LZ design FES LCD Display Technical specifications

FES FLIGHT MANUAL
Version 1.16
LZ Design d.o.o., ▪Brod 3D, 1370 Logatec, Slovenia ▪tel [phone]
[e-mail] ▪www.front-electric-sustainer.com

FES Flight Manual Version 1.16 October 2017
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Table of Content
1. General.................................................................................................................... 5
1.1 Introduction...................................................................................................... 5
1.2 Certification basis.............................................................................................. 5
1.3 Warnings, cautions and notes ............................................................................ 5
1.4 Descriptive data ................................................................................................ 5
1.5 Three-view drawing........................................................................................... 6
1.6 Abbreviations.................................................................................................... 7
1.7 Unit conversions................................................................................................ 7
2. Limitations ............................................................................................................... 8
2.1 Introduction...................................................................................................... 8
2.2 Airspeed ........................................................................................................... 8
2.3 Airspeed indicator markings ............................................................................... 8
2.4 Power-plant ...................................................................................................... 8
2.4.1 Motor.......................................................................................................... 9
2.4.2 Propeller ..................................................................................................... 9
2.4.3 Battery packs .............................................................................................. 9
2.5 Power-plant instrument markings....................................................................... 9
2.6 Weight ........................................................................................................... 10
2.7 Centre of gravity ............................................................................................. 10
2.8 Approved manoeuvres..................................................................................... 10
2.9 Manoeuvring load factors................................................................................. 10
2.10 Flight crew................................................................................................... 10
2.11 Kinds of operation ........................................................................................ 10
2.12 Minimum equipment..................................................................................... 10
2.13 Aerotow and winch- and autotow-launching.................................................. 11
2.14 Other limitations........................................................................................... 11
2.15 Limitations placards ...................................................................................... 11
3. Emergency procedures ........................................................................................... 12
3.1 Introduction.................................................................................................... 12
3.2 Canopy jettison............................................................................................... 12
3.3 Bailing out ...................................................................................................... 12
3.3.1 Ballistic parachute...................................................................................... 12
3.4 Stall recovery.................................................................................................. 12
3.5 Spin recovery.................................................................................................. 12
3.6 Spiral dive recovery......................................................................................... 12
3.7 Motor failure ................................................................................................... 12
3.7.1 Motor fail to start....................................................................................... 12
3.7.2 Power loss during flight.............................................................................. 13
3.8 Fire ................................................................................................................ 14
3.8.1 Fire on the ground..................................................................................... 14
3.8.2 Fire during flight........................................................................................ 14
3.9 Other emergencies.......................................................................................... 14
3.9.1 Loss of 12V electrical power in flight ........................................................... 14
4. Normal procedures ................................................................................................. 15
4.1 Introduction.................................................................................................... 15
4.2 Rigging and de-rigging, charging, battery pack installation ................................ 15
4.2.1 Rigging and de-rigging............................................................................... 15
4.2.3 Installing the batteries ............................................................................... 16
4.3 Daily inspection............................................................................................... 16

