vision microsystems VM1000 - Page 36

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SECTION
2
OPERATION
37
2.6.1
LEANING
YOUR
ENGINE:
Our exclusive
automatic'LEANING
MODE' makes leaning
the
engine a
simple operation,
without
the need to
remember
values.
STEP
1: STABILIZE:
the aircraft
engine
temps,
throttle, rpm and
insure
mixture
is on the
rich side of
peak
EGT.
This
can
be
verified
by enriching mixture
to
see
that all
EGT values
decrease.
Press
'BUTTON
1'
(far
left) to activate the
'Lean
EGT
Mode'.
Notice that
the
graphic
display changes
its
appearance.
The
graph
is
normalized to
the
bottom
to
give you
a
baseline
reference
while leaning.
Each bar represents
ten
degrees
in this
mode.
STEP
2:
LEAN:
the
engine
mixture smoothly
to start the bars
climbing
(about
one bar
per
2 seconds).
The computer
monitors
all
EGT
values and
detects
the
first EGT
to
lean out.
When
this happens,
the
bar
graph
for that
EGT
will
begin
flashing
and
if optionally
equipped
an
audio/visual alert
occurs. This
is
your
signal
to stop
leaning. NOTE: lf it
looks as
if
the
graphs
will
'fill
up'
before
you
achieve
leanest
EGT,
you
can simply
reinitialize
by
pressing
'BUTTON
1' twice which
're-
arms'
the Lean
EGT
mode
and
normalizes
the
graphs
to the
bottom again.
Do not
lean
further if
engine roughness occurs.
STEP
3:
FNBICH:
after
the
lean
EGT
graph
stops flashing,
noting
that
the
lean
EGT
graph
(the
graph
that
now
has a
single bar
marking
where
the
peak
was
found)
goes
up.
This signifies
that
the mixture
is returning
to-the
peak
value again,
Set
your
final
mixture
via
the
bar
graph
or by the
digital readout
(now
showing the
leanest
EGT)
according
to
your particular
engines
operating handbook.
Some
engines
require
a
mixture
50
-
75
degrees
rich
of
peak
at
high
power
settings, while others
allow
running at
peak
or even
leaner !
Consult
your
engine manual.
TIP: lnitially set
a rich fuel
flow achieving
approximately
100
degrees cooler
than the
last known
peak.
The
'PEAK
DISPLAY
MODE'
(see
'Digital
Display
Modes') can be used to
perform
this, if the system
has
previously
found
a
lean
EGT.
5010002
REv
F
VMTOOO
OWNERS
MANUAL