Chapter 7 – The Empennage (Left Elevator)
Lorin’s RV-9A Builders Log
Table of Contents:
Chapter 7 – The Empennage (Left
Elevator)
June 25, 2005 – Pulled out Left
Elevator Skins (0 hours today, xx Total)
Aug 6, 2005 – Match Drilled
Front Spar & Skin (1.5 hours today, xx Total)
Aug 7, 2005 – Cleaned left
Counterbalance (.25 hours today, xx Total)
Aug 13, 2005 – Cut & Shaped
Stiffeners (1 hour today, xx Total)
Aug 20, 2005 – Completed Front
Left Spar Sub Assembly (5 hours Today,
xx total)
Aug 23, 2005 – Match Drilled
Stiffeners to Skin (2 hours today, xx
Total)
Aug 25, 2005 – Completed Left
Elevator Stiffeners (3 hours today, xx Total)
Aug 26, 2005 – Deburred Left
Elevator Skin (1 hour today, xx Total)
Aug 27, 2005 – Started Trim Tab
Servo Reinforcement Plate (2 hours today, xx Total)
Sept 3, 2005 – Dimpled Left
Elevator Skin (2 hours today, xx Total)
Sept 4, 2005 – Completed Front
Spar Assy & Back Riveted Top Stiffeners (4 hours today, xx Total)
Sept 5, 2005 – Countersunk Rear
Spar (1.5 hours today, xx Total)
Sept 6, 2005 – Set up Upper
Skin / Spar for Riveting (45 minutes today, xx total)
Sept 8, 2005 - Completed Trim
Reinforcement Plate / Stiffeners (1.25 hours today, xx Total)
Sept 9, 2005 - Riveted Top Skin
to Spar (1.25 hours today, xx Total)
Sept 10, 2005 - Riveted
Stiffeners to lower Skin (1 hour today, xx total)
Sept 14, 2005 – Fab &
Install Brace (1.0 hours today, xx Total)
Sept 15, 2005 – Riveted Top
Skin to Skeleton (.75 hours today, XX Total)
Sept 17, 2005 – Riveted Rib to
Rear Spar (.25 hours today, xx Total)
Sept 19, 2005 – Sealed &
Clecoed Trailing edge (3.5 hours today, xx Total)
June 25, 2005
– Pulled out Left Elevator Skins (0 hours today, xx Total)
Well, I didn’t have a lot of
time this evening, but I did want to go out and “touch the plane” so I pulled
out the left elevator skin. This looks
very similar to the right elevator, with the exception of the trim tab and the
servo cover bracket. I’m still
concentrating on the right elevator, but wanted to get a good idea of the
differences – and similarities – between the two – so that I could learn from
the first.
Aug 6, 2005 – Match Drilled Front Spar & Skin (1.5 hours today, xx
Total)
It’s been awhile since I
worked on the left elevator. The first
real hick-up was I got delayed completing the right elevator. The short story is I listened to Van’s
instructions and riveted the top skin on the spar – before joining the
counterbalance rib assembly. DON’T DO
THIS!! It’s almost impossible to get the
final spar-to-counterbalance arm rivets bucked.
I decided to cheat – and drilled a 3rd rivet in the spar and
will use LP4-4 for this. It will be just
a strong – and a whole lot easier to assemble.
The other – and more real reason for the delay was my 12 year old son
came out for eight weeks this summer. We
spent most of our free time together (mind you some of that was working on the
plane!).
Today I pulled out the front
spar, skin, and the counterbalance arm.
The spar and skin were clecoed together and match drilled – both the #30
and #40 holes (I am not going to try to use solid rivets on the underside –
seems like way to much work, and a great opportunity to screw up).
Fig 7-1 Fig
7-2
Fig 7-3
Aug 7, 2005 – Cleaned left Counterbalance (.25 hours today, xx Total)
After finishing the drilling,
I went back, disassembled the parts and deburred the counterbalance arms and
primed them.
Fig 7-4
Aug 13, 2005 – Cut & Shaped Stiffeners (1 hour today, xx Total)
This evening I pulled out the
raw stiffener angles and cut the parts to length using metal masters (hand
shears). At first I was unsure about how
long to make the short stiffeners – so I laid them out on the skin and made
allowance for the front & rear spar.
