Good and bad
One thing that any structures guy can always appreciate is new structure; installing rivets in new holes can be waaaaay nicer than trying to drive a rivet into a hole that has been drilled out by 1000 numpties. The bad thing about new holes is that (in our case anyway), you need to drill them all! Not only that, but each hole needs to be laid out with respect to the manufacturers specifications and standard practice, then drilled (at least once), then deburred, and in many cases countersunk or dimpled even before you drive a single rivet.
On average, the Typhoon stringers have 2 rivets per inch of length. When you multiply this by the amount of stringer material between frame A aft to the transport joint, you get approximately 5,876 rivets. This figure doesn’t include frame rivets, other structural rivets, or any structure forward of frame A through to the monocoque. My best guess is that we will be close to twice this number for the full mono section.
While moving forward with skin installation for JP843, the first step was actually to finish up the doubler plates and reinforcing for frame A. These frame components all have flanges on the outer edges of the frame, and therefore dictate some of the rivet spacing on the skin. Drilling these through the skin would result in bad fastener edge distances and all sorts of other issues.
I didn’t count any of these holes!
With these holes drilled, I was able to start fitting the bottom skin sections to the fixture, a tricky process with these thin sheets being over 12 feet long. Having the curve rolled into the sheet helped, and so did a second set of hands (my Dad) and many cleco clamps.
While it is great to see this new change to the structure, it is a slow process. The skin you see here has been fit and removed 7 times for various work!
Re-building the monocoque section from data is very much like prototyping would have been for the first Typhoons; the first of each part needs to be carefully fit and trimmed to ensure that there are no interference issues. As each part is fitted, slight changes can be made to the production of parts or the assembly procedures, and after a few machines have come off the assembly line, things would be moving fairly smoothly…. until the engineers change something that is.
I’m currently working on the same skin for the port side…. like eating an elephant!
P.S. Can you spot my mistake with skin orientation in the last image?