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Thread: The Bucket Foundry

  1. #4726
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    10th February 2005 - 20:25
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    Quote Originally Posted by lohring View Post
    I'll start with 3D printing the parts and assembling everything to catch the mistakes I expect to find. I then need to decide how to make everything. I could send it out to be 3D printed or print the parts for investment casting. Though I have a kiln and foundry, I have more confidence in others for things like this. I can do the machining. Then comes dyno testing. It will be a long project. I may try a simpler, single cylinder 26 cc engine first.

    Lohring Miller
    I don't think that 3D printing is the answer to everything of course, but the way you propose to do it would seem to be very good for the purpose of trying everything out before committing to metal! - gets everything well within the ballpark - quickly! ...... and you get to make use of a powerful program like Fusion 360 or Design Spark Mechanical - (both for free!) - that, even 10 years ago would have been just a dream for the average person at home!!
    For anything else, I reckon the old style patternmaking is still king though!
    Strokers Galore!

  2. #4727
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    28th August 2015 - 00:01
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    Niels, we have a twin class that's limited to 64 cc from either two engines or a twin cylinder engine. People mostly run two engines, but there are a few inline twins.

    Amen brother Will. Just to give you an idea of what it takes to 3D model exhaust and transfers in Fusion 360, i wrote this for another engine builder.

    Lohring Miller

    Click image for larger version. 

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  3. #4728
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    22nd November 2013 - 16:32
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    [QUOTE=lohring;1131171998]
    Amen brother Will. Just to give you an idea of what it takes to 3D model exhaust and transfers in Fusion 360, i wrote this for another engine builder.

    Lohring Miller

    Lohring,
    Really nice work and detailed paper on your methodology. I just have limited access to Solidworks and can only just do simple stuff, but have recently done a loft. Yippee.
    Love the bifurcated inlet. Can see now why you mentioned full skirt pistons. Will you need piston pin bore plugs?
    "Success is the ability to go from one failure to another with no loss of enthusiasm.”

  4. #4729
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    28th August 2015 - 00:01
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    Thanks, I spent several years both learning Fusion and figuring out how to model two strokes. I believe a member here mentioned revolves for transfers. That paper used an older project. Again, someone on this forum suggested that a bifurcated intake would allow a boost port in a piston port engine. I'm interested in the opposed piston concept these days. I need to think of a way to visualize the scavenging flow with 3D printed parts.

    Lohring Miller

  5. #4730
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    Quote Originally Posted by lohring View Post
    Niels, we have a twin class that's limited to 64 cc from either two engines or a twin cylinder engine. People mostly run two engines, but there are a few inline twins.

    Amen brother Will. Just to give you an idea of what it takes to 3D model exhaust and transfers in Fusion 360, i wrote this for another engine builder.

    Lohring Miller
    Lohring,
    You're just a "tad" ahead of where I am at the moment! - but thanks, - I'll look at it a little more closely and hope I can get my head around it! - I (like Ken) have been doing relatively simple stuff (successfuly) - I always learn something new each time I do a drawing.
    I find that if I have a definite design in mind (other than just exercises), I do learn much more quickly! - but I'm still a long way behind!

    Ken,
    I see you got a good 'mention' from Alex on You Tube (re: your idea on piston ring design ) ........ ie when he took his bike to the salt flats. - pity the salt flats had turned into a lake again!
    BTW, don't you have similar dry lakes in Aus? (salt flats?).
    Strokers Galore!

  6. #4731
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    18th May 2007 - 20:23
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    Quote Originally Posted by WilDun View Post
    Ken, I see you got a good 'mention' from Alex on You Tube (re: your idea on piston ring design ) ........ ie when he took his bike to the salt flats. - pity the salt flats had turned into a lake again! BTW, don't you have similar dry lakes in Aus? (salt flats?).
    Yes, Lake Gairdner. https://www.dlra.org.au/2020.htm

    Jim from Team ESE has been taking his bikes there the last few years.

  7. #4732
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    10th February 2005 - 20:25
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    Quote Originally Posted by TZ350 View Post
    Yes, Lake Gairdner. https://www.dlra.org.au/2020.htm

    Jim from Team ESE has been taking his bikes there the last few years.
    Thanks TZ, all very interesting - didn't know all that existed (even though they are right on our doorstep!).

    Looks like the dry salt lakes all over have returned temporarily to salt water lakes!
    Strokers Galore!

  8. #4733
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    12th March 2010 - 16:56
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    another house lot of pattern wood, daughters kitchen rebuild. Waste not want not.
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  9. #4734
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    28th August 2015 - 00:01
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    I ran my opposed piston design in EngMod with 2 to 8 degree exhaust lead and no other changes. Detonation happens at 6 and 8 degree leads. The power is below. The peaks are very close at 4 to 8 degree leads, but 4 degree lead gives a better low end. The higher leads give better over rev, and the lower leads give better low end. The transfers have huge STA, the exhaust and intake STAs are about right for the power, but the blow down STA is low. Does the exhaust lead help with this?

    Lohring Miller

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  10. #4735
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    22nd November 2013 - 16:32
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    Foundry lesson for the day:
    Making up some sand moulds for a UHV variant. So, faced the pattern with a virgin sand/sodium silicate mix and gassed it with CO2, all good. Then have to back it up with some bulk sand. What about all the sand from a previous cast. Few hard bits, crush them up and sieved it, no lumps. Gave it the sodium silicate, packed it around the facing sand, hit it with CO2 and nothing. Didn't take, almost no bond at all. Virgin sand after was fine.
    Moral of the story: Used CO2 sand is useless.
    "Success is the ability to go from one failure to another with no loss of enthusiasm.”

  11. #4736
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    12th March 2010 - 16:56
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    yes, set off sand won't stick to new sand. I pack mold segments separately against each other, they will not stick together.
    Apparently there is a process to post treat used sand for recycling its use.

  12. #4737
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    28th August 2015 - 00:01
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    We're starting to look at scavenging flow in the opposed piston engine. I can't post the movie here, but it can be found on two stroke tech if you are a member. The most notable things so far are effects of delay from the two different transfer passage lengths and the lack of scavenging of the cylinder walls. The first runs were with straight in transfers with no swirl. Next tries will be with swirl and/or some transfers with higher up angles. Below are the flows just after the transfers open. The first is the pulse from the short transfers. Note where the pulse is in the long transfers. The second is the pulse from the second transfers.

    Lohring Miller

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  13. #4738
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    4th September 2017 - 10:39
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    Quote Originally Posted by lohring View Post
    We're starting to look at scavenging flow in the opposed piston engine. I can't post the movie here, but it can be found on two stroke tech if you are a member. The most notable things so far are effects of delay from the two different transfer passage lengths and the lack of scavenging of the cylinder walls. The first runs were with straight in transfers with no swirl. Next tries will be with swirl and/or some transfers with higher up angles. Below are the flows just after the transfers open. The first is the pulse from the short transfers. Note where the pulse is in the long transfers. The second is the pulse from the second transfers.

    Lohring Miller

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    Not using EFI led him to think that his project would not be a clean 2-stroke.
    The CFD has shown that it can be a clean 2-S, taking advantage of the difference in the transfer pulses to perform a stratified scavenging

  14. #4739
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    28th August 2015 - 00:01
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    I hope. Still the goal is a simple twin with better power than the inline twins it will run against. The packaging is better already with its flat configuration. We'll see.

    Lohring Miller

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