1/26/2021 – 2.3 hours Final horizontal stabilizer assembly continued with riveting the skins to the front spar. The HS is still in the cradle, so you have to reach deep inside the skins to buck the rivets on the front spar just like nose ribs previously. To help access the spar inside the skins, I removed the clecos from the ribs to provide a little more space for my arm to get into the skin cavity. I can get to most of the rivets, but there are a couple of areas where you need really strong, long, thin arms. Specifically, the area between the second and third ribs from the inboard edge is really tight. The ribs are close together so you have to reach straight down. I found that I could not hold my small bucking bar effectively in this space for a few rivets, so I opened up the special RV-14 elevator bucking bar. This bar is long and narrow, and it easily reached the rivets in this area. The bar is a little unwieldly, but it is the best solution for me to buck those rivets. The other thing to keep in mind is three different rivet lengths are used to attach the skin to the front spar, so pay attention to the rivet schedule in the plans and take your time to ensure you have the right rivet for the hole you are working on. I managed to set the 47 rivets for the top right skin to the spar in this work session. [3x Rivet Gun, Swivel Flat (Mushroom) Set, BB-6 and BB-7 Tungsten Bucking Bars, #40 Drill, Pin Punch, 4.5” Diagonal Cutting Pliers, Special RV-14 Elevator Bucking Bar] 1/27/2021 – 2.9 hours The work on riveting the horizontal stabilizer skins to the front spar flanges continued. I finished all of the rivets on the top left and right HS skins, and moved around to the bottom skins. I am working from the center of each skin (top right, top left, bottom right, bottom left) toward the outboard and inboard edges. I am riveting roughly every other hole with clecos holding things tight in the other holes. I ended up replacing 2 rivets – one didn't get set flush to the skin because I pushed harder with the bucking bar than the rivet gun, and the other was at a rib intersection and ended up with a really bad shop head. I've gotten really good at drilling out rivets (not sure that's the legacy I'm going for!), and both came out damage free. [3x Rivet Gun, Swivel Flat (Mushroom) Set, BB-6 and BB-7 Tungsten Bucking Bars, #40 Drill, Pin Punch, 4.5” Diagonal Cutting Pliers] 1/28/2021 – 2.6 hours Riveting the horizontal stabilizer skins to the front HS spar is complete. The biggest issue was not completely setting three of the rivets. It was pretty easy to tell when this happened because the sound of the rivet gun was more “hollow” than normal and the shop head appeared to form extremely quickly. Picking up on these clues after just a handful of taps made the process of removing the rivets very easy, and all of the unacceptable rivets came out cleanly without damaging the hole. [3x Rivet Gun, Swivel Flat (Mushroom) Set, BB-6 and BB-7 Tungsten Bucking Bars, #40 Drill, Pin Punch, 4.5” Diagonal Cutting Pliers] 1/30/2021 – 7.3 hours I riveted the horizontal stabilizer bottom skins to the HS ribs and stringer assembly. The plans have you work up the ribs from the front spar toward the aft edge of the HS, with an intermediate stop at the stringer level to rivet the stringers in place. Bucking some of the rivets near the front spar are a little tight, just like getting to the rivets on the spar itself, but it gets easier as you get further up the ribs. One particularly tricky area with the bucking bar is the two holes just forward of the stringer. The stringer blocks your vision in that area, so those rivets have to be bucked by feel. You can try to see how you did afterward by slipping a phone camera into that area. I set the rivets on the most inboard and out outboard ribs with the pneumatic squeezer. [3x Rivet Gun, Swivel Flat (Mushroom) Set, BB-6 and BB-7 Tungsten Bucking Bars, Pneumatic Squeezer with 1 1/2" yoke, 1/8” and 1/4" Flat Rivet Sets] 1/31/2021 – 5.4 hours Riveting the horizontal stabilizer skins to the inspar ribs and stingers is complete. There weren't any surprises or revelations during this session, but I did have to wear some thin protective work gloves to provide some relief to my knuckles. I did notice on the bottom skins that the area near the intersection of the stringers and the second inboard rib is especially susceptible to minor dings from the rivet gun. The gun didn't walk any more than any other area, so my guess is the damage comes from the fact the geometry of the substructure and the relative narrow stringer and web flanges compared to the width of the flat set on the rivet gun. The dings are noticeable if you look from the right angle, but almost imperceptible to feel. I received a tip that you can work out minor blemishes like this by rubbing a spoon on the backside of the damaged area to gradually unbend the skin. I tried that, and it did ease the blemishes a bit. I may spend a little more time with the spoon before I install the rear spar, which will effectively make the area between the inspar ribs inaccessible. [3x Rivet Gun, Swivel Flat (Mushroom) Set, BB-6 and BB-7 Tungsten Bucking Bars, Pneumatic Squeezer with 1 1/2" yoke, 1/8” and 1/4" Flat Rivet Sets] 2/2/2021 – 2.7 hours The final step in the horizontal stabilizer build is to install and rivet the rear spar into the assembly. The plans repeat the warning to ensure the spar is oriented correctly and not installed upside. After confirming, double-checking, and triple-checking the orientation of the rear spar, I cleco'd it to the tails of the inspar ribs along the length of the horizontal stabilizer. The spar gets riveted to the two outboard and two inboard ribs with AN470AD4 rivets, with the manufactured head on the spar for clearance with the elevators. The rear spar is riveted to the intermediate ribs with LP4-3 blind (pop) rivets. I completed the pop rivets with the hand rivet puller. There is no problem with access to the rivets with the puller, and the all went in without any issues. I plan to tackle the AN470 rivets as well as the flush AN426AD3 rivets for the skin to spar connect with the pneumatic squeezer in the next work session to finish the horizontal stabilizer. 2/3/2021 – 2.5 hours The final steps to finish the horizontal stabilizer are complete! I started this session by riveting the inboard and outboard inspar ribs to the rear spar with the pneumatic squeezer. The standard 3” yoke provided good access to the rivets on the inboard ribs, and I set the rivet manufactured head on the spar in accordance with the instructions. There is a set of 3 holes on the rear spar next to each of the inboard ribs that are empty. I went through the horizontal stabilizer plans to ensure I had not missed a step, and then found that those holes are used to attach the horizontal stabilizer to the empennage later in the build. Leaving empty holes feels strange, but it is correct in this case. The build ended by attaching the skins to the rear spar. After a quick change to a flat squeezer set, I finished this task working from the middle of each skin to the inboard and outboard edges. It takes 196 AN426AD3-4 rivets to attach the skins, but the job went quickly without any major issues. [Pneumatic Squeezer with Standard 3” Yoke, 1/8” and 1/4" flat squeezer sets, 1/8” cupped squeezer set]