Posted for "Tom Wallace" <tlwcfii@yahoo.com>:

I remember seeing some discussion on using gears on the rudder crossover
tubes.around Dec 2005. I think someone had come up with some made of nylon
or Delrin but can't find the posting. Can someone let me know why these
gears are being installed and where I could find the posting. Thanks

Blue skies,

Tom Wallace
ES Builder for a long time

 
[Tome, if you go to the archives (http://mail.lancaironline.net:81/lists/lml/List.html) and plug "rudder gears" (sans quotes) into the search box you'll get all the messages regarding rudder gears that have been posted over the last several years.  You'll notice that the messages will be distributed date-wise in clusters, and by going to the earliest post in each cluster you'll find the beginning of each thread. Look for the post from Bob Pastusek with a larger than normal file size to locate his post with the attachment.

To answer your other questions, the reason for using these gears on the ES or IV models is because there is presently no mechanism installed to complete the loop in the rudder control system and there is tension on the rudder cables only when you place your feet on the pedals.  With the airplane at rest you can grab both rudder pedals and pull them rearward, putting slack loops into the rudder cables.  Some aircraft use sprnigs from the pedals to the firewall to tension the system, but springs apply constant pressure to the rudders and interfere with rudder feel.  The gears placed on the rudder torque tubes are typically installed with the torque tube assembly removed from the aircraft and setup so the pedals are directly inline with each other and their attachment tubes vertically inclined.  With the gears on the torque tubes, moving one rudder pedal forward automatically moves the opposing pedal rearward.  I've attached Bob Pastusek's installation instructions to keep you from having to search for it.

As for the gears themselves, plastics are simply not robust enough for this installation.  Each gear needs to be split and machined to accept a tensioning screw to facilitate a solid installation, and plastic threads simply won't hold up to the torque requied to tighten each gear on its tube.  I recently machined up a batch of these gears in steel and made them available here at $150/set. They come complete with the tensioning screws as well as the proper length roll pins required to complete the installation.  That run has sold out but I could do another batch and have them available in about 10 days.  Just let me know if you (or anyone else) are interested and I'll start the ball rolling.  I typically do these in runs of 5 pairs, but could increase that number if there is enough demand.

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