Installing the HS (Horizontal Stabilizer) to fuselage fairing. WARNING! Read the plans very carefully or you could end up drilling the HS longerons oversize. The plans had me puzzled for several minutes. I knew what needed to happen, but the plans just didn't seem to translate that way until I read them a couple of times!The only thing I'm not crazy about here is that you are tapping the longerons after you have countersunk them to accept the fairing dimples. There's not a whole lot of material there afterwards, but they screws did set nicely and the attachment seems to be very strong.
