Wren 44 Gold Helicopter Owners Manual
Page 23
Autostart ECU system
The Autostart ECU (Engine Control Unit) supplied with 44 Helicopter engines is a Full
Authority Digital Engine Control (FADEC) from Gaspar Espiell. It handles all aspects of
starting, operating and shutting down the engine and maintains temperature and operating
rpm within safe levels. It has an integral failsafe which will shut the engine down within one
second of loss of datastream from the receiver. This meets the requirements of the AMA in
the USA.
The Autostart main unit should be positioned on the helicopter airframe with the socket for
the Data Terminal in an accessible position as you may need to plug this in to monitor starts
or change settings. If needed, this socket point may be made more accessible by fitting a JR
type servo extension and the socket located in a handy position on the airframe.
Alternatively, a handy mini-HDT is available which can be
permanently affixed to the airframe and this saves plugging in and
out. This has the added benefit of being backlit for easy reading
though of course the buttons may be less easy to locate and
operate.
The ECU can be mounted in any accessible position – people often use a hook & loop type
strip but keep it clear of the exhaust or hot areas. The ECU has an LED (light emitting diode)
next to the signal wire from the receiver and the data display terminal socket, that shows its
status when the terminal is not plugged in.
The fuel pump, fuel and propane valves need to be connected into the socket
positions shown on the ECU label. Note, the fuel valve label is on the side of
the ECU – not obvious from the front. The plug polarity for the valves is not
important.
The rpm and temperature cables from the engine should also be plugged into
the ECU – be careful to locate the plug brown wire to brown end of the socket.
Keep a small amount of slack in all these cables to ensure they cannot pull out
during manoeuvres. The ECU battery cable should be routed in a way which
allows the battery to be easily disconnected whilst charging. Permanent
damage will be caused to the ECU if the battery is charged without disconnecting it from the
ECU while charging. Once all items are installed and connected the ECU can be aligned (set
up) to your radio.
Setting the ECU to your radio.
Disconnect the ECU battery if it was plugged in. Plug the display (data terminal) into the
ECU. If you have a transmitter with digital trims you can simulate the trim up/down function
using the “Throttle Cut” switch, which is usually a function switched through a switch
mounted on the transmitter. Consult your radio manual for this function.
Setting the ECU using this, is done in the same way except that when “trim-up” is required
you switch the “Throttle Cut” to off, and when “trim-down” is required, you switch to “Throttle
Cut” on.
For initial testing the digital trims can be used if you don’t want to have to explore the
“Throttle Cut” function just yet. The trim up/down function is used to switch the engine to
“ready to start” and “off”, and would not normally be used to vary the idle rpm.
