March 20, 2007:
Angela
cut the shims & deburred the anti-rotation brackets.
This was done during the preassembly stage.
March 24, 2007:
Here
the shims were clecoed in place & all the holes were final
drilled. These shims will hold the nutplates used to attach
the
wing root fairings.
Done did it!
Now watch me screw it up...
March 29, 2007:
Angela deburred and dimpled the shims.
Once again the large
screw holes showed signs of cracking, so we filed those out.
April 7, 2007: I looked back over the plans for what to do with the remaining holes in the shims. This is where the plans start to get real vague… there are a few holes here you have to figure out for yourself. Anyway, here's what we did... for the nutplates that attach to the shims AND the tank attachment bracket we countersunk the nutplate attachment holes in the shims... that is all the holes accept the one that is really close to the edge (far right in the upper pic). We dimpled this one and countersunk it in the tank attachment bracket (as shown in the left side of the lower pic). The screw holes are left alone for now. We'll eventually wind up countersinking those when we attach the wing root fairings. The remainder of the skin rivet holes in the tank attachment bracket were countersunk as well.
April 7, 2007: I looked back over the plans for what to do with the remaining holes in the shims. This is where the plans start to get real vague… there are a few holes here you have to figure out for yourself. Anyway, here's what we did... for the nutplates that attach to the shims AND the tank attachment bracket we countersunk the nutplate attachment holes in the shims... that is all the holes accept the one that is really close to the edge (far right in the upper pic). We dimpled this one and countersunk it in the tank attachment bracket (as shown in the left side of the lower pic). The screw holes are left alone for now. We'll eventually wind up countersinking those when we attach the wing root fairings. The remainder of the skin rivet holes in the tank attachment bracket were countersunk as well.
May 11, 2007: After
alodining, and then applying a bit of primer to the mating surfaces
I riveted the VA-146 bearings to the tank attachment
brackets. After that a couple of nutplates were riveted to
the
upper shims. Then finally, the shims were riveted to the tank
attachment brackets along with more nutplates.
May 12, 2007:
And so starts the process of prosealing the tanks…
First
on the agenda is to soak all of the attaching hardware in MEK to clean
'em up.
All of the ribs have a couple of tooling holes in them. These holes in the end ribs need to be plugged (to keep the fuel in the tank… makes sense eh!). The plans mention fashioning some small plates and gluing them over these holes. However, its quite common to fill them with AD6 rivets since they fit the holes just about perfectly! So, out came the squeezer, and the appropriate dies. Now, as far as yokes for the squeezer go, all we have are a 4" no hole yoke, and a 3" longeron yoke. So, we used the longeron yoke. I had to cut the AD6 rivets down to a workable length since they were pretty long. I cut them so they were the standard 1.5xDiameter, but after trying to squeeze a few, I decided this was not needed. These rivets are not structural, and it turns out the squeezer, even at 110psi, was having trouble setting these things... I could only squeeze a little, readjust, squeeze a bit more, readjust one more time, and then squeeze one last time. Once I was on this last squeeze it really looked as if my yoke was bending :O So anyway, after not really liking the way things were going and since it was getting late, I decided to stop after only doing 6.
Once I was done squeezing the rivets I came back and encapsulated the shop head of each of them with proseal to help ensure a leak-free seal.
I was a little worried about the flexing our longeron yoke was experiencing so I decided to hold off an squeezing any more of the AD6 rivets for now. So, I went on to something else. Welp, when I tried to pull the pins out holding the yoke to the squeezer the pin closest to the plunger wouldn't budge! I had to force it out! Once I got the yoke separated from the squeezer I was able to see that the pin hole was warped. The yoke showed stress signs below this hole and you could physically see a bend in it... not good! I had never tried setting anything over an AD4 so I wasn't sure if I had tried to ask to much from it, or if the thing was defective. I talked to Shaun at Isham Tools (where we got it) and he indicated it shouldn't have bent, and offered to send us a new one. Nice service!
