Empennage Build Process

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Friday, July 12, 2002 (4 hrs)

 

Empennage arrived at 4:30pm… I was getting worried, as I paid extra to have it shipped 3rd day.  Where is my empennage kit!!  It finally arrived. J  I quickly inventoried the parts.  No Missing Parts and No Back Ordered Parts!  (1 hr)

 

Jumping right in, I cleco’d the front and rear spars together and match drilled.   I attached the hinge brackets and drilled them to size.  I put Sandi to work deburring the ribs.  (I needed a metal cutting blade for my band saw, so I postponed building the HS-908-L/R brackets.)

 

After Sandi finished deburring the ribs, I fluted them, using the back rivet plate as a flat plane.  Flute a little at a time, as you can definitely over flute and bow it the other direction.  The HS frame was completely assembled before dismantling for the deburring process.

 

 

This is the point at which Sandi freaked out.  “You mean you have to take it apart??”  She was under the impression that this was a ‘take it out of the box and put it together’ kind of project! J “Yes dear… it all comes apart to be deburred, cleaned, primed, etc.”

 

Disassembled HS frame and called it a night.  It was a good first night.

 

Saturday, July 13, 2002 (8 hrs)

 

It was early and Lowe’s was not open yet, so I started in on the vertical stabilizer.  This was easy and went very quickly.  No surprises here.  Apparently, they have modified the kit so you do not need a jig to build the VS anymore, as early -9 builders had to do. 

 

 

 

Ran to Lowe’s to buy a new blade for the band saw.  (Wood blades just don’t cut aluminum, trust me, I tried.)   Now it was time to start the HS-908-L/R Attach brackets.  I spent a LOT of time looking at other builder’s websites and none mentioned having trouble building these things.  These are two angles that you have to fabricate from a piece of aluminum angle.  The instructions just tell you to fabricate them.  That’s it… no hints.  Now that wouldn’t be an entirely bad thing but there are a couple of angles involved that drove me crazy.  I looked and looked at the plans trying to figure out the angle.  I even called Ray Doerr, who is also building a -9.   While initially talking to him didn’t help, it finally dawned on me what I was supposed to do.

 

Once I figured out the goofy angles, I didn’t have too much trouble until it was time to drill the holes to mate it up to the spar and doubler.   Here is what the instructions say: “Clamp a piece of angle to the lower flanges of the attach angles to hold them in proper alignment and match drill…”.  I stared at the angles and at the spar and just could not figure out what the hec they were wanting.  I couldn’t figure it out, so I just used a ruler to get as close as I could.  It was really bugging me, so the next day I went hunting on the Internet to see if I could figure it out.  I found what I was looking for on Gary Newsted’s website.  (Picture)  Now that I knew what the wanted, I had to see how close I came using my measuring method.  Damn close!!    Here they are before drilling the holes.  They came out OK but not the best.  I may order a new chunk of aluminum angle and do them again now that I know what to do.

 

 

The rest of the day was spent deburring ribs.

 

Sunday, July 14, 2002 (6 hrs)

 

Continued deburring and then dimpled all the ribs.  Was an easy task with the hand dimpler.  TIP #1: Read the instructions and the plans.  Don’t dimple the little tabs on the HS-904 ribs.  I only dimpled one rib before I caught myself.

 

Next I cut out the grooves in the supplied wood to create the cradle for the HS skin.  The instructions say to make them level and plumb but I just couldn’t see the use of attaching them to the bench and going to all the trouble.  Everything I’ve read says the holes line up dead one.  Besides, two cradles are enough.  If you locate them as the instructions indicate on either end, the skins bows out in the middle.  I tried taping the edges together to keep it from bowing out… didn’t help a lot.  In the end, I just moved them wherever they needed to be during the process of cleco’ng the ribs in place.  The only trouble I had here was getting the HS-904 holes to line up with the skin.  Once you have a couple of cleco’s in place, they line up.  I drilled the out skins to final size.  Disassembled and repeated process for the other side.