After they were cut – I found the length dead center of the
drawings!! The good news is they were
cut to the perfect length. The long
angles for the trailing edges were marked on the parts using a blue sharpie –
and then cut with a band saw. Final
shaping was completed with a 1: belt sander – and I finished up by deburring
the edges with my scotchbrite wheel. I
didn’t take any pictures – but I still have the protective blue vinyl on the
parts. I will remove this when it comes
time to do the final debur and dimpling.
Next I will need to match drill the stiffeners in place.
Aug 20, 2005 – Completed Front Left Spar Sub Assembly (5 hours Today, xx total)
I made good progress today
and completed the front spar assembly.
This went exactly like the right side so not much to say. However, I did (intentionally) set the
backing plate rivets so that you can see the shop head from the outside of the
assembly. The vinyl was removed, edges
and holes deburred & dimpled. Pieces
were cleaned with acetone and primed. One
thing I noticed was that the side rib for the elevator horn was not pre-drilled
like the right side. Hmmmmm?
Fig 7-5 Fig
7-6
Aug 23, 2005 – Match Drilled Stiffeners to Skin (2 hours today, xx Total)
With the front spar assembly coming along well, I turned my attention to the skin again. I laid a sacrificial sheet of ½” MDF on the work bench. The skin was clamped down to the MDF using thin strips of wood – and held open with duct tape (note that I used a strip of wood clamped on the taped edge to provide additional support for taped edge of the skin). Then I started to match drill and cleco the upper stiffeners to the top skin, starting at the trailing edge and working forward - drilling/clamping every other hole. I made sure that the skin remained flat and the holes were aligned. After all the stiffeners were clamped in place, I went back and drilled out the remaining holes. This only took a couple of minutes.
Top Skin clecoed and taped in place:
Fig 7-7 Fig 7-8
Bottom skin …. Same thing..
Fig 7-9
Aug 25, 2005 – Completed Left Elevator Stiffeners (3 hours today, xx
Total)
All the stiffeners have been match drilled in place. However, before removing the stiffeners from the skin and the MDF, I labeled each one so I would be able to put them back in the same position. As mentioned before, I am using a blue micro-sharpie to label the parts (and usually put the ID on the surface that gets mated – so you will not be able to see the labeling after assembly). Recall that the blue ink bleeds through the primer but will be covered up by any paint. I used a simple code – T for Top and B for Bottom. Then moving left to right – 1…2… 3… etc. So, each stiffener had a mark like T3 of B6. Just to avoid any mistakes – I wrote the number scheme on the plan drawings.
After the parts were removed, I took off the vinyl wrap, deburred and dimpled the holes, touched up the edges on a scotchbrite wheel, and finishing with a scotchbrite pad. Each stiffener was cleaned (which meant I had to remark them prior to priming). Parts were primed with the same 1 step self-etching Mar-Hyde primer in the aerosol cans.
Fig 7-10 Fig 7-11
Aug 26, 2005 – Deburred Left Elevator Skin (1 hour today, xx Total)
I had an hour or so tonight – so I taped open the left elevator skin and deburred all the holes (both inside and out).
Fig 7-12 Fig 7-13
Aug 27, 2005 – Started Trim Tab Servo Reinforcement Plate (2 hours
today, xx Total)
With the stiffeners completed and ready to be riveted, I started to work on the trim tab reinforcement plate. The plate was clecoed to the lower skin (with clamps in every other hole) and then match drilled. Once again the parts were separated, the vinyl removed and the edges cleaned up. I used a scotchbrite wheel & pads on the outside edges and a file and scotchbrite pads on the inside edges. This worked really well. All the holes were holes deburred, including the screw holes, and the part was ready for dimpling.
Dimpling the #40 skin and nut plate rivets was easy with the hand squeezer, but dimpling the holes for the #6 screws was tricky because I did not want to go too deep. Even then, I thought the thin edge distance seemed a little bent.
Fig 7-14
Now that the part was ready to be cleaned and primed – I pulled out the nut plates supplied in Van’s kit (bag #1913?). The nut plates didn’t look right because the rivet area was not countersunk. I jumped on-line and found out that several other builders experienced the same thing. Seems like Van’s shipped the wrong parts K1000-06 vs. K1100-06. RATS!! Oh well, guess I’ll can them after the weekend and see if I can get the right parts.
