More Tiedown Bars…   April 30th, 2007

The tiedown bars have no holes in them, so they have to be match-drilled to the spar. You first drill a single hole according to the dimensions in the plans. Then you put a bolt through the hole and line up the bar perpendicular to the spar flange.

Once everything is lined up, the rest of the bolt holes are match-drilled using the spar as guide. I set the spar on two sawhorses and clamped the tiedown bar and spacers with C-clamps and some wood to keep from scratching anything.

Once the tiedown bar had all bolt holes in it, you have to drill in the four platenuts that will hold the aileron control bracket. I put a bolt through a platenut and clamped it in place. After drilling the clear hole, I put a cleco in it and drilled the other one. Note that I don’t have the spacer bar in there just yet.

Once all the platenuts are drilled to the tiedown bar, it’s a good idea to mark them and know which platenut goes in which hole — Since these are not match drilled, any small variations in drilling are going to make things hard later on if the same platenuts are not used in the holes for which they were drilled.

After drilling the holes through the tiedown bars, I match-drilled the spacers, with a bolt in place just to make sure things didn’t shift.

Finally, I went to drill the lightening holes in the tiedown spacers. the plans specify a 1″ diameter hole. My hole cutter will only cut holes to 1-1/4″, so I decided not to use it (the hole would get too close to the bolt and rivet holes.

I have a Unibit that will drill 7/8″ holes, so I used it, and figured it’s better than no hole at all…

Here’s a finished spacer…

This entry was posted on Monday, April 30th, 2007 at 12:28 am and is filed under Tiedown, Wings. You can follow any responses to this entry through the RSS 2.0 feed.Both comments and pings are currently closed.

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