Glossary
Known in the USA as "hotdogging", 3D is an
impressive style of aerobatic helicopter flying. The name
refers to the fact that many manoeuvres see the model flip
through all three dimensions. The style is growing in
popularity and a standardised competition framework is emerging with international competitions held at the 3D Masters each summer in the UK.
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Cyclic Collective Pitch Mixing. This is what allows the swashplate to control lateral movement of the helicopter (cyclic, or aileron and elevator in fixed-wing terminology) whilst also providing collective control of the main rotor pitch to move the helicopter vertically up or down. All helicopters use
some form of CCPM, either electronic (eCCPM) or mechanical (mCCPM).
However, when the generic term CCPM is used it usually refers to
electronic CCPM.
eCCPM is where the mixing is carried out by either the radio
transmitter or an on-board mixer circuit, and the swashplate is
supported by the same servos that operate the cyclic
functions. These servos provide pitch changes by all
moving together, lifting the swashplate up and down the main
shaft in the process. Servos are commonly arranged around
the swashplate at 90°, 120° or 180° and each arrangement
required a different mixing program. The advantage of
eCCPM is that less components are required, reducing sloppiness
in the control system and simplifying the building and
maintenance process. The disadvantage is that it is
difficult to avoid some interaction between the cyclic and pitch
functions, hence this system is not often used on high end models
that are designed for precision competition flying.
mCCPM uses a separate servo for the pitch linkage which
operates independently of the cyclic functions. Arms and
levers are used to provide the mixing between the cyclic and
pitch functions, and this can be done in many different ways,
with the swashplate either mobile or fixed. This method
uses more components and can be sloppy in low end models, but
the high end models with mCCPM are usually better quality that
most models with eCCPM.
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This is the system we use for transmitter frequency
control. Each of the 36 channels is allocated a peg that
is normally clipped to the frequency board. Both the peg
and board are marked with the frequency channel number.
Before switching on their transmitter, each member must
take their corresponding peg from the board and keep it whilst
"live". If the peg is not on the board the
channel is already taken and your transmitter must not
be switched on until the peg has been returned.
The consequences of two people operating on the same channel
are that both pilots will lose control of their
models as soon as the second transmitter is switched on.
Obviously this is an extremely dangerous situation which must be
avoided.
Essentially, without the peg, you can't operate your radio.
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