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servos work opposite each other

Discussion in 'Scratchbuild Talk' started by rcfoamfly, Sep 13, 2011.

  1. rcfoamfly

    rcfoamfly Airman

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    I have the F18. Not using any mixer just a servo on each elevator ( left and right) connected to the RX via Y- LEAD. When i pull back on the elevator stick on the TX , one elevator goes up and the other goes down. Have do you reverse one servo? Any ideas. Alex in Australia
  2. Grey

    Grey Ace Pilot

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    Yes, you have to reverse one in some way.

    You can use an onboard mixer that tends to be cheaper than a servo reverser. Just plug the Mixer's Elev plug into the Elev port on the RX, then the 2 servo's into the Mixer. The mixer will reverse one of the servos for you. You then just quick-tie up the Ail plug from the mixer so it cant wander down and visit your proprller.

    It can also be done through some TX's mixing. You are definately better off asking someone with more experience on whatever TX you have tho.

    I only know the quick dirty way. Mix the Elev channel with the Aux or Gear channel. Set the Gear/Aux throws to 0% so the switch does nothing. Then one elevator servo goes into the Elevator port and one servo goes into the Gear/Aux port.
  3. wheelbarrowjackson

    wheelbarrowjackson Cadet

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    Why don't you just put the control arm 180 from where it is on the servo or turn the servo over?
  4. sukhoi69

    sukhoi69 Cadet

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    Doing it in the transmitter is the best. What TX do you have?
  5. wheelbarrowjackson

    wheelbarrowjackson Cadet

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    But he's on a single channel & using a Y cable. How would you reverse a single servo when they're both fed the same signal. Servos are not addressable (yet). My guess is he mirrored the installation on each side to make it look nice.

    I'd love to be wrong, because I might have use for it in the future.
  6. sukhoi69

    sukhoi69 Cadet

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    Doh teach me to read properly hahaha. Well that makes it a different matter then. Yes a mixer or time to invest in a different radio.
  7. ScottLott

    ScottLott Administrator

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    I solved the problem on our F-18 by installing the servo on one side slightly raised above the wing plate instead of flat with the wing plate. This way one servo has the control arm facing up and the other has the control arm facing down. You can see the backend of the raised servo in this picture: (Look to the left)
    http://www.rcpowers.com/v2/f18/02.jpg
  8. rcfoamfly

    rcfoamfly Airman

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    Hi guys. It's me with the problem. I tried everything you said and I still have the same problem. When I pull back on the elevator stick, one elevator goes up and the other goes down. I tried to turn one of the servos upside down but the same problem exists. I think Scotts idea of having one servo with it's arm facing up and the other servo with the arm facing down might do the trick. Also I have a turnigy 9x tx.
  9. Mertz42

    Mertz42 Cadet

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    I ran into this issue recently and I solved it with a y-harness with a reversing switch on 1 leg of the y. It works great.

    Guy

  10. rodrigo

    rodrigo Ace Pilot

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    1-the mixer solution is the simplest.... use mixer instead of the Y harness both servos connected to the output pins and the mixer connected just with the elevator port at the rx (elevator channel of course)
    2-we need your tx model to know if you can solve the problem without a external mixer...
    3-the Scott solution is really clever..... another option than I used in the past:
    [​IMG]
    [​IMG]

    is a V pushrod (normal pushrod blended) with the plastic clevis glued in the plain end and the other in the normal state for adjustment purposes... be careful with the control horns angle (same V angle) and the control arm of the servo should be in the centerline

    4- if you use the Y harness and two servos, do not invert the servo, just traslate to the other side, as in this diagram:

    servo elev.JPG

    good luck
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