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5 axis puzzle : how to ?

EmGo

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In 1961, when this was made, how would you do this in quantities greater than one ?

selwood3a.jpg


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Revolving-Block Internal-Combustion Engines.
 
Well, I think the standard procedure, would be to have anyone you showed the picture to sign a non-disclosure agreement, then start talking up how much of a percentage of the profits the guy that actually made it was going to see instead of being paid time and materials....
 
As I see it, the toroidal cylinder segments can be made fairly simply, with just an offset boring bar with a projecting cutting element (or two, three, whatever, as long as they're relatively narrow and they're all in direct alignment), then a simple rotational motion of the "block" halves (which doubtless start as cored castings) transits the boring bar/cutting edges into the open section of the block.

Around a 30* arc is needed, short enough that a ~1 to 2 bar-cutter diameter ratio should clear (or somewhere around this). Rotate the block half back to start for cutter removal.

The two end segments are truncated cones, so easy to do on a regular lathe.

The rest, as they say, is mere sweat and setup. Ah, for the old days when machinists didn't need the crutch of CNC... :D
 
"... how would you do this in quantities greater than one ?"

I think you have struck on the reason why it is not under the hood of any car today.

Seriously, if you were to make them in any number you would need a bunch of specific task machines and fixtures. The key here is that you need to sell enough of them to pay for that special/single purpose tooling. If you made only one of a new design, it could cost millions. But if you make millions of them, they only cost hundreds. You have to pay for the tooling: all in one or spread out.
 
As I see it, the toroidal cylinder segments can be made fairly simply, with just an offset boring bar with a projecting cutting element (or two, three, whatever, as long as they're relatively narrow and they're all in direct alignment), then a simple rotational motion of the "block" halves (which doubtless start as cored castings) transits the boring bar/cutting edges into the open section of the block.
Yes, I was thinking for a onesy, an indexing table mounted to a rotary table should do the job but for more than that, kind of a nightmare. The pistons are even worse, how to get a cam on them ?

I guess this is a classic case of "engineering does drawings, let the farging shop figure out how to make it" :D

Definitely an interesting engine design .... maybe use oe of these in my hybrid, instead of that ineficient gas microturbine :)

Would this make a good student project or what ? I'd give an A to anyone who built one of these ...
 
i wonder if the working version actually had the curved cylinder bores. You could imagine if there was a little radial freedom at the piston's connecting pin the cylinders could be straight. Thanks for linking to the museum of retro technology. I'm excited to go down that rabbit hole!
 
Riffing on Larry's response...An inventory of snarky answers:

- You didn't specify in 3D did you? So with tracing paper...?

- You didn't specify tolerance did you? So with a die grinder...?

- You didn't specify material did you? So with clay/ceramics...?

Seriously though, interesting design.
 
I wonder what a motorcycle with a rotating block engine would be like except super dangerous? Might be hard to steer?

Mechanical inversions of this type are interesting but are often impractical. I have worked on a few inverted clocks where the pallets were held stationary and the entire clock swings back and forth instead. They are interesting but rare, at least in part to their being a complete pain in the ass.
 
Well, historically, other complicated shapes have been made in volume using special machines, or somewhat more general machines driven by various templates.
(See various videos of how wooden airplane props are made, etc.)

For the curved cylinders, I would imagine developing a sort of "ball tool" (like a lollipop cutter on steroids) put in a special machine to move it.

Getting pistons, cylinders, rings, etc. to match the tolerances of modern engines would end up being very expensive.

It also, to my eye, has no apparent advantage.....
 








 
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