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outside admission

Discussion in 'Locomotive M.I.C.' started by expansionlink, Jun 7, 2014.

  1. expansionlink

    expansionlink New Member

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    I have read, "With outside-admission valves the eccentric or return crank is set at 90 degrees in front of the crank." Can someone please explain to me where this 90 degree angle is, as I just cannot visualise it. Thanks Ian Technophobe!
     
    expansionlink, Jun 7, 2014
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  2. John Webb

    John Webb Member

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    It's the angle between the crankpin and the end of the return crank relative to the centre of the axle when the loco is moving forwards. There are several books, including "Handbook for Railway Steam Locomotive Enginemen" (BTC 1957, reprinted by Ian Allan 1977 onwards) with various diagrams which make this clear.
     
    John Webb, Jun 7, 2014
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  3. Eightpot

    Eightpot Resident of Nat Pres Friend

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    Probably better to say that the return crank leads the main crankpin by around 90 degrees. The actual amount is dependant upon the individual layout of the valve gear.
     
    Eightpot, Nov 21, 2014
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  4. huochemi

    huochemi Part of the furniture

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    huochemi, Nov 22, 2014
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  5. Steve

    Steve Resident of Nat Pres Friend

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    does this help with understanding it?
     

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    Steve, Nov 22, 2014
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