Wing doublers (4)

4 hours

I haven't touched the wings in ages, but my parents were visiting so I thought we could knock out a task that would take an extra set of hands.

There's a doubler for each wing, and I drilled all the holes back when I built the wings.  However, before they're riveted on they need to be trimmed to leave an appropriate gap along the sides of the fuselage.  The fuselage didn't exist the last time I worked on them!

Anyway, we rolled the plane into the driveway and installed the wings.  One thing I noticed was the Sonex instructions for installing the wings have you start with the right wing and insert the main pins back to front.  This works with the seat and/or floor removed, but once it's all closed up I won't have any access to the back side of the spar tunnel.  So I think for the B model we need to start with the left wing and insert the pins from the front.

We put the wings on and then started working on fitting the doublers.  I've seen a few methods online for clecoing the doubler on one row of holes over, and then making a jig to hold against the fuselage side and trace a line.  When cut to the line, theoretically the doubler will end up trimmed correctly once moved over to the correct row of holes.  I started down this path, but I realized that the row of holes closest to the fuselage and the next row over didn't seem to be exactly parallel.  Or at least the distance between rows was slightly different on the top and bottom, and forward and aft of the main spar.  I concluded it was too complicated to try and get a perfect line drawn without having the parts in their final locations.

My plan is to use the Van's wing root gasket anyway, which calls for a 3/16" gap between the edge of the wing and the fuselage.  That's a fairly big gap so it was easy enough to sneak up on it.  So what I did was cleco the doublers in place one row over, and trace an approximate line at a distance from the fuselage that I calculated would allow me to install the doublers in the right place without interfering with the fuselage.

I cut to that line, and then I was able to install both doublers in their final position.  Then it was easy to just create a jig to trace a new line exactly 3/16" away from the fuselage all the way around.  I cut to that line and that was it!

Here's what the Van's gasket looks like.  It's like a lower case 'h'.  I checked that a 3/16" gap would work and it looked about right.

Couple more pictures of the plane with the wings on before we put everything away.

It was starting to get dark by the time we were done so we called it a day and stashed everything back in the garage.  I'll rivet the doublers on later!