Sportine Aviacija LAK-17C FES User manual

Joint Stock Company "SPORTIN ˙ E AVIACIJA ir Ko"
Poci¯ unu˛ km., Ašmintos sen., LT-59327, Prienu˛ raj., Lithuania
tel.:[phone] •fax:[phone] •e-mail: [email protected] •www.lak.lt
DOC. NO. LAK-17C-FES-AMM-00-00 MAINTENANCE MANUAL
LAK-17C FES
Powered Sailplane
with Front Electric Self-launcher system
TYPE: LAK-17 MODEL: LAK-17C FES
SERIAL NO.
REGISTRATION
DATE OF ISSUE
TVIRTINU
UAB "Sportin˙e aviacija ir Ko"
Direktorius
Vytautas Mačiulis
It is a preliminary manual. The sailplane is not certified and has not shown compliance with
airworthiness requirements.
This sailplane is to be operated in compliance with the information and limitations contained
herein.

LAK-17C FES Maintenance Manual
0.1 Record of revisions
Any revision of the present Manual, except actual weighing data, must be recorded in the following
table and in case of approved Sections endorsed by responsible airworthiness authority.
The new or amended text in the revised page will be indicated by black vertical line in the left
hand margin, and the Revision No. and date will be shown on the bottom left hand of the page.
Revision Affected Affected Approval Date of Date of Signature
Section Pages Approval Insertion
13/07/22 #0.1 0 (i)...(iv)
2 2-11
2 2-14
Rev. 13/07/22 #0.1 ( i )

LAK-17C FES Maintenance Manual
Revision Affected Affected Approval Date of Date of Signature
Section Pages Approval Insertion
Rev. 13/07/22 #0.1 ( ii )

LAK-17C FES Maintenance Manual
0.2 List of Effective Pages
Section Page Date of Issue
1 1-1 25 06 2020
1-2 25 06 2020
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2 2-1 25 06 2020
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Section Page Date of Issue
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LAK-17C FES Maintenance Manual
Section 1
GENERAL
1.1 Introduction....................................... 1-2
1.2 Warnings, cautions and notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
1.3 Descriptionofsailplane................................. 1-2
1.4 Abbreviations...................................... 1-3
1.5 Three-viewdrawing................................... 1-4
Rev. 25/06/20 #0.0 1-1

LAK-17C FES Maintenance Manual
1.1 Introduction
This Maintenance Manual contains information for pilots, technicians and mechanics about safe
and proper maintenance of the sailplane LAK-17C FES. This information is given in accordance
with requirements of CS 22.1529.
1.2 Warnings, cautions and notes
The following definitions apply to warnings, cautions and notes used in this 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 but which
is important or unusual.
1.3 Description of sailplane
The LAK-17C FES is a new generation self-sustaining/self-launching sailplane of FAI 18 m class
designed according to CS-22 requirements. Glider is equipped with Front Electric Self-launcher
system.
The sailplane has flaps, T-shaped tail, retractable main gear wheel and water ballast tanks of
188 ltr /49.6 US gal capacity (inner wings – 158 ltr / 41.7 US gal, outer (18 m) wings – 30 ltr /
7.9 US gal).
The sailplane is made of composite materials. Wing shell is of three-layer construction
(composite material – foam – composite material). Carbon rods GRAPHLITE SM 315 have
been used in spar construction.
The airbrakes are located on the upper part of wing. The fuselage is of monocoque construction.
Pilot seats and pedals of rudder control are adjustable. The cockpit canopy opens forward together
with instrument panel. In case of emergency the canopy is ejected.
Main landing gear has a wheel of 5.00-5 size and a shock absorber.
The tow release is mounted near the main landing gear and (or) in front of pilot cockpit at
the bulkhead.