 

 

 

Friday, July 19 through Friday, July 26

 

Keeping a builder’s log is going to be tough.  I need to discipline myself to write things down instead of letting a couple of weeks go by.  I haven’t been doing much during the week, primarily on the weekends.

 

Let’s see, what have I done:  Countersunk the spars, deburred all the skins, dimpled all the skins, TIP #2: Read the instructions and the plans.  (I just realized I didn’t countersink several of the holes on the HS-906, HS- 907 & HS-903!), deburred the spars and skin edges, washed all the parts in soapy water in preparation for priming.

 

I also had a site visit by Ray Doerr and his family.  Ray is also building a -9A and wanted to see how the kit had changed.  The first change was that my kit came in two boxes… his came in just one very tightly packed box.   Next, he noticed the VS ribs are now pre-punched, negating the need for a jig.  (He said it save me 5-10 hrs!)  He also noticed a couple of other parts that had changed as well.  That’s good news for me.  He offered a few tips and was on his way.  One tip that I’ll pass along.  TIP #3: Mark the skins where you’re not supposed to dimple for the fairing attach points. I did this for the HS skins but forget to on the VS skins and dimpled where I shouldn’t.  It didn’t matter anyway, because I had also dimpled the VS rib!  Geeezzz….

 

 

 

Here is the dimple table I put together.  Some builders have gone the extra mile and built better tables but these worked out real well as I could move each side as I needed to and was also able to move the dimpler forward and backwards as necessary.  They are also easy to store!  My wife helped me dimple about half the skins, saved a lot of time!

 

Sunday, July 28, 2002 (6 hrs)

 

Today was spent prepping parts.  I Alumiprep’d all the parts in a little homemade trough made out of 2x4’s and some plastic.  It worked out really well.  It was just long enough for the spars to fit in, and wide enough for the widest part.  This process will show you where you touched the parts w/o gloves! J 

 

Next I started the Alodine process.  I only had a gallon of Alodine, so I couldn’t use it in my trough because there wasn’t enough.   I used a little plastic tub for most parts to soak in.  A few of them were too long to fit, so I had to brush it on.  I have the spars to finish.  I think I’ve decided that I am going to forgo the priming process and just leave them alodined.  Tip #4: Use a little piece of wire to pull the parts out of the alodine bath.  When they are wet, the alodine wipes off very easily.  I used a piece of wire to pull them out and then dunked them in a 5-gallon bucket of water, and finished by blowing them dry with the air compressor.  I also noticed that there was some sort of chemical reaction when the parts touched the plastic container while in the alodine solution.  Not only did it not cover that part, it caused some blue stuff to appear. 

 

 

 

Before and after shots of alodining.  (As you can see, I still have the spars to do.  I was worn out and we had a couple DVD’s to watch.)

 

I also spent about 30 minutes attaching the rudder stiffeners to one skin.  I didn’t cut them until I was sure they all lined up and were ready to go.  Match drilled to size.

 

Monday, July 29, 2002 (1.5 hrs)

 

Tonight I setup a paint station outside.  I want to be ready to go when I start to prime.  (Yes, I know, yesterday I said I was not going to prime.)  I also spent some time cutting the rudder stiffeners to length and match drilled the other half of the skin.  AND, I countersunk the HS-906/907/903 parts that I missed countersinking before I prepped them.  I’ll have to apply a little more alodine where I exposed metal.

 

Tuesday, July 30, 2002 (3 hrs)

 

Tonight was spent cutting out the angle portion of the rudder stiffeners.  Deburred and scuffed the surfaces in preparation for alumiprep and alodine.  Nothing to difficult here.  I started to get anal about cutting the angle and tried to clamp a board to the band saw to get the perfect angle.  Quickly abandoned that idea and just used my ruler to draw a line and did it by hand.  No problem!

 

 

Thursday, August 1st, 2002 (1 hr)

 

I tried to alodine the spars by using a spray bottle… didn’t work.  The coating wasn’t consistent, had spots, etc.  It was also obvious that I had touched them without gloves in the week that they had been laying around my garage after alumiprep’ng.  Tip #5: Plan on doing all of your prepping and painting over a weekend.  Don’t let parts sit around after you cleaned them.  So I quite working for the evening.

