FES Maintenance manual Version 1.12
September 2016
Page 22 of 26
6. Parts with limited service life
The following FES system parts have limited service life:
-12V Pb battery should be replaced every 5 years (if is installed in a glider)
Other components of FES system are necessary to replace according their condition.
7. Placards
When sailplane is equipped with FES there should be next additional placards in the
cockpit:
-Ventilation open and ventilation closed placards
-Maximum speed to fly with motor running
8. Balancing of rotating parts
In order to have a smooth run of FES, complete assembly of motor, spinner, and
propeller blades are balanced (to vibration level of less than 0,1 IPS) with special
equipment before installation to the glider.
At that time all components are marked with small marking dots, and assembled so that all
this little dots are all located on the same side. These marks must be taken into account
when assembling spinner or propeller blades, so that they are assembled in proper
orientation as before. If these marks are not taken into account, excessive vibrations could
occur during motor run!