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Archive for January, 2010

Prep and Prime Right Side Horizontal Stabilizer – 3.5 hrs

January 31, 2010 Leave a comment

Today was a day of dimpling, deburring, cleaning and priming of parts on the horizontal stabilizer. This is one of the least fun things about building the airplane. It just takes time and patience. Since the left HS-702 spar will be replaced, I focused on the right side ribs and spars.

I used the DRDT-2 to dimple the ribs skins for the 3/32 flush rivets. The DRDT-2 makes nice consistent dimples and does it pretty quickly, although it is a bit awkward for one person to hold the skins and dimple. A helper would have been good. I was also being cautious because I didn’t want to accidentaly punch an extra hole in the skin.

I used the pneumatic squeezer on most of the ribs because they would not fit on the DRDT-2. There were a couple at the narrow end of the ribes that I could not get with the squeezer so I used the pop rivet dimple set. Those don’t seem to come out deep enough so I cleaned them up with the countersink tool.

That's me squeezing a few.

All parts were aggressively scrubbed with scotchbrite pads including the edges of the skins. Then the right side ribs and spars were scrubbed again with Simple Green and rinsed thoroughly. All parts were water break free.

After drying with a clean towel I laid those parts out on newpaper and shot three or four light coats of Dupli Color self-etching primer. That stuff dries really fast. You can shoot successive coats only two or three minutes apart. After half an hour they can be handled.

Parts primed and drying

Here is what the right side skeleton loos like after about 4 hours of drying and then reassembly.

One side primed

Oh yeah, I also removed the blue film from the inside of the skins in strips where the ribs mate. I plan to shoot a light coat of primer on those strips also before installing the skins on the skeleton. Doing it in strips will provide primer at the faying surfaces but keep the assembly a little lighter. The rest of the skin surface is Alclad and does not require primer for corrosion resistance.

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Categories: Horizontal Stabilizer

RV Training Kit

January 30, 2010 Leave a comment

Since the replacement HS-702 spar will not arrive for another few days I spent most of my time today working on the training kit. I really wanted to get some experience squeezing and bucking some rivets on the training kit before the “real” thing on the airplane. It’s a good thing I did too because there is definitely a learning curve.

Squeezing is the most straight forward. The key is setting up the squeezer to get enough of squeeze but not too much. I installed the adjustable set holder which allowed me to thread the shaft in and out with a small wrench to set the squeeze gap. Once set, the squeezer is very consistent, as long as you hold it square and center it on the rivet.

Once my confidence was up a bit, I squeezed the six rivets on the 411 bearing assembly of the rear spar. Here you can see the shop head side. The other side has the dome heads so I used the cupped set.

Then I proceeded to buck a bunch of flush rivets on the training kit. This is more challenging and I drilled out four or five that were poorly set. I found that I had to press the swivel flush set firmly against the flush head with one hand and hold the tungsten bucking bar against the shaft of the rivet with the other. If you push too hard on the bucking bar the rivet does not fully seat into the dimple. If you don’t push firmly enough with the bucking bar, the shop head does not set. It definitely helped when I started using tape to hold the rivets in the dimples.

Here is a shot of the training kit almost done. I’ve done all the riveting except for four that require a 3/16 thick bar which I don’t have, and I have yet to roll the leading edge. I’m saving that for later.

Training Kit

Categories: Horizontal Stabilizer

Replacement HS-702 Order Status

January 29, 2010 Leave a comment

I checked Fed-Ex status today on the replacement HS-702 order. Projected delivery is not until next Tuesday Feb 2. Arghh! I’ll probably go ahead and start on the vertical stabilizer in the mean time.

Categories: Empennage

First Major Mistake – 9 hrs

January 24, 2010 Leave a comment

Jan 24, 2010 – 9 hours

This morning I disassembled the skeleton of the horizontal stabilizer, deburred holes and cleaned out chips. I noticed that the front spar is supposed to have a hole for the manual elevator trim cable but I could not find instructions anywhere in the plans to drill it. So I went ahead and marked the location to the left side of centerline, pilot drilled with a #40, then used the unibit to enlarge it to 5/8 inch. After deburring that hole I reassembled the skeleton with clecos, leaving out the HS-404 and HS-405 ribs. Then I installed the left HS-601PP skin with clecos.

The next steps were:

  1. Drill thru the holes for the HS-707 aft flange and the HS-603 rear spar to #12.
  2. Install the HS-404 and HS-405 ribs and transferred the hole locations from the HS-601PP skin.
  3. Removed the HS-404 and HS-405 ribs and fluted the flanges to get them straight.
  4. Drew lines down the middle of each flange on the HS-404 and HS-405 ribs
  5. Re-installed the HS-404 and HS-405 ribs and clamped them in place confirming that I could see the mid lines on the flanges through the holes in the HS-601PP skin.

Then I match drilled the aft flange of the HS-405 rib through the HS-603PP spar. With that cleco’d I match drill the HS-405 top and bottom flanges through the HS-601PP skin.

Next was drilling the HS-702 spar and HS-405 front flange thru the pilot holes I drilled in the HS-404 aft flange. Since the aft flange of HS-404 aft flange is small, I think it worked out better to drill from this side than drilling from the HS-405 side where even a tiny alignment error could leave you with poor edge distance on the rivet.

