iKarus FUN Piccolo Notice De Montage page 23

Basics
speed is reduced; lift is also reduced. However, a motor driven
rotor system generates torque that acts on the helicopter
fuselage, twisting the fuselage in the opposite direction to the
main rotor. This torque is countered by thrust generated by a
smaller rotor on the tail (tail rotor). The blades that comprise
the tail rotor have a certain pitch angle that, when rotating at a
given speed, generate thrust and balance exactly the main
rotor torque. By increasing or decreasing the speed of the tail
rotor-and hence varying the thrust generated, the helicopter
yaws either left or right.
At this point, we have covered two of the functions required to
control a helicopter. The first: height control, via an increase or
decrease in main rotor speed. The second: yaw control, by
speeding up or slowing down the tail rotor. A model helicopter
must also be controlled about two further axes: roll and pitch.
This task is undertaken by the cyclic control system. The
system consists of servos, swashplate, flybar paddles and
main rotor blades.
The servos are connected to the lower swashplate ring. The
upper swashplate ring is connected to the flybar paddles.
When a servo moves, it tilts the swashplate and the control
input is fed by pushrods 'cyclically' up into the main rotor
system. Note that the swashplate is connected (via linkages)
to the flybar and the angle of the paddles is altered as a result.
At this stage, think of a helicopter as a flying disc. The paddles
and blades together actually resemble a disc in flight. The
cyclic controls are responsible for steering the helicopter by
tilting the disc in flight. The disc can be tilted forwards/
backwards or left/right. For example, by pushing the cyclic
stick forward in flight, the disc is tilted forwards and the nose of
the helicopter drops. The cyclic control system can move the
disc forwards, backwards, left or right and hence direct the
helicopter in a very precise way. Two servos are responsible
for cyclic control: one servo for roll control (left and right) and
one for forwards and backwards control (fore and aft).
N.B. The Piccoboard (see below) features an electronic piezo
gyro for stabilization of the yaw axis. This keeps the machine
stable in yaw and hence eases pilot workload considerably.
Included towards the rear of the manual is an exploded view of
the Piccolo. Use this as a guide prior to construction and
during construction. The associated parts list provides useful
descriptions and dimensions (where appropriate) of parts
used.
If you are in any doubt about which parts should be used
during construction, refer to the exploded view and take note
of the descriptions and dimensions of the required parts.
Measure the parts if you are in any doubt.
Be very sparing with both glue and adhesive tape. Every gram
of additional weight will reduce flight time by around four to five
seconds.
The one-piece Piccoboard (not included in kit) electronic
control system has been designed to save a considerable
amount of weight when compared with conventional, heavier
electronic control systems consisting of separate receiver,
controllers, gyro, etc.
The Piccoboard combines all these functions in one compact,
lightweight unit and also removes the need for a tail rotor
servo.
Assembly
Landing gear assembly
First, lightly roughen with sandpaper all areas to be
bonded. Identify the landing gear struts, they are in the
bag with the other small carbon fibre components. The struts
are 4 identical length carbon fibre rods. Use the exploded list
at the back of this manual as an aid to parts identification. Glue
the rear undercarriage struts
illustrated in the diagram. When the glue has cured, clip the
front struts 2 into the chassis and adjust their position so that
the assembly sits level on a table. When satisfied, add a drop
of glue. Finally, add the landing skids 3 and glue them to the
struts. Glue also the carbon fibre canopy mount to the chassis.
Make sure this sits centered on the chassis.
67380
2.
3.
rear view
86 mm
67411
Pls. note that the struts have different lenghts. When taking off
the different lengths compensate the slight vertical turning of
the main rotor axis which occurs due to the side thrust of the
tail rotor and the clockwise rotation of the main blades. Thus
taking off is easier.
1 to the chassis using CA as
67360
1.
67411
67378
67361
3.
80 mm
67378
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