re-strapping the leg of the lathe dog as done previously. Set the rotary table to +60° and cut the flat forming one side of the crank web with an end mill. The space between the side of the crank web and the crankpin journal should be reduced to 0.312". Reset to -60° and repeat for the other side.”

I’m confused by what is meant by “the space between the side of the crank web and the crank pin”? Where is the measurement taken exactly? TIA.

It is confusing but I think it is referring to this

 

[LuvToFish]

It is confusing but I think it is referring to this


View attachment 162653

That’s kind of how I had it pictured but I don’t understand where the .312 dimension is coming from? Is .312 a typeo in the magazine print?

 

[littlelocos]

It is confusing but I think it is referring to this


View attachment 162653

Hello @michael-au. Looking at the drawings and photo #24, the 0.312" shown in the instructions should be 0.031" as measured with a depth micrometer placed on the flat being milled, and measuring to the crankpin. First mill one face to the distance, and then the other, followed by milling around the pin at the same setting to form the radius at the top of the crank. Looking at Drawing 370-12, the radius at the crank pin is 3/16". The crank pin is 5/16" diameter. The difference between the two is 1/32". ((0.375-0.312)/2 = 0.031) My apologies for the typo.

Please feel free to ask any other questions you may have.
Thanks,
Todd.

 

[littlelocos]

My thoughts on making this engine if you make as a glow engine there is only one change I would make that is with the front bearing, I personally would not put it on the inside of the crankcase, I would put it on the outside so the prop driver can run against it when pushing on the prop nut to start it

This would not be hard to do, instead of machining the recess on the inside you would machine it on the outside of the crankcase

The problem I found is that the crank is pushed back in to the case and the intern pushes the diffuser back on to the backplate

Great suggestion. Thanks! I can see where the bearing could be pushed for sure. I use a prop-drive style adapter that doesn't rely on pushing a starter cone into the spinner or prop nut.

When I designed the engine, I was not confident in my ability to maintain the CL and alignment between two different set-ups in the lathe, so I designed it so it could be machined from one end only. Now, 20 years later, I'd have no problem. My lathe at the time was an Atlas 10" with a worn, second-hand 4-jaw chuck. My mill at the time was a Grizzly mill-drill. I still use it regularly, but have added others to the stable. Pip was the first engine I completed, start-to-finish, having had several mis-starts prior to that.

Thanks again,
Todd.

 

[LuvToFish]

Hello @michael-au. Looking at the drawings and photo #24, the 0.312" shown in the instructions should be 0.031" as measured with a depth micrometer placed on the flat being milled, and measuring to the crankpin. First mill one face to the distance, and then the other, followed by milling around the pin at the same setting to form the radius at the top of the crank. Looking at Drawing 370-12, the radius at the crank pin is 3/16". The crank pin is 5/16" diameter. The difference between the two is 1/32". ((0.375-0.312)/2 = 0.031) My apologies for the typo.

Please feel free to ask any other questions you may have.
Thanks,
Todd.

Thanks for clarifying Todd! Much appreciated.