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Thread: Restricted prop lever movement FX-3

  1. #1
    Senior Member Andy's Avatar
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    Default Restricted prop lever movement FX-3

    Back in May I found my FX-3 prop controls did not allow the governor control arm to be pulled to the low speed stop. I adjusted the control cable length and, at that time, the cockpit levers allowed full range of control between high and low speed stop.

    Now I find I have the same problem again. Prop levers move the control arm to the high speed stop but do not reach the low speed stop. I disconnected the cable end at the governor and the governor control arm moves freely between the stops. The cockpit prop control levers seem to be binding up long before they reach the aft end of the control range.

    Has anyone else experienced this problem? Can someone, perhaps an EX-3 builder, post details photos and/or drawings of the front and rear prop lever quadrants and linkages showing any areas that could cause restriction of movement?

    Just in case anyone asks - yes the friction adjustment was fully released.

  2. #2
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    Default Re: Restricted prop lever movement FX-3

    Andy. Here’s a link with some info. Scroll down to the prop Governor section.

    https://forum.cubcrafters.com/showth...ll=1#post22623

    Quote Originally Posted by Andy View Post
    Back in May I found my FX-3 prop controls did not allow the governor control arm to be pulled to the low speed stop. I adjusted the control cable length and, at that time, the cockpit levers allowed full range of control between high and low speed stop.

    Now I find I have the same problem again. Prop levers move the control arm to the high speed stop but do not reach the low speed stop. I disconnected the cable end at the governor and the governor control arm moves freely between the stops. The cockpit prop control levers seem to be binding up long before they reach the aft end of the control range.

    Has anyone else experienced this problem? Can someone, perhaps an EX-3 builder, post details photos and/or drawings of the front and rear prop lever quadrants and linkages showing any areas that could cause restriction of movement?

    Just in case anyone asks - yes the friction adjustment was fully released.
    Dave Embry
    "You only live once.......but if you do it right.........once is enough."..

  3. #3
    Senior Member Andy's Avatar
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    Default Re: Restricted prop lever movement FX-3

    Quote Originally Posted by Daveembry View Post
    Andy. Here’s a link with some info. Scroll down to the prop Governor section.

    https://forum.cubcrafters.com/showth...ll=1#post22623

    Dave,

    Thanks for the reply but I didn't find any images of the prop lever quadrant in the governor section. My problem is that the range of movement of the lever is restricted when the cable is not attached to the governor arm. I did find an image of the front quadrant in my build photos (thanks Zach). I don't have one of the rear quadrant.

    Possible obstructions to full aft movement appear to be spring becomes coil bound or cable attach screw or link rod screw fouling the fuel line. I hope it's possible to find the cause without having to pull the side panel.


    Front throttle+prop quadrant.PNG

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    Default Re: Restricted prop lever movement FX-3

    https://forum.cubcrafters.com/showth...ll=1#post21571

    This is the index to entire build. Feel free to look up any area in the index and them for to the posts. These post supplement or correct the manuals only.

    See post 43 for the quadrants themselves https://forum.cubcrafters.com/showth...ll=1#post22094

    https://forum.cubcrafters.com/showth...ll=1#post22510 More on cables.

    the rear quadrant is simply attached to the front quadrant with non-adjustable rods. Almost always the problem is at the Governor end.

    Quote Originally Posted by Andy View Post
    Dave,

    Thanks for the reply but I didn't find any images of the prop lever quadrant in the governor section. My problem is that the range of movement of the lever is restricted when the cable is not attached to the governor arm. I did find an image of the front quadrant in my build photos (thanks Zach). I don't have one of the rear quadrant.

    Possible obstructions to full aft movement appear to be spring becomes coil bound or cable attach screw or link rod screw fouling the fuel line. I hope it's possible to find the cause without having to pull the side panel.


    Front throttle+prop quadrant.PNG
    Dave Embry
    "You only live once.......but if you do it right.........once is enough."..

  5. #5
    Senior Member Andy's Avatar
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    Default Re: Restricted prop lever movement FX-3

    Quote Originally Posted by Daveembry View Post
    Almost always the problem is at the Governor end.
    The governor is not attached to the cable yet the prop lever movement is restricted. The problem clearly has nothing to do with the governor.

    In your builds how far aft does the prop lever go when the cable is not connected to the governor? What limits the aft movement of the prop levers?

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    Default Re: Restricted prop lever movement FX-3

    Andy, here is a page from the build manual on the rear throttle quadrant. You can see there isn't much to it, but it could be that one of the upper AN23-21A screws came loose somehow and jammed the lever. Both throttle and prop should be affected if that is the case.

    If you are going to maintain your own "experimental FX-3 you should ask for access to these manuals.

    Good luck! John

    throttle quad.jpg


  7. #7
    Senior Member Andy's Avatar
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    Default Re: Restricted prop lever movement FX-3

    Quote Originally Posted by aflyer View Post
    Andy, here is a page from the build manual on the rear throttle quadrant.
    Thanks John. Does the front quadrant drawing show the spring that is seen in the photo I posted earlier? I don't see this spring in any of Dave's photos or drawings.

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    Default Re: Restricted prop lever movement FX-3

    Per John's point, might be best to request the manuals. Spring might be shown in another drawing.

    Or drawing has been updated since John's revision. I have found this to be the case many times during and after my build.

    Also, casteliated nuts are shown facing inboard. I would like this configuration so one could possibly peek at the quadrant and see the nuts.
    Last edited by aeroaddict; 09-18-2021 at 07:03 AM.
    Dan Arnold
    KEUL

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    Default Re: Restricted prop lever movement FX-3

    No, it doesn't. And it is not on my airplane, my kit was shipped May 1, 2020. But CC makes continuous small changes.

    I'm sure it is there to balance the spring on the governor. (That spring is there to take the prop to steep pitch in case the cable fails). So, I like the idea.

    John

  10. #10
    Senior Member Andy's Avatar
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    Default Re: Restricted prop lever movement FX-3

    Ok, so the spring is not fitted to EX-3 and, from the geometry shown in my earlier photo, it appears that the spring will become coil bound long before the lever gets to the aft stop.

    Yes, the governor spring will tend to pull the lever forward but does it ever move forward on an EX-3 with normal friction applied?

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