This week we have been riveting, bolting and reaming the large bulkheads in the mid-fuselage section of the plane. These are huge, heavy bits of metal which take most of the load once the wings attach.
They are also the anchors to which a lot of the internal structure of the fuselage attaches, so once they are prepared there are a lot of ribs, stringers and other parts that get riveted onto them.
The variety and density of rivets, bolts and other hardware is like nothing we’ve seen so far in the kit – almost every hole is a slightly different size and with a slightly different purpose. We’ve had to be very careful reading the instructions as it can get very confusing very quickly if you aren’t absolutely sure which holes you’re supposed to be focusing on at any given time.
It’s made even more exciting by the fact that some holes are left open for now until another part or set of parts is ready to attach to the bulkheads later on in the kit…we already had a couple of drill-outs as we thought we’d figured out the pattern, only to find out when we counted that we’d got rivets where they shouldn’t be. This is definitely not a section of the kit to rush!
The reaming process is basically to enlarge the holes slightly using a special type of drill bit that gives a neater finish and a more accurate result than a standard drill.
Where possible, given the level of precision required, we have been using a drill press to do any reaming. For these parts, however, we’ve had to do some by hand as the part is simply too big or the wrong shape to fit in the press.
Reaming by hand is definitely two-person job, as one has to hold the drill and the other one looks at the parts and drill bit in various planes and gives instructions about how to move it around. The instructions also recommend lubricating the tool with oil to help with cooling – this seems to work well in moderation, but if you overdo it, you end up with a fair amount of it on your face and clothes when you switch on the drill (ask me how I know…).
The bulkheads are satisfyingly solid once everything is attached – as J says, “we could hang a truck off that”. We won’t be hanging a truck off it but we do hope to hang most of an aerobatic aircraft off it, so it’s just as well really!
We’ve also made progress with another pile of deburring, so hopefully we will have enough for another priming session next week 🙂
The kit seems to be coming together really well, but I’m slowing accepting that the house has probably disappeared for good – the spare bed vanished under the floor section about a month ago, and the sofa is currently a repository for side skins…