May 15, 2007: We
bent a longeron yoke while squeezing AD6 rivets to fill the
tooling holes in the end ribs (see previous step) so…
on to other things now! I installed the no-holed yoke on the
squeezer and worked on setting all the nutplates for the fuel sender
units. Basically I just coated the mating side of the
nutplate in
proseal, stuck it on the rib, installed a cleco in one hole and
squeezed a rivet in the other. Pulled the cleco out, and
squeezed
a rivet in the other one. The do it again for the rest of
them. After that, I used the same process for the vent line
anti-rotation brackets, but after trying to set one of the AD4 rivets
with the no-hole yoke and being a little skittish about it bending (ok,
I was a little gun-shy having already ruined one expensive yoke!) I
decided to just glue them on tonight and only secure them with
clecoes. While I was at it I also glued the strainer fittings
on. We should be getting our new yoke soon so we'll set
rivets in
these shortly. For tonight though I just used the remaining
pookie to cover the shop heads of all the nutplate rivets.
May 16, 2007: Alright,
with new yoke in hand it was time to finish installing
some rivets… so, using a longeron yoke once again we (Angela
came out to get her hands a little dirty) placed a little sealant
around the opening of each rivet hole, inserted a rivet and
squeezed. For the remaining AD6 rivets in the tooling holes I
just used the rivet gun with our back riveting plate... wasn't going to
chance bending the yoke again! Have we mentioned we like the ziploc bag
technique! Very little mess!
June 7, 2007:
Our plan is to follow this
process
as it seems a little less messy since you're not riveting when all the
proseal is fresh. So, first up is to glue the stiffeners
on. I mixed up 2 oz of proseal and then transfered it to a
ziploc. It looks like a lot in the pic, but it's deceiving...
it's not. Anyway, cut the corner off the bag and squeeze out
a
nice bead around all the rivet holes, and down the length of the
stiffener...
And
then place the stiffener in position on the skin. After that,
put
a cleco in every hole, and repeat… 27 more times :-)
I
also glued the drain flanges in place… this actually turned
out
to be more than enough proseal… quite a bit of it squeezed
out.
Ok, one skin down,
one to go…
And there you have
it… both skins with the stiffeners
& drain flanges prosealed and clecoed. We'll rivet
these in
the next couple of days.
June 9, 2007:
First thing today was to rivet
our fuel return fitting anti rotation brackets.
After the brackets I squeezed the rivets for the drain
flanges.
Now
on to the skin stiffeners. The common thought here is to back
rivet these, but rivets sitting proud seems to be a recurring
issue. Now that there is proseal between the rivet head and
the
skin, there is the potential for the rivet to sit proud unless enough
proseal is squeezed out from under the head of the rivet.
With
backriveting only the sleeve around the back rivet set is applying
pressure down on the skin and stiffener while the back rivet plate is
pushing up against the rivet. So basically you're relying on
the
spring in this sleeve to provide enough force to squeeze out enough
proseal for the rivet to sit flush. I suppose you could apply
additional force to the sleeve, but I've done that before and with the
number of rivets to do, my hands would be killing me! So, our
plan is to install a couple of ribs in the skin so it'll hold its
shape, and then place them in the cradles and rivet with the gun and
bucking bar. So here's Angela applying a dab of proseal to
the
rivet hole prior to inserting a rivet. For each hole we
simply
used as little proseal as possible while at the same time making sure
it at least touched the entire perimeter of the hole.
We
knew doing these things one at a time would take FOREVER, so we decided
to do 3 at a time per stiffener. In addition, to minimize
tool
cleanup we taped the rivets after inserting to keep the proseal off our
rivet set. This pic makes the squeeze out look like no big
deal,
but once you hit it with the rivet gun, theres a lot more proseal to be
seen on the tape... the rivet gun really drives that rivet in the hole
:-) Once we got going we'd pull 3 clecoes, skip 3 clecoes,
and
pull 3 more in the same line. We'd do this on both lines, for
a
total of 12 rivets at a time. The process was basically pull
the
clecoes, pooky the holes, insert rivets, tape the rivets, clean the
back side of the rivets so the bucking bar wouldn't slip, set the
rivets, pull the tape, wipe the proseal off both the tape and skin
(yep, cleaning the tape was quite easy... acetone on a paper towel, and
one quick wipe... the wide rivet tape actually comes in handy here!),
and then repeat. A long process, but hey, it's gotta be
done. And believe it or not, most of the rivets are
flush!
I think the ones that aren't are due to our technique.
