TM55-1500-345-23
7 - 4 4 . MARKINGS FOR RECIPROCATING ENGINE AIRCRAFT
arc indicates maximum continuous power; all operation
above this temperature is limited in time (usually 5
or 15 minutes).
(1) BLUE ARC. Indicates the range within which
(3) RED RADIAL. Indicates maximum permissible
operation is permitted in auto-lean. The bottom of this
temperature.
arc indicates the minimum manifold pressure desirable
in flight determined by engine characteristics. The
d. CARBURETOR AIR TEMPERATURE GAGE.
top of this arc indicates the manifold pressure at which
(See figure 7-6, detail D.)
mixture control must be moved into auto-rich.
(1) YELLOW ARC. Indicates the temperature range
(2) GREEN RADIAL OR ARC. Describes the range
within which undesirable conditions may exist such as
within which operation must be in auto-rich. The
danger of icing or poor fuel vaporization.
radial or top of this arc indicates maximum continuous
power. All operation above this manifold pressure is
(2) GREEN ARC. Indicates the temperature range
limited in time (usually 5 or 15 minutes).
o! best operation and assures good vaporization.
(3) SHORT RED RADIAL.. Indicates manifold pres-
(3) RED RADIAL. Indicates maximum permissible
sure for takeoff.
temperature, usually because of detonation danger.
(4) LONG RED RADIAL. Indicates maximum dry
war emergency manifold pressure.
(5) LONG RED RADIAL. Indicates maximum war
emergency manifold pressure with water injection.
(1) GREEN ARC. Describes the range within
which the temperature must remain during continuous
operation. The bottom of this arc indicates minimum
desirable temperature for flight. The top of this arc
(1) BLUE ARC. Indicates rpm range within which
indicates maximum continuous power. All operation
auto-lean, operation is permitted. The bottom of this
above this temperature is limited in time (usually 5 or
arc indicates the minimum rpm desirable in flight
15 minutes).
because of engine limitations, generator cut-out, etc.
The top of this arc indicates the rpm at which the mix-
(2) RED RADIAL. Indicates maximum permissible
ture control must be moved to auto-rich.
temperature.
(2) GREEN RADIAL OR ARC. Indicates rpm range
(3) RED RADIAL. Indicates war emergency maxi-
within which auto-rich operation is required. The
mum temperature.
radial or top of this arc indicates maximum continuous
power. All operation above this rpm is limited in time
(usually 5 or 15 minutes).
(3) RED RADIAL. Indicates maximum rpm.
(1) BLUE ARC. Indicates the range within which
operation is permitted in auto-lean. The bottom of this
(4) RED ARC. May be used to show region of
arc indicates the minimum torque pressure desirable
prohibited operation because of dangerous vibration or
in flight determined by engine characteristics. The
similar reasons.
top of this arc indicates the torque pressure at which
c. CYLINDER HEAD TEMPERATURE GAGE. (See
mixture control must be moved into auto-rich.
(2) GREEN RADIAL OR ARC. Describes the
(1) BLUE ARC. Indicates the range within which
range within which operation must be in auto-rich.
operation is permitted in auto-Iean. The bottom of this
The radial or top of this arc indicates maximum con-
arc indicates the minimum temperature desirable for
tinuous power. All operation above this torque pressure
flight (minimum engine warmth required for good fuel
is limited in time (usually 5 or 15 minutes).
vaporization and efficient engine operation). The top
(3) SHORT RED RADIAL. Indicates maximum dry
of this arc indicates the temperature at which the mix-
ture control must be moved to auto-rich.
torque pressure.
(4) LONG RED RADIAL. Indicates maximum wet
(2) GREEN ARC. Describes the range within
torque pressure.
which operation must be in auto-rich. The top of this
