nose rib piece is notably floppy due to the "flat" connection between
the formed piece and L-Channels. The required forces to install
the nose skin will deform the ribs.|
To resolve this situation, I designed and built a simple support fixture out of scrap hardware store angle and a miss-drilled spar cap (drilled in a mirror image of what was required).Cost .... $0.00
The spar cap served as a crossbar threaded through the lightening holes in the nose rib pieces. The spar cap had #40 holes drilled at a 1-inch hole spacing. That spacing was perfect for attaching the vertical fixture pieces to the crossbar. Since the ribs are spaced at 16-inch spacing (with the exception of the two end ribs).
The total parts were 7 vertical angles (15.25 inches in length with three holes drilled) and one crossbar (8' feet long, holes spaced to match rib spacing). Also, two #40 holes were drilled in each nose rib piece (near the tip and near the flange). Since my cross-bar wasn't the full 8' long, I needed one short piece of angle to bridge the gap between the end vertical and the crossbar.
A few Cleco sheet holders and the whole setup becomes very rigid. Yet, there still is enough flexibility at the edge of the rib to postion the rib as needed to align with the holes in the skin.
More text and a few more photos will be added soon.
Rib piece is easily bent to either side by down forces from the skin.
View of finished nose rib support fixture.
Only a few tools and a couple of hours required.
Better view of the interconnections.
Three Clecos per rib required.
If you look closely, you can see that an extra short angle
was fastened to the back of the vertical piece so as to reach the crossbar.
Look behind the angle to see the extra #40 holes drilled
in the rib nose piece.
The two vertical holes are cleco'ed to the rib.
The third hole is cleco'ed to the crossbar.
Just stuck the flanging die images here ... to be moved when I have time.
Testing for nose rib evenness by sliding 8' angle up-and-down the seven ribs.
Note: six ribs were "perfect" the end rib was off slightly due to a slight twist in the spar.