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Re: Rudders and brakes (breaks)

mhadley1@juno.com wrote:
> On Fri, 1 May 1998 11:16:51 -0700 "Al Gietzen" <alventures@email.msn.com>
> writes:
> >
> >Shouldn't we be alarmed that rudder cable breaks have been occurring in
> >Velocitys for years, and when still secure them the same way.
> >
> >Doesn't the fact that needing full rudder when landing in turbulence
> >or crosswind could also result in a firmly applied brake and a resultant
> >broken gear leg mean that a design change is needed?
> >
> >Alarmed,
> >Al Gietzen  RGE
> >
> Dear Al,
> As far as the rudder horn to cable connection, this situation could use
> some scrutiny. The cable begins to break strands when  the rudder is
> moving in and out without the pedal being depressed. This occurs whenever
> there are gusty winds on the ramp and there is no rudder locks in place.
> Pressing the pedals creates enough tension on the line so that the cable
> / nico press joint stays in-line. When the rudder is deflected without
> tension on the cable, it tries to push the cable back into the nylaflow,
> which is kind of like pushing a rope up a hill, and it invariably flexes
> the cable right at the nico press. A couple of hundred, probably
> thousands of time of this, and the strands begin to break.
> Al, it's almost 2AM...and I have a brainstorm, maybe a brain fart....  A
> simple slip joint at the rudder horn!   Manufacture a fork on the end of
> the horn. Drill a 3/32" hole in the center on the shank of a 1/4" clevis
> pin, being sure to debur and radius the edges of the drilled hole.
> Install the 1/4" clevis pin through some oilyte bushings pressed into the
> top and bottom 'fork',  liberally lubricating and placing a thin washer
> under the head of the clevis pin and a thin washer and cotter pin at the
> bottom of the clevis pin. Run the 1/16" cable through the hole in the
> shank, double back through a nico press (or ball) and  attach the nico
> press or ball firmly.

Or you can try this much simpler solution.  You need two AN111 cable
bushings which look like little pulleys and are generally shown on the
pages with thimbles.  I made the same thing out of stainless steel.  You
may have to drill the center hole out to a 4 to fit the hole in the
rudder horn.  Use a Nicropress tool to tightly attach the rudder cable
to the bushing.  I used a short AN4 bolt, some thin SS washers (one on
top and one bellow the bushing, a metal lock nut and drilled the shank
of the bolt for a small cotter pin just to make sure.  Apply a small
amount of thin grease to the bolt shank, insert through the rudder horn
and tighten the nut just enough to allow the bushing to freely rotate.  
You may want to put a slight bend/twist in the rudder horn so it will
line up with the cable conduit.  The cable will no longer twist around
the horn and when you move the rudder out by hand the cable simply forms
a soft curve as the bushing/pulley rotates.  It works for me and the
action is very smooth.

// James F. Agnew
// Tampa, FL
// Velocity 173 FG Elite ( http://www.VelocityAircraft.com/ ) under