Another day, another run at the cowl. First thing was to get the cowl-side top hinges on so I could drill the top cowl to them. This is one of those times where fit is critical, because an error here multiplies itself all over the place.
This is the arrangement I came up with to lock the hinges in place as best I could. On the relatively flat part, I used the 1/8″ aluminum pin that came with the hinges to minimize the slop, driving it in until it couldn’t get past the curved parts on the outboard end. With this set up, I measured 1″ back from the center of the hole on the firewall flange which put the hole right in the middle of the hinge meat. These things are going to take a crapload of vibration, so it’s important that the fastener loads are spread as well as possible.
With the top cowl in place, I drilled where I’d marked. I was doing three on each side until I got down to the tight-radius bend, where at that point, it really didn’t matter, because nothing was going anywhere with most of the clecos in place.
With all these guys drilled, I made the hinge pins from the .090 stainless steel provided in the kit, with 90 degree bends at the center ends, and some loops to zip-tie together. The plans say FA about securing these, so I consulted VAF again, and was given several options, one of which was the above solution. Simple, elegant, safe. I like it. I also had to taper the outboard ends of the pins so they could find their way into the eyes of the hinges. Getting them to go all the way down the length of the hinge is kind of a chore, but after a few tries, I got the knack of it, and now they insert and remove pretty easily, and the cowl doesn’t move around at all.
After that, I figured what the hell, I’ll try to fit the lower cowling. This didn’t work out so well, because it’s really big, really awkward, and I need to make cutouts for the landing gear. The idea is you’re supposed to suspend the thing below the top cowl, make everything fit, then drill the hinges. The prop is a bit of an obstacle, but it’s not too bad, what’s vexing me right now is the cutouts for the landing gear. I don’t want to eyeball it and take off too much fiberglass, because I don’t want to have to build it back up later. As usual, it’s always easier to remove material than to put it back. I might need some help on that one, but once that’s done, fitting and trimming the lower cowl shouldn’t be too hard. I also have to do the oil door, which I might get into this week. with the lower cowl on, the oil door is the only access to the area inside the cowl.