Horizontal Stabilizer 8-9-6 and 8-9-8
The final steps before starting to rivet require deburring and countersinking the front and rear spar #40 holes.
To assist in countersinking the spar flange holes, I set up supports at each end of my bench using 2x4s to which I could clamp the spar. I used a similar piece of 2x6 that I would place beneath the hole being countersunk to add support behind the hole. The 2x6 had holes drilled into it to accept the countersink pilot.
 |
| Setup to countersink the front and rear spar flange holes |
 |
| 2x6 used to add support behind the hole being countersunk. Hole spacing in this piece matches the hole spacing in the spar to minimize the number of times I need to move this piece along the spar |
In all, there are 492 holes that need to be countersunk in the spars. This took a while, but all countersunk holes turned out well. I had to be careful on the holes at the ends of the flanges as there was less support for the countersink cage. I also taped over the gaps between the spar and spar doubler, as I was countersinking the holes in those areas, to avoid aluminum chips getting caught and stuck in the narrow spaces.
 |
| Spar flange hole countersinking complete. Time to rivet! |
Build Hints
- Ensure that the spars are adequately supported while countersinking. Clamping and supporting the drilling area is very important to ensure consistency of countersinking.
- Tape over any gaps where drilled aluminum chips may fall into and get stuck.
Time Taken: 6.3 hours
Dates: September 23 - September 28 2022
Horizontal Stabilizer Total Time: 52.3 hours
RV-10 Build Total Time: 128.3 hours
Priming Total Time: 15.8 hours (not included in build time totals)