Electrical System

The engine electrical system includes the ECU (Engine Control Unit), limit switches, engine display unit with engine master switch, engine control and throttle which are inter-connected via a wiring loom.

The ECU is a digital electronic unit that controls receives inputs such as throttle setting, engine rpm and EGT (Exhaust Gas Temperature) and controls the fuel pump rate, fuel solenoids (open/closed/pulsing) and glow-plug ignition. The ECU includes a memory card that records a number of parameters such as throttle setting, engine speed and EGT, and also data points/records such as number of start-ups and error log information.

Limit switches in the front of the engine box are operated by a bell crank when the engine is fully deployed and by a cam when the engine is fully retracted. The ECU will not initiate the starting sequence if it does not receive the signal from the deployed limit switch.

If the deployed limit switch fails while engine is running, the ECU will simply cut the engine power and register an error on the engine display (and the pilot can select to retract the engine by switching to retract).

In the event of a limit switch failing while the engine is being retracted or deployed so that the engine reaches the physical stops, the ECU will stop the engine and give a kinematic error on the engine display.

Electrical power for the sustainer is provided by Li-Fe batteries, replacing the standard sealed lead-acid batteries and situated in the standard battery compartments in the centre table.

Control & Display System

The pilot controls the engine using the JDU (Jet Display Unit).  The throttle is controlled using the rotary control on the instrument while engine retract/extend/run is selected by a single toggle switch.

The engine has an automatic start-up sequence that will start only once engine is fully deployed. Throttle control will only be given to the pilot once the desired rpm is reached according to the selected power setting.

The engine display is positioned on the instrument panel according to customer preference. The display shows engine speed, EGT, fuel quantity remaining, fuel consumption, endurance, thrust percentage, battery voltage and capacity,  hours of running time. Lights on the display indicate whether the engine is fully extended (green), being extended or retracted or fully retracted.

Nose Ballast System

Fixed nose ballast weights enable a minimum pilot weight of 55kg for the pure sailplane. The ballast system allows for configurations of 2, 4, 7, 9 and 11 kg to be added in the nose.

The sustainer installation and fuel tanks are aft of the aircraft empty centre of mass so ballast weights will normally be used to offset the weight of the sustainer installation and fuel.

The standard battery in the fin will not be used when the sustainer is installed as this also assists with moving the centre of mass forward (and the additional electrical power capacity is not necessary with the Li-Ion main batteries replacing the standard lead-acid main batteries). If fitted, the brass hub tailwheel will be replaced with a Vesconite tail wheel hub.





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