L-19 Bird Dog
Fuselage top forward box section is closed up (above left). Cutouts are for weight saving. The aft fuselage box section (above right), with lightening holes, shows the construction method. Just visible is the pushrod, exiting to the aft left
of the fuselage. Scored and folded top forward decking piece (below left) D1 glued in place. Scored and folded top aft decking piece (below right) D2 glued in place over the cardboard formers.
Add fuselage formers B to the top forward fuselage, adding a 1⁄8×1⁄4-inch stringer down the centerline from A to B. Cover formers A and B with scored and folded decking piece D1. Add formers C through F to the aft fuse- lage, adding a 1⁄2-inch balsa stringer down their centerline. Cover formers C through F with decking piece D2. The cowl is made in two pieces, a fixed up-
per piece glued to the fuselage and a remov- able lower piece for access to the engine. Both upper and lower cowl are built up
from 1⁄2-inch balsa sheet sides and carved to shape. The removable bottom half of the cowl has a 1⁄8-inch ply C1 former glued to the back. The two holes in C1 must align with the blind nuts in the firewall A. Test fit the engine in the cowl and drill mounting holes.
Use a shaft extension to give adequate spin- ner clearance. Cut holes in the cowl block for the cylinder head, exhaust and needle valve. Apply epoxy to the inside of the cowl and front of the firewall. Seal all joints on the fuselage with gummed paper tape. Make the two windshield pieces W1 and
W2 from thin manila folder cardboard with a 1⁄8 × 1⁄4-inch balsa strip with beveled ends
The tail gear strut is bent to shape from 3⁄32-inch wire (above), laid on its 1⁄8- inch ply mounting plate, wrapped with nylon thread and smeared with glue and glued into the fuselage cutout. The cowl (at right) is made from 1⁄2-inch balsa sheet built up and carved to shape. The removable cowl has a 1⁄8-inch ply back which attaches to blind nuts in the rear of the engine 1⁄4-inch ply firewall A.
56 MAY 2012
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