FES Propeller Manual Version 1.23
October 2022
Page 10 of 11
7. Fix the spinner with six Inox M4x8mm countersink head screws. Tightening of all 6
screws should be gently with small torque (do not use high torque, as thread in the
aluminum plate could be damaged). Please do not use any glue to secure them, as during
rotation centrifugal force to the screws create high enough friction, which prevent
unscrewing. We prefer to cover heads of the screws with white round stickers (diameter
about 14mm), which additionally secure the screws from unscrewing, and it also looks
nicer!
7. Operating instructions
To ensure reliability and safety of the propeller, preflight check of the propeller should be
done before each flight by the pilot/owner:
- remove protection fluorescent fabric cover
- make sure that propeller surfaces are clean before each flight. Propeller full of bugs
is less efficient and in worst case they can even increase level of vibrations. For
cleaning, use wet cloth as used for other parts of the glider.
- check visually the leading and trailing edge at the root. If there are visible any
cracks or other major damages, please contact manufacturer for advice before next
flight. If is not clear, please check next chapter about acceptable minor damages.
- check that each blade is opening and closing freely with only small friction. If there
is too much friction, it is necessary to clean and lubricate the attachment bolts and
bushing. To perform this is necessary to remove the propeller blades.
8. Acceptable minor damages
1. Thin cracks up to 10 mm of length in paint are allowed, but not in the root section. Only
in the outer part of the propeller blade (15 cm or more from attachment point) such
cracks in paint are acceptable. If such cracks do occur, it is anyway advisable to consult
with qualified service or manufacturer regarding airworthiness. Please send a good photo
and information about operating time.
2. Only small damages of the paint on the leading edge are acceptable, as they are
unavoidable after long time of usage.
3. Structural cracks, deformations or de-laminations of composite structure are not
acceptable for the propeller blades. If they occur, please send propeller blades to
manufacturer for the inspection.