Later… I found out that I was wrong. Van’s did send the right parts. But only the center screw section is dimpled on the K1100 nutplates. Oh, well… I plan to dimple to mounting holes – and go from there. These are not structural – and their only function is to prevent the nutpate from rotating when putting in the screw.
Fig 7-15
Sept 3, 2005 – Dimpled Left Elevator Skin (2 hours today, xx Total)
I’ve not been able to work on the plane this week since I was
in
The evening was completed by cleaning & priming the inside of the skin. As always, cleaning was a 2 step process, first an initial cleaning to get rid of the blue sheet aluminum marking and then a final cleaning with new rags. As before, I used a couple of 2x2’s, spring clamps, duct tape and wood strips (see pics of right elevator). After the parts were cleaned & primed, I took the extra precaution to identify the location of each stiffener.
Sept 4, 2005 – Completed Front Spar Assy & Back Riveted Top
Stiffeners (4 hours today, xx Total)
This afternoon I finished the front spar assembly by riveting the counterbalance arm to the spar. Van’s directions say to do this after the tops skin is riveted to the spar – but after doing that on the right elevator and reading comments from the support group – I found it caused more problems than it solved. It was much easier to get at the joint and the rivets set well. The parts were clecoed to the top skin and each of the dimpled holes was “touched up” with the deburring tool to allow the rivet to set cleanly.
Sept 5, 2005 – Countersunk Rear Spar (1.5 hours today, xx Total)
I had previously match drilled the top elevator skin to the rear hinge spar. The top of the this spar needs to be countersunk, but I remembered from the rudder trailing edge work that countersinking thin material can be tricky. In addition, several other builders have written sad tales of elongated holes. So, to avoid making similar mistakes, I clamped the top of the spar to a sacrificial sheet of MDF. Then by drilling #40 holes through the spar into the MDF – I was able to make a “fixture” that guided the microstop and helped prevent the tool from wandering. Next, starting from the center of the spar (i.e. a lower stressed area that would not be noticed), and working outboard I carefully machined the first countersink. It was ok, but acceptable... The second was better... and the third was good. By the time I finished, they were coming out very well.
Fig 7-16 Fig 7-17
Sept 6, 2005 – Set up Upper Skin / Spar for Riveting (45 minutes today,
xx total)
With only a couple of minutes
available today, I cleaned off one workbench and setup the left elevator for
riveting the top skin to the front spar.
I first put a moving blanket on the bench, and then duplicated the same
thing I did with the right elevator. I
clamped two 2x2's on the outside edge of my work bench so they were vertical,
extending over the bench top and located to be in line with two
stiffeners on the upper skin. Next, I positioned several 1/2 x 1 1/2
wood strips on the inside of the upper trailing edge just over the tips of the
stiffeners. This was backed up by another strip on the outside of the
upper skin trailing edge. The upper trailing edge skin was now
sandwiched between the two wood strips and help in place with a bunch of spring
clamps. With the trailing edge secure so it would not bend - I
clamped the wooden strips/upper skin to the two vertical posts. The
elevator was now vertical with the leading pointing down. Following that
- I pulled the bottom skin down on the fabric covered bench top - and laid
a 2'x4' sheet of plywood on top of it.
Fig
7-18 Fig
7-19
Sept 8, 2005 - Completed Trim Reinforcement Plate / Stiffeners (1.25
hours today, xx Total)
It was a simple day in the shop
today….. debur, clean, prime, and
rivet. However, I was very pleased with
how well the nutplates came out.
Fig 7-20 Fig 7-21
Sept 9, 2005 - Riveted Top Skin to Spar
(1.25 hours today, xx Total)
More back riveting.
Sept 10, 2005 - Riveted Stiffeners to lower Skin (1 hour today, xx
total)
…. And even more back riveting. Boy – where are my helpers when I need them? The biggest problem was making sure the right parts were aligned and the wrong parts were out of the way. But… the good news is I REALLY like how the reinforcement plate came out. This is FUN!!!
Fig 7-22
Sept 14, 2005 – Fab & Install Brace (1.0 hours today, xx Total)
It wasn’t perfectly clear from the written instructions, but I figured out that I had to fabricate & install the corner brace. I found the raw material in one of the small brown envelopes – and then marked / cut it to size. All edges were deburred and the corners rounded to eliminate any chance of stress risers. The angle was made by clamping the part between two pieces of wood in a bench vice and then bending it over with a hammer against a block of wood. A few blows and the angle fit great. The part was cleaned, primed and clamped in place making sure to use pads or wood blocks so that the surface was not scratched. Then the standard process of “check, understand, drill, debur, and rivet”.
