PIP 3 Cylinder Radial

[LuvToFish]

I’ll prolly just use low temp solder when I get to this. It requires less heat and the capillary action does its thing. I’m currently building an arbor for my Quorn T&C grinder. I have a new 46 grit cup wheel I’m going to use to rough the fin cutting bit from a 3/8’s hss blank. I have fine grit wheels mounted on arbors but they load up pretty quickly when taking off a lot of material.

well so far, I still have 4 cylinders in play

 

[michael-au]

well so far, I still have 4 cylinders in play

And they are looking very nice, this is the hardest part of the build so many different setups

 

[michael-au]

Got the throttle barrel made, First step was to turn it to size and then drill a 2.5mm hole and then tap for a 3mm hex bolt then I put it in the 4th axis because I didn't want to setup the dividing head
So I didn't have to worry about the angel difference between the venture and the slot, after the milling was done I then parted it off and then drill the 1/8" hole in the other end

The weather is cold at the moment, not that good for being outside (hate winter)










Still need to do a dit of sanding work on the carb body to take the marks out of it

 

[michael-au]

I didn't mention this before but I had a lot of trouble with the big end bearing (threading it)
I made a bout 4 of these and everyone came out with a tapered thread on it, I could not work out why this was happening, I threaded it before drilling the hole so it would not collapse because it is very thin walled
I tried opening the die a bit but nothing I tried worked they were all tapered after threading
In the end I threaded it on the cnc lathe and it was fine

You might want to thread it on the lathe first

 

[LuvToFish]

Got the throttle barrel made, First step was to turn it to size and then drill a 2.5mm hole and then tap for a 3mm hex bolt then I put it in the 4th axis because I didn't want to setup the dividing head
So I didn't have to worry about the angel difference between the venture and the slot, after the milling was done I then parted it off and then drill the 1/8" hole in the other end

The weather is cold at the moment, not that good for being outside (hate winter)


View attachment 157833View attachment 157834

View attachment 157835

View attachment 157837View attachment 157838


View attachment 157836
Still need to do a dit of sanding work on the carb body to take the marks out of it

Wow! Looking awesome Michael. Very nice! It’s the hottest part of the summer here but luckily, it’s been quite mild compared to normal. That will change though as July is July and it’s always a bear here.

 

[LuvToFish]

I didn't mention this before but I had a lot of trouble with the big end bearing (threading it)
I made a bout 4 of these and everyone came out with a tapered thread on it, I could not work out why this was happening, I threaded it before drilling the hole so it would not collapse because it is very thin walled
I tried opening the die a bit but nothing I tried worked they were all tapered after threading
In the end I threaded it on the cnc lathe and it was fine

You might want to thread it on the lathe first

Thanks for the tip! I assume you’re referring to the main bearing with the threaded OD? My lathe does single point threading quite well usually.

 

[michael-au]

Thanks for the tip! I assume you’re referring to the main bearing with the threaded OD? My lathe does single point threading quite well usually.

Yep that's the one

 

[petertha]

Was the bearing threading required for assembly somehow or in order to more easily replace it on day?

 

[michael-au]

Was the bearing threading required for assembly somehow or in order to more easily replace it on day?

It has to be that way to be able to get the master rod in, there is no way to get the rod on the crank with the bearing in it, has to be screwed after the rod is on the crank

 

[LuvToFish]

Michael, you warned me about the amount of work that goes in to the cylinders in this model. You weren’t kidding!

 

[michael-au]

Michael, you warned me about the amount of work that goes in to the cylinders in this model. You weren’t kidding!

Yep it took me a while to get my head around some of the setups, a lot of potential for something to go wrong, have to check and recheck to make sure it right before cutting

 

[LuvToFish]

Any new updates Michael? I finished out the top fins and have the sleeves made and ready for honing. The molly tube I purchased is .677 ID. The tube Doug used in his proto finished at .685. That is a bit much for honing. I figure I could shoot for .680 and call it good. The instructions say to go ahead and glue the sleeves in after the top fins are cut and before any further mill work. However the photos show the work proceeding without the sleeves installed until later. Any preference on when to set in the sleeves?

 

[michael-au]

Any new updates Michael? I finished out the top fins and have the sleeves made and ready for honing. The molly tube I purchased is .677 ID. The tube Doug used in his proto finished at .685. That is a bit much for honing. I figure I could shoot for .680 and call it good. The instructions say to go ahead and glue the sleeves in after the top fins are cut and before any further mill work. However the photos show the work proceeding without the sleeves installed until later. Any preference on when to set in the sleeves?

I didn't install the sleeves until last, once I was satisfied all the work on the cylinders was done I then loctited the liners in

If you install the sleeves before machining the valve guide and plug holes you will not be able to fit the cylinder on to the jig for for drilling these holes

I haven't made much more progress yet

 

[michael-au]

Im thinking of making a stand out of aluminium

 

[LuvToFish]

Im thinking of making a stand out of aluminium


View attachment 158341

Very nice! On some RC model engines the height of the tank in relation to the carb can be a factor in its run-ability. Some say place the tank centerline even with center of carb, others want the tank lower to prevent flooding or other issues. No idea how this model will behave but I like the design!

 

[michael-au]

Very nice! On some RC model engines the height of the tank in relation to the carb can be a factor in its run-ability. Some say place the tank centerline even with center of carb, others want the tank lower to prevent flooding or other issues. No idea how this model will behave but I like the design!

Still making alterations at the moment

 

[michael-au]

 

[Rdean33422]

How about adding a three bladed prop?

Ray

 

[michael-au]

How about adding a three bladed prop?

Ray

That would be good, I just learnt how to draw a prop
I might have to have a go at a 3 blade

 

[michael-au]

How about adding a three bladed prop?

Ray