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The operating components of the turbine
The turbine's operation is completely controlled by an electronic unit known as the ECU (Engine
Control Unit). The pilot does not have direct access to the turbine and its auxiliary equipment.
The turbine is controlled by the ECU, which responds to the pilot's "wishes" passed to it from the
receiver via the transmitter channel; the ECU responds by converting the pilot's commands into
appropriate actions. At the same time the ECU monitors certain operational parameters of the
turbine, e.g. exhaust gas temperature and rotational speed, and controls the auxiliary units
connected to the system accordingly:
The fuel pump draws fuel from the tanks and feeds it into the turbine; the pump voltage
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determines the quantity of fuel pumped, which in turn dictates the speed, and therefore
power, of the turbine.
The fuel cut-off valve blocks or releases the fuel flow into the turbine.
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The gas cut-off valve controls the auxiliary gas flow during the starting procedure.
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The glowplug ignites the starting gas in the combustion chamber.
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The starter motor accelerates the turbine from rest until it reaches a rotational speed at
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which it can run on kerosene, supported by the combustion of the auxiliary gas. The starter
motor is also used to cool the turbine after shut-down.
The turbine's rotational speed is monitored by the speed sensor.
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The exhaust gas temperature is monitored by the temperature sensor.
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Operational parameter values are stored in the memory of the ECU; certain values are fixed and
invariable; others can be changed by the model flyer. The memory also stores operational data
when the engine is running, and this information can be read out and analysed after the flight.
An additional unit known as the GSU (Ground Support Unit) is supplied as standard; this is a
programming / display unit which is used for reading out and adjusting the parameters. The
GSU can be connected to an LED circuit board installed in the model in an externally accessible
position. An optional PC interface is also available which can be used to transfer detailed
supplementary in-flight data to a computer for further analysis.
The ECU is powered by its own 6-cell NC battery which is connected directly to the ECU; it
does not require its own switch. The same battery powers the other components of the turbine
control system, i.e. the starter motor, fuel pump, gas and fuel valves, LED circuit board and also
the GSU, when connected. A circuit in the ECU ensures that its own power supply is switched
on when the pilot switches on the receiver to which the ECU is connected. Each flight lasts
around 13 minutes, including starting and post-run cooling, and during this time approximately
400 - 550 mAh is drawn from the battery. The fast-charge 1250 mAh NiCd battery supplied
therefore lasts no more than two flights before it needs to be recharged. In the interests of
safety we actually recommend that you recharge the pack after every flight.
To recharge the power supply battery it must be disconnected from the electronics, as many of
the chargers currently on the market send negative pulses to the battery, with the purpose of
avoiding gas bubble formation in the cells. These negative voltage pulses would destroy the
electronics (ECU).
The battery may only be left connected, and recharged using a Y-lead, if you are absolutely
certain that this is not the case with your charger. The electronics must never be connected
directly to the charger, i.e. without a battery connected.
A overview of the electrical wiring of the individual turbine control system components is shown
in the diagram on the next page.
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