Goldberg "Gas Bird" Construction Project Session #9

By Tommy Gray
AMA 17063

Since last time I have started working on the pylon.  Last time, I added the sheeting in between the front stringers and cross pieces so that the pylon could be mounted.  I began by adding the vertical plywood pylon support.  Sorry, I do not have a picture of it by itself.  My camera batteries died again and I did not have any replacements handy (gotta stop leaving the thing turned on when it is plugged into the computer!!).  The first picture I have is of the pylon framed up.

Here, you can see that I have added the precut top, front, and rear pieces, and also the ply vertical brace that came with the kit.  I also took some scrap 1/8" balsa and cut out some ribs for the pylon.  There were none in the kit so I had to freehand them according to the plan picture.  The only thing that gave me any idea of how the ribs should be shaped is the curvature of the pylon side sheeting in the picture, where it meets the fuselage at the bottom.  I made an educated guess and as you can see in the picture below, I managed to get the ribs cut and installed.

In the next picture you can see how the pylon is attached to the structure.  There is more to it than just being glued to the top of the fuselage.  The ply center brace straddles the top longeron, and goes through the sheeting, where it is glued to an internal brace of 1/4" balsa.  This securely attaches it to the structure.  I did this before I added the rest of the pylon pieces.

Next, I glued some pieces of firm 1/16" balsa into a one-piece side panel.  I made them for both sides, gluing them with Aliphatic resin glue and letting them sit  with a weight on them overnight to get them pressed out straight and ready for use.  I then sanded the pieces with a sanding block to smooth out the glue seams, and we are ready to start sheeting the pylon sides.

I sanded a curve into the bottom of the side sheeting so that when it was pressed against the pylon, it would mount flush with the fuselage side sheeting, and still follow the curvature of the pylon ribs.

I put some slow, thick CA glue on one side of the structure and held the sheet panel in place until the glue setup, which only took about 30-45 seconds.  I then cut out the excess balsa and securely glued it all the way around for a final fit. Once dry and roughed out, I did the same for the other side.

  Here you can see the right side with the roughly cut panel in place.

Here is the left side with the sheeting roughly cut to size.

.I added a small amount of balsa colored filler to the fuselage/side panel joint to cover up the tiny glue seam.  When sanded it should be almost invisible.

Well, that is all for today.

More to come....Tommy!

 Click Here to go to the next page (10)....