F-1222 Wingtip Extensions Prepared For Final Instillation

After letting the flox mixture cure overnight, the remaining two #30 holes were drilled into the F-1222 extensions, through the cured flox and into the W-1204E wing tip ribs. Upon drilling the two holes in each extension, they were removed and the clay plug was removed and that area cleaned up … although not necessary, some of the excess blobs of flox were cut away with a Dremel tool.

Drilling the second of the two #30 holes that needed to be drilled into the W-1222 extension, through the flox and into the W-1204E wingtip rib.

The W-1222L wing tip extension after removing the clay plug and trimming away some of the excess flox. Now knowing what the end game is supposed to look like, far less flox could have been applied to the part.


Looking at the above photos, one can see there is no flox on the outer edges of the extensions. When the extensions are Clecoed in place, I noticed there was a small area where there was somewhat of a gap between the extension and W-1204E wing tip rib right at the forward edge of the extension. Not wanting to stress the fiberglass when it is riveted, after all the countersinking coming up next was completed, a small amount of flox was added to that area on both extensions and they were Clecoed back in position to let the flox cure overnight.


There are three mounting holes that need to be drilled into the W-1222 extensions for the mounting bracket for the nav/strobe lights. There are tiny dimples molded into the W-1222 extensions to help position the mounting brackets for drilling. The mounting bracket is centered as best as possible over the dimples and clamped in position for drilling using a #27 drill bit. After each hole was drilled, a screw was placed in the hole to help hold position. Once the three mounting holes are drilled to #27, the W-1222 extensions require machine countersinking.

The mounting bracket for the left nav/strobe light is clamped in position on the W-1222L wing tip extension and ready for match drilling using a #27 drill bit.


With the mounting holes for the brackets now drilled, per Van’s instillation instructions, the W-1222 wing tip extensions require some machine countersinking for all the holes common to the outer surface of the W-1204E wing tip ribs using a #30-120 degree bit for the flush rivets that will be used in this area. Because the DOG Aviation RV-12 is using flush rivets on all the outer surfaces, in addition to machine countersinking the required rivet holes mentioned above, all the remaining rivet holes in the W-1222 wingtip extensions were also machine countersunk for flush rivets.

Machine countersinking the line of rivet holes in the W-1222L wingtip extension common to the W-1204E wingtip rib using a #30-120 degree countersink bit.

Completed instillation of the mounting bracket for the nav/strobe lights on the W-1222R wing tip extension.


At this point, I drove home to get a small hand held vacuum that could be slipped in through the access hole in the wing tip so all the metal chips from the drilling could be removed from inside the wing. By the time I got back to the hangar and finished with cleaning up the debris from inside the wing, it was getting a little late to continue on … so mixed up a small batch of resin and flox and applied it to the previously mentioned area where there was the small gap, Clecoed the extensions in position and left them to cure overnight.