Build your first flying scale Jet - Chapter 7 - Finishing the fuselage

The fuselage spine needs to be cut from a suitable piece of balsa - to get the plan view correct, the shape was cut out from plan and stuck to the block using restickable glue stick.

For stuff like this (and balsa props) I tend to use one of these cheap and cheerful craft knives where you snap off the tip periodically to keep a sharp tip. The blades are quite flexible, and are great for carving if you are using soft wood. Just be careful though and only expose as much blade as you need.

After getting the plan view correct, the profile of the spine was cut from the plan and stuck to the side of the block. Note a little extra has been left at the base to allow for the curvature of the fuselage cross section. The top profile was then shaped to match the pattern.

Here is the block prior to final shaping

The curved cross section was roughly carved, then sanded to shape.

To keep the weight down, the spine was hollowed out. The first stage was to hack out what I could with a knife.

Final material was removed using a rotary grinder in a Dremel multitool (well, actually a cheap Dremel copy I picked up in Woolworths a few years ago!) How thin you go is up to you - the part is under no load, so just try not to make a hole.

Test for fit on the fuselage - you may have to chamfer the edges a little to get a snug fit. When happy, glue into position, and then stick the fin into its slot.

The gap between the spine and the fin is filled with this piece of 1/16" sheet. Fit carefully, and when the glue is dry, sand to blend seamlessly into the surrounding contours. When happy, brush on a couple of coats of sanding sealer to the spine, sanding gently between coats.

The next job is to line the motor trough. I am using ordinary copier paper, but you could use thin balsa sheet if you wanted to. Because the trough does not have a straight run to the rear, but is curved slightly, I chose to add three pieces of paper. The photo shows just the rear two. The shapes were developed by trial and error - you can leave an overlap at the sides to be trimmed later.

Here the rear two pieces of paper have been glued in position using wood glue (less flammable than balsa cement!)

The front piece was a bit of a fiddle as it has to slide in under end of the motor tube. To be honest, the exact section you achieve in this area is not critical - just make sure you have some clearance to the motor tube.

Here is the final trough with the outer edges trimmed using a new scalpel blade. The joins will be covered later when you apply the aluminium lining.

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