4
Horizontal Tailplane
The horizontal tailplane is to be built directly on the plan protected with
a clear plastic film in similar manner as the wing. Pin down the spruce
trailing edge (3x5x405 mm)
11
overlapping on both two ends. Glue the
balsa centre plate (3 mm – 30x80 mm)
13
to the trailing edge
11
. Glue the
spruce leading edges (3x5x197 mm)
10
to the centre plate and pin them
down overlapping on both two ends. Cut to size and glue in place the dia-
gonal ribs
12
made of 3x5 mm balsa stick. Start with the outer diagonal
ribs first; then proceed towards the centre of the horizontal tailplane.
Glue the spruce main spar
14
(3x5x395 mm) to the top of the horizontal
tailplane framework. Fit and glue the front balsa upper plate
16
(3 mm
– 30x30 mm) and two rear plates (3 mm – 13.5x45 mm)
17
. Align the
outer edges of the plates
17
to match the bottom plate
13
leaving about
2.5 mm slot between them to fit the bamboo dowel
18
later. Sand the
gussets
15
to fit and glue them in place.
Once the glue has cured thoroughly, remove the horizontal tailplane from
the building plan. With a sanding block, shape the tips and centre plates as
indicated on the plans (
Det. A-A
). Round the leading and trailing edges and
the tips (
Det. A-A
). The horizontal tailplane has been finished for now; once
covered with the tissue, glue the bamboo dowel (Φ2.5x50 mm)
18
between
the plates
17
extending behind the trailing edge by 15 mm.
Fuselage and Fin
The fuselage consists of the tail boom made of spruce sticks and balsa
blocks and the front fuselage block made of Ceiba plywood with poplar
plywood side covers offering enough space for the ballast and timer (if
you decided to install one).
Start with the tail boom; glue it on the building board in order to make
the tail boom true and straight. Glue the front balsa block
20
to the
spruce stick (2x8x600 mm)
22
taking care the outer edges of the block
matched the edges of the stick. Note – the rear balsa block
21
will be
glued to the bevelled side of the front block later. Now apply glue to the
rear part of the spruce stick
22
and block
20
; attach the rear balsa block
21
matching the edges of the stick. Glue the other 2x8 mm spruce stick
23
to the tail boom.
If you consider installing a timer (either mechanic or electronic) and
dethermalizer, now it is the time to trim the openings in the fuselage
block
24
as needed. Do not forget to cut appropriate opening in one of
the side covers (
26
or
28
) as well.
Insert the tail boom in the notch in the fuselage block
24
. Trim the notch
if necessary. Remove the tail boom, apply a generous coat of glue into the
notch and insert the tail boom. Glue it on the building board in order to
make the fuselage true and straight.
Insert the two beech dowels
25
(Φ4x32 mm) into the fuselage – no glue
yet; the dowels will help with the correct alignment of the side covers.
Apply glue to the left side of the fuselage block; align and attach the side
cover
26
. You can lay the fuselage down onto your building board and
weigh the cover down to cure. Insert and glue the main ballast
27
into
the nose opening. Glue the other side cover
28
in place.
Glue the reinforcement plate
30
into the fin
29
. Make the front horizontal
tailplane seat: Glue the spruce stick (3x5x25 mm)
32
to the plywood plate
(1 mm - 25x15 mm)
31
.
Mark the position of the tailplane seat to the fuselage according to the
building plan and glue it to the tail boom. Lay the horizontal tailplane
down on the seat in order to check the tailplane was square to the fusel-
age sides (when looking from the nose to the tail) and also square to the
longitudinal axis of the fuselage (when looking from above). Glue the rear
tailplane seat (balsa 1.5 mm – 8x10 mm)
33
to the fuselage. Glue the fin
29
to the fuselage. Use the horizontal tailplane as a reference again; the
fin has to be square to the horizontal tailplane and exactly in the longi-
tudinal axis of the fuselage. Round the leading and trailing edges of the
rudder
52
; the brass rudder hinges
45
will be installed after dopind and
covering of the model.
Now glue the plywood wing seat plate
36
. Keep it centred and square to
the side of the fuselage.
Glue the beech wing hold-down dowels
25
into the fuselage. Mark the
position of the holes for the horizontal tailplane hold-down dowels
34
and
35
(bamboo Φ2.5x25 mm) and glue them in place. Glue the balsa
bottom fin
37
to the fuselage.
Doping and Tissue Covering
Lightly sand the entire airframe with the fine sand paper. Before the
frames are covered, all EXTERNAL surfaces MUST be primed with the ad-
hesive dope (diluted at least 1:1 with the thinner; the dope must have the
viscosity of water - never use the dope unthinned!). Use a soft flat brush
to apply the dope and, when dry, lightly sand all doped surfaces with the
fine sandpaper. Apply the second coat, sand lightly again.
Sheets of the Vlies covering tissue are supplied in the kit. You can glue
it to the airframe using water thinned white glue or clear dope. Always
align the „grain“ of the tissue the long way - from tip to tip of the wing
or horizontal tailplane.
Horizontal Tailplane:
If you are new to the dope and tissue business,
you should start with the horizontal tailplane in order to gain the skills on
smaller part of your model featuring no curves. Cut a piece of the tissue 10
mm oversized all around the outline of the horizontal tailplane. Apply the
thinned white glue or adhesive dope around the external edges of the lower
side of the tailplane and to the diagonal ribs and centre plate; IMMEDIATELY
set the tissue in position and smooth the edges with finger tips before it has
a chance to dry. Cut the tissue all around the outline of the tailplane leaving
it 4-5 mm over size. Bend and glue with thinned white glue or clear dope the
overlapping tissue around the entire tailplane.
Cover the upper side of the tailplane in the same manner – apply thinned
white glue/adhesive dope to the trailing and leading edges, main spar,
centre plates and tips. Do not apply the glue to the diagonal ribs!
Wing:
Cut four or six pieces (a skilled builder could cover the entire bo-
ttom side of the wing using just one long strip of tissue; the upper side of
the wing centre section and wing panels are to be covered by separate
strips) of the tissue 10 mm oversized all around the outline (do not forget
the upper sheets have to be wider due to the airfoil camber). Again, start
with the bottom side of the wing – apply the glue/dope to the leading
and trailing edges and all ribs, attach the tissue and smooth the edges
with finger tips. Cut the tissue all around the outline of the wing leaving
it 4-5 mm over size. Bend and glue with thinned white glue or adhesive
dope the overlapping tissue around edges of the entire wing. You will
have to cut the tissue against the wing panels joints and in short 4-8 mm
portions around the wing tip in order to follow the curve of the tip.
Cover the upper side of the wing centre section in the same manner (the
tissue overlapping over the wing panel root ribs
47
) – apply thinned
white glue/adhesive dope to the trailing and leading edges, main spar
and ribs.
Cover the wing panels with separate strips of tissue; attach the tissue to
the rib, using a pencil and steel ruler or a piece of flexible plastic draw
the line marking the joint of
5
and
47
ribs on the tissue. Trim the tissue
to the line and glue in place in the usual manner. You will have to cut the
tissue in short 4-8 mm portions around the wing tip in order to follow
the curve of the tip.
