KOR MODEL Zlin Z-37A Cmelak Assembly Instructions Manual

Zlín Z-37A Čmelák ("Bumblebee”) -

1 530mm

Assembly Instructions and recommended equipment of the RC model

2

Parts needed for the finishing of the model:
Carbon Strip (stringer) - 5x0,6 mm 3 pc

Pushrod connectors (linkage stoppers) 6 pc

Adhesives:

 Cyanoacrylate (CA) glue (super glue) thin +

medium

 Activator (Kicker) for Cyanoacrylate glue
 Polyurethane (PU) glue (e.g. Ponal PUR glue in

bottle or UHU PU MAX in bottle or Purex Rapid)

 Epoxy

Technical information:

Wingspan: 1530 mm
Overall Length: 920 mm
Flying weight: ~1 700g
RC Functions: Rudder, elevator, ailerons, motor (throttle), flaps (optional: spreading unit activation)

Recommended equipment:
Brushless motor: Turnigy 3639 1100kv (~500W) 1 pc
+ shaft extension (~70 mm long) 1 pc
Electronic Speed Controller (ESC): 40 A 1 pc
Propeller: APC 13x4“ + Propeller adapter 1 pc
Servos: 20 grams with Metal Gear 6 pc
Battery: 3S Li-pol 2700-3000 mAh
Receiver: minimum 5 channels

Parts included in the set:

Fuselage parts 4 pc
Center section of the wing with flaps 1 pc
Outer Wing parts with flaps (Left + right) 2 pc
Outer Wing parts with ailerons (Left + right) 2 pc
Engine cowling 1 pc
Engine shutter – 3D printed part 1 pc
Walking grid – 3D printed part 1 pc
Tail group (empennage) 3 pc
Plastic nuts + screws 2+2 pc
Plywood plate 1 pc
Main Landing gear wire (Left + right) 2 pc
Tail Landing gear wire 1 pc
Main Landing gear plastic covers 2 pc
Tail Landing gear plastic cover 1 pc
Main Landing gear wheels 2 pc
Tail Landing gear wheel 1 pc

Steel wire for pushrods (ø 1 mm) 1 pc
Wheel stop collars ø 4 mm 2 pc
Wheel stop collar ø 2 mm 1 pc

Foil for windscreen & windows 3 pc
Plastic tubes for landing gear braces
Set of Fiberglass parts (engine bulkheads, control horns, hinge levers)

Tools needed to assemble the model:

A sharp knife or scalpel, pins, drywall sanding mesh, steel ruler, soldering iron, paint (water based,
synthetic or color sprays: Montana, Duplicolor, PrismaColor…) and common modelling tools.

All parts are glued with super glue (CA), unless stated otherwise.
Before starting the assembly, read carefully the Assembly Instructions!

3

Assembly procedure:

(If you purchased a spreader unit along with the model and you want to spread, remember to create
the space in the fuselage behind the cockpit – hopper (spreader material reservoir). It can be made
later as well, but it will be more difficult.

When assembling the fuselage, some weight can be saved by making the rear fuselage lighter - by
scooping out material, this can avoid additional weight in the front. It must be noted, however, that this
may affect the durability of the model. We recommend leaving a wall that is at least 15-20 mm thick.
The electronics will be located inside the fuselage above the wing, the battery and Electronic Speed
Controller (ESC) between the wing and the engine mount.

Wing:

(The wing is attached to the fuselage by two screws and dowels).
All larger EPP (Extruded Poly-Propylene) parts are to be glued by the following procedure:
Apply the PU glue to one of the surfaces to be joined and only in the center of the part, approx. 8-10

mm from the outside perimeter of the part shall not be covered with the PU glue to avoid the PU glue
foaming out of the surface and making the joint less attractive. Then put both glued parts together,
align them and fix together with pins. When both surfaces match each other, apply thin CA glue to the
whole outside perimeter of the joint. The CA glue prevents the PU glue to foam out of the joint.

First glue the parts of the outboard wing sections together, i.e. glue the part with the aileron to the
coresponding part with the flap cutout. Do this for both outboard wing sections. Then glue both
outboard wing sections to the wing mid section.

4

Make a slot with a sharp knife into the underside of the wing, for the milled fiberglass spars and carbon
stringers, 90 mm from the leading edge at the wingcentre (approx. 60 mm at the wingtips). The bottom
spars have V-Form for the wing dihedral and an eyelet roughly in the center of the bottom side for
mounting of the landing gear. Extend the spars with a 5x0.6mm carbon stringer till the end of the
wings with an approximate overlap of 65 mm on the spars. With the remaining part of the stringer,
connect both spars in the wing mid section.

Cut the slot for the spars and stringers on the upper side of the wing in the same way. (Make the slot
for the spars with a sharp knife and push them in - you can use a small hammer). Level the wing on a
flat surface (table or floor), check the wing is straight and with the same dihedral on both wing tips,
then glue the spars and stringers into the wing with thin CA glue.

"Spread" the spar and carbon stringer joint so that the glue soaks deeper inside.

Level the flap according to the aileron and attach with pins from top (the depth of the wing in the mid
section including the flap is 298 mm).

5

Cut slots at a right angle into the flaps at a distance of 120
mm for the 90° levers creating hinges (shorter inner flaps in
the wing mid section - 130mm distance). Use the extended
levers in the flaps (for flaps control) on the place, where the
wing mid section is joined with the outboard wing section.
Cut slots into the wing for the oposite parts of the hinges,
which have to be glued together according the following
image (push two pieces of wire through the parts, then glue
them together) 

Before gluing all the hinge-levers into the wing and flaps, push a long piece of steel wire through all
hinges of each flap in order to level the hinges and properly align the flaps with the wing. (Check for
ongoing trailing edge and maintaining the shape of the airfoil). Glue all the hinge parts with thin CA.

After you glue the hinges in place, remove the steel wire and clip short pins, about 5 mm long, push
them back into the hinges, and add a drop of thicker CA glue on both sides carefully.

Cut the aileron servos into the wings idealy in front of the stringer and cut a slot for the lever into the
aileron in the servo lever axis. Push the servo cables into a slot made with knife and bring them (along
with the flap servo cables) to the center.

6

Create a "pocket" in the mid wing section from the top of the profile (covered by the fuselage), and
lead all the servo cables from the ailerons and flaps there and add connectors.

In the center of the leading edge of the wing mid section, cut two
vertical slots at a distance of 90 mm for connecting plates ­dowels. Mark the place of the cut according to the counterpart.

Take particular care here !!!

Glue the fiberglass plate for even distribution of screw pressure to the bottom side of the wing profile in
the centre of the wing.