Sportine Aviacija LAK-17C FES Technical specifications

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-AFM-00-00 FLIGHT 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.
THIS MANUAL SHOULD ALWAYS BE KEPT ON BOARD OF THE
SAILPLANE

LAK-17C FES Flight 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 the case of approved Sections, endorsed
by the responsible airworthiness authority.
The new or amended text in the revised page will be indicated by a black
vertical line in the left hand margin, and the revision number will be shown
on the bottom left hand of the page. Revision number contains the following
information:
Rev.20/04/20#0.0
RevisionNumber
IssueNumber
DateofIssue:DD/MM/YY
Revision Affected Affected Approval Date of Date of Signature
Chapter Pages Approval Insertion
02/10/20 #0.1 0 (i). . . (iv)
1 1-1. . . 1-4
14/07/22 #0.2 0 (i). . . (iv)
2 2-5
6 6-8
Rev. 14/07/22 #0.2 ( i )

LAK-17C FES Flight Manual
(continued)
Revision Affected Affected Approval Date of Date of Signature
Chapter Pages Approval Insertion
Rev. 14/07/22 #0.2 ( ii )

LAK-17C FES Flight Manual
0.2 List of Effective Pages
Section Page Date of Issue
0 (i) 02 10 2020
(ii) 02 10 2020
(iii) 02 10 2020
(iv) 02 10 2020
(v) 20 04 2020
(vi) 20 04 2020
1 1-1 02 10 2020
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LAK-17C FES Flight Manual
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Section Page Date of Issue
7 7-1 20 04 2020
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LAK-17C FES Flight Manual
0.3 Table of Contents
General (an non-approved section) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . §1
Limitations (an approved section) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . §2
Emergency procedures (an approved section) . . . . . . . . . . . . . . . . . . . . . §3
Normal procedures (an approved section) . . . . . . . . . . . . . . . . . . . . . . . . . §4
Performance (a partly approved section) . . . . . . . . . . . . . . . . . . . . . . . . . . . §5
Weight and balance / equipment list
(a non-approved section) ............................................. §6
Sailplane and systems description
(a non-approved section) ............................................. §7
Sailplane handling, care and maintenance
(a non-approved section) ............................................. §8
Supplements (a non-approved section) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . §9
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LAK-17C FES Flight Manual
INTENTIONALLY LEFT BLANK
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LAK-17C FES Flight Manual
Section 1
GENERAL
1.1 Introduction.............................1-2
1.2 Certification basis . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
1.3 Warnings, cautions and notes . . . . . . . . . . . . . . . . . . . 1-2
1.4 Descriptivedata ..........................1-2
1.5 Three-view drawing . . . . . . . . . . . . . . . . . . . . . . . . 1-5
1.6 Abbreviations............................1-6
1.7 Unitconversions ..........................1-6
Rev. 02/10/20 #0.1 1-1

