Wings Main Spar Drill

Starting with the Wings, I immediately feel the much more condensed build manual. With the Empennage the manual is setup as a detailed check list that describes every step and has a checkbox in front of every step. With the wings these descriptions are reduced to a single sentence, without a checkbox, just some reference to the drawings.
The idea is that you learn and improve as you go.

We started with the first sentence and had to drill holes in the Main Spars of the Wings. This being one of the most expensive parts, I didn’t want to screw this up.
The holes need to fit a #8 screw together with a dimpled (Tank) skin of 0.025″. A rather big hole!

Before I was half way I was doubting my actions and started to call other builders, check the Van’s Airforce Forum and look at other blogs. Turns out the holes are indeed huge. Moreover, now I understand the “flutter” remarks I read on some blogs. If the hole is this big, the pilot of the countersink drill is useless. So as many other builders did before me, I created a jig from a piece of longeron Aluminum.

This guides the countersink pilot and prevents “flutter”, which means that the drill is jumping around in the hole, making terrible edges.
It took over three hours before I was confident enough to finish the first hole. I finished the rest of the holes on the top side of the Left Wing in 30 minutes.

With this knowledge I can finish up the first sentence in the next session. I hope I won’t need two days for every sentence in the manual.

Time: 4 Hours, Rivets: 61/1


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