Rotary valve twin steam engine

Discussion in 'Photos and Videos' started by max corrigan, May 26, 2010.

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  1. May 29, 2018 #21

    Anatol

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    Thanks Gary! I found it via google docs.
    I've been thinking a lot about this design. Can anyone explain to me why the valve linkage has to be so complex? Surely a longer crank, and/or shorter valve lever arm, would permit removal of the middle linkage?
     
  2. May 29, 2018 #22

    adolfgalland

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    Anatol, I am sure the center linkage could be removed rather easily if someone wanted to. Some of us say ( The more movement the better ). When I did my version of the Rudy Kouhoupt beam engine from the Aug 1969 addition of Popular Mechanics I did the opposite of what your asking and added another linkage. Gary

    dd5e57bd8a8150c270bf544116014e5d.jpg My Toys 012.JPG
     
  3. May 29, 2018 #23

    Anatol

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    Hi Gary
    did you do this for mechanical reasons or for aesthetic reasons?
     
  4. May 29, 2018 #24

    Anatol

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    Gary
    this link
    http://www.john-tom.com/MyPlans/Steam Engines/RotaryValveEngine.pdf
    is the one I previously had for the identical text, not sure what magazine its from.
    but Frostick's name isn't on it.
    interesting
     
  5. May 29, 2018 #25

    adolfgalland

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    Anatol, I find quite often that when I make engines from someone's plans that I end up changing this or that like in the following photos. The original was from a guy named David Kerzel. Mine has a rotary valve rather than CO2 design As for my beam engine I changed the linkage and a another thing or two just for the heck of it. Gary

    TwinKerzelCo22_th.jpg My Toys 024.JPG
     
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  6. Jun 10, 2018 #26

    Anatol

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    Gary
    I looked for plans to this Kerzel engine but could not find. Do you know where I can find?
    I don't know anything about CO2 engines, Howard they different in operation from Steam/compressed air?
    I'd like to know more about your rotary valve
    thanks
     
  7. Jun 10, 2018 #27

    fcheslop

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  8. Jun 11, 2018 #28

    adolfgalland

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    Anatol, If you found David's plans on john-tom then you probably have seen how the co2 type engines work. If not the top of the piston has a pin which lifts a ball off a seat at TDC which gives it a shot of air to drive the piston down. In a rotary valve like mine part of the crankshaft has flats milled which line up with ports in the block to allow air in and out. Not sure if I explained that very well. One photo is of a version David's engine showing the pin and ball design. The other shows a rotary valve from Rudy Kouhoupt's Radial 5. I went with the rotary valve because you can run the engine on much less air pressure for a slow running engine. Gary

    Dario%20Brisighella%2000427.jpg 024a-Valve-16-DSC_8828Sm.jpg
     
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  9. Jun 11, 2018 #29

    Anatol

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    Thanks Gary

    "the top of the piston has a pin which lifts a ball off a seat at TDC"

    ah, so its a 'bash valve'. I've looked at lots of plans. I've noticed authors seldom give a basic technical summary and you halve to work it out from the drawings. :(

    "In a rotary valve like mine part of the crankshaft has flats milled which line up with ports in the block to allow air in and out."

    So the crankshaft functions as the valve. I'd thought about this kind of solution, it certainly reduces moving parts. I wonder why one does not see it so often?

    thanks again

    "a rotary valve from Rudy Kouhoupt's Radial 5."

    Is this similar to the one you made? What are the downsides? How does it seal? How does it wear? What metals did you use for valve and seat? I see you used a delrin position, so presumably this is not designed to run on steam?
    thanks again.
     
  10. Jun 12, 2018 #30

    terryp

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    Wow, nice looking engine. I am in the process of building the same engine and thought it would be the only one in the world! Not! If I can figure out how to post photos I will do so here. Soooooooo this is an Elmer engine?
     
  11. Jun 13, 2018 #31

    adolfgalland

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    I think I kind of got this thread hijacked and I did not mean to. If I should stop adding to this thread would someone let me know.
    Anatol, Sometimes the rotary valve is part of the crank. In Rudy's case he called it ( the valve ) but I think of it as the rear half of the crank. On the twin cylinder that this thread featured I think of it as a camshaft with flats rather than lobes although the author said he filled the shaft rather than milled it. The seal is as good as you are at making a shaft a perfect fit in a bore. The materials can be different combinations. I typically use either steel/brass or brass/aluminum. My engines get very little running time and I would guess they have little to no wear. Did you mean to say Delrin piston. That engine is not mine but rather some other guys version of Dave's. I do use some of the high performance plastics for pistons on most of my engines because they are self lubricating but you do need to pay attention to their coefficient of thermal expansion so your engine won't seize when the room temperature rises. Teflon has the best coefficient of friction but the worst for expansion. I do not run any engines on steam.
    terryp, If you are referring to the V-twin it is not a Elmer engine but rather David Kerzel's. Mine was copied from his plans but with many changes such as double scale, rotary valve, square cylinders and cylinders in line like a Harley rather than staggered like David's. Gary
     
  12. Jun 13, 2018 #32

    Anatol

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    Gary
    "I think I kind of got this thread hijacked and I did not mean to. If I should stop adding to this thread would someone let me know."
    I started a thread on rotary valves at
    https://www.homemodelenginemachinist.com/threads/rotary-valves.30193/
    we can continue the conversation there.

    "I do use some of the high performance plastics for pistons on most of my engines because they are self lubricating but you do need to pay attention to their coefficient of thermal expansion so your engine won't seize when the room temperature rises. Teflon has the best coefficient of friction but the worst for expansion."

    right, and it gets squishy.

    " I do not run any engines on steam."

    I'm planning to run on steam so my interest is in self-lubricating non-hydroscopic materials with minimal thermal expansion. (I haven't found any yet ;)
     

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