I decided early on during the build process to add two access panels forward of the canopy. I have an avionics shelf located between the sub-panel and the instrument panel and this modification will make maintenance easier in that area. I purchased these two panels from Race Consulting. They make a lot of parts for Zenith Aircraft, but also make these panels. They are CNC cut from 6061-T6 aluminum for added strentgh. They come with instructions, but most builders won't need them. The nutplates are already installed in both doublers, the access panels are drilled and dimpled for number 6 stainless screws (included). Also included was a bag of rivets for riveting the doubler.
The first step is to layout the location for the panels. Fortunately for me the forward skin has not been riveted so I could work at a bench and from the bottom of the skin. I initially drew a center line where I wanted the longitudinal center of the panel to be located. Then two lines two inches from the leading and trailing edge. This marked the forward and aft edge of the doubler.
In image one you can see the center line, I placed the doubler centered on that center line and marked a few of the prepunched rivet holes and the four corners of the panels screw locations (marked through the existing nutplate.) The rivet hole marks make sure I can located the doubler in the correct location and the screw hole marks are to locate the access panel. Next I placed the access panel over the screw holes and marked around its outer edges to define the area to be cut out (see image two.)
I placed both panels and doublers in position to check location and spacing. I have not drilled any holes yet and the instructions suggest you do not drill until you have cut the acces panel opening. If you manage to cut the panel opening slightly off center you can relocated the doubler to match. I am planning on not needing that option, but I will still wait to drill until later.
Marking the doubler location
Area to cut out marked
Both doublers and panels in place to check location
