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Archive for November 26, 2011

Started Riveting Bottom Skins, Left Wing – 5 hrs

November 26, 2011 Leave a comment

Saturday Nov 26, 2011

Before hitting the sack last night I was thinking about how I had routed the pitot heater wires yesterday and it occurred to me that I forgot to twist the power wires. A friend who is an electrical engineer told me that twisting the wires was one of the most effective ways of minimizing the electromagnetic coupling between wires. If there is any RF noise on these wires twisting them will minimize the radiation to/from other wires such as antennae and strobe lights. So first thing this morning I pulled the red/black wires back out and twisted them together as a pair, then ran them back through the wing. You can see the result in this picture. There’s no way I’ll ever know how much this helps but if I didn’t do it and I have electromagnetic noise issues later I would kick myself.

After that I torqued a few more bolts in the bellcrank area and applied torque seal. I mixed up a small batch of ProSeal and applied a small amount to the electrical conduit at each of the wing ribs. This is to keep the ribs from cutting through the conduit over time due to vibration. Then I spent about two hours cleaning off the work bench and the area around it before moving the left wing onto the bench to install the bottom skins. The shop really needed some cleaning and it is much more pleasant to work in now. Here is the wing moved into position for skin riveting.

I did the first few rivets solo along the rear spar in the first three bays. I taped the tungsten bucking bar to a piece of wood to give me a better reach into the wing.

After that I got some help from one of my daughters to complete the first three ribs in the wing walk area. This is one of the toughest parts of the project so far. I hate bucking rivets when I can’t get eyes directly on the shop head and most of these rivets are blind and the hand positions are awkward at best. But like Bruce Swayze said on his web site, you just focus on one rivet at a time and keep plugging away. This fourth row looks like it will be a challenge as well as the remaining rivets on the aft spar.

With the first three ribs completed I shifted from bucking from the inboard end to the outboard side. I used a piece of rope attached to the garage door track to lift up the outboard edge of the skin. I seems to work better with one person focused on bucking and one shooting the gun without having to worry about holding the skin up. I’m being cautious here because I don’t want a kink in this skin.

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Categories: Skins, Wings