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4.4 Pre-flight inspection ........................................................................................ 16
4.4.1 Preflight test run .......................................................................................... 17
4.5 Normal procedures and recommended speeds .................................................. 18
4.5.1 Aero tow launch ........................................................................................ 18
4.5.1 Aero tow launch ........................................................................................ 18
4.5.2 Winch launch ........................................................................................... 18
4.5.3 Auto tow launch ........................................................................................ 18
4.5.4 Taxiing procedures .................................................................................... 18
4.5.5 Self-launch and climb................................................................................. 19
4.5.6 Free flight ................................................................................................. 19
4.5.7 Low speed flight and stalling behavior ........................................................ 19
4.5.8 Cruise and climbing with running motor ...................................................... 20
4.5.8.1 Propeller stop with electronic braking....................................................... 20
4.5.8.2 Propeller positioning ............................................................................... 21
4.5.9 Approach .................................................................................................. 21
4.5.10 Landing..................................................................................................... 22
4.5.10.1 After Landing........................................................................................ 22
4.5.10.2 Removing the batteries ......................................................................... 22
4.5.11 Flight with water ballast ............................................................................. 23
4.5.12 High altitude flight ..................................................................................... 23
4.5.13 Flight in rain.............................................................................................. 23
4.5.14 Aerobatics................................................................................................. 23
5. Performance .......................................................................................................... 24
5.1 Introduction.................................................................................................... 24
5.2 Approved data ................................................................................................ 24
5.2.1 Airspeed indicator system calibration .......................................................... 24
5.2.2 Stall speeds............................................................................................... 24
5.2.3 Take-off performance ................................................................................ 24
5.2.4 Additional information................................................................................ 25
5.3 Non-approved further information .................................................................... 25
5.3.1 Demonstrated crosswind performance ........................................................ 25
5.3.2 Glide performance ..................................................................................... 25
5.3.3 Flight polar................................................................................................ 26
5.3.4 Powered flight performance ....................................................................... 26
5.3.4.1 Rate of climb.......................................................................................... 26
5.3.4.2 Cruising flight ......................................................................................... 27
5.3.4.3 Maximum operational altitude.................................................................. 27
5.3.5 Noise data................................................................................................. 27
5.3.6 Electromagnetic interferences..................................................................... 27
6. Weight and balance................................................................................................ 28
6.1 Introduction.................................................................................................... 28
6.2 Weight and Balance Record and permitted payload-range ................................. 28
6.3 Weight of all non-lifting parts........................................................................... 28
6.4 Maximum weight............................................................................................. 28
7. General sailplane and systems description................................................................ 29
7.1 Introduction.................................................................................................... 29
7.2 Cockpit controls .............................................................................................. 29
7.3 Instrument panel ............................................................................................ 29
7.4 Landing gear system ....................................................................................... 29
7.5 Seats and safety harness ................................................................................. 29
7.6 Pitot and static system .................................................................................... 29

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7.7 Air brakes system............................................................................................ 29
7.8 Baggage Compartment.................................................................................... 30
7.9 Water ballast system ....................................................................................... 30
7.10 Powerplant................................................................................................... 30
7.11 Battery packs ............................................................................................... 30
7.12 Electrical system........................................................................................... 30
7.13 Miscellaneous equipment .............................................................................. 30
8. Sailplane handling, care and maintenance................................................................ 31
8.1 Introduction.................................................................................................... 31
8.2 FES inspection periods..................................................................................... 31
8.3 Sailplane alterations or repairs ......................................................................... 31
8.4 Ground handling / road transport..................................................................... 31
8.5 Sailplane trailer ............................................................................................... 33
8.6 Cleaning and care ........................................................................................... 33
9. Supplements .......................................................................................................... 33
10. Revision history .................................................................................................... 33

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1. General
1.1 Introduction.
The FES flight manual has been prepared to provide:
1. Pilots with information for the safe and efficient operation of the sailplanes
equipped with Front Electric Sustainer/Self-launcher system.
2. Sailplane manufacturer of specific type of sailplane equipped with FES, with all the
information necessary to prepare flight manual of the sailplane after FES installation.
Chapters of this manual are written as it is requested by CS-22 requirements.
1.2 Certification basis
This type of powered sailplane has been designed in accordance with CS 22
Certification Specifications for Sailplanes and Powered Sailplanes, and in accordance with
Special Conditions for electric powered sailplanes.
1.3 Warnings, cautions and notes
The following definitions apply to warnings, cautions and notes used in the flight
manual.
Warning: Means that the non-observation of the corresponding procedure
leads to an immediate or important degradation of the flight safety.
Caution: Means that the non-observation of the corresponding procedure
leads to a minor or to a more or less long-term degradation of the flight
safety.
Note: Draws the attention on any special item not directly related to safety
by which is important or unusual.
1.4 Descriptive data
Sailplane is equipped with a high-tech powerful FES front electric propulsion system
developed for high performance powered sailplanes. Main parts of the FES system are:
•Brushless electric motor
•Controller for motor
•Foldable propeller
•FES GEN 2 Battery packs, with internal BMS (Battery Management System)
•Charger (600W, 1200W or 2000W)
•FCU (FES control unit) instrument
•LXUI box with Shunt (for current and voltage measurements)
•FCC box (FES connecting circuit)
•Power switch
•DC/DC converter (converts high voltage to 12V)

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1.5 Three-view drawing
Typical FES equipped powered sailplanes are Discus 2c FES and Ventus 2cxa FES

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1.6 Abbreviations
CAS
- calibrated airspeed means indicated airspeed of a sailplane, corrected for
position (due to position of pressure ports on sailplane) and instrument error.
Calibrated airspeed is equal to true airspeed in standard atmosphere at sea level
C.G.
- centre of gravity
daN
FES
FCU
- decanewton
- Front Electric Sustainer/Self-launcher
- FES Control Unit
H
- hour
IAS
- indicated airspeed means the speed of a sailplane as shown on its pitot –static
aircraft indicator and is uncorrected for the system error
M
- meter
Kg
- kilogram
Km
- kilometre
S
- second
Ltr
- liter
1.7 Unit conversions
1 bar = 14,5 pounds per square inch (psi);
1 decanewton (daN) = 2,25 pounds force;
1 kilogram (kg) = 2,2 pounds (lbs);
1 meter (m) = 39,4 inches (in.) = 3,28 feet (ft.);
1 millimeter (mm) = 0,0394 inches (in.);
1 liter = 0,2642 U.S. gal;
1 square meter (m2) = 10,764 sq.ft;
1 kg/m2= 0,204 lbs/sq.ft;
1 m/s = 1,944 knots (kts);
1 km/h = 0,5396 kts;
1 kW = 1,34 HP.

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2. Limitations
2.1 Introduction
This chapter includes operation limitations, instrument markings and placards,
necessary or safe operation of the sailplane equipped with Front Electric Sustainer system.
2.2 Airspeed
Airspeed limitation for the use of FES system and their operational significance are
shown below:
Speed
IAS; km/h /
(kts)
Remarks
VPO
Maximum speed with
rotating propeller
160 / (86)
Do not exceed this speed with rotating
propeller (at any power setting)
VPOmin
Minimum speed to
start motor
80* / (43*)
Do not start rotate motor below this
speed
VPOmax
Maximum speed to
start motor
160 / (86)
Do not start rotate motor above this
speed
* Warning: select your motor start/stop speed correctly:
- flaps must be at positive position; (depend on glider type)
- make sure your selected speed for motor start / stop is at least 8…10 km/h
(4…5 kts) higher as if stall speed for your flight configuration.
2.3 Airspeed indicator markings
FES equipped sailplanes do not have any special markings compared to pure
gliders. Blue line marking on airspeed indicator can be added representing range of best
rate of climb speeds but it depends on glider type. Usually is between 80-90km/h, with
positive position of flaps.
Marking
(IAS) value or range
Significance
Blue line
80-90km/h
Best rate-of-climb speed
2.4 Powerplant
Warning: When FES is installed on 18m class sailplanes like Ventus 2cxa or
Discus 2c, it is a sustainer system, and it is prohibited from taking-off
solely, if not specified differently in flight manual.
On lighter UL sailplanes like Silent 2, or MiniLAK FES it is a self-launch
system.

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2.4.1 Motor
Motor manufacturer: LZ design d.o.o.;
Motor model: FES-xxx-Myyy;
xxx - represent version of motor for specific glider type
yyy - represent motor length
More detailed data about motor which is used on specific type of FES powered sailplane
are described in separate FES motor manual!
2.4.2 Propeller
Manufacturer: LZ design d.o.o.
Model: FES-xxx-Pv-yyy;
xxx - represents type of sailplane for which the propeller is designed
v - represents version of propeller for specific glider type
yyy - represents propeller diameter in mm
2.4.3 Battery packs
FES needs two Battery packs wired in serial. Each Battery pack has 14 cells, so
altogether there is 28 cells.
Maximum allowed total voltage of both Battery packs
118 V
Minimum allowed total allowed voltage of both Battery packs
90 V
Nominal capacity of each cell
40 Ah
Energy storage capacity
4,2 kWh
Maximum voltage per cell
4,16 V
Middle voltage
3,7 V
Minimum voltage of each cell
3,2 V
More detailed data about battery packs which is used on specific type of FES
powered sailplane are described in separate FES Battery pack manual!
2.5 Power-plant instrument markings
FES power plant has a FCU instrument with high resolution sunlight visible colour
display. More detailed data about FCU and its operation can be found in separate FES
FCU INSTRUMENT manual!

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2.6 Weight
FES system can be installed only on such type of sailplanes which have enough
margin in maximum weight of non-lifting parts. Total weight of all FES components
including reinforcement ribs for battery compartment box is about 50kg. However, 12V
batteries are not required anymore (except one which is required as buffer battery-usually
tail battery remains), so they can be removed from a glider to save some weight (2 pcs of
standard 12V-7Ah Pb battery have total weight about 5kg).
Exact FES weight depends on type of sailplane, and installed FES components.
2.7 Centre of gravity
Components of FES system are positioned so that after FES installation C.G. position
remains as much as possible on the same position as with pure sailplane. After installation
sailplane C.G. must be checked and corrected if necessary.
Warning: Flying with removed motor is not allowed, if not specified
differently for certain type.
Warning: Flying without battery packs is not allowed, if not specified
differently for certain type.
2.8 Approved maneuvers
Aerobatic maneuvers with FES equipped sailplanes are not permitted, unless it is
specified differently for a certain glider type.
2.9 Maneuvering load factors
Depends on type of sailplane.
2.10 Flight crew
Depends on type of sailplane.
2.11 Kinds of operation
Flights must be conducted under Day / VFR conditions.
Warning: Flying under power in heavy rain is not allowed! Make sure that
cover of battery compartment is sealed with plastic tape.
Warning: For sailplanes equipped with sustainer system it is prohibited from
taking off solely by the means of its own power.
2.12 Minimum equipment
As specified in flight manual of pure sailplane.

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2.13 Aero-tow, winch and auto-tow launching
As specified in flight manual of pure sailplane.
2.14 Other limitations
As specified in flight manual of pure sailplane.
2.15 Limitations placards
Additional limitation placard needs to be added for FES equipped sailplanes:
Speed IAS:
km/h
Kts
Power-plant operation
VPO
160
86
Max. engine start
VPOmax
160
86
Min. engine start
VPOmin
80
43

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3. Emergency procedures
3.1 Introduction
According flight manual of pure sailplane.
3.2 Canopy jettison
Warning: Before canopy jettison, stop motor and switch OFF power switch,
if there is still enough time to do that.
3.3 Bailing out
Warning: Before you bail out, stop motor and switch OFF power switch, if
there is still enough time to do that.
3.3.1 Ballistic parachute
If sailplane is equipped with a ballistic parachute, a special switch is installed which
stops motor automatically in case of activation!
3.4 Stall recovery
As specified in flight manual of pure sailplane.
3.5 Spin recovery
As specified in flight manual of pure sailplane.
3.6 Spiral dive recovery
As specified in flight manual of pure sailplane.
3.7 Motor failure
3.7.1 Motor fail to start
If the motor fail to start, continue flying as a pure glider.
Note :Check if you maybe forgot to switch ON the Power switch.
Reminding message (on the FCU)“Check power switch” should appear if
there was high enough throttle set.

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3.7.2 Power loss during flight
If power is lost during flight, propeller will still rotate as windmill. Push the control
stick forward gently, to sustain desired airspeed! Than you can do next actions:
1. Check first if you maybe unintentionally switched OFF power switch!
Warning: This can happen during retraction of landing gear on some glider
types (LAK17A&B FES) where “Power switch” (toggle switch with red
protection cover) is located on the same side of cockpit like landing gear
retraction handle.
If this happened, just switch Power switch ON again and adjust throttle knob.
Note: On earlier software versions (below v2.13), it was necessary to
manually reduce throttle bar to zero, otherwise motor did not start due to
safety. When throttle was reduced to zero than motor started normally.
On new versions (from FCU v2.13) throttle bar goes to zero automatically!
2. If Power switch was not unintentionally switched OFF, as described in 1st point, proceed
with next actions:
•switch OFF “Power switch”and then also FCU.
•turn ON FCU and check it for any strange behaviour.
•If everything is Ok switch on Power switch, and try to start motor again.
If motor starts and there is any strange behaviour under power:
•stop the propeller from the wind milling phase with the electronic brake.
•After propeller is stopped, switch OFF Power switch and FCU as usually.
In case that you are not able to stop propeller with electronic brake, you will need to land
with the propeller in wind-milling phase. Note that with reducing airspeed down to
minimal speed is not possible to stop propeller from wind-milling. In such
situation try to land carefully on both landing wheels simultaneously, to avoid possible
damage of the propeller.
Note: If there is a grass runway in good condition available it is probably
better to use it than concrete runway.
If there is a grass runway with some holes than it is probably better to use a
concrete runway if is available.
Warning: Try to avoid landing into high grass or similar.
Note: L/D of sailplane with propeller in wind milling phase is only a little
degraded, so you might have enough time to choose a suitable landing place
if you have enough altitude.
Please study FES FCU Instrument manual for detailed behaviour and necessary
actions after appearance of certain messages or LED lights.

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3.8 Fire
3.8.1 Fire on the ground
•switch OFF the “Power switch”
•switch OFF all instruments, and master switch of instruments
•get out of cockpit
•extinguish fire
3.8.2 Fire during flight
In all FES equipped gliders must be installed independent fire warning system
which warns a pilot via very bright red blinking LED light, installed on top middle area of
instrument panel, in case when temperature in battery compartment reach more than
88°C.
In certain cases, pilot could recognize fire also by smell. Next actions are proposed:
•stop motor immediately
•switch OFF the “Power switch”
•open front ventilation if not already opened
•open canopy side window
•land as soon as possible (or bail out if appropriate)
•extinguish fire after landing
3.9 Other emergencies
3.9.1 Loss of 12V electrical power in flight
During soaring flight:
If electronic instruments (radio, flight computer, FCU etc) stop working, during
soaring flight, then continue to fly as a pure sailplane. In such case you will not be able to
start FES.
However, in case that FCU still works, you can try to start motor if necessary.
During powered flight:
If FCU stop working during powered flight, then also motor stops working. However,
propeller would still rotate as windmill and it would not be possible to stop it. You will
need to land with rotating propeller. In such case try to land on both landing gears
simultaneously, to avoid damage of propeller.
If case that only some of the instruments would stop working during powered flight,
but motor and FCU would still work fine, then you can continue to use motor.

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4. Normal procedures
4.1 Introduction
This chapter provides checklists and explanations of procedures for conducting
normal operating procedures. Normal procedures associated with optional equipment can
be found in Chapter 9.
4.2 Rigging and de-rigging, charging, battery pack installation
4.2.1 Rigging and de-rigging of sailplane
Same as described in manual of pure sailplane.
Warning: Make sure that connecting cable is not installed, between Battery
packs (if they are fixed inside the fuselage)
4.2.2 Charging the batteries
Valid for FES Self-launchers:
For self-launching FES battery packs must be always recharged, so that maximum power
for good climb rate is available. This is especially important for:
-cold batteries, when voltage drop under high power load is bigger
-short runways
-high altitude runways
-hot summer conditions
Valid for FES Self-sustainers:
Before each flying day, battery packs should be recharged, especially if motor was
significantly used during previous flights, and long cross-country flight is planned; so that
maximum energy will be available when needed.
Note: It is recommended to recharge Battery packs just a day or two before
flight is planned. However, plan charging so that there will be enough time
for properly completed charging process!
Detailed instructions about charging of Battery packs are described in separate FES
Battery pack manual.

