Marine Installation Manual 2021-08 2-16
2 Engine Power and Speed
2.7 Prohibited operation area
X72DF
Power/speed range for
CMCR [Rx] =
85 % R1—R2 speed
In Figure 2-9, the engine’s CMCR speed is rated at 85 % of the R1 — R2 speed. At
this speed, a minimum engine power (point F) of 10.4 % is required, below this is
the prohibited area of operation for the CPP at small (to zero) pitch and discon-
nected propeller.
Point E is always defined at 70% of the R1 —R2 speed and has a minimum
power of 5.8 %, however in Figure 2-9 this equates to approximately 82% CMCR
speed.
Figure 2-9 The prohibited operation area (CMCR speed = 85 % of R1 — R2)
40 50 60 70 80 90 100
[rpm]
110
100
90
80
70
60
50
40
30
20
10
0
5
7
8
CMCR [Rx]
Field A
Engine speed
[% Rx]
E
F
11
12
Prohibited operation area
10.4 [% Rx]
37.830.3 45.4 53.0 60.5 68.1 75.7
X72DF
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