Wednesday, March 27, 2013

Landing Light Lens Tweaked & Left Wing's Leading Edge Rivets Set

Before beginning the closing out of the left wing, I thought it best to try tweaking the landing light lens a little more while access was still good. Following the advice of the EAA tech councilors, I first heated the entire lens and then spot heated the edge I wanted to reshape using a heat gun from inside the wing. The reason suggested for heating the entire lens, is to help prevent the development of streaks in the lens from uneven heating.

The shop was quite cold this morning so the heater was kept far away from the lens at first so it could warm up slowly. As the lens slowly warmed up, the heater was moved closer and closer in small increments while the ambient temperature was monitored.
              Preheating the landing light lens with a heater before applying a heat gun to the lens from the back side.

After about a half hour the lens was quite warm to the touch so a heat gun was used to heat the one edge of the lens that was bothering me. A cap for a 1 ½" PVC pipe was a fairly close radius for the area I was trying to tweak and it was pressed into the inside edge of Plexiglass from behind and held in place as the lens cooled. This was done to several locations but I was afraid to use a lot of heat gun, so perfection was not achieved but the end result turned out 100% better than it was. Now there is just a very small gap between the lens and the wing skin and not sure the risk trying to make it better is worth it … so it is time to move on.
                           Photo of the left landing light lens fit prior to heating ... note the large gap on bottom left.
                                                  Left lens after being heated and tweaked … not perfect, but a
                                                  much better fit was achieved, hardly any gap on the bottom now.

For some reason the reflection on the glass makes the gaps look larger than they really are compared to the first photo with the blue tape which has no reflection.

Moving on … it is time to close out a wing. The plans instruct the builder to rivet the first 5 rows of rivets from the leading edge aft on the W-1201,02 and 03 wing skins … excluding the rivets in the area where the wing walk doubler goes, because the doubler is riveted in place later. The aft 9 rows are left open to enable the aft edges of the three skins to be lifted up to allow the J stiffeners built into the top skins to drop into the cutouts in the W-1208 nose ribs.
                                Using a soldering iron to remove the blue plastic from the rivet lines prior to riveting.
                                                Setting the first rivet on the leading edge of the W-1201-L skin.
Setting the last rivet in the fifth row aft of the wing’s leading edge. Ready for the top skins to be set in place for riveting.