Staget 4:: Buildingil i thet Empennage
As you did with the ailerons on the lower wing, the horizontal stabilizer and the ver- tical stabilizer (or fin) will be built with the elevator and the rudder attached and then cut loose. Reference Figures 4/1 through 4/5 while you construct them on full-size Plan D02.
PARTS LIST FOR STAGE 4:
WP3673-24 | Leading edge brace | 2 | 5/64 x 5/64 wood strips |
WP3680-24 | Diagonal brace | 2 | 3/64 x 3/64 wood strips |
WP3688-24 | Fin attachment supports | 2 | .02 x 5/64 wood strips |
WP40264 | Elevator pivot rod | 1 | 5/64 x 5 1/2 brass rod |
WP40264 | Rudder pivot rod | 1 | 5/64 x 2 1/4 brass rod |
WP3202-40 | Stabilizer rim (laminated) | 5 | .02 x 5/32 Tanganyika wood strips |
WP1860 | Hinges | 6 | 1/4” aluminum tape strips |
WP3631-24 | Stabilizer & elevator spars | 2 | 1/8 x 1/8 wood strips ñ special prep |
WP3660-24 | Elevator brace | 1 | 3/64 x 1/8 wood strip |
WP3673-24 | Fin braces | 2 | 5/64 x 5/64 wood strips |
WP3688-24 | Ribs | 14 | .02 x 5/64 wood strips |
Ni28-062 | Control horns | 2 | Britannia metal |
WP3202-40 | Rudder rim (laminated) | 5 | .02 x 5/32 Tanganyika wood strips |
WP3673-24 | Vertical brace | 1 | 5/64 x 5/64 wood strip |
WP3660-24 | Vertical brace | 1 | 3/64 x 1/8 wood strip |
WP3631-24 | Rudder post & main spar | 2 | 1/8 x 1/8 wood strips ñ special prep |
J006 | Stabilizer/elevator jig | 1 | laser-cut wood part 5/32 thick |
J007 | Fin/rudder jig | 1 | laser-cut wood part 5/32 thick |
Stabilizer and elevator:
This one is the real test of your bent lamination skill. The stabilizer rim is a continu- ous lamination that runs completely around both the stabilizer and the elevator. This ulti- mately will give you the leading edge of the stabilizer and the trailing edge of the ele- vator. Laminate the stabilizer rim using five Tanganyika wood strips(WP3202-40) against jig J006 to form the correct shape. Make sure the glue is completely dry before you unpin the shape from the jig.
Cut to length and glue in the stabilizer and elevator spars using 3x3mm wood strips(WP3631-24). These require special preparation before attaching. One face must be grooved into a shallow ìCî channel that will locate the pivot rod(WP40264) when the grooved sides face each other. See Plan D02. The easiest way to cut the groove is to score it the length of the strip with a razor saw, then to file the channel with a round rif- fler. The angle of the file end of a riffler to the center handle makes it easier to keep your hand out of the way. It is important that the pivot rod not be completely enclosed when sandwiched between these spars, otherwise the elevator will not operate.
The elevator brace is made from 1x3mm wood strip(WP3660-24), the fin braces and the leading edge brace from 2x2mm wood strip(WP3673-24). Next add wood strips(WP3688-24) to create the topside ribs in an airfoil contour. Turn the assembly over and glue on the underside ribs, then add the two fin attachment supports from wood strips(WP3688-24). When all is dry, saw through the rim and ribs where indicated in Figure 4/3 to separate the elevator from the stabilizer.
Referring to full-size Plan D02 and Figure 4/4, cut four dadoes into the elevator spar to clear the outside of the elevator hinges. Next, glue the elevator pivot rod(WP40264) into the groove of the elevator spar. Locate and attach the control horn(Ni28-062) to the
center of the elevator leading edge. Finally, cut the indicated lengths from the 1/4” aluminum tape(WP1860). Carefully fold the strip lengthwise in half, adhesive side inside, then trim to 3/16” wide and bend the hinges. They pass through the slot created by gluing the pivot rod to the elevator spar and are glued around the sta- bilizer spar only.
Fin and rudder:
The procedure for constructing the fin and rudder is essentially the same as for the stabilizer and elevator. Especial care must be taken in building the fin because the elevator control horn must later be located within this structure.
Begin by forming the rim from five wood strips(WP3202-40) around jig J007. Prepare the rudder post and main spar(WP3631-24) with a groove, as you did for the stabilizer and elevator spars. Glue these in place, making sure the grooves face each other. Make the leading edge brace from WP3673-24, vertical braces from WP3673-24 and WP3660-24 as indicated, and diagonal braces from WP3680-24. Complete this step by adding the ribs from WP3688-241 to achieve a like curvature on both sides. Note how the ribs are paired on both sides of the horizontal joint between the fin and the rudder (Plan D02).
Referring to full-size Plan D02, saw the rudder from the fin and cut two dadoes into the rudder spar. Attach the rudder pivot rod(WP40264) to the rudder spar and make hinges from the aluminum tape(WP1860) the same way you did for the elevator. Finally, locate and attach the control horn(Ni28-062) to the rudder.
