I had ordered some AN hardware for the lower wings from Wicks. I was dreading opening the package, because of the thought that there would be a box of jumbled nuts, washers and bolts staring at me...instead, I found an amazing picture of order and regimen. Every single sub-order had been separately bagged and labeled! At least now I know what they are...
I glued on the compression struts and tacked them using nailer blocks. Trying to clamp these in place free-hand was a nightmare, so I made a couple of bench blocks cut at the correct height for the struts to sit on while clamping. After gluing on the compression struts I then glued on the drag' blocks. To provide plenty of key for the glue, I scoured the back of the blocks with a sheet rock screw. The blocks were then applied dead center the spa center line. Each block was then marked either side 1/16 above and 1/16 below center line and center punched, these will be where the drag wires go through. Drilling above and below center line each side of the blocks will ensure that the drag wires do not clash at the cross-over point in the bays.
Almost gotcha: Make sure that the over/under sequence of wires ensures that you have an 'over' wire in the bellcrank bay to avoid a potential clash with the bell crank [thanks to the Biplane Hangar mailing list].
The bell crank ply doublers were notched around the drag block and then glued in place. I then cladded the I-strut area with 1/4 ply as per plan. These doublers were also notched for the square 4130 drag wire washers that will be residing there.
While I am waiting for a few pieces in order to continue, I decided to take a look at the tip bow area. I marked the center pivot point of the 21R on the rib at St. 101 1/4, and attached a length of timber to use as a kind of compass. I then placed a pencil on the end, moving the pencil/stick around the pivot point, I marked the cut lines on the 2 spars.
Gotcha: I had glued on the idler ply doublers and wished I hadn't...cos now I am going to have trouble drilling the drag wire block at rear St.35 1/4 due to a rib tail being in the way...I think the rib tail may bend out of the way to provide just enough clearance...