Building the (Old) FLYLINE Great Lakes 2T-1A Kit (10)

Let’s get started on the fuselage. This kit is “old time traditional” in that the fuselage consists of two identical side frames built up of “sticks” (3/16″ sq. balsa) which are subsequently joined by more 3/16″ sq. in the form of crossmembers. Once the basic “box” structure is established, we add formers cut to specific shapes and then stringers and balsa sheet to fill out the shape of the finished fuselage. This is in fact a replication in miniature of the way a great many classic full scale aircraft were built, the difference (other than size) being that the big airplanes were built from welded steel tube.

This is the basic fuselage side frame with all the 3/16″ sq. balsa components cut to size, pinned in place over the plan, and glued. I used thin (fast) cyanoacrylate for this job. Notice that the plan has been covered with a sheet of clear food wrap to prevent the parts sticking to the plan as well as to each other.

This is the side frame at the front end of the opening where the removeable lower wing will eventually be attached. Notice that the ends of the 3/16″ sq. longeron and upright are cut to fit as closely as possible, as are the wing saddle component at the right and the FS1 gusset. These parts are stout enough that I am comfortable using pins directly through the wood to hold the assembly in place.

Once the first side frame is complete, I used a big sanding block to smooth off any rough spots, placed another layer of clear wrap over the complete structure, and layed out the second side directly over it. This is the best way to ensure that both fuselage side frames are exactly alike.

Here both fuselage side frames have been removed from the board. All the pins and clear wrap are gone and I have cleaned up any glue bumps or scraps of film that might have been sticking around. I will smooth the surface of each frame, top and bottom, with a a finer sanding block before going on to assemble them.

Most good plans include a top or bottom projection of the fuselage assembly as a guide to assembly. As is often the case, the upper fuselage longerons of this airplane are flat/straight as viewed from the side and coincide with the structural centerline. We can take advantage of the flat top surface this provides to assemble the fuselage box exactly square in place upside down on the building board.

This is the fuselage box structure as seen from the middle. You can see that the shaped sheet balsa parts that form the lower wing saddle were built in place as part of each side frame and now define the location and angle of the lower wing mounting.

The plywood "F1" former, traditionally referred to as the firewall, defines the structure of the nose and provides a base for the motor mount to come later. In the case of this kit, the firewall was printed on 1/8" plywood stock with adjoining structural member positions marked. I took advantage of this by glueing the printed face to the fuselage box. The original kit, which is intended for a glow engine, shows the firewall without openings. As this is going to be an electric airplane and requires a way for both motor power wires and some cooling air to pass through, I used a Forstner bit to cut a neat opening before finishing the assembly.

Here's the same structure from the front. You can see how the F2 through F4 formers, which are cut from 3/32" balsa sheet, are simply glued to the upper surface of the corresponding crossmembers. It's a good idea to use a square to ensure that each of these formers lies perpendicular to the top longeron, as shown on the plan.