SECTION 5. Engine operation details
5
Engine operation details
5.1
Radio Control (RC)
Only one channel is needed for the RC’s throttle signal. With the throttle channel, the engine can be started,
controlled and shut down. The additional channel available (labeled
AUX
on the housing, see Figure 1a) can be
used by connecting an auxiliary input patch cable (1-to-1) and can be configured either for digital trimming or
a smoker valve (see Section 5.8).
The throttle channel’s timings must be learned using the GSU (see Section 4.5.2), while the auxiliary
channel does not need this as it can only have the states
ON
and
OFF
.
5.2
Throttle positions
The ECU recognises three throttle positions.
5.2.1
Defined positions
1.
Off:
Both throttle and trimming are set to minimum. Engine is off.
2.
Neutral:
Throttle set to minimum and trimming is set to maximum. Corresponds to idle RPM.
3.
Full:
Both throttle and trimming are set to maximum. Corresponds to maximum RPM and thrust.
If the RC uses digital trimming, the additional auxiliary channel (see Section 5.8) can be configured in the
corresponding menu via GSU (see 4.5.2).
5.2.2
Starting, running and stopping
1.
Off to Standby:
When the engine is in
off
mode, move the throttle first to
neutral
and then to
full
position. This will put the engine into
standby
mode.
2.
Start:
When the engine is in
standby
mode, move the throttle from
full
position to
off
position. If the
throttle is then set to
full
position within three seconds, the ECU will initiate the
autostart
sequence.
3.
Running:
After successfully completing the
autostart
sequence, the ECU puts the engine in
automatic
mode. In this mode, a throttle position between
neutral
and
full
controls the engine’s RPM and thrust.
4.
Stop:
When the engine is running, it can be stopped by moving the throttle to the
off
position. The ECU
will shut down the fuel pump and run the cool-down sequence before switching the engine to
off
mode.
5.2.3
Throttle curve
The throttle position on the RC will command a certain engine RPM. The
neutral
setting will always correspond
to idle RPM, while the
full
setting will always correspond to the maximum RPM. Between these two settings, it
is a matter of personal preference and control whether the throttle position should command the engine’s RPM,
the thrust, or a convex combination of the two functions describing this.
There is an approximately cubic relation between thrust and RPM:
F
≈
a
·
(
RPM
)
3
with
a
∈
R
>
0
. This
means that
• If the throttle position commands the RPM, the thrust near full RPM becomes hard to control, as e.g.
90% RPM correspond to 72
.
9% thrust (see Figure 4b, the line corresponding to
c
1
=
0). If an analogue
controller is used, this means that almost 30% of the thrust is governed by only 10% of the lever stroke!
• If the throttle position command the thrust, the RPM near idle become hard to control for the same
reasons, as 10% of the thrust already correspond to
≈
46
.
4% of the full RPM (see Figure 4a, the line
corresponding to
c
1
=
1).
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