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LAK-17C FES Maintenance Manual
Technical data of the LAK-17C FES
Wing span....................................18m (59.06ft)
Wing area.....................................10.32m2, 111.08 ft2
Wing aspect ratio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31.39
Wing dihedral angle . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 °
Fuselage length. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6.55 m (21.506 ft)
Height........................................1.29m (4.23ft)
Max airspeed in calm air . . . . . . . . . . . . . . . . . . . . . . 275 km/h (148.5 kts)
Max airspeed in rough air . . . . . . . . . . . . . . . . . . . . . 190 km/h (102.6 kts)
Max gross weight. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 600 kg (1322.8 lbs)
Min wing loading. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36.47 kg/m2(7.47 lbs/ft2)
Max wing loading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58.13 kg/m2(11.9 lbs/ft2)
Min sink rate..................................0.53m/s
Best L/D without ballast at 104 km/h . . . . . . . . . 50.2
Best L/D with ballast at 121.5 km/h . . . . . . . . . . 50.2
g limits without water ballast. . . . . . . . . . . . . . . . . .−2.65/+5.3
g limits with water ballast . . . . . . . . . . . . . . . . . . . . .−2.65/+5.3
1.4 Abbreviations
Abbreviations used in this document:
A – ampere
Ah – ampere hour
°C– degree Celsius
C.G. – center of gravity
cm – centimeter
daN – decanewton
g – gram
h – hour
kg – kilogram mass
kG – kilogram force
km – kilometer
L/D – glide ratio
ltr – liter
m – meter
mm – millimeter
MPa – megapascal
V – volt
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LAK-17C FES Maintenance Manual
1.5 Three-view drawing
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LAK-17C FES Maintenance Manual
Section 2
DESCRIPTION OF THE SAILPLANE AND SYSTEMS
2.1 Introduction....................................... 2-3
2.2 Airframeconstruction ................................. 2-3
2.2.1 Wing....................................... 2-3
2.2.2 Fuselage..................................... 2-4
2.2.3 Verticaltail ................................... 2-4
2.2.4 Horizontaltail.................................. 2-4
2.2.5 Landinggear .................................. 2-5
2.3 Controlsystems..................................... 2-5
2.3.1 Ailerons and flaps control system . . . . . . . . . . . . . . . . . . . . . . . 2-5
2.3.2 Elevator control system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
2.3.3 Trimmer control system . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
2.3.4 Rudder control system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
2.3.5 Airbrakes control system . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7
2.3.6 Water ballast control system . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7
2.3.7 Tow release control system . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7
2.3.8 Main landing gear control system . . . . . . . . . . . . . . . . . . . . . . . 2-8
2.3.9 Landing gear brake control system . . . . . . . . . . . . . . . . . . . . . . 2-8
2.4 Equipmentandsystems ................................ 2-8
2.4.1 Pitot and static system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8
2.4.2 Flight and navigation instruments . . . . . . . . . . . . . . . . . . . . . . . 2-9
2.4.3 FCUinstrument................................. 2-9
2.4.4 Electric and radio equipment . . . . . . . . . . . . . . . . . . . . . . . . . 2-11
2.4.5 Canopy ventilation system . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-12
2.4.6 Cockpit canopy and its emergency jettison system . . . . . . . . . . . . . . 2-12
2.4.7 Cockpitequipment ............................... 2-13
2.4.8 Fasteningofbaggage .............................. 2-13
2.5 FESsystem ....................................... 2-13
2.5.1 Generallayout ................................. 2-13
2.5.2 Motor ...................................... 2-13
2.5.3 Batteries..................................... 2-14
2.5.4 Motorcontrols ................................. 2-16
2.5.5 Propeller..................................... 2-16
2.6 Placards and marking of controls . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-16
2.7 Dataforrigging..................................... 2-16
2.7.1 Allowed clearances in connections of aggregates . . . . . . . . . . . . . . . 2-16
2.7.2 Allowed clearances in control systems . . . . . . . . . . . . . . . . . . . . . 2-16
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LAK-17C FES Maintenance Manual
2.7.3 Allowed forces in control systems . . . . . . . . . . . . . . . . . . . . . . . 2-16
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LAK-17C FES Maintenance Manual
2.1 Introduction
In this section there is given description of sailplane aggregates, systems, equipment, tables and
markings and information about proper sailplane maintenance.
2.2 Airframe construction
2.2.1 Wing
Sailplane wings (fig. 57-00-01, fig. 57-00-02) are made of composite materials and consist of four
parts: right inner wing (pos. 1), left inner wing (pos. 2) and two outer wings with winglets.
For wingspan 18 m of length, the outer wings 3500 mm of length (pos. 3) are used. The wing
airfoils:
s (m) c (m) Airfoil
0.0 0.741 LAP7-150
1.2 0.711 LAP7-131/17
4.6 0.625 LAP7-131/17
6.5 0.5 LAP7-129/18
8.0 0.38 LAP7-128/19
8.855 0.226 LAP93/148
Construction of wings is of one spar monocoque type. Their spars are 2-T shape in section.
