My airplane needs a bunch of external antennas on top of the fuselage… one WAAS GPS antenna for each 430W, and a combined GPS/XM antenna for the G3X system. I cut up some 0.063" alclad and made a doubler for each antenna:
I chose to put the two WAAS GPS antennas on either side of the canopy track, about halfway between the F-706 and F-707 bulkheads. As long as they're not placed too far forward, the canopy will pass over the top of them as it lifts up and slides aft. I couldn't put them all the way at the aft end of the canopy track, since the upper fuselage stringers taper together and make it too narrow to for the antenna doublers to fit. I used a yardstick as a spacer to make sure I drilled the doublers parallel to the fuselage centerline, and to ensure adequate space for the canopy slider block to pass by.
Lots of big and small holes drilled in the top of the fuselage… no turning back now! The doublers will be riveted to the inside of the skin, of course, but it's way easier to drill them from the outside. I also had to shape them a bit with hand seamers, since a perfectly flat doubler won't quite lay down on the curved fuselage skin.
The third antenna doubler is located just aft of the F-707 bulkhead. There's plenty of room for the canopy slider block to fit between the antenna and the end of the track, so there should be no problem removing/reinstalling the canopy.
I alodined the doublers and fuselage skin for good electrical bonding, and riveted on floating nutplates.
John came over to help buck the rivets, while I crawled back into the tailcone to drive them from the inside.
The actual riveting went pretty quickly:
A shot of the finished rear antenna doubler:
Now the fuselage has sprouted a crop of antennas:
Victory! Thanks to John for the help.
