Nov 08, 2022     Horizontal Stabilizer Forward Spar - (3 hours)       Category: Empennage

After getting confirmation from Vans that there were no issues with the relief holes I started in the forward spar, I cut out the edge of the web with a band saw to open up the notch and smoothed and rounded out the edges with a file and sandpaper. I then trimmed the inboard ends of the front spar flanges per the drawings and flattened the remainder of the bend. It took me a while to figure out how much of the flange to remove because the drawing and instructions reference a rivet hole that is not already drilled in the spar. I ended up measuring the length of the cut on the plans and using that to make the cut. I bent the spar tabs to match the angle on the spar reinforcement and splice angles and then countersank the angles and dimpled the spar where they meet in the middle. I finished up by notching the HS-00006 ribs to fit around the angles. I attached the skin to see how everything fit together.

  Nov 07, 2022     Vertical Stabilizer - (4 hours)       Category: Empennage

I began work on the vertical stabilizer while I waited for a response from Vans on the rivet spacing issue I had with the relief hole I created in the front spar of the horizontal stabilizer. I clecoed the spar doubler and hinge brackets to the rear spar and drilled all holes per plans. I began preparing the ribs by deburring, fluting the flanges, and filing down the forward edges of the flange notches to prevent faceting. This took some getting used to. I temporarily attached the skin to test the rib fit. I ended up taking off too much material on the nose of VS-705 with the scotch brite wheel while trying to get it to fit. While I don't think this created any edge spacing issues, I wasn't happy with how it looked and knew I could do better so I ordered a replacement part.

  Nov 07, 2022     Horizontal Stabilizer Forward Spar Assembly - (2 hours)       Category: Empennage

I bent the HS-810 and HS-814 angles in a vice by sandwiching them between two pieces of square mahogany. I routed a 1/8" radius on the edge of the wood that the angles were bent over to help achieve the radius indicated in the plans and used a cardboard template to check the bend angle as recommended.

I then marked and drilled the #30 relief hole on the forward spar and expanded it to 1/4" with a unibit. I achieved the 5/16" deep notch called for by the instructions, but I noticed that I did not have the edge distance typically required by the MIL-SPEC for one of the rivet holes in each of the doublers. I emailed Vans to get their thoughts and they replied: "This is one location in the aircraft where we have a known short edge distance on a rivet. This rivet was added due to the SB linked below. Your photo looks correct and no corrective action is required. Keep building." So it looks like I did it the right way.

  Nov 06, 2022     Horizontal Stabilizer - Rear Spar + Front Spar Assemblies - (6 hours)       Category: Empennage

I countersank the holes in the upper and lower flanges of the elevator hinge brackets. Then I match drilled the HS-411 brackets to the VA-146 bearing, deburred the brackets and bearing, primed the bearing, and then riveted them together. At first I squeezed a few -5 rivets as the plans call out, but after measuring the shop heads with calipers, I found that they were not meeting the minimums required by MIL-R-47196A. This may have to do with the added thickness from the primer, but I know from reading VAF that this is a common problem. So I drilled out the few rivets I already squeezed and then squeezed -6 rivets in all holes. The shop heads were much better after that. I finished work on the rear spar assembly by enlarging the bolt holes that will attach the bracket/bearing assembly to the rear spar.

Then I started work on the forward spar assembly by separating the spar doublers and drawing the rivet lines. I spent a lot of time on this part because the plans are missing a good amount of information. After searching VAF, I found out that this part exists because of a service bulletin that addresses potential cracking issues in the forward spar. After reading the SB I got a better feel for what they instructions were talking about. With that info I was able to draw the rivet lines and match drill the doublers to the front spar. I finished the day by tapering and smoothing the ends of the reinforcement angle (HS-801-1) and splice angle (HS-814-1). This went much faster than when I did the same task on the rear spar reinforcement bars, so I guess I'm getting the hang of this.