Carbon rods GRAPHLITE SM 315 are used for spar shelves. Wing shells are stuck of two parts:
an upper and lower shell parts. The shell is of three-layer construction. External and internal
shell layers are made of carbon and glass fiber. Between them there is foam. Thickness of foam
of wing shells is 6 mm.
Spars of right and left wings are joined together with the help of two pins. Spar panel of right
wing is cut off pyramid-shaped. Spar panel of left wing is fork-shaped. An outer wing is connected
to the wing with the help of outer wing spar pins. The pins are fixed by the help of special key.
There are adjustable hubs in the wing root ribs to fasten the wings to the fuselage.
Wings have flaps and flap-aileron type ailerons. Their shell structure is analogical to the wing
shells structure.
A flap has 6 hinges. Its length is 3.42 m, area 0.4 m2.
Length of ailerons is 5.05 m, area 0.445 m2. As the outer wing is connected to the inner wing,
the part of an aileron on the outer wing is connected to an aileron on the inner wing automatically.
On an upper part of wing shell there are covers (pos. 16) of airbrakes. Their contour coincides
with the wing surface.
Air gaps between wings and control surfaces are closed with seals (fig. 57-00-03, fig. 57-00-04).
The Seals-Turbulator scheme also shows the positioning of turbulator. The sealing tape on the
lower part of the wing must close the gap and connect the control surfaces and the wing surfaces.
On the upper part of the wing only the control surfaces are covered with sealing tape. Mounting
the seals must ensure the free movement of control surfaces.
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LAK-17C FES Maintenance Manual
2.2.2 Fuselage
The sailplane fuselage (fig. 53-00-01, fig. 53-00-02) is made of composite materials, construction
is monocoque. The fuselage is oval-shaped in section (fig. 53-00-02), slightly narrowing at top and
turning into circle at the fuselage end part. The fuselage end part is cone-shaped turning into fin.
The fuselage shell is glued of two symmetric parts, right and left (pos. 2, 3). Shell gluing
seams are in vertical plane (in upper and lower shell parts).
Glass and carbon fiber are used in shell construction. Kevlar is used in the pilot cockpit zone.
The fuselage is reinforced by a metal girder (pos. 4) at wing attachment to the fuselage zone.
Landing gear (pos. 5) is fastened to it. The gear is fully retractable. Its recess has a hermetic
hood in order to avoid getting dirt and dust inside the body. As the gear is retracted the landing
gear door is closed.
The tail wheel (pos. 6) is fixed at the fuselage end part. The pilot cockpit is covered with a
canopy (pos. 1) which opens upward.
2.2.3 Vertical tail
The vertical tail (fig. 55-30-01) consists of a fin (pos. 1) and a rudder (pos. 2).
The fin is made together with the fuselage. The fin shell is of monocoque three-layer
construction. Its internal and external layers are molded of composite materials and between
them there is foam 6 mm of thickness. The frame of the fin consists of a spar (pos. 3) of
three-layer construction, a rear wall molded together with right fin shell (pos. 4) and 3 ribs
going from nose till the spar, an upper, middle and lower (pos. 5, pos. 6, pos. 7).
A water ballast tank (pos. 8) of capacity 8 ltr is fitted inside the fin between nose and spar
and between lower and middle ribs.
Along the spar forward side a container for batteries (pos. 9) is mounted between the middle
and upper ribs.
The radio aerial (pos. 10) is fixed in the vertical tail.
An elevator push-pull rod (pos. 12) is in the space between fin spar and rear wall.
A rudder (pos. 2) is hung up on the right fin shell with 3 suspended brackets of composite
materials with bronze hubs (pos. 13). Shells of the rudder like ones of the fin are of three-layer
construction (an external layer, foam 3 mm of thickness, an internal layer).
The wall of the rudder (pos. 14) is of three-layer construction, as well.
2.2.4 Horizontal tail
The horizontal tail (fig. 55-10-01) consists of a stabilizer (pos. 1) and an elevator (pos. 2 and
pos. 3).
The stabilizer is made of composite materials and construction of its shell is similar to wings
shell construction.
