Wing rigging #5

Tonight I got to the airport and started right in on getting the upper wing rigged properly. I rigged the sweep to be identical on both sides so that when I build the I-struts they will be identical and should rig without any trim washers. I had to do numerous iterations of tightening and loosening of drag/anti-drag wires. After I got the correct sweep I had to re-adjust to get the spars straight again which was much easier than I thought. Briefly you can get the wing to sweep forward by tightening the wire that start at the front cabane and end at the mid span of the rear spar and also tightening the the wire that starts at the front spar mid span and ends at last compression rib near the wing tip of the rear spar basically the two parallel wires. Vice versa for sweeping the wing aft. Now to get the sweep to stay the same while adjusting the spars to be straight you have to tighten or loosen (depending on weather the mid section is too far forward or aft) the wires that cross and connect at the mid span compression rib while doing the opposite to the the most opposing most out board wire and most inboard wire that would be perpendicular if allowed to cross. Anyway that is a lot of words and just playing with it if you’re not a word person is very helpful.

Anyway I got the upper wing set and then I started to tighten the wires one half turn of the nuts at a time. I was able to get my flying wire tensometer inside the wing to get a reading but I mis-placed the chart that tells me the tensions for each type of wire that company calibrated the tool for. So I will have to call Holloway Engineering to get the sheet faxed to me tomorrow. The good news is that I can use the tool which I think is better than guessing what it’s currently at. The pitts maintenance manual says 250 to 350 lb of tension.

Time spent today 3 hours
Total time spent 403 hours

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