Main Spar Countersinking

Time: 6 Hours

After lunch today I ran to Harbor Freight to grab a couple of moving blankets, the kind you would see in a U-Haul moving truck. I figure these would be a nice padding source to lay the fuel tanks on so I could regain the use of the workbench. I capped off the vent line with a -4 flared cap similar to the one I used for the flop tube line so that fuel wouldn’t drain as the vent line would be at the bottom of the tank as I laid them on their top skins. To prevent to tanks from getting damaged from expansion I removed the fuel drains, as they are now in top, to vent the tanks. I’ll let the tanks sit in this configuration for a few more days.

I then moved on to the main spars. You need to countersink every hole that the skins will get riveted to so that the skins dimples have a place to rest. I had to remove both leading edges to get to those holes.

All I can say is there are. Lot of these holes and my cordless drill is working very hard. I stopped after one full length to let it cool down. This isn’t very hard work, just tedious as there are 377 holes to countersink per wing! It took me 5 hours to drill all 754 holes! My hands hurt from holding the drill for that long! I cleaned up the shop and called it a night and look forward to another good weekend.

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