Specification
Main rotor diameter:
Tail rotor diameter:
Length:
Height:
Weight:
Introduction
The Crown III model helicopter you have purchased is a
member of the robbe family of helicopter products.
The model is supplied factory-assembled; all you have to do
to complete construction is to install the motor and the
receiving system.
The drawings corresponding to the numbered stages of
construction can be found in the German instructions.
The tools and accessories required to complete the model
are listed on a separate accessory sheet.
Notes on the radio control system:
All the pushrod lengths and servo output arm lengths assu-
me the use of robbe/Futaba servos. If you wish to use other
makes of servo you may need to make allowance by adju-
sting the stated dimensions slightly.
The building instructions are grouped according to the heli-
copter's sub-assemblies, and are divided up in a logical
sequence of stages.
An assembly drawing is included for each stage, showing
how the parts fit together.
Each stage includes supplementary notes and tips which
should be read carefully while you are assembling the model.
Replacement parts
It is vitally important that you use only genuine replacement
parts when required. Pictures of the replacement parts and
the associated numbers are to be found in the appendix to
these instructions. The numbers and descriptions are listed
in the Replacement Parts list on the final page.
Please store these building instructions in a safe place so
that you can refer to them later when maintaining or repairing
approx. 630 mm
your model. The red Quality Control sheet and any other
approx. 142 mm
supplementary sheets in the kit should also be kept safely.
approx. 570 mm
approx. 210 mm
Please state the original Order No. when ordering replace-
min. 545 g
ment parts, as this avoids problems and delays in obtaining
spares. Replacement parts are only available in the stated
sets.
If you think you have cause for complaint, or wish to make a
claim under guarantee, please note that you must state the
Control Number and include proof of purchase.
The electric motor
Read and observe the instructions supplied with the motors
and speed controllers.
Speed controllers must be operated in helicopter mode.
Controlling a model helicopter
The most important feature which differentiates a helicopter
from a fixed-wing aircraft is that its power element - the main
rotor - is also the essential control element.
The helicopter is controlled by varying the settings of both
the main rotor and the tail rotor. The main rotor head inclu-
des what is known as an auxiliary rotor (flybar and paddles)
which transfers the control movements to the main rotor its-
elf.
The swashplate is a sub-assembly mounted on the main
rotor shaft, or mast. It is capable of moving in all directions,
and its purpose is to transfer mechanical control movements
from the servos to the main rotor.
How the swashplate works:
Helicopters are capable of flying forward, backward and to
both sides, and these movements are controlled by tilting
the main rotor in the desired direction.
These movements are generated by varying the pitch angle
Assembly instructions
Crown III
3
of the rotor blades according to their momentary position in
each cycle
= cyclic pitch control
To produce vertical movement in either direction the pitch
angle of the rotor blades is varied simultaneously
= collective pitch control
Four primary functions have to be controlled:
- Climb and descent: „collective pitch, throttle"
The pitch angle of both (all) blades is altered, and at the
same time the throttle setting is changed to deliver the
appropriate level of power to the rotor.
- Roll: „roll-axis"
(movement around the longitudinal axis)
The main rotor plane is tilted to right or left as required
- Pitch: „pitch-axis or forward / back cyclic"
(movement around the lateral axis)
The main rotor plane is tilted forward or back as required
- Yaw: „tail rotor"
(movement around the vertical axis)
The pitch of the tail rotor blades is altered as required
= Use Loctite
Fig. 1
- When working on the motor and speed controller be sure
to read the instructions supplied with the units.
- Solder the connector contacts to the motor wires.
- Fit the pinion on the motor shaft.
- Fit suitable connectors to the motor wires and battery
wires attached to the speed controller.
Figs. 2 and 3
- Fix the motor to the chassis using the screws supplied.
Adjust the gearbox meshing clearance so that the gears
engage fully, but without any trace of binding.
- The pinion and main gear must engage over their full
width; adjust the position of the pinion on the motor shaft
if necessary.
Order No.
S 2610