FES Propeller Manual, Version 1.21
September 2020
Page 4 of 10
Warning!
Users of FES powered sailplanes should recognize that various types of risks are
involved, and they should take all precautions to minimize them, since they cannot be
eliminated entirely.
The propeller blades are one of the most critical parts of powered sailplane, having
vital importance to the flight safety. They are subject to constant torque loads from the
motor, airflow, and high centrifugal and bending loads. A mechanical failure could cause a
forced landing or create vibrations sufficiently severe to damage the glider. Unusual
vibrations should be investigated and fixed immediately, as it could be a warning that
something is wrong.
Please pay your attention, especially to the section dealing with inspections and
maintenance. It is essential that the propeller blades are properly maintained according to
the service procedures and intervals described in this manual.