The elevator consists of two parts: left (pos. 3) and right (pos. 2). Control surfaces are
partially balanced and made of composite materials. Each part of the elevator is fastened to the
stabilizer with 3 pins.
The horizontal tail is attached onto the upper fin part (fig. 55-10-10).
The elevator is joined to control system automatically.
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LAK-17C FES Maintenance Manual
2.2.5 Landing gear
The landing gear consists of a retractable main wheel (fig. 32-30-01, pos. 5) and fixed tail wheel
(fig. 53-00-01, pos. 6).
Landing gear main wheel type TOST 045100 with Simplex shoe brake (or BERINGER wheel
with brake) is attached to metal girder (fig. 53-00-02, pos. 4) by the help of stands (fig. 32-30-01,
pos. 6, pos. 7) and a shock absorber (fig. 32-30-01, pos. 8). The opening for the wheel is covered
with a main wheel box (fig. 32-30-01, pos. 9). It protects the fuselage internal space from dust
and dirt.
With main wheel up the landing gear door (fig. 32-10-02, pos. 2) is closed.
Tail wheel (fig. 32-40-20) 6x1 1/4" (or 200 x 50) of size is attached to fuselage shell with help
of an axle (pos. 4), bolt (pos. 3) and washer (pos. 1).
2.3 Control systems
2.3.1 Ailerons and flaps control system
In order to ensure required rigidity and reduce unsteadiness, ailerons and flaps control system
(fig. 27-10-01, fig. 27-10-02, fig. 27-10-03) is made of metal levers and rods. The ailerons are
suspended, i.e. with changing flaps position ailerons deflect as well.
Movement from the control stick (pos. 1) is transmitted by help of rods and intermediate
bellcranks (pos. 4, 5) to coaxial ailerons-flaps shaft (pos. 7) which transfers this movement by
help of an automatic joint to shaft in the wing (pos. 9). Further the bell crank (pos. 10) turns
rotational movement to forward movement and transmits it to summary mechanism (pos. 11).
From this mechanism the movement is transmitted by help of rods and differential bellcranks (pos.
12, 13, 14) to an aileron and deflects it in required direction. There are three ailerons. Aileron 2
is connected to control rod. The movement of aileron 2 is transmitted to aileron 1 and aileron 3
by the help of root and tip ribs of the ailerons.
The control handle of the flaps (pos. 2) is attached to the left side of the cockpit. Movement
by help of rods and a bell crank (pos. 6) is transmitted onto coaxial shaft (pos. 7) and by help
of an automatic joint is transmitted to flaps shaft (pos. 15) in the wing. The movement from the
shaft is transmitted onto the flaps by help of the bell crank (pos. 16), summary unit (pos. 11)
and differential bell cranks (pos. 12, 13, 14) deflects the ailerons.
The position of flaps is fixed by a plate at control handle in the cockpit.
Ailerons and flaps deflection angles are given in table:
Position of flaps Hanging up angle ±1◦ Ailerons deflection angle ±2◦
Flaps Ailerons
−1−3◦−3◦−15◦/+ 22◦
00◦0◦−16◦/+ 21◦
+1 5◦5◦−20◦/+ 20◦
+2 10◦10◦−22◦/+ 18◦
+3 15◦14◦−24◦/+ 14◦
L20◦17◦−25◦/+ 10◦
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LAK-17C FES Maintenance Manual
2.3.2 Elevator control system
The elevator control system (fig. 27-30-01) consists of metal rods and bellcranks. In order to
ensure rigidity the main rod in the fuselage is supported by guide rollers (pos. 5).
Movement from the stick (pos. 1) by help of rods and intermediate bellcranks (pos. 2, 3, 4) is
transmitted to the elevator and deflects it in required direction.
2.3.3 Trimmer control system
An adjustable trimmer for the elevator (fig. 27-30-02) takes over long-lasting loads on the control
stick from the pilot and levels the sailplane in all ranges of airspeeds, C.G. positions and allowed
flap angles.
The trimmer is mounted on the left side of the cockpit in a molded trimmer box (pos. 1). It
consists of:
•a handle (pos. 2) with a hub welded, a fixing edge and a plate for springs,
•a bronze bar (pos. 3) the handle is moving along,
•a ring (pos. 4) screwed to the elevator’s rod,
•a fixing plate with teeth (pos. 5) riveted on trimmer box side,
•two springs of the same tension 16 ×1.6mm (pos. 6). The front spring connects the
trimmer handle to a plate (pos. 7) on control stick shaft and the end spring – the handle
with a ring (pos. 4) on the elevator’s rod.
Max motion of the trimmer handle is 80 mm. As the handle moves it pulls or pushes the stick
in the same direction.
The trimmer’s handle has a drop-shaped tip (pos. 12) painted in green.
The trimmer forces (force measuring place on stick – hand holding center):
Trimmer position Force on control stick, daN
forward 2.0÷2.5
backward 2.0÷2.5
2.3.4 Rudder control system
The rudder control system (fig. 27-20-01, fig. 27-20-02, fig. 27-20-03) is of combined type: steel
cable from pedals to a bellcrank in the middle part of fuselage and steel rod 16 ×1mm, from
the bellcrank till the rudder.
Pedals are adjustable according to a pilot height. The control handle of pedals is mounted on
the right side of cockpit, on the ailerons control rod hood.
Pedals junction (pos. 1) is mounted on longitudinal pipe with holes for fixing drilled on it.
Pedals cross pipe leans upon cockpit floor by textolite disks. The disks are fixed with wire pins
at the ends of the cross pipe.
The control rod (pos. 7) in the cylinder-shaped fuselage is supported by two guides (pos. 8)
molded on frames. An adjustable rod tip is connected to the rudder.
Motion of the rudder is restricted by a bellcrank (pos. 5) in the fuselage which is supported
by two non-adjustable supports (pos. 6) mounted at the center section girder.
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LAK-17C FES Maintenance Manual
2.3.5 Airbrakes control system
The airbrakes control system (fig. 27-10-01, fig. 27-10-04, fig. 27-10-05) comprises the control
handle (pos. 3), attached to the left side of a cockpit and rigid rods and bellcranks. Movement
from control handle by help of an intermediate rod is transmitted to the shaft (pos. 8) which
through an automatic joint transmits the movement to the shaft (pos. 17) in the wing. The
bellcrank (pos. 18) transfers rotational movement into longitudinal one and through intermediate
rods transmits it to lifting equipment consisting of a bell crank (pos. 19) and shoulders (pos. 20,
pos. 21).
The airbrakes are fixed in the closed position by an over-center lock which prohibits
spontaneous opening of the interceptors. Sudden breaking angle of the lock is adjusted by fixing
bolt (pos. 22).
As an optional variant, the airbrakes control handle may also control the hydraulic brake of
the main landing gear wheel (fig. 32-40-03).
2.3.6 Water ballast control system
The water ballast control system (fig. 41-20-01, fig. 41-20-02, fig. 41-20-03, fig. 41-20-04) consist
of integrated tanks in inner wings, outer wings and fin. The water ballast system of inner and
outer wings is controlled by the handle (pos. 1) located at the right side of the cockpit. The
movement of the handle is transmitted by rod (pos. 2) to a shaft in a fuselage (pos. 3). The
movement of the shaft in a fuselage is transmitted by automatic joints to the wing shafts (pos.
4). The shaft in the wing lifts an arm (pos. 5) with a plug (pos. 6) and opens the water tank.
The plug is sealed (pos. 7).
The movement of shaft (pos. 4) is transmitted by rod (pos. 8) to lever (pos. 9) and carbon
rod (pos. 10). Adjustable rod end push the valve (pos. 14) of the inner wing tank water tap. The
tank of the inner wing is filled through the opening located at the end of the inner wing, the front
side of the rib.
The fin water ballast system is controlled by the handle (pos. 16) located at the right side of
cockpit.
The movement of the handle is transmitted by the carbon rod (pos. 17) to the water tap of
the fin tank (pos. 18). The fin water ballast tank is filled through the opening (pos. 19) at the
top of the fin.
The wing and fin water ballast tanks have drainage systems and openings for drainage.
Warning: Before filling up the water tanks check that the drainage openings are not
plugged up
2.3.7 Tow release control system
A towing hook (fig. 40-10-01, fig. 40-10-02, pos. 6) is arranged in central part of fuselage at the
main frame and (or) in pilot cockpit at the bulkhead. If mounted, both towing hooks are operated
with one handle.
