Wing tip closeout began by flipping the wing over to expose the wing tip skeleton. The W-1204D-L wing tip close-out skin is the one that had the multitude of tabs, each requiring custom bending to various angles. I was prepared to fight and fight with it but amazed me how well it fit … astounding! Here again, praise to Van’s design team … it fit virtually perfect. There was still the one tab to form which I purposely left unbent and the 17 degree tab was tweaked to improve the fit after trial fitting the W-1204H-L wing tip trailing edge.
Left wing upside down exposing the wing tip
skeleton about to be closed-out.
The forward wing tip rib was purposely not riveted
when called for in the instructions so a custom fit of the first tab at the
leading edge would be easier. I’m not sure if what I did was worth it or not,
but I made an effort to close the large gap that is common between the leading
edge tab (the one normally bent to 116 degrees) on the W-1204D-L skin and the forward wing tip rib. Was able
to close the gap by approximately 50% without re-drilling the hole. Taking
measurements, it was discovered if the gap were closed totally the hole would
not lineup without re-drilling approximately a half hole or more off. I did not
want to do that, so there is still a little gap.
Tab prior to bending ... it would go straight
across the forward wing tip rib as shown then have a 116 degree bend at the leading
edge thus leaving the large gap between the skin and the forward wing tip rib underneath
it.
I was able to close that large gap by about 50%
by first bending the tab down to the forward wing tip rib and then using the
bending tool to form the bend from that point.
Bending the tab down onto the forward wing tip
rib.
Using the bending block to bend the tab in small
increments until the fit was acceptable.
Getting close … at this point the tab was tweaked
just a little more for a good fit.
Now that the overall fit of the W-1204D-L skin was
tested to be very good, the skin was removed and all the holes were then
dimpled. Sadly, in my haste to move on and finish up the wing today, I forgot to
take a photo of the final outcome of the tab bending.
Using the pneumatic squeezer to dimple the tabs
on the W-1204D-L wing tip close-out skin.
The W-1204D-L wing tip close-out skin was then
secured in place with Clecos and riveted in place.
Builder Tip:
CAUTION – If you are building an RV-12 wing and
also planning to install the wing tip navigation/strobe lights, there are three
rivet holes you will want to leave open when riveting the W-1204D skins – those
rivet holes are pointed out in the next photo. Also … if you are dimpling you’re
RV-12 for flush rivets and also installing the nav/strobe lights, you DO NOT
want to dimple the three holes mentioned above and pointed out in the photo
below. Those holes will be used to mount the fiberglass mounting fixture on the
wing tip for the nav/strobe lights. The fiberglass is plenty thick (at least 44
thousands) for countersinking. It is not good practice to dimple the fiberglass
so countersink it and leave the metal below the countersunk holes flat. You don’t
want to countersink the fiberglass and have voids underneath in the form of
dimples.
The Clecos in the three rivets holes that need
to be left open if installing the wing
tip fiberglass mount for the nav/strobe
lights are wrapped in blue tape.
W-1204D-L wing tip close-out skin secured with
Cleco’s and ready to rivet.
Beginning the riveting of the W-1204D-L wing tip
close-out skin, working from the leading edge back.
Making progress - headed towards the finish line.
Road block - the rear portion of the aft wing
tip rib challenges the builder. The rivets no longer seat properly in the holes
because the shaft of the rivets hit the rivets already set on the other side. (By
the way, you will have this issue regardless of using flush rivets or Van’s
LP4-3 rivets).
Rivet interference from the set rivet on the
opposite side prevents the rivet from seating correctly in the hole.
NO WORRIES MATE - there is a good way to deal with
this and have perfectly set rivets. I have been keeping the air pressure low on
the pneumatic puller so I can slowly set a rivet if desired by slowly pulling
back on the trigger … it gives great control. I know the pneumatic puller would
work in this situation if used carefully, but the tip on mine is so large, it hides
the rivet so it is hard to see the angle of the rivet as it is being set
(probably more of an issue for me because of the flush rivets). The DOG
Aviation suggestion is to use the close quarters pop rivet puller AND the
pneumatic squeezer. Why both? Because if you have used the hand rivet puller
much, you know it kicks up after the rivet mandrel breaks and you never know
which way or how far it will move (plus it is very easy to pinch your hand when
the rivet’s mandrel breaks… ask how I know?).
The solution … use the hand rivet puller and
push down on the tip while giving the handle a SLOW steady full squeeze. As you
squeeze, your downward pressure will seat the rivet down into the hole as the
mandrel is drawn up into the tool and you can adjust the angle easily. One full
pull will not break the rivet’s mandrel but will fully seat the rivet into the
hole.
Using the close quarter rivet tool to partially
set the rivet by applying downward
pressure while giving the tool one slow full
squeeze of the handle.
Rivet after one full pull with the close
quarters hand riveting tool.
After the rivet is partially set and flush, the
pneumatic puller was then used to finish off the job. The method works great!
Final setting of the rivet with the pneumatic
rivet puller.
The final piece to the left wing puzzle is the
W-1204H-L wing tip trailing edge. I had this piece on and off a couple of times
improving the fit. This part also requires being match drilled after the
trailing edge is verified to be parallel to the aft edge of the wing skins.
Once the piece was match drilled and removed for deburring, it was dimpled.
Final piece of the puzzle – the W-1204H wing tip
trailing edge being set into place.
Builder tip:
When riveting the W-1204D tip skin in place, I left two rivet holes open - the one
for the forward hole in the W-1204H and the next hole forward. This was done to
improve the look by allowing the skins to be lifted slightly to allow the tip
of the W-1204H part to slide UNDER the skin at the rear spar which I feel
improves the look and removes the edge from the airflow.
The forward edge of the W-1204H-L wing tip
trailing edge slipped
under the skin at the rear spar makes for a better
transition.
After the W-1204H wing tip trailing edge is
secured with Clecos, a measurement needs to be taken. Van’s suggests clamping a
straight edge across the W-1204H and verify it is parallel with the aft edge of
the wing. Rather than eyeballing it, this seemed to be another perfect place to
use the new digital level. The level was placed onto the rear spar and the
bevel button pressed to make that the “zero” reference point. The level was
then moved back onto the W-1204D-L wing tip trailing edge. The trailing edge
was then tweaked slightly until the level read zero. For me, that was moving it
only .2 degrees.
Making sure the wing tip trailing edge is
parallel with the wing before
match drilling into the W-1204-D-L wing tip
trailing edge.
Once zero reading was obtained, the six holes along the
aft end of the W-1204B skin were used to match drill into the aft edge of the
W-1204D-L wing tip trailing edge. Then the part was removed for deburring and
dimpling placed back in place with Clecos and riveted in place completing the
construction of the RV-12’s left wing.
The RV-12’s completed left wing!
Now where do I put it to build the right
wing? Will have to make a wing cradle tomorrow
to store the wing so construction can begin on the RV-12’s right wing.
