Long ago I decided to add a ground power receptacle of some sort to the plane. After weighing the options I went with the mil type 3-prong receptacle. The next decision was where to mount it. I chose to go with perhaps the most complicated route – mounted to the bottom of the tailcone and accessed via a hinged panel. As with most “off plans” mods, this ended taking more time than I originally envisioned. I first roughed out some measurements for the base plate/doubler that the GPP will sit on and that also forms the flange for the access panel. I cut a piece of .032 scrap to size and then traced the GPP’s shape onto it and used a combo of my Dremel and my nibbler to rough out the opening. I then moved on to the making the bracket that the GPP bolts to out of the trim bundle that comes with the kit. Again, I cut the sheet to size and then bent the bracket to shape using my bending brake. I then used the base plate to locate the opening for the GPP and cut the hole the same way I did on the base plate. I then went back and determined the exact size of the hole in the skin for the access panel, accounting for the hinge, and cut it out. I then cut some hinge to size, and made the access panel itself out of more scrap. Then all I did was locate and drill 3/32 rivet holes for all the components. I test fitted everything together and once satisfied with the fit, I located and drilled the 2 holes for the Camlocs (I’m using the 2 that came the kit for the oil door which I wasn’t using because I have Hartwell latches for that) that will fasten the door closed. I did have some interference between the inboard side of the bracket and the adjacent J-channel, so I cut a relief notch in the bracket to clear the channel. I also added a couple of shims to the hinge to “lift” it up a little out of the airstream. I then deburred and dimpled/CSK’d all of the parts. Finally, I made a second bracket out of some .063 angle that I riveted to the top of the GPP bracket and drilled two ¼” holes as a convenient place to bo
