Tuesday 16 December 2014

Joystick Assembly - Part 1

Start by identifying all the components shown in the factory drawings. The joystick itself is supplied assembled joined by two [2] aluminium sleeves fixed using three [3] M5 x 10 cap head screws.

Before dis-assembly it is critical that the correct relationship of the sleeves in their current position be maintained. The sleeves have been machined with the three [3] machine derived BUT the each hole has been tapped through the steel tube making each one unique. Tapping in this manner ensures that there will be full bearing on the screw threads and effectively locking the completed assembly into one solid unit. Pop mark near the top screws using a auto center punch to produce dimples unique to both sides. Place the same unique pattern onto a mating face of the passenger joystick mount.

Remove all M5 screws and place to one side and slide sleeves off tube to break the assembly into its three parts.

On this builder aircraft the following work was undertaken on the parts supplied.

  1. Dress inside face of clevis where rod ends mount - check before assembly as if they are tight this cannot be done in situate
  2. Check the length of the rear joy stick from the pivot to the rode center-line matches the front unit when assembled
  3. Cut slot to allow to allow cables from the selected handle to exit the joystick. The design precludes exit through the base
  4. Ream both holes in clevis to 0.25'' [1/4'']







The slot location was opened up with a step drill to suit the 10 mm loom tube then joined using a Dremel Metal Cutting disc and the opening is dressed using flat files. Polish opening to remove any sharp edges and trial fit loom tube.

Thrust Assembly
The assembly has to have a fixed location in the aircraft and to do this a series of thrust ring's and packer washers are supplied.

Thrust washer location

The drawings shown this location at the rear of the passenger joystick and is to be located between the rear thrust washer and the face of the rear coupling bush. On this builders kit the thick spacer washer have been punched and were a tight fit and would have required dressing to allow them to slide on the steel tube.

This lead this builder to re-examine the task. If the rear spacer washer is relocated to the gap between the front sleeve and the face of the mounting bush with the same result achieved in a more precise manner. 

Revised Thrust Assembly

The weld edge on the tube was lightly dressed with a file and the spacer washer trial fitted - once satisfied with the fit it was installed with Loctite 263 and allowed to cure. The gap between the two items was measured and the loose thrust washer machined to suit - overall width [measured] minus 0.5 mm nom. to allow float. Dress the face of the bearing to remove any paint that was applied when primed.

This is an unapproved modification refer disclaimer.

Final Assembly
Disassemble - linish steel face using 400 wet & dry in the area of the bearing then clean. Using a suitable grease lightly coat the bearing face and the working faces the aluminium thrust washer's. Check for free operation. If all is working correctly assembly can commence.



No comments: