LZ design FES-LS8-P1-102 User manual

FES PROPELLER MANUAL
Version 1.21
Type: FES-LS8-P1-102
This manual is accepted by DG Flugzeugbau as manual for the
propeller FES-LS8-P1-102, if used in the LS8-e.
Issued
(DE/EI) LZ Design Checked (CVE/MPI)
Wassenaar Approved
(HoOA/LMPL)
Dirks
Date April 2019 Date 20.APR.2021 Date 20.APR.2021
LZ design d.o.o.  Brod 3D, 1370 Logatec, Slovenia  tel [phone]
[email protected]  www.front-electric-sustainer.com

FES Propeller Manual Version 1.21 April 2019
Page 2 of 11
Table of Content
1. Important notices ..................................................................................................... 3
1.1 Limited Warranty ................................................................................................. 3
2. Technical data .......................................................................................................... 5
3. Model designation .................................................................................................... 5
4. Construction ............................................................................................................ 6
4.1 Certification standards ......................................................................................... 6
4.2 Construction Material ........................................................................................... 6
4.3 Surface finish ...................................................................................................... 6
5. Removal of propeller blades ...................................................................................... 7
6. Installation of propeller blades .................................................................................. 8
7. Operating instructions............................................................................................. 10
8. Acceptable minor damages ..................................................................................... 10
9. Maintenance and repair .......................................................................................... 11
10. Shipping and storage ............................................................................................ 11
11. Revision history .................................................................................................... 11

FES Propeller Manual Version 1.21 April 2019
Page 3 of 11
1. Important notices
Owners and pilots who use FES system should read this manual thoroughly. It
contains important information about operation, maintenance and service of FES propeller
blades, having a vital importance to the flight safety.
1.1 Limited Warranty
This product is warranted to be free from defects in materials or workmanship for
two years from the date of purchase. Within this period, LZ design will, at its sole option,
repair or replace any components that fail in normal use. Such repairs or replacement will
be made at no charge to the customer for parts and labor, but the customer shall be
responsible for any transportation cost. This warranty does not cover failures due to
abuse, misuse, accident, or unauthorized alterations or repairs.
THE WARRANTIES AND REMEDIES CONTAINED HEREIN ARE EXCLUSIVE AND IN
LIEU OF ALL OTHER WARRANTIES EXPRESSED OR IMPLIED OR STATUTORY, INCLUDING
ANY LIABILITY ARISING UNDER ANY WARRANTY OF MERCHANTABILITY OR FITNESS
FOR A PARTICULAR PURPOSE, STATUTORY OR OTHERWISE. THIS WARRANTY GIVES
YOU SPECIFIC LEGAL RIGHTS, WHICH MAY VARY FROM STATE TO STATE. IN NO EVENT
SHALL LZ DESIGN BE LIABLE FOR ANY INCIDENTAL, SPECIAL, INDIRECT OR
CONSEQUENTIAL DAMAGES, WHETHER RESULTING FROM THE USE, MISUSE, OR
INABILITY TO USE THIS PRODUCT OR FROM DEFECTS IN THE PRODUCT.
Some states do not allow the exclusion of incidental or consequential damages, so the
above limitations may not apply to you. LZ design retains the exclusive right to repair or
replace the parts, or to offer a full refund of the purchase price, at its sole discretion.
SUCH REMEDY SHALL BE YOUR SOLE AND EXCLUSIVE REMEDY FOR ANY BREACH OF
WARRANTY.
To obtain warranty service, contact your local LZ design dealer or contact LZ design
directly.
© LZ design. All rights reserved

FES Propeller Manual Version 1.21 April 2019
Page 4 of 11
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
entirely eliminated.
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.

FES Propeller Manual Version 1.21 April 2019
Page 5 of 11
2. Technical data
FES propeller is assembly of foldable, fixed pitch composite propeller blades which
are mounted on special hub with attachment bolts at certain angle.
Number of propeller blades: 2
Maximum power on a propeller shaft: 23 kW;
Maximum rotational speed: 4500 RPM;
Propeller blade mass excluding attachment bolts: approximately 260 g each blade;
Diameter of the propeller: d=1000 (+20,-0) mm;
Service time between periodic controls: 50 hours or 12 months
Service time between special controls: 200 hours
Type of propeller: tractor;
Sense of rotation: clockwise looking at direction of
flight.
Operating conditions: the propeller can be operated in any
normal environment conditions
except hail, sand storm or similar.
3. Model designation
Propeller model designation is the following:
FES LS8 P1 102
(1) (2) (3) (4)
where:
- (1) designed for application;
- (2) designed for specific sailplane type;
- (3) model version;
- (4) Propeller diameter in cm;
Propeller serial-number is identified as follows:
XXX (L and R) - YYYY
where:
- XXX (L and R) - serial number of the propeller;
left blade is marked as L
right blade is marked as R
- YYYY - year of manufacture.
Propeller identification placard is located on the propeller sticker (transparent sticker glued
on lower surface of the propeller close to the blade suspension).
NOTE: Propeller type FES-LS8-P1-102 is identical like FES-VEN-P1-102. It is marked
differently due to different type and manufacturer of the sailplane.

FES Propeller Manual Version 1.21 April 2019
Page 6 of 11
4. Construction
4.1 Certification standards
Propeller type FES-LS8-P1-102 described here is designed and tested according to
CS 22 Subpart J.
This manual is intended to comply with CS‐22.1903, providing the essential
information for installing, servicing and maintaining the propeller.
4.2 Construction Material
Propeller blades are made of CRFP (carbon fiber reinforced plastic). They are
produced in accurate metal molds, which were manufactured using modern CNC
technology. This made it possible, to have very accurate profile geometry. At attachment
point of propeller blade is integrated hardened steel bushing with very accurate tolerance,
so that play is minimal.
Propeller hub is CNC milled part, from Aluminum alloy 7075, black anodized.
4.3 Surface finish
High quality acrylic white paint (PPG D700) is used to protect the composite body
against moisture and erosion. Each blade pair is sanded and polished so that mass
difference is only about 0,1g (0,3g is maximum weigh difference tolerance). Paint is
resistant against fuel, oil and other chemical products. This type of paint has also an
excellent flexibility. Only tips of the propeller blades can be painted in other colors as a
safety mark. Otherwise only allowed color is white as this is structural part.

FES Propeller Manual Version 1.21 April 2019
Page 7 of 11
5. Removal of propeller blades
1. Carefully remove white round stickers which are glued over 6 screws, which hold the
spinner. Unscrew all 6 M4 countersink screws, with 2,5mm sized hex key, to remove the
spinner. Note that 2 screws are 2mm shorter!
2. Before starting removal process of propeller blades it is strongly recommended to close
motor openings with a tape, as show on photo above in order to prevent any of the small
parts entering the motor, if it falls through the fingers by coincidence. If this would
happen, it is usually necessary to remove and open motor, which is quite demanding job,
so it is much better to tape openings.
Flatten and remove split pin, which secure M8 crown nut on each end of propeller blade
attachment bolt. Carefully unscrew crown nuts, and remove M8 spacers
3. Push attachment bolt out of the hub. If is not possible to push them out with hands,
you can use small plastic or wooden hammer and carefully push them out completely.
Propeller blades are then free to take out.

FES Propeller Manual Version 1.21 April 2019
Page 8 of 11
6. Installation of propeller blades
1. Before installation of new propeller blades, check that marking on the label, which is
located on lower inner surface, confirms the correct type. For LS8 equipped with FES,
propeller type is FES-LS8-P1-102. Left blade is marked as L and right blade is marked as
R.
2. Left and right propeller blade have slightly different shape of top center surface due to
asymmetric shape of the spinner. When each of them is installed on proper side, and
aligned with the fuselage, top surface of the first 3cm need to have contour nicely aligned
with spinner shape.
3. Before inserting the bolts, lubricate the shaft of the bolt with thin layer of grease. We
recommend using white silicon grease (use only clean grease, from closed tube). Then
insert such lubricated bolts to each propeller blades bushing, from each side, so that thin
film of the grease will be also transferred to inner surface of bushing. Clean away any
exceed amount of grease. If there is too much grease, it will be later spilled to inner
surface of the spinner by centrifugal force, so we recommend using only a minimum
amount of grease. Take out the bolts, and put them on clean surface, to be ready for
assembly.
4. Align propeller blade so that its fixing hole is nicely aligned with hole of propeller holder.
From back side of the holder, insert lightly lubricated, special bolts. This means that
head of the bolt must be on trailing edge side of propeller as on picture below!
One of the two special bolts is marked on the head with a small dot. Be sure to install it
to proper side of propeller holder which is marked with small dot.

FES Propeller Manual Version 1.21 April 2019
Page 9 of 11
5. Before placing washers, crown nuts, and split pins, it is strongly recommended to close
motor openings with a tape, as show on photo in previous chapter in order to reduce
possibility that any of the small parts could enter into the motor, if it falls through the
fingers by coincidence. If this would happen, it is usually necessary to remove and open
motor, which is quite demanding job, so it is much better to tape openings.
6. Place M8 Inox washer to the threaded side of a bolt, and then a crown nut M8. Tighten
the crown nut with key number 13, so that there is some tension in holder forks, which
created enough friction so that bolt can not rotate freely. If there is too much tension in
the forks, propeller blades would not be able to open and close freely. If this is the case,
un-tight crown not so that blades can move free, and it is also possible to insert split pin
into the hole in the pin trough crown nut. Carefully insert new safety pin of
1,4mm diameter x 22mm length, and bend its two ends, around crown nut.

FES Propeller Manual Version 1.21 April 2019
Page 10 of 11
7. Fix the spinner with four Inox M4x8mm countersink head screws, and two M4x6mm
screws. Two screws which are 2mm shorter are located at 60deg and at 300deg
angle (upper left and right). 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 (optional equipment).
- 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.

FES Propeller Manual Version 1.21 April 2019
Page 11 of 11
9. Maintenance and repair
1. Periodic control of propeller is required after every 50 hours of motor run or after 12
months, whatever comes first, by air-worthiness controller:
- 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 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.
- check condition of rubber part, glued to the root section of each propeller blade. If
rubber parts have signs of wear or they are damaged, they should be removed and
replaced. New rubber part should be glued to each propeller blade with Loctite Super
Attak quick glue or similar.
- inspect the leading edge of the blades for minor paint damages from small stones;
If such damages are found, they should be repaired with small droplets of white
acrylic paint. When droplets of paint are dry, any excessive paint need to be carefully
sanded so that is in line with other surface. Only qualified persons are allowed to
perform such minor repair. Do not repaint complete propeller blades, as repainting
might affect balancing of the propeller. Maximum acceptable weigh difference
between the propeller blades is 0.3g.
2. Special control of the propeller is required at 200h of motor run. It can be performed by
manufacturer or by workshops which are approved by manufacturer.
10. Shipping and storage
If shipping or storage is required, careful packing is the best protection against
damage. Especially the tips and trailing edge should be sufficiently protected. The easiest
way is to use a few layers of bubble wrap for each propeller blade, and then place them
into thick cartoon or wooden box.
The propeller blades should not be stored close to heat source or in rooms with
extreme changes in temperature or humidity.
11. Revision history
March 2019 Initial release of manual, v1.21