Electric motors used for RTP flying are all rated at 12 volts D.C. but current varies with motor type. When choosing a power unit it is important to ensure that the current output is adequate to support the motor(s) to be used. Power unit voltage output must also be considered, as volt drops in the RTP wiring system must be compensated by allowing as much as 5 volts per metre of flying line length.
For instance, the 4523 power unit has a maximum power output of 28 volts and is therefore restricted to supporting a maximum line length of 5 metres, where the combined motor load does not exceed 2.5 amps. In practice this means either one or two models using 0.75 amp motors or one model using a 2.5 amp motor.
Other important points with the power unit are that the D.C. output must be electrically smooth to allow motor to develop full power without overheating. Some form of safety cutout must be included to prevent damage to the power unit transformer and other equipment in the event of the inevitable short circuit or overloading of the pole wiring. Our units have been designed to satisfy all the requirements and have been tested through practical flying over many years. Many are in use with A.T.C. squadrons, schools, clubs and individual modellers.
Under the European Toy Safety Regulations, it is considered unsafe for children under the age of 14 to use transformers where the output exceeds 24 volts.