Today I made scrap aluminum. Lots of it! The F-996C (Drawing 38) is a simple part to make. It's just a piece of angle cut to length with various angles and holes. I made a left and a right version based on the drawings, set them in place, and immediately saw that the holes were way off. I checked and double checked. I did everything correctly, but there was no way anything was going to match up with the pre-existing holes in the skins and longerons. I had always heard people talk about the fact that they had to make these pieces multiple times, but I had never really grasped why. Well, it turns out the dimensions shown on the plans are wrong, that's why! It's a bit puzzling why Van's would rather answer questions over and over about these parts for the past 20 years instead of take the 10 minutes to update the dimensions.
With my first two attempts in the scrap bin, I started attempt three. I just cut the angle to size and then decided to match drill the first hole with it clamped in place on the skin. While this went okay, the hole ended up very close to the end of the piece (the hole is drilled to #30 right now, but will be enlarged to 3/16" later, making the edge distance even worse). I was already three deep at this point, so figured why not try for number four! I cut another angle (not taking the time to make the beveled sides yet) and was very slow about sneaking up on the length - I made it as long as it could possibly be and still slide in between the two longerons it perches on. I drilled the pilot hole, and sure enough, the edge distance was still pretty bad. I'm fairly certain there is no physical way to get the hole any further away from the edge since it is matching the holes already put in place on the longerons/skins. After four attempts, I wasn't seeing straight, so I decided to just move on. I emailed Van's to ask them what the story is. Not only are the drawing dimensions wrong, but there are actually call-outs in the instructions that contradict some notes in the drawings. We'll see what they have to say. I've looked at a lot of pictures of other builds today, and as far as I can tell, that hole that is super close to the end of the piece is just the way it is. Since this is a reinforcing piece for ultimately bolting on the front tank bracket from the wing, I figured pausing and checking with Van's is the way to go though. The good news is, when I bought the used wing kit, he had apparently ordered two extra longerons (those super long ones that I bent for the fuselage). Messing up a 20 foot longeron comes with super expensive shipping, so a lot of people order extras just in case. Since I got my longerons right on the first try, I now have a whole lot of angle left over to play with. Thankfully it's the same size as what is needed for this 996C piece. So I can make this over and over until I'm happy with it.
