Specifications
CG, CofG, Center of Gravity
The point at which an object's center of mass appears to be; its balance point
Channels
A measure of the number of separate signals that can be handled by a Tx and/or Rx. This
usually refers to the number of separate control surfaces or servos/speed controllers a Tx
can control, so typically a simple helicopter will need at least four channels.
Cogging
A bumpy effect noticed as the shaft of a iron core rotor (non-coreless) motor is rotated.
This is due to internal magnets are attracted to the iron core of the motor windings.
Coning Angle
Some helicopters like the FP Piccolo are designed so the rotor blades are flexible and will
bend upwards in flight. The amount which the blade bends upwards is called the coning
angle. The coning effect is good for beginner helicopters because it makes hovering more
stable, but is bad for forward flight because it makes the helicopter pitch up which makes
forward flight difficult.
CP
Collective Pitch. A helicopter that adjust vertical lift by changing the pitch of the main rotor
blades.
D
Disc Loading
The weight of the helicopter divided by the rotor disc size
Similar to the "wing loading" figure for airplanes. "High disc loading" means the helicopter
is heavy for its rotor size, or conversely, the main rotor blades are short for its weight.
Dissymmetry of Lift
The advancing side of the rotor disk moves faster than the retreating side and thus pro-
duces more lift. This causes the helicopter to bank in forward flight. This is usually
dampened by flapping or seesawing blades.
For further information see Section 30.1.6.1, “Dissymmetry of lift”
Drag
The friction experienced by a object moving through the air.
Dual Rates
A feature of some Tx models which allows you to flip a switch to make the controls more or
less sensitive. Usually set as some % of the normal rate.
Dual Conversion
A type of receiver which converts the incoming frequency through two intermediate stages.
This type of receiver rejects interference better than single-conversion receivers, but with a
size and weight penalty. This type of receiver uses a different crystal than single-con-
version receivers.
E
eCCPM
See CCPM
Glossary
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