Adam Dickson

Wing Rib 1 enlarge pitot static holes and bottom flange holes

Wing ribs 2, 3, 4 all have pitot/static/electric cable holes of 9.5mm (3/8") diameter. For some reason rib 1 had 9mm holes. This was corrected up to 9.5mm. The grommets supplied HW-GRM-005 call for a hole diameter of 12mm. I am reluctant to upsize the holes to this size, as the grommets suited to a10mm diameter tubing, while the pitot static tube supplied has a OD of only 7.5mm. In any case I am likely to use snap bushings instead of these grommets, and 1/4" snap bushings anly require a hole of 9.5mm which is perfect. Also, I am likely to use a pitot static kit which will likely come with tubing with an OD of 1/4" - a perfect match.

The bottom flange holes were drilled to 3.2mm, while the bottom skin holes are 4mm. I decided to upsize these now, as the misalignment mentioned in a previous post can be tackled by other means. These include applying a little force along the rib to cause it to bed down on the main rear spar, correcting a slight bend angle error at the end flange of rib 1

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Entry: Tue Jul 07 2020

This post is from Adam Dickson