Excess Drag On Wheel Pilot With Clutch Disengaged - Simrad WP10 Service Manual

Issue 1.1 23/09/03
FOR THE ATTENTION OF THE SERVICE MANAGER
NUMBER
PRODUCT
SUBJECT
DATE
Background Information
Technical Note PS152 dated 5 July 2001 described the very limited occurrence
of excessive drag on Wheel Pilots with the clutch disengaged which made the
wheel difficult to turn. An urgent investigation was initiated to quantify the
problem and seek a solution.
Reported Occurrences
Less than 50 occurrences, of varying severity, were reported of some 3000
Wheel Pilots of all types in use.
Investigation
The investigation concluded that the problem was a fairly rare combination of
Pilot "spinnings" at the extreme limit of production tolerance coupled with a
different version drive belt which was introduced to provide improved friction
and thus increased load handling characteristics. However, though the new
version met the specification, it has since proved to be less flexible than
desired.
Solution
The spinnings tolerance is as tight as manufacturing constraints allows. The
new version drive belt has therefore been suspended pending further Research
and Development effort to improve the Wheel Pilot geometry to allow the higher
load characteristic belt to be used.
Technical Note
: PS 155
: Wheel Pilots WP10 / WP30
: Excess Drag on Wheel Pilot With
Clutch Disengaged
: 4 October 2001
SIMRAD
49