Jim,
What with the recent discussion of tailplane issues and my need to
address mis-aligned TP13 bushes, I came across your post in 2006. After
reading resultant posts on your thread, I'm curious how you proceeded
and how you feel about your results. When you mention using a machine
shop to make your holes, does that mean you removed your torque tube
---From your completed aircraft in order to do the shop work? What kind of
a job was that?...I didn't realize it was feasible...
Fred
A194
On Monday, October 23, 2006, at 04:05 PM, Jim Butcher wrote:
> Recent inspection has revealed excessive play in our port tailplane.
> The problem is play in the torque tube pin. We incorporated Mod 62
> (larger pins) during our build so that=92s not an option.
>
> Our Tech Counselor suggested using AN386 taper pins. He said they are
> commonly used for similar applications in certificated aircraft. AC
> 43-13 confirms that AN386 pins are used in joints where "the absence
> of play is essential".
>
> A search of this forum suggested that the inner tube (TP4) would crush
> and bind in the bearing (TP11) if tapered pins were used. Our thoughts
> are to Loctite a 12" length of 1.375" OD .093" wall 4130 steel tubing
> centered inside of TP4. This would prevent the crushing of TP4 and 12"
> allows it to span the TP11 bearings. We would use a machine shop to
> accurately make the tapered holes for AN386-3 pins. The tapered pins
> would be installed vertically since there is not much material left on
> TP9 (the center bracket) from the installation of 3/8", Mod 62 pins.
>
> In the original design, the pins also locate TP10 sleeves against TP11
> bearings inside the fuselage to prevent left - right torque tube
> movement. We would like to locate TP10 independently of the pins. Our
> thoughts are to machine TP10 sleeves to fit outside the fuselage
> between TP12 and TP11 to achieve the same purpose. Alternatively, we
> could split or slot TP10 and secure them to TP12 inside the fuselage
> with hose clamps (Oetiker style for 360 deg contact).
>
> Comments?
>
> Jim & Heather Butcher
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