Then I match drilled the HS-405 front flange, the HS-702 spar, and the HS-710 and HS-714 reinforcement angles from the rear as Vans instructs. In this case the target is bigger and there is more room for error. I think all four holes turned out nicely.

Here you can see from the HS-405 side that all holes came very close to my target alignment marks.

Almost home, I match drilled the HS-404 top and bottom flanges through the HS-601PP skin. Then finished drilling all other holes in the skin into the skeleton that have not already been drilled. Cleco then take a breath.

That’s when I realized I mis-measured the location of the manual trim cable hole in the HS-702 front spar. The drawing says 4 ¾ inches left of centerline and I marked and drilled it 3 ¾ inches left of centerline. Rats! I realized because the cable hole does not line up with the hole in the aft spar and the hole through the HS-405 rib. Hoping that Vans support might say it’s not a problem, I redrilled the hole in the proper location. I’ll call Vans tomorrow. Here is a view showing both holes in the spar. I wish I could make the inner one go away.

Categories: Horizontal Stabilizer

A Minor Mistake – 7 hrs

January 23, 2010 Leave a comment

Jan 23, 2010 – 7 hours

Started right in this morning match drilling the holes for the rear spar stiffeners and the hinge bearing assembly. Here you can see the hinge bearing brackets cleco’d to the stiffeners and spar with the bearing installed and three cleco clamps holding the two faces of the brackets flush to the bearing flange. Aluminum chips are from passing the #30 drill through the stiffeners and spar.

I put clecos in every other hole, drilled through the open holes, then moved the clecos over one space and repeated.

Oops, my first mistake. When I match drilled the two bearing brackets I didn’t remember that the bearing flange is pre-drilled. When I match drilled the set I created a new set of six holes through the flange. Luckily they are almost half way in between the factory holes so they don’t impact the strength of the flange. But I noticed that my new holes don’t put the axis of the bearing perfectly concentric with the holes in the brackets. So I reassembled and aligned the factory holes with the holes in the brackets and after clecoing the assembly back onto the spar I match drilled again. This restored the bearing to proper alignment to the bracket centerline. I then disassembled and marked the bearing holes to make sure I used those on final assembly.

Notice the markings on the hinge brackets. I numbered each one from left to right so I will know how to match them up later at final assembly. This whole thing comes apart later for deburring and priming.

Moving on to the front spar, I got up the courage to bend the spar stiffeners. I was anxious about this but it was easier than expected. Like many other, I clamped the end in my vice between two pieces of scrap aluminum angle and simply pulled on the stiffener to create a nice clean bend along the line that I had transferred directly from the front spar halves.

Next I modified the flanges of the front spar halves as described in the plans in preparation for bending the 6 degree angles to match the stiffeners. I drilled the prescribed pilot holes first then opened them up with the unibit. Then I removed most of the web material with my new shears and cleaned it up on the belt sander. Here you can see the relief cuts in one of the spars. As others have reported, when you follow the directions you get a small lip on each side where a bit of the radius remains from the web. Fortunately its only cosmetic and no one will ever be able to see it after the horizontal stabilizer is installed.

Here is a shot of the two stiffeners installed on the two spar halves with the matching 6 degree bends.

The next step was a big one. The spars and ribs of the horizontal stabilizer are assembled with clecos. The flanges of two ribs had to be modified per the plans and two several are marked for match drilling later. Also, six ribs had to be fluted prior to installation. It’s starting to look like an airplane part!

Here you can see my first fluting job. Notice the dimples along the top edge of the rib? It was actually easier than I expected but it does take time to get it right. Maybe I was too conservative because I took very small bites with the fluting pliers and inched my way along until the ribs were straight. I hope I get faster before I start the wings.

I also primed the outside surfaces of the bearing using Dupli-Color self etching primer in a rattle can. I prep’ed the bearing first by masking the bore and seal areas of the bearing and scrubbing with simple green to get a water break free surface. Then I rinsed with clean water and let it dry. I wore nitrile gloves to avoid contaminating the clean surface with body oils. The primer wet on in a thin even coat. I followed the directions to put down several very thin coats, waiting a few minutes between coats for the etch action to kick in. Here you can see the green primer on the bearing in the assembled brackets, ready to be riveted. Now if I just had that rivet squeezer.

Categories: Horizontal Stabilizer

Isham Kit Arrives!

January 22, 2010 Leave a comment

Jan 22, 2010

The Isham kit arrived today! All except the DRDT-2 dimpler and the pneumatic squeezer which are on backorder and should be here by the 26th of January. It took about an hour to go through the tools and take inventory. Everything looks good. First thing I did then was to install the scotchbrite wheel on my grinder and smooth the edges of the stiffeners. That took longer than I expected.

Then I cleco’d the rear spar to the stiffeners and mounted the bearing brackets In preparation for match drilling. I couldn’t resist setting up the air drill with a #30 drill and a spring stop in preparation for work tomorrow.

Categories: Horizontal Stabilizer

Checking on the Tool Kit Order

January 18, 2010 Leave a comment

Jan 18, 2010

I called Isham this morning to inquire about the status of my tool kit order. They said it has not been shipped because they are out of stock on the squeezer and the DRDT-2 dimpler. The squeezer should be in stock by Thursday but the dimpler won’t be available until the 29th. I asked if they could ship everything else now and the gentleman said that would not be a problem. I received an email shipping notice about 2 hours later.

Categories: Horizontal Stabilizer