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4.2.3 Installing the batteries
Warning: Make sure that both battery packs are fully charged before
installation into sailplane. Both battery packs must have approximately the
same voltage level of each cell (close to 4.16 V per cell). There should be
less than 1V difference, between total voltage levels of each battery pack!
1. Check batteries for any visual damage
Warning: Even small visually detectable damages imply that the affected
battery is not airworthy.
2. Open battery compartment cover
3. Check: Power switch (Key) OFF
4. Check: Sailplane main switch (fuse) OFF
5. Insert first pack (terminals facing forward) and slide it back to rear position
6. Insert second pack (terminals are facing rearward)
7. Place pair of fixation plates in the middle of rear pack, above carrying strap and
tighten fixation knob
8. Secure forward battery in the same way
9. Lift power cables from side support
10. Plug in shorter cable, with 8mm pin in BLUE (or BLACK) housing, to minus marked
8mm socket of front battery pack
11. Plug in longer cable with 10mm pin in RED housing, to plus marked 10mm socket of
rear battery pack
12. Insert DATA cable connectors, to each battery pack DATA connector
Caution: Prior to insert DATA cable connector make sure that the orientation
is correct. Connector should be plugged in straight direction, otherwise pins
could be damaged.
13. Close battery compartment cover.
4.3 Daily inspection
Please keep in mind the importance of the inspection after rigging the glider and
respectively each day prior to the first take off. As a minimum check the following items. If
any problems are found they must be corrected before flight.
•Check the sailplane as required for each type according its Flight Manual.
•Check the FES system visually especially propeller blades condition
•Check function of fire warning flashlight by test button (must light up brightly,
about one time per second, if necessary exchange 9V battery)
4.4 Pre-flight inspection
•Check the sailplane itself as requested before a flight
•Perform short preflight test run as described below

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4.4.1 Preflight test run
After battery packs were recharged, it is always required to perform short motor
run, so that FCU instrument can recognize recharge and new charge level is stored to the
FCU memory.
Short motor run is also recommended before first flight in flying day.
1. Remove propeller covers and a tail dolly
2. Open battery compartment cover
3. Check: Power switch OFF
4. Switch ON, BMS on each battery pack, and wait until initial check is completed
5. Insert Connecting cable between the battery packs
6. Close battery compartment cover, and seal it with tape
7. Seat into the glider, and close canopy
8. Check that no one is around propeller zone, in front of glider or in line of propeller
9. Switch ON, FCU instrument
10. Switch ON, Power switch
11. Wait about 5 second, for FCU to show all battery bottles
12. Start motor but use only low power to check proper operation
Caution : In case that you would like to test, system at maximum power,
somebody must hold a fuselage tube down, so that glider cannot lift tail,
which could result in damaged propeller blades.
Warning : Do not run the motor for longer time, on the ground, especially
not at high power! When motor is stopped, also cooling is stopped, and so
motor temperature can rise very quickly, which can lead to damaged motor!
13. Stop motor and check if automatic positioning is working fine
14. Switch OFF Power switch

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4.5 Normal procedures and recommended speeds
As described for a pure sailplane, but have in mind that with installed FES your glider
has higher wing loading, so you have to adjust speeds accordingly.
4.5.1 Aero tow launch
Before take-off, always switch ON the FCU instrument. Double check that “Power
switch” is OFF before somebody approach front area of the glider in order to attach tow
rope to the hook. All the time during tow, “Power switch” should be OFF!
Warning: It is not allowed to start FES motor during aero tow!
4.5.2 Winch launch
Before take-off, always switch ON the FCU instrument. Double check that “Power
switch” is OFF before somebody approach front area of the glider in order to attach
towing cable to the hook. All the time during winch launch, “Power switch” should be OFF!
Warning: It is not allowed to start FES motor during winch launch! Towing
rope must be always released before running FES motor.
4.5.3 Auto tow launch
Before take-off, always switch ON the FCU instrument. Double check that “Power
switch” is OFF before somebody approach front area of the glider in order to attach
towing rope to the hook. During tow, “Power switch” should be OFF!
Warning: It is not allowed to start FES motor during auto tow launch!
Towing rope must be always released before running FES motor.
4.5.4 Taxiing procedures
Warning: Taxiing is not allowed when FES is installed as sustainer system!
Your sailplane needs to be factory equipped with steerable tail wheel, and small
wing tip wheels to be suitable for taxiing. Do not try to use tail dolly for taxiing!
For taxiing, use only concrete or good grass runways with short grass. Do not try to
taxi if runway is with a holes, otherwise propeller blades can be damaged!
To start moving, use a little bit more power, but then decrease it quickly, so that
you will not be taxiing too fast. Try not to use a wheel brake, or use it very carefully, to
avoid damaging propeller!

