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Thread: Oddball engines and prototypes

  1. #3091
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    7th October 2015 - 07:49
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    JU-87 Stuka engine gear. Looks like teeth edges rounded directly in form at forging process.
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  2. #3092
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    Quote Originally Posted by katinas View Post
    JU-87 Stuka engine gear. Looks like teeth edges rounded directly in form at forging process.
    I wonder what purpose this rounding might serve. Maybe to maintain an oil film between the side of the gear and whatever it may be leaning against in case of lateral forces?

  3. #3093
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    7th October 2015 - 07:49
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    The first thought that comes to mind, is teeth cracking prevention. This is the crankshaft gear that turns propeller gear.
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  4. #3094
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    21st June 2012 - 14:20
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    Yes,I agree that those fillets are to prevent cracking in that highly loaded part..I continue to be amazed at the very high quality of the parts built during wartime conditions with manual machines from all of the nations..My hat is off to all of the masters who have lived before us and that we may continue in their foot steps!

  5. #3095
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    18th April 2017 - 23:08
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    I read a bit about that a while ago.
    https://www.geartechnology.com/issue...geardesign.pdf
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    Last edited by Muhr; 17th March 2021 at 08:51. Reason: I misunderstood the question
    No amount of experimentation can ever prove me right; a single experiment can prove me wrong.

  6. #3096
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    22nd November 2013 - 16:32
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    This makes con rods just so "ho hum"....

    http://www.nadiraksoy.com/
    "Success is the ability to go from one failure to another with no loss of enthusiasm.”

  7. #3097
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    4th September 2017 - 10:39
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    Quote Originally Posted by ken seeber View Post
    This makes con rods just so "ho hum"....

    http://www.nadiraksoy.com/


    It reminds me of how diesel pumps work.
    This type of pump is serving as an orientation to create a specification for the two stroke engine
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  8. #3098
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    28th August 2015 - 00:01
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    Radial piston hydraulic pumps and motors have been built in a similar way for years. The translation into an IC engine hasn't worked. It's a lot harder to seal a piston that's not bathed in oil at moderate temperatures.

    Lohring Miller

  9. #3099
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    7th October 2015 - 07:49
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    Finally engine run today with intake through transfers type, adapted for Honda RS 125 GP cylinder. Still not ready for riding or dyno tests, just checked if this could work at all, without damage. Add short video https://www.youtube.com/watch?v=uK-MLMWTl-g
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  10. #3100
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    Quote Originally Posted by katinas View Post
    Finally engine run today with intake through transfers type, adapted for Honda RS 125 GP cylinder. Still not ready for riding or dyno tests, just checked if this could work at all, without damage. Add short video https://www.youtube.com/watch?v=uK-MLMWTl-g
    Very beautiful, it is a pleasure to behold.
    Excellent work, I keep seeing them over and over again.
    congratulations on a job well done

  11. #3101
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    7th October 2015 - 07:49
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    Thank you Ceci, but I have some doubts. Intake through transfers scheme, with Honda Rs cylinder, have one down side. Two wide exhaust ports restrict intake ( red zone) through whole A transfers area. Only at TDC piston fully uncovered A. With one exhaust port type cylinder, A is not restricted, but exhaust became restricted.
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  12. #3102
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    Quote Originally Posted by katinas View Post
    Thank you Ceci, but I have some doubts. Intake through transfers scheme, with Honda Rs cylinder, have one down side. Two wide exhaust ports restrict intake ( red zone) through whole A transfers area. Only at TDC piston fully uncovered A. With one exhaust port type cylinder, A is not restricted, but exhaust became restricted.
    I disagree that the problem is filling, I see more restrictions in the evacuation of cargo trapped in the crankcase

  13. #3103
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    4th September 2017 - 10:39
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    Quote Originally Posted by ceci View Post
    I disagree that the problem is filling, I see more restrictions in the evacuation of cargo trapped in the crankcase
    The imperfect evacuation of charge from the crankcase becomes an intake problem

  14. #3104
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    7th October 2015 - 07:49
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    Quote Originally Posted by ceci View Post
    The imperfect evacuation of charge from the crankcase becomes an intake problem
    Yes, this could be huge restriction if the all flow mass, that goes into crankcase through A and B, evacuated only through the bottom crown side reeds.
    But with this concept, I guess the most interesting thing is that the bigger part of the mass flow returns to the transfers channels, again through A and B windows when the piston moves down. The previous inertial flow from carb collided with returned flow, intake reed valve closes and all this increases the high pressure in the transfers tunnels. And this is why, maybe it is possible extract something from this concept.
    Yes, crankcase separation crown with reeds, just needed to evacuate what left in the crankcase and later this helps to increase negative pressure just before the intake process started through A and B, when piston moves up.

    As flow through A and B goes in both directions, before they opened for scavenging, even small restriction could be critical for build up high pressure in transfers tunnels.

    Would be good to do three main comparisons tests with the same cylinder.
    1 Spec piston and separation crown with side reeds (intake through A and B).
    2 Spec piston and opened crankcase ( normal intake )
    3 Std RS 125 piston and opened crankcase ( normal intake )

    Still not ready for tests, but not many things left to do.

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