Wing Spars

After completing nutplate city, you then go on to the tie-down attach brackets.  I made a significant mistake here by not fully clamping all of spacers and mount together prior to back-drilling the spar.  This resulted in one elongated hole on the spar (see below), and one elongated hole in the mount.  The mount was not acceptable to me, so I ended up ordering a new piece.

I ended up attacking this a different way when I tried again.  I got some depp throat clamps.  I also used double-sided tape to secure the spacers prior to setting the clamps:

To mount the nutplates, I just screwed them to the bracket and clamped one side while drilling the other.  I then replaced the first hole with a cleco to drill the other side.  You will note that the nutplate rivet holes are very close to the edge of the spacer.  Since the rivets only act to prevent rotation of the nutplate I did not worry about this.  I called Vans jus to be sure, and they told me that they even have some nutplates with only one rivet.  Once complete the spacers get riveted to the support...I primed the inside of the spacer and support prior to riveting.

If you're bulding the 7, then you have to remove a portion of the rear spar.  I kept them clecoed together while cutting so that both pieces would be exactly the same.  Bandsaw to get the major chunk off, then sander/scotchbrite to finish it off.

Same thing for the aileron tube...you have to cut out the stiffener to match the spar.  Yes, the hole is really supposed to be oblong.  I left them clecoed for this task to keep them perfectly even.  Dremel with the little sander wheel is invaluable here:

After priming, everything gets riveted together.  Be careful to leave out the rivets that will eventually have other stuff connected (ribs, etc.).

That's it for the spars...