Having spent most of the day running errands and dong chores on Friday, didn’t get into the shop until very late in the afternoon to finish up removing the rest of the plastic film from rivet lines of the W-1202B upper center skin and securing it onto the left wing skeleton.
Removing blue protective film along rivet lines
on the W-1202B-L
upper center wing skin after melting the film with a soldering
Fellow RV-12 builders will notice I’m not
riveting the W-1201 wing skins just yet as called for in the plans. The plans
instruct the builder to rivet the W-1201 skin except for the wing walk doubler
area, then rivet the outboard W-1203 outboard skins, followed by riveting the
W-1202 center skins. I suspect Van’s has the builder assemble in this fashion
because of the large number of Clecoes required to do the entire wing at once. The
number of Clecos they suggest necessary to build the RV-12 is NOT enough to Clecos
to properly do the entire wing at one time (but keeps builder tool costs to a
minimum). Early on in the project, the DOG Aviation procurement department
procured many extra Clecos knowing they come in handy (and have already during
construction of the tail cone).
In an effort to ensure the best possible uniform
fit, all the skins are being secured in place onto the left wing skeleton
before riveting. There are a few potential problem areas a builder should be
cognizant of … in particular, those locations where a single flange (or tab) on
the ends of the ribs are under the main spar and rear spar. Because I dimpled
the rear spar along with all the W-1210 rib's single aft flanges, the dimple secured the single flanges so there were no problems
here for me … but builders not dimpling should exercise care in both these areas.
Lifting the aft edge of the W-1202B-L skin and
using a flashlight and mirror to verifying
the flanges under the main spar did
not get pushed down from the rivet being inserted.
first thing I’ve been doing is verifying the tabs under main and aft spars are
perfectly centered. Some tabs tend to want to move a tiny bit after they are
positioned so once the skins are placed on the wing skeleton, the first thing I
do prior to clecoing is use a center punch that is the same size as the rivet
hole to center the tab then place a rivet into the holes that have single flanges BY HAND. This helps ensure there is not enough pressure on the rivet to bend the flange out of the way as
the rivet is seated into the rivet hole. Placing a rivet into a rivet gun and
shoving it into a hole at these locations is just asking for a flange to be bent
out of the way and ultimately not riveted.
The last item that needed addressed was the wing
walk doubler plate. Van’s has the builder place a couple of dimples in it and
then set it in place to test the fit of the leading edge. (I of course, had
already dimpled so those dimples were already there plus many more). The plans
then say if the test fitting results in a gap, break the edge of the doubler to
improve the fit. Can’t do it using a breaking tool because the rollers get hung
up on the dimples! The breaking tool just won’t work AFTER the skin is dimpled!
I worked and worked on the edge and spend a lot of time on it only making a
small improvement … it would have been SO much easier to have broken the skin’s
edge first prior to dimpling.
Using a metal plate to press the wing walk
doubler tight to the edge of the workbench
while working the edge with a piece
of PVC to place a small break on the edge.
Do yourself a favor and break the forward
edge on this skin before dimpling or even trial fitting … you will be glad you
The last task for the evening was to prepare the
W-1201 skins for primer in the area where the wing walk doubler plate will be covering
the top of those skins.
Zinc chromate primer sprayed onto the portion of
the wing where the wing walk doubler plate will be placed.