 

Friday, August 2nd, 2002 (3 hr)

 

I cleaned the spars again with soapy water and did the alumiprep process again since it was obvious they were dirty.  After that, I started in on assembling the rudder spar and various little pieces that get attached to it.  Cleco’ng, drilling, deburring, etc.   Tip #6: If holes don’t line up, check yourself... don’t assume that the kit is mispunched.  A couple of times in the last couple of days I’ve thought that some holes were misaligned, only to discover it was my fault, not Van’s.  HOWEVER, tonight I did discover that my R-916 rudder trailing edge has 12 holes in the upper portion that do not line up exactly.  If I force cleco’s in to make it line up, I get pillowing.  I’ll call Van’s on Monday and see what they say about this.

 

Some of you may have noticed that I am already into playing with the rudder and haven’t even banged a rivet yet!!  Well, I’ve been avoiding the priming process.  I’ve been debating whether or not to prime or not to prime…. A subject of much debate on the Internet.  My EAA Tech Counselor recommends that I do prime.   I just don’t want to!!

 

Saturday, August 3rd, 2002 (2.5 hr)

 

Today was the day for priming.  I’ve putting it off long enough and Sandi is ready to bang some rivets and make some airplane parts.  I had to run to Home Depot to get an air adapter for the paint gun.  I bought some zinc chromate primer from Aircraft Spruce that also has a reducer.  Instructions say to reduce 1-1.  So, I mixed up a batch and started in on the rudder stiffeners.  Tip #7: Run a piece of wire or rod through the stiffeners to hold them in place while spraying them.  They have a tendency to move around!!  PRIMING SUCKS!!  The primer was way to runny given the 1-1 reduction and not only did I get drips/runs, in certain places it didn’t cover.   I added some more paint to make it a bit thicker and also turned down the air pressure.  For my second batch of stiffeners, I heeded Tip #7 to keep them from blowing around.  Moved on to the HS and VS skins and then did the HS front and rear spars and attach brackets.  Other then the rudder stiffeners, they came out OK.

 

 

 

Sunday, August 4th, 2002 (5 hr)

 

Sandi and I started the riveting process today!  We worked on the left side of the HS.  I don’t know how people do this by themselves, w/o a bucking partner.  The two outer nose ribs were fairly easy, but the center nose rib was a challenge.  So much so, that when we finished the nose ribs, there was a good sized depression in the skin.  It looked pretty bad.  Fussing with it, I found a rivet not completely set that helped.  (After searching the Matronics archives, I discovered this is a fairly common problem.) We moved on and finished a good portion of the left HS.  We drilled out quite a few rivets, either I didn’t get a good shop head or Sandi let the rivet gun bounce, letting the rivet sit ‘proud’.

 

Monday, August 5th, 2002 (2.5 hr)

 

Finished up the left HS skin riveting and moved on to the right HS skin.  After our problems with the left HS skin and the depression/pillowing, I vowed not to let it happen on the right side.  Here’s what I posted to the Matronics RV-9 list on how to do this part and get good results:

 

My wife and I riveted in the HS nose ribs on one side of the HS and ended up with a horrible depression in the skin on the top side along the rivet line.  (Why couldn't it have been the bottom.)  After doing some reading online it appears to be a fairly common problem and I resolved not to let it happen again on the other side.
 
Here's what we did last night and ended up with a beautiful right side skin. (I only hope your reading this BEFORE you start riveting!)
 
Quite honestly, the key is to spend a little time ensuring the rib matches the shape of the skin.  I think we get so used to things lining up dead on, that we don't pay attention to well.  (Ok.. maybe just me.)
 
1) Flute and prep as normal, making sure the holes are all in a straight line.
 
2) Place the skin in the blocks and cleco in the inboard and outboard nose ribs.
 
