TM 55-1520-240-23-4
5-139
PITCH LINK CORRECTIONS FOR AUTOROTATION % RPM
(Continued)
5-139
4.
Enter chart (1) at density altitude (step 1). Follow
line to % RPM. If % RPM is within limits, go to
Follow-On Maintenance.
5.
If % RPM is not within limits, figure pitch link
adjustment as follows:
a.
On chart (1), draw line parallel to nominal
(desireable) rotor speed line from % RPM
down to 0 density altitude line.
NOTE
A five-mark adjustment of pitch link
turnbuckle changes % RPM by
about 1 percent. Adjustment of one
complete turn (35 marks) changes %
RPM by about 6.5 percent.
b.
Read % RPM at 0 density altitude line. If %
RPM is low, subtract from 100 percent. If
% RPM is high, subtract 100 percent from
% RPM.
c.
Note difference from 100 percent in step b.
To reduce % RPM by 1 percent, turn pitch
links five marks toward +. To increase %
RPM by 1 percent, turn pitch links five marks
towards -.
6.
Adjust all six pitch links by equal amount as
figured in step 5c. Shorten links if % RPM is low.
Lengthen links if % RPM is high (Task 5-94).
FOLLOW-ON MAINTENANCE:
None
END OF TASK
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