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Thread: Kitfox-4 elevator trim systems, rans wheel or electric ???

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  1. #1
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    Default Kitfox-4 elevator trim systems, rans wheel or electric ???

    Well I am confused on installing a trim system for the model 4, and hoped to get some insight from the group. My old model 2, to trim for pitch you just moved the flapperion handle a little (actually, it was not good for much else, didn’t really seem to work well as a flap). However, I understand the model 4 flapperions work more like real flaps, and thus adding pitch trip is necessary, correct? (or do I just move the flapperion handle again?).

    Kitfox offer an electric trim system, but I see they want you to buy a special elevator that accepts it. But I hear the Rans trim wheel system might also work (sold my aircraft spruce). Has anyone used the Rans? Will it work with the standard kit elevator, or is the trim tab model needed?



  2. #2
    Super Moderator Av8r3400's Avatar
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    Default Re: Kitfox-4 elevator trim systems, rans wheel or electric ???

    I have a flying model IV. It does not have a trim system on the elevator. Trimming is (supposedly) done with the infinitely adjustable flapperons.

    There are several reasons why I don't like this.


    1. You can not trim the plane to fly hands off while on approach. At low power settings the nose is very heavy. (Not to mention eliminating the use of the "flap" feature - which is effective)
    2. Cruise trim is just barely maintained. I have the fixed horizontal stab set to max nose up position and with full reflex on the flaps, it will just maintain level flight
    3. Safety factor. Without a trim tab, if the linkage ever fails, this means game over. I've tried some approaches using power and flapperon "trim" and found that it can't be done. During my private training we constantly practiced landings with one of the three axis of control failed.

    On my 1200 rebuild, I will be modifying the elevator to accept a trim tab. Maybe electric, maybe cable operated. I have seriously contemplated adding the Rans tab you referred to on my 1050 flying plane for the above reasons...
    Av8r3400
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  3. #3
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    Default Re: Kitfox-4 elevator trim systems, rans wheel or electric ???

    FYI on the Rans wheel trim. Rans released a scary notice saying that it has led to elevator flutter, due to the usage of a spring in the trim system.
    They have recommended going to an electronic servo type trim system, with a ridged pushrod arm, or a mechanical system one with a ridged push rod or tube.

  4. #4
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    Default Re: Kitfox-4 elevator trim systems, rans wheel or electric ???

    Roger,
    I sent my 4 elevator off to Lowell at Highwing LLC and had him install the elevator trim. I installed the trim button in my stick and I now have a terrific system !!! No more "mickey mouse' flap trim. Its really great to trim the pressure off on approach as well as level flight. This is the only way to go !!
    Dick
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    Default Re: Kitfox-4 elevator trim systems, rans wheel or electric ???

    WRT to Rans Trim Wheel, I'm installing one of those. There is no spring in the system. It uses a solid wire push/pull system. Eric Ashman has one on his IV and it works great.



    What *is* a concern on these push/pull systems is to make sure the wire and sheath are secure.


    What I've use on these cables is safety wire on the outside as well as Loctite "Black Max" 380 adhesive. This will bond the sheath to the wire as well as to the metal locking ferrule.

    Just me, I like the mechanical trim more than an electric servo.

    Cheers,

    Mark Napier

  6. #6
    Super Moderator Av8r3400's Avatar
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    Default Re: Kitfox-4 elevator trim systems, rans wheel or electric ???

    Here's the RANS trim system from Spruce.

    What I like about this is the tab can be attached to the rear of the elevator not needing covering repair or cutting / welding. Plus the wheel is a nice infinite adjustment.
    Av8r3400
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