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4.5.5 Self-launch and climb
Warning: Self-launch is not allowed when FES is installed as sustainer
system!
Before a self-launch be always prepared, what actions you will do in case of motor
failure, during different stages of take-off. Take into account wind conditions, airfield
altitude, length of runway, obstacles at the end of runway, outside temperature etc.
If runway is very short, with a lot of obstacles and without alternatives in
case of motor failure, then simply do not fly there!
Caution: Always avoid performing take-off with tail wind!
Self-launch procedure:
1. Check that tail dolly and propeller covers are removed
2. Seat into the glider, fasten your seat belts and close the canopy
3. Check that airbrakes are closed, and trimmer set to proper position
4. Position flaps to proper position for take-off (depending on type of sailplane)
5. Check that motor ventilation is opened
6. Check that no one is around propeller zone, in front of sailplane or in line of
propeller (call “clear prop”)
7. Switch ON FCU instrument
8. Switch ON Power switch, and wait until all parameters become visible
9. Ask for take-off permission by radio, and wait for approval
10. Start motor with rotating throttle knob in clockwise direction to low RPM
11. Gently rotate throttle knob clockwise to maximum power
12. Accelerate, adjust flaps position and gently lift off at suitable speed
13. When safe altitude is reached, reduce power and continue with climbing
14. Retract landing gear
Caution: During Self-Launching, pay attention to any other traffic in the
circuit –which may not be familiar with electric self-launching sailplanes (and
may not expect your aircraft to launch unassisted)
4.5.6 Free flight
As described for a pure sailplane, but have in mind that with installed FES your glider
has higher wing loading, so adjust speeds accordingly. FCU instrument should be always
ON during soaring flight.
4.5.7 Low speed flight and stalling behaviour
As described for a pure sailplane, but have in mind that with FES, your glider has
about 5kg/m2 higher wing loading, and as result of that minimum speed is higher.

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4.5.8 Cruise and climbing with running motor
FES can be used for long continuous cruise at low power settings, or climbing at
higher power settings!
Caution: During motor operation, ventilation must be fully opened (depends
on type of sailplane; usually ventilation lever must be pushed fully forward).
Warning: I case that you forget to open ventilation; warning message
“Check ventilation” will appear on the FCU screen. FCU monitors temperature
rise gradient, and when gradient is more than usual with opened ventilation
such message will appear!
Motor starting procedure during flight:
1. Check that all values on the FCU instrument are in normal range (FCU must be always
switched ON during flight)
2. Turn ON Power Switch
3. Check if there is green LED ON (left lower LED), check Voltage level
(If there is no green LED or red LED is blinking motor will not run). Read FES FCU
instrument manual for detailed FCU description
4. Start motor with Throttle knob rotating in clockwise direction gently.
Use about 4kW of power for horizontal flight, and more for climbing. Maximum climb
rate depends on glider type and it is affected by its weight, speed, flaps position etc.
Available maximum power is reducing slowly due to voltage drop, during discharging
of battery packs. Maximum power can be used only until any of temperature values reach
yellow warning. (motor and controller at 70 deg, battery packs at 45 deg)!
Note: You can reduce power in thermals, and use more power in sinking air
Do not use high current at lower voltages; this mean below 95V. Always try to fly as
much as possible on lower power settings where efficiency of complete system is the
highest!
During soaring flight always keep the FCU turned ON.
Switch OFF Power switch if motor is not running.
4.5.8.1 Propeller stop with electronic braking
To stop propeller with electronic braking, you need to rotate Throttle knob in
counter-clockwise direction for 1 step, from zero throttle, so that throttle line on display
starts blinking red!
Note: For successful stop the motor should reach about 1500 RPM,
otherwise braking will not work, due to insufficient induced voltage
(regeneration function of controller is used for propeller braking).