Finally, spring has sprung, or at least it's warm enough to get back into the garage. During the past month I'd been thinking about the panel mock up that I'd built (http://tailwindbuild.blogspot.com/2008/03/blog-post_22.html) and working out how to translate that into a final arrangement. There were two errors in the design that became apparent now that the panel mount is installed in the airframe. Firstly, the position of the radio needed to be higher to pass over the top of the tank but not too high to avoid running into the combing as it angles down towards the window. Secondly, the power distribution tray needed to sit above the lower panel support and be shorter to avoid hitting the front of the fuel tank. Once these design changes had been drafted up and checked it was time to cut the panel. 3-1/8" and 2-1/4" holesaws were used in the bench drill to cut out the holes for the instruments. Used carefully these produce a beautifully clean hole. The two rectangular holes for the instrument stack and for a homebuilt system monitor (more on this later) were cut out using a 1mm cutting disk in a 115mm angle grinder. This produces nice clean holes which are quick to clean up with a file. Then the mounting holes were drilled using homemade templates to position the holes. The templates were produced by cutting 3-1/8" and 2-1/4" holes in pieces of 0.063" steel plate and then drilling though the mount holes of a couple of old instruments into the plates to accurately locate the mounting holes. Next the holes for the switches, breakers and headphone sockets were drilled using a step drill. Finally the cutouts for the VSI and altimeter were shaped to fit round the adjust knobs. The bottom aluminium angle was then match drilled and riveted to the panel to provide additional stiffness.
