Chapter 5: Fuselage Sides


My camera decided to bite the dust at the start of Chapter 5 so I don't have any pictures of the sides going together. I followed the plans exactly with the exception of attaching the side foam to the jigs.

My Fuselage Side Weights:

Port

10.6 lbs

Starboard

11.1 lbs

 

Step 1 – Jigs and Top Longerons

I saved some time in Chapter 5 by borrowing Bil Kleb's fuselage jigs he borrowed from someone else. It saves lots of time when you can reuse someone else's stuff. Bil and Mary Kleb are building an AeroCozy and they live only 15 minutes from my house. They're rocket scientists, too.

I should have moved the F28 upper longeron doubler back a half inch or so to correspond to F28 being mounted at 6.25 inches from F22 to provide enough room for mounting the canard wing.  A lot of builders find out later that they have to move their F28 bulkhead back a bit to make room for the trailing edge of the canard.

Steps 2-3 – Fuselage Side Forms, Contouring the Insides, Glassing the Inside Layups

Instead of mounting the fuselage jigs directly to the table, I made two "jig boxes" by mounting the FJA's through FJE's onto 1-inch pine stringers and closing off the ends with 5-inch pine boards (16 inches wide). In this manner, I had two jig boxes that I could bolt onto the table or unbolt and remove from the table at will. I drilled reference holes at all four corners of both jig boxes so that I could always repeat the side-by-side setup as shown in the plans.

Be careful when nailing the masonite to the side jigs.  It's everyone's natural tendency to nail the masonite flat against the jigs. If you do this, the masonite takes on a funky, convexed bend in lower, aft areas where the landing gear bulkheads will be. This is my theory why some builders are horrified when their LG bulkheads don't fit against the sides when assembling the fuselage in Chapter 6.   What I did to "correct" this was to renail everything aft of the A jigs. (The masonite can be nailed flat to the A jigs. There's no much vertical curvature there.) Beginning with the B, D, C, and E jigs, the masonite touches only at the corners and does not lay flush against the top surface of the C and E jigs.  You’ll end up driving the nails into the inside corners of the jigs.  I was rewarded later in Chapter 6 as all my bulkheads fit perfectly.

Not wanting to face the prospect of repairing/filling holes left from the 5-minute glue, I used dry-wall screws to hold the foam sides to the masonite. After cutting the masonite sides, I drilled a series of small holes, checkerboard style, one every 18 inches or so. I also drilled holes on the perimeter every 6 inches or so. With the jigs being supported off the edge of the table, I put the foam sides onto the top of the jig, then screwed in the drywall screws from the underside of the masonite.  I tried using double-sided carpet tape, but the foam didn't stick. The archives say that some people are having success using double-sided grip tape, the kind used to secure grips to golf clubs. It didn’t work for me. L  Anyway, the drywall screws were well worth the effort! When I released the sides from the jigs, there were no holes or torn foam of any kind. No repairs. The holes left from the dry-wall screws are so small that there's really nothing there to fill. And it didn't take but maybe 30 minutes longer to set up the jigs. 30 minutes seems like a good investment of time when one considers the amount of time needed to fill gouges from the 5-minute glue, not to mention the fill and sand, finishing work needed 6 years (??) from now on the exterior layups. (I know, I know...some of you out there were lucky enough not to have problems with the 5-minute glue method. My hat's off to you!)

Step 4 – Installing the Upper Longerons

If you've never handled long strips of UND cloth, you're in for a big surprise when doing the 4-UND upper longeron layups. Once the selvage edge is cut, the stuff unravels and single strands get all over the place. I wish I knew then what I know now about handling strips of UND cloth. Now, I first press down strips of masking tape onto the cloth, then cut through the middle of the masking tape. I wet out the strips, then trim the tape off.

I didn't radius the corners of the upper longerons and had a helluva time getting the 4-UND upper longeron layups to stick at the corners. Yeah, Chapter 3 says to radius all corners at least 3/16th inch for UND, but that applies when the fibers are at 90 degrees. On the upper longeron layup, the fibers are running at zero degrees. Still, do yourself a favor and radius the corners just enough to get the UND to lay down properly. Else, you'll be out there every hour like I was tacking the corners down until cure.

Step 5 – Installing the Lower Longerons

I found it hard to hold the triangular longerons in place with clamps alone.  Instead, I used drywall screws to hold them in place.  I predrilled the lower longerons deep enough to get enough screw threads to hold the longerons in place. In some places, especially in the curvy sections, I had to drill a deeper hole so as to apply enough hold-down force to get the lower longeron to screw down and sit properly onto the foam spacers. The way I did this was to dry fit everything before microing or floxing. With one hand, I held everything is position (PVC, spacer, lower longeron). With the other hand, I drilled from the bottom through the masonite, PVC, spacer, and then into the longeron. Then I put the screw in. I repeated this about every 6 inches. After I was happy, I disassembled everything, micro'd, and reassembled.


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