Bearhawk 4 Place Plans #1582

Entry: Sat Aug 08 2020

Mission Flanges Complete

Spent Thursday evening and most of the day today (Saturday) making the tip ribs and flanging all the .032 center ribs and aft tank ribs.

Thursday evening I started by installing bushings in the master form block. Next up I drilled the 3 rough blanks I had cut a couple months back when I was making blanks from the rolled aluminum. Normally I've been making two extra of every rib and leaving them flush routed and deburred with lightning holes but without any flanges or trimming for spar location. This way if I have any oopsies along the way I just need to send the spare through the shop press then pound the edes over and back on track. Since the tip ribs are so large I opted to create only one spare at this time. With the Jig holes established everything gets sandwiched between two form blocks and were ready for flush routing.

Today, I started by drilling access holes in the lightning holes for the flush router bit. Once the holes were drilled I used the router table with a flush trim bit to match the blanks to the template. Deburred all the edges and then it was time to chamfer the lightning holes of the templates so they can be used for flanging. Once chamfered a quick trip (ok probably 6-7 cycles each) of the shop press and lightning holes are flanged. Then into the forming bock and the edges get hammered over to complete the initial forming process. Once the .025 tip ribs were done I processed all the .032 center and aft tank ribs through the forming blocks.

So today all ribs are officially formed and flanged. My next task will be to straighten flatten and square up each rib!

I should also note that I haven't made any of the aileron, flap, or pocket ribs because i'm hoping to use the ones provided when I bought my wing materials.

I must say I'm happy to be done pounding flanges!

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