Movement from the control handle (pos. 1) on the left side of a cockpit by steel cable (pos. 2)
is transmitted to the shoulder (pos. 5) which opens the hook. The cable looseness is eliminated
by an adjustment junction which comprises the junction (pos. 3) and fixing nut (pos. 4).
The travel of the release handle in the case of only one hook is 55 mm. In the case of two
hooks the release handle travel is 92 mm.
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2.3.8 Main landing gear control system
The landing gear control system (fig. 32-30-01) controls retracting and releasing of the main wheel.
It consists of a control rod (pos. 1) on the right side of cockpit, an intermediate rod (pos. 2)
and a bellcrank (pos. 3). A gas spring (pos. 4) makes it easier to retract the wheel. The control
handle in the retracted and released positions is fixed in the slots of plate (pos. 5).
2.3.9 Landing gear brake control system
The hydraulic brake (manufacturer: BERINGER) is controlled via the lever on the control stick
(fig. 32-40-02). The movement of lever (pos. 1) is transmitted to the master cylinder (pos. 2) by
the cable (pos. 5). The master cylinder is connected to brake fluid reservoir. The brake fluid is
transmitted by hoses (pos. 8) through the pressure limiter (pos. 4) to the brake caliper (pos. 3)
In order to eliminate loosening of the cable (pos. 5), the adjustment junction is mounted on
the cockpit floor under the pilot seat. The junction consists of cable support (pos. 6) and fixing
nut (pos. 7).
The brake fluid DOT4 is used in the brake system. To fill the brake system, recommendations
of the manufacturer shall be used (www.beringer.fr).
As an optional variant, the landing gear brake may be controlled by the air-brakes control
handle.
Optional landing gear brake control system. The brake is controlled by the air-brakes
control handle (pos. 1) (fig. 32-40-03). The movement of air-brakes shaft (pos. 2) is transmitted
to the master cylinder (pos. 4) by control rod (pos. 3). The master cylinder is connected to brake
fluid reservoir. The brake fluid is transmitted by hoses (pos. 7) through the relief valve (pos. 6)
to the piston caliper (pos. 5). To control the brake cylinder, only a half of the air-brakes control
handle’s travel is used.
To adjust the travel of the master cylinder, a threaded plate with slot (pos. 8) is used. The
plate is fixed by nut (pos. 9).
2.4 Equipment and systems
2.4.1 Pitot and static system
Pitot and static system of the sailplane is shown in fig. 34-10-01. The system consists of:
1. Static pressure receiving ports (pos. 9) which are located at a two sections on a fuselage skin
from the inside (distances from sailplane nose to the ports is given at fig. 34-10-01). Static
pressure receivers consists of a glass fiber tanks with air inlet as a holes drilled through the
fuselage skin.
There are static pressure lines S1 and S2. The air gets from three receivers located on the
fuselage skin every 120°.
Warning: During a sailplane preflight inspection the holes of static pressure receiver on
the fuselage sides shall be checked for cleanliness.
2. Pitot (pos. 10) is a steel pipe mounted on the fin and right against the air flow. This line is
marked by the letter D.
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3. Compensated pressure receiver (pos. 11) is a special Nix pipe mounted in fin. This line is
marked by the letter N.
4. Flexible polyvinylchloride pipes of different colors transmit air pressure from receivers to
corresponding measuring instruments on the sailplane instrument panel. Each separate
pressure line has pipes of different colors:
•red – for total pressure line (D),
•yellow – for static pressure lines (S1 and S2),
•green – for compensated pressure line (N).
2.4.2 Flight and navigation instruments
These flight and navigation instruments as option are mounted in the sailplane:
No. OPTION A OPTION B
1 air-speed indicator LUN-1106, scale
50. . . 300 km/h, with range markings
air-speed indicator WINTER 6 FMS 421
2 altimeter BD-10K or VB-10PS with
altitude corrector
altimeter WINTER 4 FGH 20
3 mechanical variometer LUN-1141 variometer BOHLI
4 side-slip indicator LUN-1211 electronic variometer FILSER LX5000 or
FILSER LX7000
5 compass KI-13A fly computer display FILSER LX5000 or
FILSER LX7000
6 FCU instrument side slip indicator LUN 1211
7 Radio ATR 600 radio Becker AR 4201 or Filser ATR 600
8 Fire warning system OPTION 1 or
OPTION 2
FCU instrument
9 Fire warning system OPTION 1 or
OPTION 2
All the instruments, except for the compass KI-13A, are mounted in the instrument panel.
