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Thread: Prop adjustment angle

  1. #1

    Join Date
    Dec 2011
    Location
    Clark Fork Idaho
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    54

    Default Prop adjustment angle

    Have my model 7 just flying and find my RPM is a bit much. Have the 912ULS with 3 blade Whirlwind prop. The info with prop suggests starting at 17deg. but think this is way too flat.
    Anyone else with this prop and what is working for them before I go on a fishing trip with this. Jeff in N. Idaho

  2. #2
    Senior Member
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    Sep 2008
    Location
    Winchester, KY
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    299

    Default Re: Prop adjustment angle

    I have the same setup on my SS7. Had the same result as you at first. Measure in 12 inches from the tip, place a piece of tape at that point on each blade and recheck you blade angle there. Being off a small amount will make a difference. After rechecking mine and getting things reset my takeoff RPM is 5600 at full throttle.

    Dick B

  3. #3
    Senior Member jiott's Avatar
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    Jun 2010
    Location
    Portland, OR
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    2,959

    Default Re: Prop adjustment angle

    I also have the 3-blade Whirlwind GA prop and I set it at the factory recommended angle of 71.5 degrees measured as follows:
    • airplane in flight level attitide.
    • 12" in from blade tip
    • with one blade horizontal (level on trailing edge)
    • place digital level on backside of the blade at the 12" mark
    • hold tight against the backside, especially at trailing edge
    • adjust until you read 71.5 degrees
    • repeat on other two blades
    This setting is a good starting point and should give you 5100-5200 rpm static at WOT. This is a compromise between climb and cruise, and I found it to be more toward a cruise setting.
    Jim Ott
    Portland, OR
    Kitfox SS7 flying
    Rotax 912ULS

  4. #4
    Senior Member
    Join Date
    May 2011
    Location
    MN
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    469

    Default Re: Prop adjustment angle

    Are you guys using the WW supplied wooden tool with a digital level?
    I also have a 3 blade WW and I found the factory reccommended setting to be less than ideal also.

  5. #5

    Join Date
    Dec 2011
    Location
    Clark Fork Idaho
    Posts
    54

    Default Re: Prop adjustment angle

    Am using the tool (jig) that came with the prop from Whirlwind and it seems to be a good method. As mentioned, I went from the 17deg to 22deg and now getting 5100 static. Weather permitting may fly tonight and see what it does in cruise.
    Is there a source for the Nord-Lock washers (prop attach) other than Whirlwind? North Idaho

  6. #6
    Senior Member jiott's Avatar
    Join Date
    Jun 2010
    Location
    Portland, OR
    Posts
    2,959

    Default Re: Prop adjustment angle

    In my sequence of steps below, I am NOT using the Whirlwind supplied wooden tool; just holding the level against the blade.
    Jim Ott
    Portland, OR
    Kitfox SS7 flying
    Rotax 912ULS

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