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Thread: DIFFRENT ROTOR BARS???

  1. #1

    DIFFRENT ROTOR BARS???

    WHAT ARE THE REASONS OR PURPOSE OF DIFFERENT LENGTH OF THE ROTOR BARS?

  2. #2
    Joe, I ain't no expert but I'll give you a simplified un-expert answer and then wait for the experts to clarify it!

    The size of the rotor disk determines how much weight it will lift. So, obviously using different length hub bars will determine the size of the rotor disk; the larger the diameter the more weight it will lift.

    Yes, there is a 'hole' in the middle, where the hub bar is, where no lift is generated although you might get an argument from people who fly Skywheels rotors.

    In any case the inner diameter is traveling at a significantly slower foot per minute speed than the outer part of the rotor blade so doesn't contribute much to the overall lift. So, an increase/decrease in size of the 'hole' as determined by hub bar length has little effect. The longer a rotor blade is the faster it travels and the more lift it generates. However, the autorotation speed is set by the weight so once the a gyro has reached flying speed and left ground effect then the speed doesn't change except when it is loaded in a bank where it sees the load as weight and momentarily speeds up.

    To summarize, a longer hub bar creates a larger rotor disk which generates more lift.
    Dean Dolph
    PRA #8907
    Katy, TX.
    281-391-3731
    Email - topspin38@comcast.net

  3. #3
    PRA Secretary JOHN ROUNTREE 41449's Avatar
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    OK I wasn't sure he meant hub bars! That's why I could not anwser.

    As Dean pointed out most of the lift is generated at the blade tips and diminishing slightly as you reach the hub bar so having a longer hub will give you more lift allowing you to fly at higher density altitudes with the same blades.
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  4. #4
    that is good news. i purchased a used gyro in fla. i am going through it and making it fit me. that is moving petals moving the stick. removing wires that go no where and toggle switches that go no where. there is no paper work with this machine. hour meter says 400 on it. when i get it working on the ground will i be able to legally fly it?

  5. #5
    PRA Secretary JOHN ROUNTREE 41449's Avatar
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    Good morning Joe!

    I'm not an expert! Should really post this questions on Ton Milton's DAR forum.
    However the way I understand it is it either has to be an true ultralight weighing 254 Lbs or less.

    Or if not an ultralight then you must re-build 51% of it and get it registered with you being the builder.

    Now I do know of several that have solely strip the paint, replaced a few parts, painted her, and put her back together with new bolts and SAID they rebuilt 51% and did get it registered.
    PRA- Director
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    U.S. Agent for Aviomania Aircraft... the most stable gyroplane on the market today.
    See: Aviomania USA http://www.AviomaniaUSA.com

    OEM Dealer for MGL Avionics - glass cockpit EFIS for Experimental aircraft Ask about DISCOUNTS for PRA MEMBERS

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