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Thread: The Bucket Foundry

  1. #2026
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    Slider update:
    This is sort of how it'll look with the adapter plates waiting to be zapped onto the crankcases, followed by some machining. Head blank is underway, having a friend at the local uni being able to wire cut it out to a rough shape.

    Click image for larger version. 

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    Been quiet here, surely someone is splashing some hot metal around somewhere?

  2. #2027
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    Can I use it for me racer

    sent for a divine source
    "Look, Madame, where we live, look how we live ... look at the life we have...The Republic has forgotten us."

  3. #2028
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    I'm out for now, I've got to work for a living for a while, You know the stuff that keeps to toys paid for.
    Suddenly real busy with gearbox manfacturing, orders for nine. Big time for us
    In saying that I have found a YZ gearbox, local, for the donkey cases. Just in time.
    Nice looking setup there Ken.

  4. #2029
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    Quote Originally Posted by ken seeber View Post
    Slider update: This is sort of how it'll look with the adapter plates waiting to be zapped onto the crankcases, followed by some machining.
    Click image for larger version. 

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    I see you rotated the cylinder base stud pattern through 30°, compared to Flettners universal crankcases, which seems like a sensible move to me. Of course Flettner could easily add another six ears to his cases.
    But wouldn't it be wise to rotate the cylinder another 180° in order to avoid a collision of the right-hand exhaust in your picture with the carburettor?

  5. #2030
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    Quote Originally Posted by Frits Overmars View Post
    But wouldn't it be wise to rotate the cylinder another 180° in order to avoid a collision of the right-hand exhaust in your picture with the carburettor?
    Frits, as usual, everything I post is dodgy. In this case the plates need to be welded to the crankcase halves and then match machined. After that the holes will go in. The crankcases are bisexual in that they are the same casting for both sides, so potentially, as some have done, one could mount 2 reed valves and carbs, after opening up the wall between the crankcase and the unused reed cavity. So, the cylinder can have the "on axis" exhaust exiting on the opposite side to the carb. However, instead of just putting in the 6 holes, I may as well put in 12 so we can keep the options open. One consideration here is that the A/R pin in the piston will have to be positioned to suit the orientation used, but have that one covered. Another is the communication created by the piston pin bore uncovering both the exh and transfer in certain positions. This could be solved with piston pin plugs, but at this stage I'll live with it.

  6. #2031
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    What is so wrong with having the exhaust at one end of the cylinder and the inlet at the other? Uniflow.
    It would offer a clean cylinder fill with (tuned right) no transfer charge escaping, especialy if using a small air buffer between the inlet and exhaust. No EFI required. Out of phase cranks can provide enough exhaust blow down (not needed anyway apparently), with smooth balanced operation.
    Combustion chamber is compromised by having two pistons against each other (without having to have odd shapes), plugs need to be in the side of the cylinder. If same size pistons there is no squish.
    If some trickery were used to make the exhaust piston cause HCCI (assumimg same size pistons) then back off and provide an exhaust path, ie open some exhaust ports, what if?
    On all my Uniflow engine designs I've used the gear train as a power take off, the revs are already reduced. This reduction in revs is almost always needed in IC applictions anyway. So the perceived complication of needing a drive from one end of the engine to the other is partly null and void.
    All my Uniflow engines to date used two cylinders and four pistons to get the crank case pumping charge the correct volumes, as it happens this my have been the wrong approch, perhaps enough pumping to fill half the cylinder, using the exhaust (chamber) to do the rest. In other words make a simpler single cylinder with two pistons, crank case pumping only from one end (transfer end). Exhaust end would be like a fourstroke, in oil, or perhaps a Ryger?
    The trick is in the mechanisim that makes the exhaust piston "suddenly" increase compression just at the right time and then just work like a normal piston until next cycle.

  7. #2032
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    Quote Originally Posted by Flettner View Post
    What is so wrong with having the exhaust at one end of the cylinder and the inlet at the other? Uniflow.
    It would offer a clean cylinder fill with (tuned right) no transfer charge escaping, especialy if using a small air buffer between the inlet and exhaust. No EFI required. Out of phase cranks can provide enough exhaust blow down (not needed anyway apparently), with smooth balanced operation.
    Combustion chamber is compromised by having two pistons against each other (without having to have odd shapes), plugs need to be in the side of the cylinder. If same size pistons there is no squish.
    If some trickery were used to make the exhaust piston cause HCCI (assumimg same size pistons) then back off and provide an exhaust path, ie open some exhaust ports, what if?
    On all my Uniflow engine designs I've used the gear train as a power take off, the revs are already reduced. This reduction in revs is almost always needed in IC applictions anyway. So the perceived complication of needing a drive from one end of the engine to the other is partly null and void.
    All my Uniflow engines to date used two cylinders and four pistons to get the crank case pumping charge the correct volumes, as it happens this my have been the wrong approch, perhaps enough pumping to fill half the cylinder, using the exhaust (chamber) to do the rest. In other words make a simpler single cylinder with two pistons, crank case pumping only from one end (transfer end). Exhaust end would be like a fourstroke, in oil, or perhaps a Ryger?
    The trick is in the mechanisim that makes the exhaust piston "suddenly" increase compression just at the right time and then just work like a normal piston until next cycle.
    Food for thought, Neil.
    My first, instinctive reaction: for proper scavenging of an uniflow cylinder you'd need a scavenging column with a diameter equal to the bore. Radially aimed transfer ports won't do that. Pockets of spent gases will remain just above the ports, unless you give the ports a lot of axial angle. But then there will remain a central column of spent gases. Besides, large axial angles will result in smaller cross flow areas and in transfer flows that don't slow each other down sufficiently, so you will have a scavenging column that moves too fast and has insufficient density.

