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Advice about flap quadrant interference

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  • Advice about flap quadrant interference

    I have found a minor problem with the interaction between my flap quadrant, and the locking pin & assembly inside my flap handle.

    This issue initially caused the flaps to retract automatically on occasion, then (once the quadrant wore-down) resulted in my being unable to select and lock 2 notches of flap completely - which was cause for some concern!

    The interference causing the issue is shown below, it only happens on the second notch in my case, the geometry of the 3rd and 4th mean a partial engagement of the pin is sufficient (but only just!!) The first notch is immune from this problem, owing to it's dissimilar geometry. See drawing.

    Mine was a recent QB kit assembly, so QB owners might want to check for this issue. The best fix will be to lengthen the slot on the INNER TUBE push-button & lock pin assembly, by roughly 1/8".

  • #2
    Do you have this notice? The quadrant is different than your drawing. http://mybearhawk.com/changejan06.html

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    • #3
      Originally posted by alaskabearhawk View Post
      Do you have this notice? The quadrant is different than your drawing. http://mybearhawk.com/changejan06.html
      Yes thanks - I modified the photocopy of the drawing to show my problem on a smaller bit of paper. My quadrant is the same as the drawing you posted.

      I lengthened my slots in the inner tube using a 3/16" reamer, and now it all works great.

      --> The main thing is:
      If you have notches in any location on your quadrant, it would be worth checking that the locking pin is engaging properly.
      Last edited by Battson; 12-22-2013, 02:00 PM.

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      • #4
        So is the issue that the slot isn't quite wide enough for the pin?

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        • #5
          I read it as- the slot on the inner tubing was not long enough I.E to allow the pin to sit home in the quadrant notch completely as it seems (the inner tubing ) is touching the rear face of the quadrant , so the remedy was to file out the slot on the inner tubing (more clearance behind the pin) to allow only the pin to make a positive contact !!

          hope that makes sense !!
          Paul Dennington plans #1257

          scratch built 4 place

          England

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          • #6
            Originally posted by nuggets View Post
            I read it as- the slot on the inner tubing was not long enough I.E to allow the pin to sit home in the quadrant notch completely as it seems (the inner tubing ) is touching the rear face of the quadrant , so the remedy was to file out the slot on the inner tubing (more clearance behind the pin) to allow only the pin to make a positive contact !!

            hope that makes sense !!
            Yes that's exactly what the situation was.

            I flew it yesterday after increasing the clearance behind the pin. All the notches of flap have a much more positive-locking feel, and no more auto-retracting second notch!

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            • #7
              To check whether you have this problem:

              Select 3 notches of flap.

              Look to see if there's clearance between the quadrant and the slot in the "inner tube" (the tube which houses the 1/4" pin). The lower end of the inner tube's slot should not be touching the quadrant.

              You will see the problem as shown in the attached photo.

              Remember to check top and bottom of the inner tube for interference, there's a slot in each side.

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              • #8
                This is an old thread, but I do have a question about the problem and the solution: it appears that the notches in the quadrant for the first two stages of flap have a "ramp" that allows you to deploy those stages without pressing the button, correct? It also looks like if you ground a ramp into stages 3 &4 that the problem would (might) be solved. Is there any reason why you wouldn't/couldn't do this? What about if you didn't have the interference problem, but just wanted a "ramp" on all 4 stages?

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                • #9
                  You can put a ramp on whichever stages you like, it's just personal preference. It means you can pull the handle and the flap keeps coming, rather than automatically stopping at non-ramp notches.

                  The ramp won't solve the problem though, it only removes the interference on the low side of the quadrant. The top side will still hit the quadrant before the pin is fully engaged.

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