With
the holiday and all we've been a little slack with logging time.
We've only been able to get out in the shop off and on and rarely did
it involve taking pictures of our progress. The majority of what
was done was busy work (deburring, dimpling, etc) and we had a few
"issues" that were less than motivating. So here's a brief look
at some of it...
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July 3, 2006 (9-16 step 5): I
tried my hand and got quite frustrated with the trim tab closeout tabs
on Monday. The first bend was a breeze. I had forgotten the
double sided tabe Van's calls for in the plans to help aid holding the
wedges in place during the process. I didn't have any problem
though. On the second bend I decided to go ahead and use the tape
'just in case'... turns out that was a bad idea (explained
later). As you can see the results were less than stellar.
As I was tapping the second bend around the first one the wedge was
being pushed inward and I didn't realize it for a bit. This in
effect caused the bend in the first tab to move inward also (following
the wedge) resulting in more material being forced into the tab until
it eventually met the opposite skin. Once this happned the only
other place it could go was the opposite direction which was to push
the bend down (as you can see in the picture, although the piece has
been turned over). This is when I noticed what was going
on. A couple of crappy attempts to fix it did nothing, and I
finally decided I needed to walk away from this for now...
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July 4, 2006 (9-7 step 9):
Angela did a lot of the hole deburring and dimpling. She
got the elevator tip ribs and counterbalance skins taken care of.
We deburred the edges of the skins and then scuffed the inside surface
in preparation for priming later. Here Angela is dimpling one of
them.
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Unfortunately
we had a minor setback during the dimpling of one of the skins.
The lever arm of the DRDT-2 dimpler was swung all the way up (at least
we thought so) while the skin was being adjusted to line up the next
hole. Apparently the arm was nearly vertical with a slight lean
towards the direction of coming down... well, gravity finally took over
and down it came under its own weight, and we didn't quite have the
hole lined up in the dimple dies yet. These elevator skins are
only .016" thick so it doesn't take much to bend them. It put a
nice little dimple slightly offset to the side of the hole. No
problem, we'll just redimple it in the correct location... so that's
what we did. Unfortunately either the original dimple or the
second one created a crack in the skin radiating out from the hole past
the edge of the dimple. Bummer! Ideally the crack would
only extend away from the hole a distance that would allow us to drill
the hole out (taking the crack with it) for the next size rivet.
Unfortunately thats not the case here. The next size rivet up is
shown in the pic for reference, and drilling the hole out and
redimpling for it won't remove all the crack. A quick email and a
copy of the pic to Van's requesting possible fixes wasn't very
promising either... we can either replace the skin, or "just rivet it
(maybe with an extra rivet nearby) and move on". Hmmmm... I'll
leave the interpretation of that to the reader... but for me, it
doesn't leave me with a warm fuzzy. We're really trying not to
replace the skin either, so it was off to do some research for some
other possible fixes. Based on some of the things we've found our
current thinking right now is we'll leave it as is, and during final
assembly apply some proseal between the spar and skin in this
location. This hopefully will dampen any crack inducing vibration
in this area. We've got an email out to our tech advisor
suggesting this, so we'll see what he thinks about it.
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July 5, 2006 (9-16 step 5): Ok,
feeling a bit rejuvenated, I decided to tackle the trim tab closeout
tabs again. There was a lot of trial and error here, but I
eventually figured out that the tape was almost acting like a lubricant
in a way. Sounds weird I know, but with the tape, the wedges had
a tendency to be squeezed out... without it, I never once had any
problem... period! Needless to say, I didn't use the tape
anymore. Once I figured this out, and got a technique down, the
remainder of the tabs were relatively painless! I basically did
them just as the plans call for: bend with a block by hand, and
then follow up with a flush rivet set in the rivet gun. I think I
had the pressure down to about 12 or 13 psi and only held the trigger
about a half second at a time.
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(9-17 step 4): Back
in a good mood about building again I decided to truck on with the trim
tabs. Now that the closeout tabs were bent the next step was to
cleco the spars back in and match drill the holes in the closout
tabs. The next step in the plans called for removing the spar and
bending the lower skin. However, right after that you put the
spar right back in. Not seeing any reason otherwise, I decided
I'd bend the lower skin after I had done everything I needed to do with
the spar clecoed in place in order to save me the time of pulling it
out and putting it back in again. So, with the spar still in I
clecoed the trim tab horns in place, and final drilled them. The
plans aren't quite clear if they mean for you to final drill all the
skin holes to the spar as well. After reading through all the
trim tab plans I finally decided I needed to so here I'm final drilling
the skin holes to the spar.
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(9-17 step 2):
The
last step remaining in the trim tab preparation was to remove the spars
and bend the lower edge of the skin up 15 degrees. These tabs
will be attached to the rear spar of the elevators by the edge of
the top skin. Putting this bend in the lower skin allows it to
clear the
elevator rear spar flange when the trim tab swings down. This
wasn't exactly easy, and again time consuming, since the only method I
could get to work was using my hand seamer. It's pretty late,
which is probably part of the problem, so I'll sleep on it and try and
figure out a better way to do the other one.
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