Wrote them an email asking for new not used parts, and got this friendly reply:
Most empennage ribs have strait bends so we can use 2024-T3 (hard) aluminum with blue vinyl. But if rib has compound curves, we must use 2024-T0 (soft) aluminum. If it’s (soft) aluminum it must go through a heat treating process after we press the part. We can’t use the blue vinyl with 2024-T0 (soft) aluminum because it will clog up the punch press and it won’t survive the heat from heat treating. When we punch parts without the blue vinyl It will have some small scratches in the part, so we use scotch bright pad to clean it up. The slight bend in the side of the part number E-903 is intentional to accommodate the overlap of the skins. You will see this on page 9-2 and 9-9 of the plans.So ok... I'll carry on, hat in hand.
This is basically what you get after finishing the first page. Counterweight ribs assembled and ribs cut out and cleco'd together.
The four skins are identical between left/right but unique top to bottom. You have to bend some tabs, and the direction they bend determines which side they fit on. Took my time with that, I could see it would be easy to mess up.
I'm SO glad you found out what the deal was with those parts because I have been wondering the same thing! I haven't started the elevators yet but I did ask Van's about them in an email (I didn't get an answer to what they were but the email had other more pressing questions in it). I'm sure they get asked about those parts often enough that it would make sense to include an explanation of them in section 5.
ReplyDeleteGlad it helps, I sure felt dumb! If your not there yet, they tell you to flute the flanges to make a nice outside profile. I just made one flute mark and then used a pliers to "twist" the flange so it made a decent curve. If you want to know more hollar, it was the only challenging part so far. Well that and running out of 1/8 clecos (100 is not enough!)
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