3) Put in the center nose rib and secure it with a couple of cleco's towards the aft edge of the skin.  (Don't put any in toward the leading edge.)
 
4) Relocate the blocks to be just on either side of the center nose rib...maybe 4".  (Be careful, it's like a see-saw now and will tip easily.)
 
5) Push the skin down into the blocks forcing the skin to squeeze together... but don't bottom it out... just so it is real snug.
 
6) Now you can look in the end of the HS down into the center so that you can see how the rib fits the shape of the skin.  The rib needs to be flush (or nearly so) with the skin WITHOUT cleco's pulling it towards the skin. (If there is a gap, the cleco will pull the flange to the skin.. but the rivet won't, so it needs to site flush without a cleco holding it.)  Remove the rib and adjust as necessary.  (There was some suggestion on the list that you could run the outside of the rib flange on a belt sander to take out all of the high spots.  I didn't have to do this but I can see where this has merit.)
 
7) Repeat steps 3-6 until the rib sits flush against the inside of the skin. (You should also do this for the other two nose ribs.)
 
8) Place the ribs in the skin and cleco every hole, except the first one on the leading edge.  Get a bucking partner!!  I don't recommend trying this by yourself at all.
 
9) Time to rivet!  I'm not sure if the order matters, but I riveted the outboard nose rib first, then moved to the center 
rib and finished with the inboard.  TIP: RIVET THE TOP SIDE OF THE SKIN FIRST, then the bottom side.  IF you end up with some pillowing/depression, it will be on the bottom by doing it this way.  (On of the reasons you get this pillowing is that the skin gets pulled to the rib, instead of the rib being pulled to the skin, particularly once the other side is already fastened in place.)  We also laid the HS on it's side (in the flying position) so that the riveter has easier access.  This portion of the skin isn't flat so it is easy for the rivet set to slide around.  I used the head off my Avery squeezer as a bucking bar for the first couple of rivets.  The person operating the rivet gun needs to apply firm pressure but so much as to distort the skin.  We riveted one side starting at the leading edge and going back, then flipped it over and riveted the other.  Came out looking great.
 
This is how we did it.. your mileage may vary.  FWIW, I saw a post about splitting the rib in half and turning it into more of a stiffener then a rib.  I asked Van's about this.. here was Gus Funnell's response: "I wouldn't split the HS ribs. The issue is not a depression in the center (after all the ribs are identical), but a bulging of the skins either side
of center. The bulge doesn't matter but the increased flexibility of the HS would be bad. "
 
Good luck!

 

There ya have it!  Right side come out looking good.  Time to call me EAA Technical Advisor for a visit before I close up the HS with the rear spar.

 

 

Wednesday, August 7th, 2002 (2 hr)

 

We’ve worked so hard this week we don’t even remember what we did! J  Here’s some pictures though.

 

   

 

Thursday, August 8th, 2002 (2 hr)

 

Called my EAA Tech Ken Perkins today and had him come out and do an inspection.  Got the green light and a “Your doing excellent work”.  He pointed out a couple of rivets that were leaning a bit but no biggie.    After he left, we finished a few miscellaneous rivets, including the L&R Attach angles.   Tip #8: Wait until after you rivet in the front spar before riveting the attach angles.  This will give you more room to rivet the two inboard 904 ribs to the spar.  (Even without the attach angles, I had to drill out one rivet twice before I got a good shop head.)  All we have left on the HS is one side of the trailing edge to rivet!  Sandi is getting excited and thinks we are master riveters now! J

 

 

Friday, August 9th, 2002 (3 hr)

 

Tip #9: Don’t wear out your partner.  Sandi’s arm is worn out after 3 days of riveting and an evening of weed-whacking.  I did a lot of riveting tonight by myself for the first time on the HS.

 

Finished the last row of rivets tonight on the HS.  We have finished the Horizontal stabilizer!!  Yee-Haw!!

 

(Click for full size version if you dare.)

 

The prep work on the VS has already been completed, so we are riveting the VS.

 

  

 

… and we are finished with the Vertical Stabilizer!!

 

     

 

 

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