So begins the long job of preparing the wing ribs. I have completed 12 of 28 so far, and it takes me about 40 mins per rib. First of all I remove the jagged saw teeth from the edges using a file.
Then use the 3M Cut & Polish Wheel Medium to smooth the edges.
I find that the Light 3M Cut & Polish Wheel is great for smoothing the external nooks & crannies. It removes the burrs without having to worry about grinding too much material away.
I use my Angle Grinder with the 3M Cut & Polish Wheel – 1” to debur the lightening holes. If you align the wheel with the edge, then a groove quickly forms in the wheel and they are used up fast! To avoid this I have found it best to carefully position the wheel at an angle, avoiding the formation of grooves a bit longer.
Next the flange holes have to be final drilled #40. I use a reamer. Then deburred of course.
The flanges have to be fluted to remove the slight bend in the rib caused by the pressing process.
This tends to bend the flanges slightly, so they have to be gently bent back to 90º.
Using a little set square to check the flanges are perpendicular to the web.
The ribs are really only curved on the front flanges … I found the rear top flange does not require any fluting, and only about 3 flutes on the rear bottom flange.
Checking the fluting has resulted in the holes being nicely straight.
Finally the flange holes are dimpled for the skin. Vans say to only dimple the bottom flanges at this stage, leaving out the tabs which fit under the spar. Reading ahead I can see this is because 4 ribs per wing are not dimpled on the top in the area of the walkway. I have decided it will be easier to dimple the top flanges of the other ribs now … so I’m carefully selecting my walkway ribs and only dimpling the bottom flanges of those.
That’s it, only took 40 mins. Only snag is, there are 28 to do! Oh well, here goes another …