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50 degree flap deflection in 3 notches

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  • 50 degree flap deflection in 3 notches

    I finished rigging up the flaps and am getting all the 50 degree deflection with only three notches of flaps. Scratching my head on what to do. Reducing the tension in the cables is not helping. If it gets too lose then the first notch does not move the flaps.

    Any thoughts please?

  • #2
    Cable tension should not be the issue, it would have to do with the ratio of throw. I would double check that everything is rigged correctly with and the right sizes.


    • #3
      Is your build a kit or plans? The ratios are set by the length of the horns obviously, and the angle of the horns a bit less obviously. Even with the right length, if you start or end the stroke in the wrong place you can get the wrong throw.


      • #4
        The drawing below is of the inboard flap lever on the Patrol plans. I annotated on the drawing two red arrows from the rear spar to the hole in the flap lever where the cable shackle attaches.

        What are your measurements on your installation compared with the plans?

        I adjusted my flap cable turnbuckles so that the measurement of the short red arrow complied with the plans when the Flap Handle is set to Full Flaps (fourth notch of Flaps). I used a digital caliper to measure this value. I was able to get the tolerance quite accurate on both sides.

        With the turnbuckles properly adjusted, I then stowed the Flap Handle (fully retracted the Flaps to the Up position). The Flap Arms rested on the Flap Support Frame, and the flap cable had some slack in it, but when the first notch was pulled, the flap arms raised up off the support frame about 1 inch.

        So my experience showed that the flap cable length (not tension) adjustment at full flaps sets everything.

        Screen Shot 2019-01-11 at 9.11.05 PM.png
        Brooks Cone
        Southeast Michigan
        Patrol #303, Kit build