LAK-17C FES Flight Manual
1.1 Introduction
The sailplane flight manual has been prepared to provide pilots and instructors
with information for the safe and efficient operation of the LAK-17C FES
sailplane with Front Electric Self-launcher system.
This manual includes the material required to be furnished to the pilot
by CS-22. It also contains supplemental data supplied by the sailplane
manufacturer.
1.2 Certification basis
This type of sailplane has been designed in accordance with CS-22
Certification Specifications for Sailplanes and Powered Sailplanes,
Amendment 2, March 2009 and in accordance with Special Conditions issues
for FES.
Category of Airworthiness: Utility.
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 but which is important or unusual.
1.4 Descriptive data
The LAK-17C FES is a modification of the single seat high performance
sailplane of FAI 15 m / 18 m class LAK-17A designed according to CS-22,
category “U” specifications. It is a mid-wing glider with flaps, T-tail,
retractable main landing gear and water ballast tanks of 188 ltr /49.6 US gal
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LAK-17C FES Flight Manual
capacity (inner wings – 158 ltr / 41.7 US gal, outer (18 m) wings – 30 ltr /
7.9 US gal).
Without water ballast (MTOW = 455 kg), the sailplane is classified as a
powered sailplane and is allowed to take-off solely by means of it’s own power.
With water ballast (MTOW = 455. . . 600 kg), the sailpane is classified as a
self-sustaining powered sailplane and is prohibited from self-launching.
The inner wing water ballast is filled in and poured out through the holes
at the bottom of the inner wings. The outer wing water ballast is filled in
through the hole in the end rib and poured out through the hole at the bottom
of the outer wing. Sailplane is equipped with Front Electric Self-launcher
system. Main parts of the FES system are:
•Brushless electric motor,
•Controller for motor,
•Foldable propeller,
•FES BATTERY PACK GEN2 with internal BMS (Battery Management
System),
•Charger (one 1200 W or two 600 W),
•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 12 V).
The sailplane is made of hybrid composite materials (Kevlar, carbon and
fiberglass). The wing spar is made of modern carbon rods GRAPHLITE
SM315 and has a double T section. The airbrakes are located on the upper
wing surface only. 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
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LAK-17C FES Flight Manual
The cockpit is of monocoque construction. The manually controlled
seatback and an adjustable head rest together with optimally arranged
controls offer notable comfort for the long flights. The one-piece Plexiglas
canopy hinges forward.
On the left side there is a sliding window for additional ventilation. The
instrument panel folds up together with a canopy.
The retractable landing gear with shock absorbers has a 5.00-5 6PR ply
tire. The mechanical main wheel brake is actuated via the handle on the stick
(or via the airbrake control handle / with the BERINGER wheel and brake
system). The rudder pedals are adjustable in flight. All controls, including the
water ballast system, hook up automatically or semiautomatically. Towing
hooks are mounted: near the main landing gear (C.G. / winch / autotow
hook) and/or in front of the pilot cockpit at the bulkhead (aero tow hook).
Both towing hooks are operated by the same handle. The wings incorporate
forktype spar tips, joined with two pins.
The T-tail (fixed stabilizer with elevator) of the LAK-17C FES provides
stable and responsive pitch characteristics. The elevator hooks up
automatically during assembly. The glider is fitted with a fin ballast tank of
8 ltr (2.11 US gal) capacity in order to adjust the optimum C.G. position.
The antenna is mounted in the vertical fin.
FES parameters are controlled by the FCU (FES Control Unit)
instrument, produced by LX NAV d.o.o. company. The motor is operated
with the Power and brake button located on the FCU instrument.
Electronic safety devices are provided to avoid misoperation.
Technical data of the LAK-17C FES
Wing span . . . . . . . . . . . . . . . . . . . . . . . . . . 18 m (59.06 ft)
Fuselage length. . . . . . . . . . . . . . . . . . . . . .6.55 m (21.506 ft)
Height . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.29 m (4.23 ft)
Max gross weight. . . . . . . . . . . . . . . . . . . .600 kg (1322.8 lbs)
Max weight with water ballast . . . . . . 600 kg (1322.8 lbs)
Powered take-off max weight . . . . . . . 455 kg (1003.1 lbs)
Mean aerodynamic chord. . . . . . . . . . . . 0.6072 m (23.905 in)
Wing area...........................10.32 m2(111.08 ft2)
Wing loading:
minimum . . . . . . . . . . . . . . . . . . . . . . . . . . . 36.47 kg/m2(7.47 lbs/ft2)
maximum . . . . . . . . . . . . . . . . . . . . . . . . . . . 58.13 kg/m2(11.9 lbs/ft2)
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LAK-17C FES Flight Manual
1.5 Three-view drawing
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LAK-17C FES Flight Manual
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. – center of gravity
daN – decanewton
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 – kilometer
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/m20.204 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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LAK-17C FES Flight Manual
Section 2
LIMITATIONS
2.1 Introduction.............................2-2
2.2 Airspeed...............................2-2
2.3 Airspeed indicator markings . . . . . . . . . . . . . . . . . . . . 2-3
2.4 Power-plant information and operation limitations . . . . . . . 2-4
2.4.1 Power-plant.........................2-5
2.4.2 Batteries ..........................2-5
2.5 Mass(weight)............................2-6
2.6 Centerofgravity .......................... 2-6
2.7 Approved manoeuvres . . . . . . . . . . . . . . . . . . . . . . . 2-6
2.8 Manoeuvring load factors . . . . . . . . . . . . . . . . . . . . . 2-7
2.9 Flightcrew .............................2-7
2.10 Kinds of operation . . . . . . . . . . . . . . . . . . . . . . . . . 2-7
2.11 Minimum equipment . . . . . . . . . . . . . . . . . . . . . . . . 2-8
