Dimpled Rudder Skins - 1 hour

Again...pretty wore out from work today and tired. So I just puttered away in the garage and set to dimple the rudder skins. At first I set the dimples so they were pointing up in the press but found out that the point on the die can scratch the skin (Darn) so the other side of the skin, I flipped it around. Much better.

Dimpling stiffeners - 1 hour

Unfortunately, I didn't seem to have a lot of energy to putting hours into the build. Work is really busy and taking a lot out of me. I managed to dimple the rudder stiffeners. My standard dies don't clear the radius of the stiffener, but after a little head scratching, I used my 3/32" tight fir dimpling die from Cleveland tool in the press, which worked out very well.  I ended up putting another order into cleveland tool for the small diameter dimple dies, as well as a screw on mandrel that I am missing for deburring operations. I also put an order in to Aircraft Spruce for some Dow Corning RVT #3145 clear. I thought about going Ultra Blue from Permatex, but I opted for the expensive stuff since I am applying it to my stiffeners and skins which are epoxy primed. 

Priming the Vertical Stabilizer and Rudder - 4 hours

I started priming the Vertical Stabilizer and Rudder today. After a bunch of reading on the forums, my priming tests and a quick discussion at the recent EAA meeting I had decided on a non alodine treatment. I figured just a straight 2 part epoxy primer would suffice. I do not live in a maritime environment so I figure that the maximum protection alodine would provide would be overkill for my needs. I settled on a good surface prep and then a 2 part epoxy primer. This morning I decided that I wanted to get a bunch of priming done on my parts before I go away next week. I picked up two big 50 gal containers from Lowes. I would use these to wash my parts.

Here is the priming process;

1. Parts are deburred and checked. Parts are gone through with a light scrubbing with scotchbrite red.

From this point on, all parts are handled with gloves on.

2. Just a few parts are washed thoroughly with water and Dawn detergent.

3. Those few parts are rinsed and scuffed with red scotchbrite in the water (gray scotchbrite for skins)

4. Parts are then dried with air and a clean microfibre cloth.

5. Everything is wiped down with Pro-Form wax and degreaser.

6. Everything is then wiped down with MEK.

7. Parts are primed with spray cans of Spray Max 2K primer

8. Repeat step 2 thru 7 for the next few parts.

I chose this process as it allowed the parts to be thoroughly cleaned and minimized the exposure of the newly scuffed layer of aluminum to oxygen before the primer is applied. It is fairly tedious, however with some good music playing time flys by and I can take comfort that I am at least getting the best surface prep that I think I am capable of.

The ugly side of the priming is that I do notice the increased weight of the 2K primer (Darn!!). I am giving the skins a light coat with the emphasis being applied to areas of mating surfaces so hopefully I mitigate weight as much as I can with the primer. The benefit of the 2K primer is that it is extremely tough so it will offer a level of protection when I get into riveting.

At the end of the day, I know I will be penalized for weight on the priming....however I intend to shave some weight in other areas (i.e. VFR Glass EFIS instrumentation, LED lighting, Beringer brakes and wheels, Fixed pitch propeller, etc) so hopefully things will balance out in the end.

As a side note....Its taken just over 2 full cans of primer to do the Rudder skins and the VS assembly. There's not much in a can. Ouch...that's an expensive method of priming. I estimate that it will take another 3 or 4 cans to complete the empennage. Also....it oversprays like crazy. Gets cloudy quickly in the garage when I spray!

Finished assembly of the HS - 2 hours

Checked, Checked and rechecked alignment and level. It is very very close. It's difficult to confirm level on the structure without the skin on as everything wants to twist, but after 1/2 hour of messing with it, I am 1/16" out of horizontal from one tip to the other. Ends up being about 1/32" each side.

Really not bad for home garage work.

 I finished off drilling all the holes in the front spar outboard of the bend line. I didn't want to take any chances getting holes out of alignment so i set up the drill press on the bench and started to drill the holes. I used a torpedo level to ensure the piece I was drilling was flat to the drill press.

After I was done, I took the assembly apart and checked all the pieces. There was a dramatic improvement with how holes where aligned compared with my first attempt at the front spar. With the exception of the one minor edge distance hole...the front spar turned out near perfect.

Tomorrow I will start the very first round of prepping and cleaning the parts for primer. Now to do a bunch of reading on the subject!!

A call to Vans

I called Van's in the morning and explained my situation. Support said that it was not a critical structural area. He said it was unfortunate but all will be ok as its just a web attachment point to a spar. Build on.

I reasoned on the matter throughout the day. I felt much better after talking to Van's Support. The area is well exposed for periodic inspections. The edge distance is just under the minimum on the flange by a hair. I also measured the HS00001 doubler and found that the hole in the doubler is still within the minimum specifications for edge distance. Although it is not the most ideal situation, still its not that bad. I really don't want to take another step back, but I will chalk it up to a lesson learned.

Below is the picture of the edge distance issue. Looking at the top most hole on the flange; the rib on the right is correct, while the rib on the left is just a bit too tight for comfort. Very very close...

If anything I can always run it by the very experienced eyes in the local EAA group.

Build on.

Just about finished assembly of the HS - 3.5 hours

I started off the evening working on the left side HS. I fitted the new HS00005 and 000006 ribs to the assembly. I checked, checked and re-checked the fit before i started to drill. My first set of holes were in the aft flange of HS00005.  Then in the aft flange of HS00006 through to HS00005. I was very pleased with how everything lined up. 

I then noticed that my edge distance on my top hole of HS0005/00006 was just a bit high about 1/16". I was a tad bit concerned about edge distance. The holes line up perfectly....although getting these holes drilled perfect is extremely difficult. its hard to get the appropriate dimensions in there with the skin on and all the surrounding clecos. At worst I have an edge distance of 0.209" (0.155" from the edge of hole to edge of rib) on the top most #30 hole in the forward flange of HS00005 where it attaches to HS-710. I see the listed edge distance minimum is 0.219, so I am just ever so slightly over the limit.  I will email vans and double check that I am ok.

(Darn...what its a tough spot to drill and there is little room for error!!)

UPDATE: See October 22, 2014.

I finished up by cleco'ing the HS assembly together. Whew....Just about done. All I need to do is drill the holes outboard of the bend line in the front spar.

I took the skins off the HS and started to double check how straight everything is. I will save the drilling for another day as it is getting late.

First EAA chapter 30 meeting

Tonight was my first EAA chapter meeting. The group was a bit larger than I thought there would be. The president of the chapter gave a presentation of his recent trip to New York filled with tons of little tips. Met a couple of nice folks. Mike is working on an F1 rocket and is just a bit farther ahead than me. Jim, was eager to help with advice. In just a 10 min conversation I picked up more from him than I have in 30 hours of building. The EAA chapter is just a great resource.