Rootes blower rotor question??

Discussion in 'PSI Superchargers Tech Questions' started by RUGSTER, Nov 21, 2009.

  1. RUGSTER

    RUGSTER New Member

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    Just a short(and possibly easy question to answer??)
    Does a Hi-Helix rotor weigh more than a standard helix of the same material?? Lighter or heavier?? The more i think about it the more my answer changes!!
    Given the cases are the same and only difference is the extra "Twist" in the design,i'm interested to hear the thoughts behind the answers:rolleyes:

    Jason:cool:
     
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  2. secondwindracing

    secondwindracing top alcohol

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    if more by very little..Dave
     
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  3. Ken Sitko

    Ken Sitko Super Comp

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    Most of the hi-helix blowers have billet rotors, the standard blowers do not, so the hi-helixes tend to be heavier, I think.
     
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  4. Don Onimus

    Don Onimus New Member

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    weight

    I know my Kebelco sure is heavy. Don
     
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  5. Relentless

    Relentless www.bretitanium.com

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    Might give an idea, our old Mooneyham 14-71 weighed 52 lbs

    Our current Kobelco 14-71 weighs 104lbs
     
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  6. Mike Canter

    Mike Canter Top Dragster
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    Given that the rotors are the same diameter and the same length then the 120* twist will weigh more than a 60* twist rotor. Stop and think here...... with more twist then more rotor is contained within that 14" length. If you twist something then it normally shrinks in length so you would have to add length back to it to keep it the same.
     
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  7. T.A.D. 776

    T.A.D. 776 New Member

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    Rotors weight difference alone is the question.

    Picture this- Straighten out the twist in the two rotors, the high helix or more twisted rotor is going to be longer. Therefore heavier.

    The amount of weight that close to center is going to be so little in rotating resistance in can almost be discarded from the equation. The extra air the rotor moves is going to be what counts as the higher helix traps more air per rotation.
    So in turn the high helix rotor is going to use longer striping thereby increasing rotational resistance per revolution. This would have more effect than the extra weight on power needed to turn the blower.

    Now you know why that perfectly clearanced and timed blower that is just broke in will go faster. Actually a perfectly clearanced blower will not need breaking in. But we live in the real world.

    Gel lube a crutch for an improperly clearanced or worn out blower. But good stuff as it is cheep to use. Down side is it increases rotational resistance. Up side is it helps get another few rounds out of a blower.

    Trying to lighten the rotors if there was any decreased stiffness would be detrimental beyond what you could hope to gain in weight reduction from loss of seal and increased friction.

    A center bearing plate in a long rotor would help reduce rotor flex. Just figure out how to time them. This would also strengthen the case increasing seal.
     
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  8. T.A.D. 776

    T.A.D. 776 New Member

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    Mike supplies the short version while I am typing the long version.

    I like your answer Mike.
     
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  9. RUGSTER

    RUGSTER New Member

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    Thanks for your thoughts guys:)
    Mert tells me if they are billet rotors they DO weigh the same!:rolleyes:
    He weighed two Kobelco rotors, one a 60 the other 120 and they are near identical?
    Could have fooled me:eek:
    jason.:)
     
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  10. Mike Canter

    Mike Canter Top Dragster
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    Please click one of the Quick Reply icons in the posts above to activate Quick Reply.
     
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  11. Mike Canter

    Mike Canter Top Dragster
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    Ooops, sorry about the previous post I hit the wrong button.

    Please understand that when we say that the HH twist rotor weighs more that it just will weigh some amount more. Not saying that it weighs ten grams more, maybe an gram or two more. Saying they are nearly identical is not identical. We are just answering your question with the fact that it is going to weigh some amount more.
     
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  12. RUGSTER

    RUGSTER New Member

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    Sorted!!:D Thanks Mike!!
    Jason...
     
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