Van's RV-9A in Aurora

The Big Picture

The Big Picture
Flying! 8/28/2011

Saturday, September 27, 2008

Final prep work prior to countersinking spars. After such a long layoff, I was almost afraid to cut into the spar, finding all sorts of tasks that amounted to delaying the countersinking. Built a quick pair of spar cradles to support the spar during countersinking. Yes, that's recycled crate material! The pine sideboards are nice and soft and don't scratch the spars. No carpeting or felt is required.

Using the highly scientific method of holding the drill at an angle that felt comfortable, I measured the tilt at ~30 degrees. So I use that to layout the form, cut it out on the bandsaw, and cleaned it up on the sander. These work great! I can't imagine having to hold the drill horizontal or vertical for all those countersinks. With this setup I can just lean into the work in a natural way with almost no fatigue.

Spent about 2 hours charged to misc on all the various prep tasks.
After lunch, couldn't put it off any more, and started with the #40 to final drill all of the platenut rivets on both spars.

Then setup the #40 countersink, and countersunk all 148 platenut rivet holes. Deburred the insides.

I'm trying to decide if using the platenuts as a countersink guide is superior to using some other sort of guide. I'd like to prime all of the cuts at one time, and installing the platenuts first gets in the way and forces two priming passes. Also, all the shavings from countersinking will get into the platenuts.
Tried one platenut for one of the #6 access panel screws. This worked OK, but I'll try another method, using a backing plate with a drilled hole before commiting.

2.3 hrs of actual wing build time!