2.12 Aero tow, winch and auto tow launching, self-launching . . . . 2-9
2.13Otherlimitations..........................2-9
2.14 Limitation placards . . . . . . . . . . . . . . . . . . . . . . . . . 2-10
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LAK-17C FES Flight Manual
2.1 Introduction
Section 2 includes operation limitations, instrument markings and placards,
necessary for safe operation of the LAK-17C sailplane with Front Electric
Self-launcher system, it’s motor, standard systems and standard equipment.
The limitations have been approved. Compliance with these limitations is
mandatory.
2.2 Airspeed
Airspeed limitations and their operational significance are shown below:
Speed IAS, km/h / (kts) Remarks
18 m
VNE Never exceed
speed
Do not exceed this speed in
any operation and do not
use more than 1/3 of control
deflection at:
275 / (148) 0 - 4 000 m (0 - 13 100 ft)
260 / (140) up to 5 000 m (16 400 ft)
245 / (132) up to 6 000 m (19 680 ft)
220 / (119) up to 8 000 m (26 250 ft)
195 / (105) up to 10 000 m (32 800 ft)
VPE Maximum
operation with
motor running
160 / (86) Do not exceed this speed
with the motor running (at
any power setting)
VRA Rough air speed 190 / (102) Do not exceed this speed
except in smooth air and
then only with caution.
Rought air is in lee wave
rotor, thunderclouds, etc.
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LAK-17C FES Flight Manual
Speed IAS, km/h / (kts) Remarks
18 m
VAManoeuvring
speed
190 / (102) Do not make full or abrupt
control movement above this
speed, because under certain
conditions the sailplane may
be over stressed by full
control movement
VFE Maximum flap
extended speed.
Flap setting:
Do not exceed these speeds
with the given flap setting
–1 up to 0 275 / (148)
+1 up to L 190 / (102)
VWMaximum winch
and auto-tow
launch speed
140 / (76) Do not exceed this speed
during winch or auto-tow
launching
VTMaximum aero
towing speed
160 / (86) Do not exceed this speed
during aero towing
VLO Maximum
landing gear
operations speed
190 / (102) Do not extend or retract the
landing gear above this
speed
VPO min Minimum speed
to start motor
80 / (43) Do not start the motor
below this speed
VPO max Maximum speed
to start motor
160 / (86) Do not start the motor
above this speed
Warning: At higher altitudes the true airspeed is higher than the
indicated airspeed, and VNE is reduced with altitude.
2.3 Airspeed indicator markings
Airspeed indicator markings and their color code significance are shown below:
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LAK-17C FES Flight Manual
Marking IAS value or range
km/h / (kts)
Significance
White Arc 99. . . 190 / (53. . . 102) Positive Flaps Operating Range:
Lower limit is 1.1 VSO in landing
configuration at maximum weight.
Upper limit is maximum speed
permissible with flaps extended
positive.
Green Arc 108. . . 190 / (58. . . 102) Normal Operating Range: Lower
limit is 1.1 VS1 at maximum
weight and most forward C.G.
with flaps neutral. Upper limit is
rough air speed.
Yellow Arc 190. . . 275 / (102. . . 148) Manoeuvres must be conducted
with caution and only in smooth
air.
Red Line 275 / (148) Maximum speed for all operations.
Blue Line 85 / (45) Speed for best climb Vy, flaps in
position "+3".
Yellow
Triangle
95 / (51) Approach speed at maximum
weight without water ballast.
2.4 Power-plant information and operation limitations
LAK-17C FES is equipped with Front Electric Self-launcher system. The use
of the power-plant has some limitations which needs to be observed:
•start motor in flight only at the speed range VPO = 80. . . 160 km/h
(43. . . 86 kts);
•do not fly glider with motor running at the speed higher than VPE =
160 km/h (86 kts).
•the time limit for the use of take-off power – maximum 1.5 minute
or until any of temperature values reach yellow warning (motor and
controler at 70 °C, battery packs at 45 °C).
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LAK-17C FES Flight Manual
2.4.1 Power-plant
Motor
Motor manufacturer. . . . . . . . . . . . . . “LZ design”
Motor model . . . . . . . . . . . . . . . . . . . . . FES-LAK-C100
Out runner BLDC brushless synchronous permanent magnet motor with
electronically controlled commutation system 3 phase, air cooled.
•Up to 26 kW (with 14S packs) for shorter time.
•Diameter 180 mm, length 100 mm.
•Weight of motor – 7.3 kg.
•Efficiency more than 95%.
Maximum power . . . . . . . . . . . . . . . . . 26 kW (35 hp), at 5100 RPM
Continuous power . . . . . . . . . . . . . . . . 18 kW at 116 V
Max motor RPM . . . . . . . . . . . . . . . . . 5100 RPM
Recommended RPM for
max. altitude gain . . . . . . . . . . . . . . . 4000-4300 RPM
Recommended RPM for
level flight. . . . . . . . . . . . . . . . . . . . . . . .3000-3200 RPM
Propeller
Diameter. . . . . . . . . . . . . . . . . . . . . . . . .1.0 m (3.28 ft)
Manufacturer . . . . . . . . . . . . . . . . . . . . “Sportin˙e aviacija ir Ko”
Model. . . . . . . . . . . . . . . . . . . . . . . . . . . .FES-LAK-P11-100
2.4.2 Batteries
LAK-17C FES has two battery packs wired in serial. Each 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
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LAK-17C FES Flight Manual
More detailed data about battery packs are described in separate FES Battery
pack GEN2 with integrated BMS (Battery Management System) manual,
v1.19.
2.5 Mass (weight)
Maximum take-off mass of the LAK-17C FES is:
with water ballast: 600 kg (1322.5 lbs);
without water ballast: 455 kg (1003 lbs).
Maximum landing mass: 600 kg.
Note: When landing on a rough and hard surface always dump all
water ballast before landing.
Maximum mass of all non lifting parts: 282 kg (621.7 lbs)
Maximum mass in baggage area: 7 kg (15.4 lbs)
Caution: Heavy pieces of baggage must be secured to the baggage
compartment floor
2.6 Center of gravity
Position of C.G. in flight:
front limit: 206 mm aft of wing root rib leading edge;
rear limit: 328 mm aft of wing root rib leading edge.
Warning: The sailplane may be safely operated only when loaded in the
range defined in the Section 6 of this manual.
2.7 Approved manoeuvres
This sailplane is certified for normal gliding in the "Utility" category according
to CS-22. Aerobatic manoeuvres are not permitted.
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