Rudder Mass Balance - Part 2

Before modification- nose
rib inverted

When the D-Nose was inspected, it was noted that the lower rib was close to the base of the hinge which could have made bolting difficult later. It was decided to invert these at the top and bottom to create more space.

This had a unforeseen benefit when it came time to rivet these to the D-nose as they can now all be supported by hand when drilling as the ribs flanges have a tendency to move away from the drill.

The aluminium faring attachments should be installed at this time.

Mass Balance Skin
The factory skin was formed to a included angle of 80 - 90 deg. about the panel center on a 30 mm OD mandrel [aka the broom handle] putting the initial form into the skin, then hand massaged to suit by rubbing around the edge of the plastic table. The skin was then held in position with both ends placed under the rudder skin and taped into a fixed location.

The first hole was matched drilled and clecoed then inverted and repeated at the opposite side. After a check all top rib holes were marked and drilled after removing the skin. 


The M10 threaded rod was installed with an aluminium tube [scrap fuel tube] to set the correct spacing and secured with an M10 nut. As the flange of the threaded bush is located on the base of the rib, the lower rib was tapered slightly to place the base of the flange just proud of the line of the skin to prevent fouling the rudder stab. 

The skin was re-installed and holes for the spar attachment marked then removed and trimmed using the factory jig and Ofla knife.


Mass Balance Installation.
The M10 nut was ran down to the face of the mass balance but not tightened - The thread in the base was run out and Loctite 222 applied and ran back till the weight bottomed out and when cured the M10 nut was tightened onto the weight.

Finished assembly ready to rivet