    In big uniflow diesels the transfer ports are offset tangentially so they create a swirling column that flings to the bore surface, leaving a column of spent gases in the center. Those big diesels have overhead exhaust valves that offer an exit for those spent gases. But if you use exhaust ports in the bore circumference, the fresh mixture will take the easy way out and the spent gases can't get to those exhaust ports because the centrifugal movement favours the high-density fresh mixture and keeps the lower-density spent gases trapped in the middle.

    Maybe you're thinking of alternating high- and low-axial angle transfers. It could be the best of two worlds, or it could be combined drawbacks.
    Well, I think I've done my best to discourage you . Now it's up to you to prove me wrong. If anybody can, it's you .

  8. #2033
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    I was hoping you would take the bait, you know Frits, I'm getting lazy, I find it easier to filter design feed back through you than bother spending hours reading other people's work and then trying to digest it.
    Lucky for me you have some experience with these matters
    The transfer issues you elude to are certainly real. In my last two Uniflow engines I have indeed offset the transfers alternate with one aiming up (approx 20 degrees and radial approx 20 degrees) and the next aiming in underneath it, flat and aiming to the center. I'm sure there is a sensible compromise somewhere. In the last engine (not finished) I had an air buffer between the inlet and exhaust.
    I'm thinking about how the Ryger transfer system might be of some use in the Uniflow scavange system or some combination.
    Don't worry, I'm not starting a new project (no time anyway) but just thinking, as you can see I'm just expanding on the HCCI engine I've got and trying to work it in with the Uniflow design.

  9. #2034
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    Quote Originally Posted by Flettner View Post
    I was hoping you would take the bait, you know Frits, I'm getting lazy, I find it easier to filter design feed back through you than bother spending hours reading other people's work and then trying to digest it.
    My pleasure Neil.

    as you can see I'm just expanding on the HCCI engine.
    I'm glad you do. I think HCCI is the way to go, for two-strokes, four-strokes, wankels, you name it.
    Speaking of wankels, do you know the LiquidPiston engine? http://liquidpiston.com/technology/how-it-works/ I think it is an improvement on the wankel.
    The rotor tip seals that are so critical in a wankel, do not reside in the rotor any more, but in the housing, where they can be lavishly lubricated and cooled.
    The LiquidPiston engine also avoids the wankel's heat losses because it has lovely compact combustion chambers and constant-volume combustion, begging for HCCI. And I regard the 'crankshaft' kinematics as the ultimate form of a hypocycloidal drive.
    I think you cannot design a more compact intermittent combustion engine (as opposed to a turbine, but those are fuel guzzlers).

  10. #2035
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    Quote Originally Posted by Frits Overmars View Post


    Speaking of wankels, do you know the LiquidPiston engine? I think it is an improvement on the wankel.
    Frits, is that the same engine which a Russian guy (Veselovsky I think) was experimenting with quite a while ago? I was quite interested in it at the time.
    Strokers Galore!

  11. #2036
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    Quote Originally Posted by WilDun View Post
    Frits, is that the same engine which a Russian guy (Veselovsky I think) was experimenting with quite a while ago? I was quite interested in it at the time.
    Maybe, Will. Veselovsky doesn't ring a bell but if you go to http://liquidpiston.com/company/ and click the About Us-tab, you'll find the names Dr. Nikolay Shkolnik and Dr. Alexander Shkolnik. Sounds Russian to me.

  12. #2037
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    Slider update.

    The crankcase is decked and drilled/tapped allowing the cylinder/water jacket combo to be screwed down.

    Click image for larger version. 

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    As it is an SI engine, it'll need something to hold the spark plug, probably a cylinder head. That's next then. Where's all that damn time going?

  13. #2038
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    Just bung HCCI in it, no need for a sparkplug Still need a head though I guess.

  14. #2039
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    HCCI fun on a Sunday afternoon.

    http://autoflightnewzealand.blogspot.co.nz/

    Bit of a seizure at the end but worth the wait.

    Thankyou Brett S for the fuel Injection idea, works fine.

  15. #2040
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    Quote Originally Posted by Flettner View Post
    HCCI fun on a Sunday afternoon.

    http://autoflightnewzealand.blogspot.co.nz/

    Bit of a seizure at the end but worth the wait.

    Thankyou Brett S for the fuel Injection idea, works fine.
    It seemed to really take off when it was leaned out though.
    Quote Originally Posted by Katman View Post
    I reminder distinctly .




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