2.1.1 Joining Leading Edge Wing Cores to the Spar

The first step in building a wing is to prep the spar.  The book tells us to sand all four sides to make sure that the mold release compounds are cleaned up.  Here I’ve got the spar on my worktable before the sanding begins.  I use a heavy 36-grit sandpaper on my electric palm sander to clean this up.  Makes for a nice, dusty mess!

Prepping the Left Wing Spar

Once the spar is sanded, I need to make sure that it’s level horizontally.  It helps that my hangar floor is VERY level and that when I built this table, I also made sure that it was level.  Here I am checking level between the two main outboard wing bolt holes, which is the reference point for anything to do with the wings.

It's Level!

Can’t get much closer than that! There’s a point on the spar called the “knee”.  This is where the spar slightly bends. The Velocity has swept wings and this bend in the spar is what helps to set the sweep.  The inboard leading edge foam core (which helps to shape the wing) needs to be set 2” back from the knee, which also happens to be the center point of those two wing bolt holes.

Checking Knee Alignment

The wood blocks you see that are temporarily Bondoed to the spar help to hold the foam cores in position.  The inboard core also needs to be leveled vertically, and here you can see that it is.  Again, the bolt holes are used as a reference point.

Checking for Square

Perfect! I also need to check the wingtip side to make sure that it’s square. I used a plumb bob for that (not shown in the photo).  Since we know that the spar is level, using the plumb bob verifies that the wingtip side is also level. (In fact, I needed to use some thin foam shims to get everything perfectly level and straight, which is typical.)

End Alignment

Finally, all three foam cores are now in place and leveled, so the last thing I need to do is glue them down with a special mixture of Velocipoxy and glass beads (known as Micro).  The leading edge is now glued down.  Next step is the trailing edge.

Aligning the Wing Foam Cores

Click here to see how the trailing edge cores for the left wing are aligned and glued on.

Right Wing Glued and Curing (1)

Here is the completed right wing. Lining up and gluing down the leading edge cores is identical to the left wing. You can see those cores hanging upside down in the photo above. The trailing edge cores presented a bit of a problem for me since the inboard core was miscut at the factory. That’s the one closest to the right side in this photo. Click here for more information about the fix for that problem on the trailing edge.

ui© John Trautschold 2018