Of course, everything
seems to take longer than expected, so
we only completely finished one skin tonight. We started the
second one, but quickly realized the remaining proseal started setting
up. Even though we could still squeeze it out of the ziploc,
the
rivets weren't sitting flush any longer... yep, time to quit!
Speaking of rivets
not sitting flush (like how I made that
transition ;-) I thought it was appropriate to show a pic of our first
rivet we shot tonight. It had been a while, and I put a tad
too
much force on the bucking bar and pushed it out of the hole while
Angela was setting it. Oh well, I'll need to drill this one
out.
June 10, 2007:
Today we finished up the second tank skin. After
setting
all the rivets I used the remaining proseal to go back and encapsulate
all the shop heads of the rivets. A long, boring, tedious
task,
but I'm convinced this is much easier using the ziploc to just squeeze
it on there. One skin down, one to go. Whoops...
not much
proseal left, so I guess the other skin will have to wait.
I had JUST enough
proseal to cover all the drain flange rivets.
June 19, 2007: Tonight while I waited for Angela to come out & help rivet I sealed up the stiffener rivets on the right tank skin.
June 16, 2007:
Angela & I discussed it and decided we're just going to
concentrate on the left
tank for now. We want to validate our assembly strategy and make
sure
all goes well, so from this point on we plan to finish & pressure
test the left tank
before continuing any further on the right. Anyway... like the
stiffeners in the previous step, the fuel cap flange and vent line clip
(barely visible at the bottom of the fuel cap flange in the picture)
were glued on a day prior to riveting. In addition, they were
glued on at the same time as the ribs and J-stiffener (steps 6 & 7
below). We plan to rivet all this stuff tomorrow night.
July 2, 2007:
Ok, maybe it wasn't the next night [sigh]... anyway, Angela
& I prosealed and set the fuel cap flange rivets on the left tank.
June 16, 2007:
This step was done in conjunction with step 5 above, and step 6 below. We mixed up 2-oz of pookie,
transferred it to a ziploc, wiped down all the mating surfaces with
acetone, and then started squeezing a bead on all the rib rivet lines.
There's a lot more to
do here than it looks… Our hands would cramp after squeezing
for a bit so we swapped out every so often.
After all the rib
rivet lines and the J-stiffener rivet line were
covered in proseal, we began clecoing the ribs in place. As
you can
see, the first thing we did was cleco the first 4 or 5 holes of the top
rib flanges to the skin. This is so we can install the
J-stiffener
later. After it's in, we'll cleco the remainder of the top
flanges.
Next though, we clecoed the entire bottom flange of each of the ribs to
the skin.
June 18, 2007: Tonight was a long night…
much longer than we expected. There are a lot of rivets in these
tanks, and prosealing them all just added to the time. We did all the
rib rivets, but left the J-stiffener & fuel cap flange for a later
date. Poor Angela… we bucked the last rivet at 11:59pm and she looked
tired... I just told her to go. I cleaned up the shop just a bit, took
some pics and then called it a night myself.
July 21, 2007: Here I'm sealing up all the rivets on the ribs & J-stiffeners inside the left tank.
I also ran a bead of proseal around the end ribs.
June 16, 2007:
This step was done in conjunction with steps 5 & 6 above. After a few of the top rib
flange clecoes, and all of the bottom rib flange clecoes were
installed, we positioned the J-stiffener into its slot in the ribs, and
then attached it to the skin with a few clecoes. We then
finished
clecoing the top flange of all the ribs to the skin, and then clecoed
the remainder of the J-stiffener.
June 19, 2007: With Angela's help we
set the rivets in the J-stiffener on the left tank using the same
method as before: pull 3 clecoes, pookie the holes, insert rivets,
tape them, wipe the excess pookie off the shop head side of the rivets,
and then set them.
July 2, 2007:
We plan to install & rivet the tank attachment bracket in
place as opposed to gluing it, and then letting sit overnight. With the tape
over the head of the rivets the rivet gun isn't affected by wet
proseal, and the shop head side is the same regardless... so we thought
we'd give it a shot.
Woops…
probably shouldn't have done that. Right after we set this rivet,
I started looking at it funny. Something just didn't seem
right. Then it dawned on me that the aft portion of the inboard
rib goes there, and this rivet is supposed to attach it as well.
Oh well, get to drill out another :-(
Ok, there… the tank attachment bracket riveted to the skin.
