Building The Horizontal Stabilizer; Building & Installing The Elevator - Model Airways CURTISS JN-4D JENNY Instruction Manual

joint that intersects with the steel rod.
On the third rib from the top, add the two filler
blocks above and below the rib at the leading
edge. Drill the hole for the control horns.
Finally, glue the two photo-etched copper fit-
tings (R2) for the control horn brace wires
and add the britannia cast control horns (C2).
Since the rudder is so narrow, shorten the
pins on each horn so they both will fit in the
drilled hole. Epoxy the horns in place.
illustrates the assembled rudder.
Figure 2-2
The hinges on the real aircraft rudder
Note:
are very small and so are faked on the model.
1/64" x 1/16" brass strip is provided. Cut slots
in the rudder leading edge, the vertical stabi-
lizer, and the fuselage tailpost for the fake
hinge strips. Also, the control horns are
actually bolted together with four bolts
on the real aircraft.
For now, do not mount the rudder. It is best
installed after the horizontal and vertical stabi-
lizer are glued to the fuselage during Stage 7.

3. Building the Horizontal Stabilizer

The airfoil has a flat bottom, so the stabilizer
can be built directly on the plan. However, it
is suggested that some shims be placed under
the leading and trailing edges to keep the
parts off the plan a bit.
The horizontal stabilizer on the real aircraft
has a steel tubing leading edge. For the model,
it's just a solid steel wire. Bend it to the plan
shape and pin it to the plan. The trailing edge
on the real aircraft is a rabbeted wooden spar.
For the model, two separate pieces are used to
form the rabbet for butting the cap strips. Glue
these together and taper the ends.
The ribs are laser-cut wood parts; the spar and
diagonal stiffening are wood strips. First, add
the vertical web stiffeners in way of lightening
holes to each side of the ribs just like you did on
the wings. Lay down the leading and trailing
edge, then glue the ribs in place. Next, add the
front spar. On the real aircraft this is a continu-
ous spar, but for the model, fit pieces between
the ribs. Make sure they are aligned on each
side of the ribs so they look continuous. The
spar tapers at the end as shown on the plan.
The main spar and the leading edge has some
blocking for U bolts to secure the stabilizer to
the fuselage. When installing the stabilizer
you could dispense with the bolting or install
thin brass or copper wire to represent the
bolts. Your choice.
Install the small chocks at the trailing edge
and in way of the struts under the stabilizer.
Finally, add the diagonal stiffeners that taper.
The upper cap strips can be added while the
stabilizer is still on the plan. Add the lower
cap strips after the stabilizer is removed from
the plan.
You could glue the cap strips top and
Option:
bottom prior to installing the ribs. However,
be sure you extend the strips past the rear end
of the ribs, since the caps lie on the rabbeted
trailing edge.
Cut the slots for the fake hinges in the trail-
ing edge. Add the self-adhesive copper strips
FIG. 2-3 HORIZONTAL STABILIZER ASSEMBLY
CENTERLINE
BOLTING BLOCK
1/16"-DIA. STEEL ROD
LEADING EDGE
SUGGESTED
SHIMS TO
KEEP PARTS
OFF PLAN
CHOCK BLOCK
SUPPORT FOR STRUT
TO FUSELAGE
S2
FIG. 2-4 ELEVATOR ASSEMBLY
CONTROL HORN CASTING C2
(TOP AND BOTTOM)
DRILL HOLE
(TOP AND BOTTOM)
SUPPORT PADS AND
FILLER BLOCKS
SLOTS FOR FAKE HINGE
1/16" X 1/16"
SPLICE WITH
THREAD
1/32"-DIA. STEEL ROD
TRAILING EDGE
at each rib over the leading edge. Install the
brace wire fittings (R1) into the trailing edge
as shown. This completes the horizontal sta-
bilizer. The assembly is shown in
There are two wooden struts from the hori-
zontal stabilizer to the fuselage on each
side. Install these later along with the stabi-
lizer. However, you can make them now and
set aside. The struts are a streamlined sec-
tion and have an R1 fitting in each end.
These fittings are for bolting to the fuselage
and stabilizer. For the model, they can just
be glued.
4. Building & Installing the Elevator
The elevator leading edge is the same cross
section as the horizontal stabilizer trailing
edge. The trailing edge has a short piece of
wood from the leading edge, then has a tube
15
COPPER TAPE AT RIBS AND STIFFENERS
1/32"
S1
3/64" X 5/32"
SPAR – FIT
BETWEEN RIBS
S1
1/32" STIFFENER –
FIT BETWEEN
RIBS
1/16" X 3/32"
BRACE WIRE
FITTINGS R1
"RABBETED" TRAILING EDGE
SLOT FOR FAKE HINGES (BRASS BAR)
LEADING EDGE HAS SAME CROSS SECTION
AS HORIZONTAL STABILIZER TRAILING EDGE
RIB S4
.020" X 1/16"
S3
CAP STRIP
1/32" X 1/32"
S3
1/32" X 1/32"
ROUNDED
TO DOWEL
secured to it for the remaining trailing edge.
On the real aircraft the tubing was either an
oval tubing or a V-shaped bent steel plate.
For the model, you will use a round steel
.
Figure 2-3
rod. At the splice between the steel rod and
wooden section, wrap with black cord.
Ribs are laser-cut and are fitted with cap
strips. Build the elevator like the stabilizer,
over the plan. Install the upper cap strips
while the elevator is on the plan. Add the
blocks in way of the center ribs to provide a
seat for the control cable horns.
Install the tapered diagonal stiffeners and
the stringers. The stringers are located at
the top and bottom of the ribs. Round the
square stock into a dowel, and fit the
stringers between the ribs (or, as an option,
leave them square). You could also use a
continuous stringer and cut notches in the
.020" X 1/16" CAP STRIPS
(TOP AND BOTTOM)
.020" X 1/32" RIB WEB
STIFFENERS – APPLY
BEFORE INSTALLING
RIBS
CHOCK
S1
BLOCKS
1/32" – FIT
BETWEEN RIBS
SUPPORT BLOCKS
.020" PADS ON TOP
AND BOTTOM,
FILLER BLOCKS
IN BETWEEN
RIB CAP STRIPS
1/32" X 1/8"
(SEE FIG. 2-3)
LEFT SIDE SHOWN
(RIGHT SAME TO
OPPOSITE HAND)
BRACING WIRE
FITTING R2
COPPER
TAPE