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F-105 Thunderchief | Main gear issue resolved


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4 Responses to “F-105 Thunderchief | Main gear issue resolved”

  1. Scott says:

    Bob, did you try a small air cylinder that would push up like your spring that could unlock the gear. You could hook it up to the gear cylinder line so you don’t need any other sequencing device. just a thought.


  2. AndWho says:

    No need for springs or extra cylinders, if the linkage geometry was symmetric. Think servo control surface linkage.
    You have a very asymmetric linkage geometry causing the problem.

    When the gear is halfway in or out you should have a 90 degree angle between hinge line and cylinder linkage attach point, or equal angles when in and when out. Symmetry.

  3. Sid says:

    Having seen your gear first hand I think “AndWho” is on the right track. I think I remember that when your gear is in the down and locked position your attachment point is nearer 85 degrees rather than nearer 45 degrees. You probably need slightly more than 90 degrees of travel so the linkage is over center and locked. When you start the rotation at close to 85 degrees the mechanical advantage is very small and consequently hard for the gear to unlock.

  4. AndWho says:

    Hmm, on further though this is a trickier problem.
    I was thinking 90 degree travel at the gear leg, But the cyliner/piston is not attached to the gear leg.
    It is attached to the upper lock bone. And thus you will get near 180 degree travel, or even more.
    This is a mechanical nightmare, 180 degree rotation from the linear movement of the piston. To do such magic it is usualy best to convert from linear to circular movement with a gearwheel on the rotating part and gear rack on the linear part. Or two wheels and a pull-pull wire system.

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