Brief Description: Preparing HS parts for initial fit-up
I did some prep work while I'm waiting for the new HS-403 spar webs.
First, I checked into how I went wrong on alligning the spars the first time. I traced it to two things: 1) I apparently got a little sloppy when I snapped the chalk line on the jig and it ended up with a curve. 2) The plans call for filing notches into the inboard edges of the spar webs so you can see the line underneath. It turns out that this isn't really accurate enough to prevent the kind of misalignment I saw. I found that strecthing a string over the top of the spar is a better way to see the any deviation from a straight line. I'll use this method when I match-drill the new spar webs to the spar strips.
Per the plans, I polished all edges of the spar strips with 400 grit dry sandpaper. These need to have a smooth finish in order to prevent cracks. I'll finish them with 400 and 600 grit wet sandpaper just before priming and final assembly.
I'm starting to flute the HS ribs. To do this, you begin by planning the approximate locations for the rivets. This takes a bit of careful staring at the plans and visualizing how everything goes together. Note that the plans give some leeway on exact rivet placement. Particularly, I found that the example placement shown on the drawings doesn't really work.