Fig 7-23 Fig 7-24
Sept 15, 2005 – Riveted Top Skin to Skeleton (.75 hours today, XX
Total)
Based on the experience I learned from the left elevator – I dove right in and riveted the bottom skin to the skeleton. Just like the right elevator - there were no real problems or issues. As usual – keep everything clecoed as long as possible. Use the deburring tool to clean out all dimples. Oh, the one important thing is to make sure the elevator is flat when riveting the joint. I did this by laying a ¾” piece of MDF on the skin – and then adding the extra weights of a few cleco bins. The only other thing I did was clamp a few thin strips of wood to the trialing edge to make sure it remained straight and was not dinted by an accidental bump.
Fig 7-25 Fig 7-26
Sept 17, 2005 – Riveted Rib to Rear Spar (.25 hours today, xx Total)
Ok – This one had me baffled for awhile. Why were “flush head” rivets called out for the rear spar-to inboard rib joint?? Duh!! This is where the hinge pin get safety wired against the rear spar. OK… I can deal with it, just a few simple squeezes with Avery hand riveter and we are done!
BTW – Note the yellow clamp holding the piece down to the table top. Whenever possible – secure your work piece. It makes it much easier and usually results in a better quality job!
Fig 7-27
Sept 19, 2005 – Sealed & Clecoed Trailing edge (3.5 hours today, xx
Total)
Just like on the right elevator-
a sacrificial sheet of particle board as clamped to the work bench and then
‘straightened” by sandwiching it between an aluminum level and a piece of 2x2
angle iron. After making sure the table
top was perfectly flat I marked the wedge as directed and set it in place. Each
end of the assembly was drilled using a cardboard guide to make sure the angle
was right. Clecos were installed into
the sacrificial particle board at each end to make sure it did not move. Then it was just a matter of drilling and
clecoing. To minimize the chance of warpage
or buckling, I did the ends first, and then drilled/clamped one in the
middle. After that I just kept
“splitting the difference. When all the
holes were drilled / clamped - I marked them since I planned to use the same
holes for the final proseal gluing & clamping. The holes in the wedge were
then deburred. I decided to call it a
night because it was starting to get late and I didn’t want to mess up when
countersinking the wedge.
I adjusted the microstop
machine countersunk all holes on one side of the wedge. Since the wedge was next to the edge of the
board we avoided the problem of the microstop hitting the table surface before
completing the prep and causing a misaligning of the countersink. After the first side – I did the second
side. Also, by using the hole in the
particle board I was able to support the countersink cutter – so that we
avoided any chatter. This was especially
important when working on the back side of the wedge. The angle of the hole in the board also
helped keep the countersink parallel to the surface of the wedge.
The wedge was wiped down with
acetone and primed. Next, a batch of
proseal was mixed up and a very thin coat was applied to both inner surfaces of
the skin. A 2x2 laid inside the elevator
kept the skins apart and provided ample room for working with the proseal. I double checked that the surface was clean
& perfectly flat, inserted the wedge, and removed the 2X2. Starting from the center and working outward
- alternating between sides – I clamped the whole assembly in place. A heavy sheet of MDF was put on the elevator
to keep the part flat.
The microsttop was carefully
adjusted and I machine countersunk all holes on one side of the wedge. Since the wedge was next to the edge of the
board I avoided the problem of the microstop hitting the table surface before
completing the prep and causing a misaligning of the countersink. After the first side – I did the second
side. Also, by using the hole in the
particle board I was able to support the countersink cutter – so that I avoided
any chatter. This was especially
important when working on the back side of the wedge. The angle of the hole in the board also
helped keep the countersink parallel to the surface of the wedge.
The wedge was wiped down with
acetone and primed. Next, a batch of
proseal was mixed up and a very thin coat was applied to both inner surfaces of
the skin. A 2x2 laid inside the elevator
kept the skins apart and provided ample room for working with the proseal. I double checked that the surface was clean
& perfectly flat, inserted the wedge, and removed the 2X2. Starting from the center and working outward
- alternating between sides – I clamped the whole assembly in place.
Fig 7-28 Fig 7-29