Just about 5 hours (including a few short breaks) to countersink the holes on the top flange of the right hand main spar. About 308 holes, so roughly 1 per minute. Only about 930 left to go…I’m beginning to see why it takes people over 2,000 hours to build an RV-10!
Steps 2 and 3 on Page 13-3 of the RV-10 Wing plans can be rather confusing as to which holes to countersink. The language seems to be rather precise, and if taken literally, has you looking for holes that aren’t there.
The confusing sentence in Step 2 is
“Machine countersink those rib to spar flange attach rivet holes that are in line with the nutplate attach rivet holes and are inboard of the most outboard fuel tank attach nutplate.”
It’s not a difficult sentence to parse, particularly, and the latter third is quite clear. The first half, however, indicates that there should be some (rib to spar flange attach) holes IN LINE with the nutplate rivet holes. Well, if taken literally, there are NO SUCH HOLES. There are some holes that partially fit the description, but they are not exactly in line with the nutplate rivet holes–but their centerlines are about 1/16″ of an inch aft of the nutplate rivet holes’ centerlines. To someone like me who tends to read things very literally, this sentence has the potential to introduce significant confusion and frustration.
I had read aloud and thought about these steps for FAR too long, and finally decided that someone else surely has had the same confusion. So a simple search on Van’s Air Force Forums produced this gem of a thread, which I recommend to anyone as confused as I was.
A link from that thread, provided by Mike Jimenez, contains some helpful photos.
I came away with a great haul today from Hamilton Tools. I had been looking for a right angle threaded drill attachment and talked to the proprietor of HT a couple of weeks ago. He came up with an ATS attachment, looks well used, but there’s little backlash in the gears, it runs smoothly, and it came in at about 1/3 the cost of a new one.
All in all it came out to $80 for the whole purchase. I love Hamilton Tool!
8hr today on the wing box stiffeners and tank attach nutplate rivet hole countersinking.
Clecoed and final drilled the left win spar extension and associated plates. Deburred. Time 1.75 hrs. Will prime later. Also worked on page 10-22 and completed tail cone top deck installation–1 hr.