Saturday, July 23, 2016

W-1222 Wingtip Extensions Floxed

In order to finish off the repair of the leaky fittings on the brake master cylinders, it was necessary to bleed the brake lines once again. This time, Bernie and Mike K. were able to lend assistance yesterday morning with the brake line bleeding chore. The left and right brake lines were filled with fluid from the calipers up using the same pump oiler and method used before.  However, this time around it appeared the brakes were still a little spongy, so with most of the air out of the lines we switched tactics. I got inside the cockpit to pump on the brake pedals as Mike continually added fluid to a tube connected to the brake fluid reservoir while Bernie worked the bleeder valve at the caliper and monitored for air bubbles coming out of the line. The whole process took us a while, but the brakes appear to be quite solid now and so far, the fittings on the master cylinders are remaining dry.

With the brakes functional again, it was time to get back to working on the W-1222 wingtip extensions for the navigation & strobe lights. The next step for installing the W-1222 wingtip extensions involved flipping the wings upside down which Mike helped me do. With the wings upside down, a batch of resin mixed with flox is applied to the inside edge of the W-1222 extensions to fill the void between them and the W-1204E wingtip ribs. Prior to applying the resin/flox mixture, the areas around the wing that could come in contact with the flox are to be covered with wax … as is typical at DOG Aviation, this was taken one step further, in that the contact areas were covered with clear packaging tape and then Vaseline was smeared onto the tape as the release agent. There is also an area on the W-1222 extensions that needs to be protected from the flox so a nut can be installed later in the assembly process … Van’s suggests using a plug of modeling clay to protect the area from the flox, which was done.
A plug of yellow modeling clay is used to protect a location that will be used for a nut to secure the mounting bracket for the  nav/strobe lights. Looking closely at the area my finger is pointing to, one can see the line of the packaging tape which was rolled over the outer edge of the wing tip. Another strip of tape was used on the other side of the wing adjacent to the outer edge. Prior to applying the flox, the packaging tape was slathered with Vaseline so the extensions can be removed to work on the electrical connector and the mounting bracket attachment after the flox mixture cures.

After applying the flox mixture to the inside edge of the W-1222 extensions that will contact the W-1204E wingtip ribs, the extensions are secured onto the wingtips using Clecos. It appears the main reason flox is used here is to fill a void between the W-1222 fiberglass extensions and the W-1204E wing tip ribs … because after the flox mixture cures, it is necessary to drill two more rivet holes through the extensions and into the W-1204E wingtip ribs … that area can be seen between my fingers in the photo below.
After the resin/flox mixture is applied to the inside edge of the W-1222 wingtip extensions, the extensions are secured onto the wing using Clecos to hold position as the resin/flox mixture cures. After the flox has cured, the area between my fingers will receive two #30 holes for rivets.

Prior to leaving the hangar for the day, I wanted to get a little more done so the ELT antenna and bracket was installed. This has remained off for access, but now that the fuel tank and rear window are now installed, figured it was time to mount the ELT antenna. Nothing out of the ordinary here so no photos were taken since this was covered earlier this year ...  it was just a matter of installing three screws and attaching the antenna wire to  the connector on the base of the antenna.

Now that the flox has had time to cure overnight, the first order of business today will be  drilling the two#30  rivet holes, then remove the extensions to continue with the mounting of the bracket for the navigation & strobe lights and the electrical connections.