Tuesday, October 23, 2012

Fluting of RV-12 Wing Ribs Completed

Fluting continued today on the remaining twenty eight W-1208 ribs ... fourteen left and fourteen right. Compared to the W-1210 ribs, they were a little trickier to flute because of the tighter curve at the forward end of the rib and the J stiffener cutout. I continued using Allan Gilmore’s method of fluting which quickly got the ribs in the ballpark. Discovered that to really get the ribs totally flat, it required a little extra work by placing shallow flutes between all the flanges towards the forward end of the rib where the curve is more pronounced.
      Example of a W-1208-R rib prior to fluting … note the bow in the rib allows the pen to be slid under the rib.

After all the ribs for both wings are fluted, the plans call for removing the rear flange on all of the W-1208-L ribs, except one, and about half of the W-1208-R ribs. In addition, the plans call for removing the first upper and lower flange nearest the forward edge from some of the W-1208 L&R ribs.
                                       Using the band saw to trim off the aft flange of one of the W-1208-L ribs.
                        W-1208 rib aft flange on the left is uncut … aft flange of the rib on the right is removed.

I decided the easiest way to remove upper and lower flanges as called for in the plans was to just use a pair of pliers to flatten out the flange, followed by using a soft hammer to totally flatten the flange and then removing the flattened flanges with metal snips. After the flanges were removed, a Scotch-brite wheel was used to smooth the edges.
                         Flattened upper and lower forward flanges on one of the F-1208 ribs … ready for removal.
                          Cutting off the flattened upper and lower forward flanges from one of the F-1208 ribs.
W-1208 rib uncut upper and lower forward flanges on the left … removed upper and lower flanges forward flanges on the right.