At some point during today's session, after scratching my head trying to understand why the plan drawing was missing one of my parts and had measurements that seemed off, I realized that Vans had sent me the horizontal stabilizer drawing for the RV-7 instead of the RV-8! Luckily the assemblies are pretty similar and after comparing the drawing I had been working off of to the preview plans drawing, I realized that I had thankfully not made any mistakes due to the drawing switch up. I requested the correct drawing from Vans.

As for the primer, I have decided to go with Stewart Systems EkoPrime waterbased primer. My shop is in my basement and I cannot spray outside (due to cold winters and very close neighbors) and would prefer the convenience of spraying in my shop. I have sprayed solvent based finishes before, like nitrocellulose lacquer, and know how nasty and dangerous they can be. I think I could build a good enough spray booth to alleviate the risks that a different primer could have, but I also don't think I want to deal with that. I've heard good things about EkoPrime, and the primer is going to be in places that will never be touched (other than the cockpit, which I may use a different primer for or which may be sufficiently protected by paint), so I'm not worried that it might not be as tough as some alternatives. The only problem I have had so far with the primer is that a lot of solids build up on the bottom of the can and it takes a bit of time with a drill spun stirrer to mix it up.

  Nov 05, 2022     Horizontal Stabilizer Rear Spar Assembly - (2.5 hours)       Category: Empennage

Final drilled the holes attaching the rear spar reinforcement bars to the rear spar and the holes attaching the elevator hinge brackets to the rear spar. Enlarged the holes connecting the HS-708 main rib to to the rear spar.

  Nov 05, 2022     Horizontal Stabilizer Rear Spar Assembly - (1.5 hours)       Category: Empennage

I continued using the random orbital sander with 220 grit sandpaper to remove all scratches on the rear spar reinforcement bars and then took them to 320 grit and finished with a maroon scotch brite pad to give it the satin finish called for by the plans.

  Nov 04, 2022     Horizontal Stabilizer Rear Spar Assembly - (2 hours)       Category: Empennage

Today I attempted to remove the vixen file tool marks from the edges on the rear spar reinforcement bars. I tried to keep the edge profile called for by the plans, but I ended up rounding all the edges. The plans say you can round an edge if needed so that the bars will fit properly against the rear spar. But that's only one edge, not all four. Out of an abundance of caution I reached out to Vans to confirm that I didn't mess anything up by rounding the edges and they told me the edges looked good and there is no concern about removing too much material.

I began putting the satin finish on the rear spar reinforcement bars. I started with a maroon scotch brite pad, but I wasn't getting anywhere. Then I tried 400 grit sandpaper, which worked a little better, but was still taking forever to get out the deeper scratches in the metal. So I went down to 220 grit and that worked better, but was still taking forever by hand. So I ended up using my random orbital sander with 220 grit sandpaper, which made things easier, but I didn't have enough time to finish getting all the scratches out today.

  Nov 03, 2022     Horizontal Stabilizer Rear Spar Assembly - (3 hours)       Category: Empennage

I started work officially today on the empennage after taking a few days to finish getting my shop set up and doing my third control surface practice kit. The first kit I did with Synergy in an all day sheet metal basics class. Then I did two more at home to hone the techniques. I'm still having trouble riveting the last rivet connecting the skins to the side rib flanges near the trailing edge. In the Synergy class we placed a beat up looking piece of steel on the shop head end of the rivet to indirectly back rivet those rivets.

Today I broke the edges of the rear spar reinforcement bars (HS-609) with a vixen file and rough rounded the ends with the band saw and then refined with the vixen file. I definitely spent more time than needed on the edges, but once I figured out how to use the file it went much faster.

  Oct 31, 2022     Empennage kit inventoried - (3.5 hours)       Category: Empennage

Unpacked the empennage kit and made sure I received everything in good order. Everything looked good except one of the HS-603 rear spar pieces. There was a scratch that was deep enough to really catch my fingernail and even though I'm sure I could buff it out, I did not want to risk the possibility that the scratch would weaken such an important part, even if only marginally so. I emailed Vans about the issue and they graciously offered to send me two new spar pieces. I organized all parts by empennage section on rolling shelves and separated the hardware by part in part organizers. I can't wait to get started!