Decided today to continue moving forward through the plans and began preparing forward fuselage parts for primer and top-coating while the weather is still cooperating. The plans at the beginning of Section 22 have the builder doing quite a bit of machine countersinking and some dimpling. Two nutplate rivet holes are dimpled on the aft side of the stainless steel F-1201C bottom firewall. There are already quite a few factory dimpled rivet holes on the bottom firewall so it seems odd Van’s didn’t dimple the remaining two rivet holes for the fuel return line nutplate. It’s no big deal, so the pneumatic squeezer was used to place the called for #40 dimples into the metal on the aft side of the F-1201C firewall. The bottom firewall still requires more attention, but will continue with it later since the stainless on the firewall won't require primer or paint.
There are two F-1272 tunnel ribs, a left and
right. The tunnel ribs will run down the center of the forward portion of the cockpit
and create a tunnel for the fuel lines, electrical wiring, rudder cables, tubing, and probably become a collection point for dropped rivets, lost
tools, knuckle skin, etc. as well. After using a file to knock down
the edges of the tunnel ribs they were deburred using the Scotch-Brite wheel
and some hand sanding. Once smooth, both ribs required quite a bit of machine
countersinking on the nutplate rivet holes along the upper flanges. The
nutplates will be used to secure the tunnel's cover plate.
Using the countersink cage outfitted with a
#40-100 degree bit to machine countersink
nutplate rivet holes along the upper
flange of one of the F-1217 tunnel ribs.
The plans also have the builder place some
#30-120 degree machine countersinks along the forward flange of the F-1217 -L&R tunnel ribs at strategic
locations. The countersinks on the forward flange of the tunnel ribs must correspond
to factory dimples already placed in the F-1201C firewall bottom. To make certain the correct
rivet holes would be countersunk, the F-1217 tunnel ribs were placed on the
F-1201C firewall and marked accordingly. Note: The F-1217-R has one additional
hole to machine countersink for a total of five along its forward flange … the
left tunnel rib only receives four countersinks on the forward flange.
Pointing to the four holes on the left and the
single hole on the right that
must be machine countersunk in the F-1217-R
tunnel rib’s forward flange.
Moving forward, the F-1272 forward fuselage skin
was filed and deburred. The plans call for machine countersinking all 26
nutplate rivet holes on the bottom (outside) of the skin. All the nutplate
rivet holes were countersunk with a #40-100 degree bit.
Machine countersinking all 26 nutplate rivet
holes on the bottom of the F-1272 forward fuselage skin.
The last item worked on today was the F-1288
bracket. The bracket comes with a little extra material on it that was removed per
the plans using a band saw. The plans tell the builder to machine countersink
the upper rivet hole on the firewall side of the bracket to #30-120 degrees … this countersink will correspond
to a factory dimple already on the F-1201C firewall. What the plans fail to mention is
you also need to machine countersink #40-100 degree all the nutplate rivet holes in the
F-1288 bracket to mate with the factory holes already dimpled in the stainless steel
F-1201C firewall. Guess Van’s is trying to see if the builder is paying
F-1288 bracket sitting on the F-1201C firewall after
countersinking … the rivet hole being pointed to on the far left requires a
#30-120 degree countersink and to mate properly with the firewall, all the #40 nutplate
rivet holes also required countersinking … an omission in the plans.