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Stephens Web Site
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Date: 2-15-2015
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Number of Hours: 3.00
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Manual Reference: Section 7
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Brief Description: Prepare T-712 Attach Brackets
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After much research on the VAF website I decided to follow the tank bracket assembly/drilling method described by Wirejock, also formerly known as the Checkoway Method, with some of the hole placements offset per advice by several other posters. I took seven brackets and marked them as "root" and #1 - 6 to identify their positions on the spar. I also put tape on the spar and marked the locations. Next was orienting the brackets as per the plans and marking them. I used the centerlines previously drawn and marked the center of each bracket on the spar side. I then offset the root bracket hole 1/32 inch away from the bracket web for socket clearance. I offset the mark on bracket 1 - 5 (root toward tip) by 1/16 toward the web for additional clearance when pop riveting these brackets to the tank baffle. The end bracket, #6, will have solid rivets and I used the exact center for this bracket. Drilled the center hole on each bracket, deburred, and bolted them to the spar. Used a square to set each bracket and double checked using the centerlines that were visible through the spar holes. Used the spar as a drill guide and drilled one hole to #12 and inserted another bolt, then drilled the third hole through the spar. Repeated this process for brackets 2 - 6. I had already installed the nutplates on the spar for the root bracket, so I bolted the bracket using several washers so the bolt would not go all the way through the nutplate, squared it up and used a #25 drill through the nutplate to make a pilot hole. Removed the bracket, drilled the hole full size and reinstalled the bracket with two bolts. Repeated the process for the third hole. Deburred all holes. I used a 10-32 tap to open three nutplates to use them as drill guides. Bolted them to a tank bracket, drilled one ear and inserted a cleco, then drilled the other ear.
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Orient and number brackets
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Square to spar
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Drill nutplates
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