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Edwards Radial 5 build thread --- PHOTOS!
- Thread starter JRaut
- Start date
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- Sep 28, 2013
- Messages
- 4,399
that was exactly my reaction too!
- Joined
- Oct 7, 2020
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- 2,434
I have to say that I agree whole heartly with Firstram. WOW! What a nice job!
Parts look great. I don't think there is a right or wrong with the spinner nut. Depends on the look you are after, possibly some size/functionally features if you intend to start with a rubber coned RC starter motor or drill.
I'll point out one thing, maybe you are getting there, but just in case. Usually the spinner nut has some means to tighten (and loosen!). Like a thin hex portion or cross hole to put a matching shaft through. People are tempted to put their hex wrench in there because the shaft is strong & has a handle. But it can also chowder up the hole from the flats so best to use a rod based tool.
I'll point out one thing, maybe you are getting there, but just in case. Usually the spinner nut has some means to tighten (and loosen!). Like a thin hex portion or cross hole to put a matching shaft through. People are tempted to put their hex wrench in there because the shaft is strong & has a handle. But it can also chowder up the hole from the flats so best to use a rod based tool.
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- Joined
- Mar 9, 2018
- Messages
- 461
Good to know. I was planning on trying it as-is first (without flats or a hole).
But I’m going to keep the little threaded arbor thing I made so that I can add a couple flats later on if needed.
Maybe I should just add them now while it’s still fresh in my mind.
- Joined
- Mar 9, 2018
- Messages
- 461
Episode 26 || Oil Pump
Well. I am EXTREMELY pleased with how this oil pump turned out!
I’ve put it off until now because there are all sorts of ports, tubes, ball bearings, springs, tight tolerances, etc. involved in making it. But ain’t nobody gonna do it but me, so do it I did.
Unlike many glow engines which are lubricated via mixing oil in with the fuel, the Edwards radial 5 uses a completely independent oiling system. Oil (castor oil is what’s recommended) is pushed around the engine with a pump driven off the crankshaft, and collects in a dry sump at the bottom of the motor.
Here are a few snapshots from Fusion; it’s hard to get a feel for how oil is intended to flow through the pump without a detailed study of the mechanism. But the crux of it is thus: the plunger is activated by an eccentric driven by the crankshaft, and that drives the pumping action. There are actually two completely separate oil pumping circuits --- a lower and an upper. The lower circuit pumps oil from a separate reservoir tank and sprays into the crankcase and cam gears; the upper circuit pumps oil from the dry sump and back into the reservoir tank.
Pump Cover
I started on the pump cover using a suitable bit of aluminum and the help of a hacksaw. I proceeded to square it up to size on the mill. You can start to get a feel for some of the porting if you take a look at the drawings in the photo.
Then over to the mill to bang out a bunch of holes/ports.
The cover has 8 little 1/8” OD brass tubes sticking out the front and sides, so I made quick work of those at the lathe. I (of course) used my favorite tool to part them off.
I used a dab of Loctite 603 retaining compound and pressed the tubes home in my bench vise.
I didn’t get many photos of making the pump body, so the photos here make it look like less work than it actually was. There are a ton of different holes cutting all through this bit of aluminum in all different sizes, and each hole has one or more counterbores. Not to mention that it has to mate up perfectly with the pump cover. Anyway, here are some action shots.
Misc. Other Bits
There are a couple plugs that go into the side, which are retained by a washer. Just bits of aluminum for both. Here’s a photo turning one of the plugs. Nothing special here.
And here we are machining the plunger from 416L stainless. Took a couple tries to get this right. I was getting a horrendous surface finish using HSS, so I ended up just leaving a couple thou to take off with some emery cloth and a bit of WD40. The plunger fits inside the body extremely well, probably just a few tenths clearance on both of those two key diameters.
Side Note
The drawings say that the pump may need some weak springs behind each of the 4 ball bearings (which act as check valves) in order for the pump to operate correctly/efficiently. That absolutely seems to be the case. The very smallest springs that McMaster sells seem like they’ll do the trick. I’ve got them in my shopping cart and will install them once I get a more sizable order put together.
Assembly
And here we have it! All’s here except for the springs.
TIME ON OIL PUMP: 10.5 hours
CUMULATIVE TIME: 420 hours
Well. I am EXTREMELY pleased with how this oil pump turned out!
I’ve put it off until now because there are all sorts of ports, tubes, ball bearings, springs, tight tolerances, etc. involved in making it. But ain’t nobody gonna do it but me, so do it I did.
Unlike many glow engines which are lubricated via mixing oil in with the fuel, the Edwards radial 5 uses a completely independent oiling system. Oil (castor oil is what’s recommended) is pushed around the engine with a pump driven off the crankshaft, and collects in a dry sump at the bottom of the motor.
Here are a few snapshots from Fusion; it’s hard to get a feel for how oil is intended to flow through the pump without a detailed study of the mechanism. But the crux of it is thus: the plunger is activated by an eccentric driven by the crankshaft, and that drives the pumping action. There are actually two completely separate oil pumping circuits --- a lower and an upper. The lower circuit pumps oil from a separate reservoir tank and sprays into the crankcase and cam gears; the upper circuit pumps oil from the dry sump and back into the reservoir tank.
Pump Cover
I started on the pump cover using a suitable bit of aluminum and the help of a hacksaw. I proceeded to square it up to size on the mill. You can start to get a feel for some of the porting if you take a look at the drawings in the photo.
Then over to the mill to bang out a bunch of holes/ports.
The cover has 8 little 1/8” OD brass tubes sticking out the front and sides, so I made quick work of those at the lathe. I (of course) used my favorite tool to part them off.
I used a dab of Loctite 603 retaining compound and pressed the tubes home in my bench vise.
I didn’t get many photos of making the pump body, so the photos here make it look like less work than it actually was. There are a ton of different holes cutting all through this bit of aluminum in all different sizes, and each hole has one or more counterbores. Not to mention that it has to mate up perfectly with the pump cover. Anyway, here are some action shots.
Misc. Other Bits
There are a couple plugs that go into the side, which are retained by a washer. Just bits of aluminum for both. Here’s a photo turning one of the plugs. Nothing special here.
And here we are machining the plunger from 416L stainless. Took a couple tries to get this right. I was getting a horrendous surface finish using HSS, so I ended up just leaving a couple thou to take off with some emery cloth and a bit of WD40. The plunger fits inside the body extremely well, probably just a few tenths clearance on both of those two key diameters.
Side Note
The drawings say that the pump may need some weak springs behind each of the 4 ball bearings (which act as check valves) in order for the pump to operate correctly/efficiently. That absolutely seems to be the case. The very smallest springs that McMaster sells seem like they’ll do the trick. I’ve got them in my shopping cart and will install them once I get a more sizable order put together.
Assembly
And here we have it! All’s here except for the springs.
TIME ON OIL PUMP: 10.5 hours
CUMULATIVE TIME: 420 hours
