PT-20 Build – The Wings

Posted on March 31, 2013 by John

The plans say this wing will build itself – that’s closer to true than I might have imagined! It quite literally took more time to pop the die-cut ribs out of their sheets and clean them up along with the leading and trailing edges than it did to build BOTH halves of this wing.

PT-20 Wing - removing from plans

PT-20 Wing – removing from plans

In the picture above you can see the construction is very straightforward… once you get the center spar pinned down and the rib webbing pressed into it, the ribs just slide into the notches in the web. Next, press fit the top spar onto the web, trapping the ribs. Align the trailing edge and ribs, glue. Repeat for the leading edge. Just make sure you keep everything flat as you go! Got it all lined up? CA does the rest.

PT-20 Wing Centerline Mating Surfaces

PT-20 Wing Centerline Mating Surfaces

Because I am building the “B” sport wing, I used the dihedral gauge to mark the proper angle and then used a razor saw to cut the LE, TE and Center spars/webbing along that mark – keeping in mind that the cut (front to back) needed to be 90 degrees to these parts. You’ll need to get this correct the first time because you don’t get much of a 2nd chance with it. You can see, I got pretty close – hopefully some careful sanding will get these closer to perfect.

PT-20 Wing - mock join

PT-20 Wing – before joining