Sunday, December 7, 2008

give me some skin

6 hours

I finished pulling the wingtip conduit in the right wing then moved on to the skins.  First up was fabricating the wing walk doublers, then match drilling them to the inboard top skins.

To skin the wings I used all but two of my silver clecos... 498 of them in action!

the blue protective film on the skins looks quite dramatic 
skins coming out of the crate 
match drilling the wing walk doubler skin to the wing skin
starting to fit the top skins to the wings
fitting the top skins to both wings
bottom skins in place
truing the wing to take out any twist
There is no twist in the wing and it is important to ensure that none is introduced during fitting, match drilling, and riveting process.  With the wing leveled, drop a plumb bob from the main spar to the trailing spar and measure the offset at both the inboard and outboard ribs... adjust as needed to eliminate any twist.

after some adjustment each wing was true
Slight differences in the level of the wing stands introduce slight differences in the recorded offset.  More carefully matching the cross level of the stands would match the offset.  The important issue for evaluating twist was within the individual wing in its own stand.

The wing skins are made up of two overlapping pieces joined by a double row of rivets
 The wing skins are made up of two overlapping pieces on each side rather than a single long piece, primarily for ease of handling during construction and to allow for thinner sheet material outboard.  Where they meet there is quite a visual overlap.  To help to smooth and hide the join a scarf is called for at the corner to blend the two pieces down to a lower height.

marking out the locations for the scarf joints