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Cozy MKIV - Chapter 16

Building the Control System

Start Date: January 8, 1997

pilot side torque tube The first step was to cut out the all the metal tubing and pieces for the torque tubes and pushrods. I fabricated the CS-50's and CS-1A's (the pushrod/torque tube steel rod end inserts) myself in the machine shop. I assembled all the tubing, and then fabricated the four plywood and delrin (changed from the phenolic called out in the plans) bearings and bearing blocks. I positioned the bearings in place in the fuselage with the control rods, and then 5-min epoxied them in place. I floxed and glassed them to the fuselage sides.


duct work I also decided to deviate from the plans a bit by making the electrical ducts in place on the fuselage sides, rather than flat on the worktable. You can see the tape covered urethane male molds for the electrical ducts taped in place on the fuselage sides, as well as the raw plywood bearing blocks glued in place prior to glassing.

After trimming the glassed bearing blocks, I reinstalled the torque tubes and floxed the bronze bushings in place in the firewall. I also floxed the electrical ducts in place, and then routed the rudder cable conduit from the instrument panel through to the firewall on top of the ducts. I floxed and glassed the rudder cable conduit in place with 1 BID spaced every 6 inches or so.


wing pushrods I cut the tubing and bent the sheet metal for the wing pushrod assemblies. I installed everything like so:


End Date: January 28, 1997


Addendum: August 16, 1997

front torque tube bearings In order to fix some hysteresis problems in the roll trim system, I replaced the front control system torque tube bearings with ball bearings and a mounting system that I fabricated from Delrin. The system holds the bearings and the torque tubes in exactly the same position as the previous delrin plain bearings, but reduces the friction substantially.

It did not, however, completely clear up the hysteresis - I still have a bit of it. Oh, well. People tell me that many EZ's have this characteristic and that it does not pose a problem. I'll see.


Addendum End Date: August 31, 1997


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Copyright 1997, All Rights Reserved, Marc J. Zeitlin