PCM
Pulse code modulation.

PPM
Pulse position modulation

PVA
A water based glue used in modelling, also known as white glue.

Peak Charger
When a battery is charging it reaches it optimal capacity then drops off slightly this is known as the peak, so a peak charge will recognize this and stop charging as the battery is 100% charged.

Pitch
The planes upwards or downward position in relation to the ground, either nose up or nose down.

Pitch Axis
The planes axis controlled by the elevator.

Pitch Curve
The degrees that the main rotor blades of a helicopter deflect.

Power Panel
A control panel that distributes the correct voltage for accessories like electric starter, glow plug clips and fuel pumps. This unit is mounted in to a field box.

Programmable mix
Used to operate multiple servos for specific operations like mixing two servos to operate in tandem to move a rudder on large aircraft.

RPM
Revolutions per minute how fast something, motor or propeller rotates

Receiver
Part of the radio control system fitted into the plane that receives the signal from the transmitter.

Reset
Used to reset timers on radios and also model sub-menu used to reset part or all of a specific models settings.

Retract servo
A dedicated servo used for mechanical retracts, it is not a proportional servo, and it travels through 180 degrees, extending or retracting the landing gear

Retracts
Retractable landing gear, this is where the wheels and struts fold up into the airplane, generally into the wings.

Roll
The plane rotates 360 degree around its horizontal or vertical axis.

Rudder
The hinged control surface on the vertical stabilizer that controls the left or right steering movement of the plane

Rudder to Aileron
A radio mix used to counteract undesirable roll, which often happens with rudder input, especially in the knife-edge manoeuvre.