With everything aligned, wing is straight and no twist, the center ribs were drilled to the rib attach angles on each spar, clecoing them in place. Here is a tip for assuring proper alignment of the ribs to the rear spar. Using a couple of scrap pieces of .032 aluminum and some side grip clamps, simulate the wing skin by clamping the pieces to the spar flange and the rib as shown below:
This aligns the rib perfectly to assure a nice smooth transition from rib to spar when you later skin the wing.
To install the nose ribs and get them all lined up properly there are a couple of options. One is to run a string through all of the nose rib jig holes, pull it tight and make sure the string is center in the jig hole before clamping and drilling (click here to see that mehod). When I built the RV, I used a couple of long pieces of 1/4" all thread , slipped through all of the jig holes with nuts threaded on between each rib to hold the ribs in place both vertically and side to side.
On this wing I used a Bob Barrows idea that I read in the October 1997 Beartracks newsletter. The alignment tool is a 4' long piece of aluminum angle with a couple of reference pieces riveted on. The braces and jig hole on the alignment tool are set up using the installed full length Tip Rib as a guide. Here is a picture of the tool in action:
The alignment tool is 4' long and is clamped to the main spar and rear spar. There is a short brace that rests on the lip of the main spar just outside of the spar capstrips, right near the bend of the spar flange. The top brace has a 1/4" hole drilled at the precise location needed for the nose rib jig hole. To align the nose rib side to side, I used the old simulated skin as previously described to assure a smooth transition of the skin from spar to rib.
The tool did a good job of aligning all of the nose ribs for drilling but I prefer the string method.
Here is a picture of the left wing at this point.
Click here to go to Assembly page 3