Post Title: Started Matchdrilling Right Wing
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Tue, 08 Feb 2011 20:30:58 +0000
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Well, after 50% clecoing the right wing yesterday, I finally broke out the plumb bobs and measured my wing twist again. It was within a millimeter (sorry, I could only find my metric rule tonight).
After a quick celebration dance (I must have misplaced the video of the dance, sorry), I fired up the air compressor and put a drillstop on my #40 bit.
First, I matchdrilled every other hole on the top side of the right wing, then moved all of the clecos over one hole and matchdrilled the remaining holes. Keep in mind that I have about 600 clecoes, 500 of which are in the right wing right now. That's a lot of drilling and cleco-moving.
I then moved to the bottom side and drilled all of the open holes, then started moving clecos, and got tired. Later this week, I have to finish moving clecoes on the bottom side of the right wing and matchdrill the remaining holes.
To help you understand how tedious it is to move all of these clecos, I'll leave you with the following pictures.
Jack and Ginger, walking each other down the street.
Oh, I almost forgot! The ceremonial plans change!
(Triumphant music...)
Okay, so there is lot's of talk about the Checkoway method and what that is, but no one really does a good job of explaining it. I'll give it a shot, and try to give credit where credit is due.
Basically, Van's wants you to:
?Install the z-brackets (after some steps to get both sides of them drilled)
?Cleco on the baffle ("back wall" of the tanks) to the z-brackets.
?Cleco the skin to the baffle, then adjust fit as necessary by elongating holes in the baffle.
?Remove the skin and cleco in the ribs.
?Cleco the skin back on.
?Remove the whole thing for matchdrilling off the wing.
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The Checkoway method (from what I can tell, because I never actually made it to his site before he took it down...):
?Drill only the aft side of the z-brackets, then bolt them in place.
?Attach a clecoed tank into position
?Drill the inboard baffle-to-z-bracket holes (doing this now, instead of before, ensures the tank is perfectly aligned.)
?Remove the leading edge to drill the outboard baffle-to-z-bracket holes
?Remove skin and ribs, leaving baffle in place.
?Now finish baffle-to-z-bracket holes.
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The Checkoway method basically has you wait until you ensure propoer tank alignment before starting to drill holes in the front flanges of the z-brackets. If you do it Vans' way, you might misdrill a z-bracket, and it will throw off the whole tank alignment.
Anyway, many sites have kind of hinted at this stuff, but
Ethan really spelled it out nicely, and I have to give him some credit.
Of course, I'm out in the garage, so iPhone saves the day.
Ooh, remind me to charge up tonight, looks like I'm a little low on electrons.
After some really precise (HA!) line drawing. I finally used my center punch to mark a good starting point for my #12 drill. (#12, because that's the holes size for AN3 bolts.)
Punched.
Inboard bracket drilled.
Second one drilled.
After drilling the second one (actually, I checked before drilling, but didn't snap a picture till after), I held a nutplate over the hole to make sure I didn't get too close.
Looks good.
Then, I needed to bolt these in position to drill the other 2 (of 3) holes. I spent a few minutes removing the lower inboard right wing skin and laid (Emily!!) the brackets in position.
I love working on the airplane. Therapy for the soul.
Okay, I have my centerline and a hole. Let's bolt them up. (I added tape and a washer for spar-protection.)
Centerline through both holes...
So, I just moved it to the top side, knowing I'll have to backdrill from underneath. No biggie.
See, worked great. (You can see I used sacrificial nutplates, instead of regular nuts...easier to tighten since once you get it started you don't have to hold the nut.)