The compass is attached to the canopy glass or on the instrument panel.
There is room left in the instrument panel for extra instruments (fig. 31-00-01).
It is possible to use other standard flight and navigation instruments and change instruments
positions on the instrument panel (fig. 31-00-01). These instruments must correspond with
national regulations. Max instrument panel weight in flight – 4.1 kg.
2.4.3 FCU instrument
FES parameters are controlled by the FCU instrument, produced by LXNAV Company. The
motor is operated with the Throttle knob located on the FCU instrument. Electronic safety
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devices are provided to avoid miss operation. The details of the instrument are given below.
Operation. The FCU instrument was designed to control and improve safety of motor use.
FCU instrument must be continuously switched on during flight.
Warning: Keep FCU instrument power supply always switched on during flight.
Instrument indications. The FCU instrument for LAK-17C FES sailplane has on its front side
three LED showing the most important states of the system during all operation time. Additional
LCD display gives more detailed information about the same states and other values. On the
front side are also “ON/OFF” main FCU switch and THROTTLE/BRAKE/RESET button. On
the back side are connectors.
FES control unit instrument
Description Description of function
Switch ON/OFF for FCU instrument
Throttle, brake, reset Power button from minimum to maximum RPM
Push button to reset and second screen
LED 1 – red colour alarms from FCU, see detailed specification of errors
LED 2 – green colour if green LED is ON then controller is ready for operation
LED 3 – red colour if red LED is blinking then something is wrong on controller – see error
codes
LCD Color display V meter, A meter, Power meter, Temperature of motor, controller,
Bat1, Bat2, RPM, Alarm messages
Alarm buzzer Voltage level in batteries reached minimum, release throttle or stop
operation
Temperature of motor is too high, release throttle or stop operation
Power switch ON/OFF for controller (not on FCU but on cockpit right side)
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Buzzer. The buzzer gives additional acoustic information to the pilot during handling errors,
dangerous motor states. After buzzer starting, reason is displayed on the LCD display.
Handling errors produce a pulsed buzzer tone.
High temperature of motor, low battery voltage produce a continuous buzzer tone.
Operating environment. The FCU instrument is designed for operating at environment of
the −20 °C(−4°F) to +60 °C(+140 °F) temperature range. At lower or higher temperatures FCU
instrument can function improperly.
The FCU instrument was designed to improve safety of motor use. This important FCU
function can only obtained when FCU instrument is always switched on during flight. Any other
use is outside of manufacturer agreed FCU instrument operation mode.
If FCU instrument is switched off during motor run, all safety in motor operation is lost.
To have a sure detection for use outside agreed operation, FCU instrument stores error and
operation information.
More detailed functionality of FCU is described in separate FES FCU INSTRUMENT manual
latest approved revision.
2.4.4 Electric and radio equipment
The sailplane electric system is shown at fig. 72-97-01. The sailplane may be equipped with other
instruments (GPS or board computer) and an existing scheme enables to connect them easy.
Accumulator batteries of two types are used in sailplane:
•three accumulators NP 2.1-12 is fitted in a special container. The container is located in the
fin (fig. 55-30-01).
•two FES battery packs from 14 high power Lithium Polymer cells each. FES battery packs
are located in the FES battery box (fig. 72-00-00).
LAK-17C FES two battery packs are wired in serial. One battery pack has 14 cells, so
altogether 28 cells. Nominal capacity of each cell is 40 Ah, at middle voltage 3.7 V (minimum
3.2 V, maximum 4.2 V).
Min total allowed voltage of batteries . . . . . . . . . . . . . . . . . . . . . . 90 V;
Max total voltage of batteries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118 V.
Battery charger KOP1001 BMS version or two KOP602 BMS version. Charger is
programmable and appropriate charging settings are programmed at delivery.
Approved Battery Management System: FES-BMS-9R which is integrated in GEN2 battery
packs.
More detailed data about battery packs are described in separate FES Battery pack GEN2
with integrated BMS (Battery Management System) manual, latest approved revision.
If FES was used during flight, take batteries out for recharging.
Rev. 13/07/22 #0.1 2-11