Sportine Aviacija LAK-17B FES mini Technical specifications

Joint Stock Company "SPORTINĖAVIACIJA ir Ko"
Pociūnųkm., Ašmintos sen., LT-59327, Prienai, Republic of Lithuania
tel.: [phone] ●fax:[phone] ●e-mail: [email protected] ●www.lak.lt
FLIGHT MANUAL
For the
LAK-17B FES sailplane
Type (Muster): LAK-17
Model (Baureihe): LAK-17B FES
Serial Number: _______________
Registration: _______________
Date of Issue: _______________
with Front Electric Sustainer system
Pages identified by "Appr." are approved by the European Aviation Safety Agency
Original date of approval: 31 October 2014
EASATCDS No.EASA.A.083, Issue 03
This sailplane is to be operated in compliance with the regulatory information and
limitations contained herein.
This Manual should always be kept on board of the sailplane

LAK-17B FES Flight Manual

LAK-17B FES Flight Manual
Page i
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 Chapters, 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 and date will be
shown on the bottom left hand of the page.
Rev.1 0 iii 02.12.2014
Rev.1 2 2-3 02.12.2014
Rev.1 2 2-4 02.12.2014
Rev.1 2 2-7 02.12.2014
Rev.1 4 4-2 02.12.2014
Rev.1 4 4-5 02.12.2014
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Rev.1 4 4-8 02.12.2014
Rev.1 4 4-9 02.12.2014
Rev.1 6 6-5 02.12.2014
Rev.1 7 7-4 02.12.2014
Rev.2 0 iii 09.09.2017
Rev.2 0 iv 09.09.2017
Rev.2 2 2-7 09.09.2017
Rev.2 4 4-1..4-15 09.09.2017
Rev.3 0 iii 20.10.2017
Rev.3 0 iv 20.10.2017
Rev.3 2 2-5 20.10.2017
Rev.3 2 2-8 20.10.2017
Rev.3 3 3-4..3-8 20.10.2017
Rev.3 4 4-4 20.10.2017
Rev.3 4 4-7 20.10.2017
Rev.3 4 4-9..4-11 20.10.2017
Rev.3 4 4-13 20.10.2017
Rev.3 4 4-16 20.10.2017
Rev.3 7 7-1..7-3 20.10.2017
Rev.
No. Affected
Chapter Affected Pages Date of Issue Approval Date of Approval Date of Insertion Signature

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No. Affected
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LAK-17B FES Flight Manual
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Table of contents
Chapter
GENERAL (a non-approved chapter)................................................................. 1
LIMITATIONS (an approved chapter)............................................................... 2
EMERGENCY PROCEDURES (an approved chapter)................................... 3
NORMAL PROCEDURES (an approved chapter)............................................4
PERFORMANCE (a partly approved chapter).................................................. 5
WEIGHTAND BALANCE / EQUIPMENT LIST
(a non-approved chapter)......................................................................................6
SAILPLANE AND SYSTEMS DESCRIPTION
(a non-approved chapter)......................................................................................7
SAILPLANE HANDLING, CARE AND MAINTENANCE
(a non-approved chapter)......................................................................................8
SUPPLEMENTS (a non-approved chapter)....................................................... 9

LAK-17B FES Flight Manual
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LAK-17B FES Flight Manual
Rev. No. 0 Date: September 23, 2014 Page 1-1
Chapter 1
GENERAL
1.1 Introduction.............................................................................................1-2
1.2 Certification basis....................................................................................1-2
1.3 Warnings, cautions and notes..................................................................1-2
1.4 Descriptive data.......................................................................................1-3
1.5 Three-view drawing................................................................................ 1-5
1.6 Abbreviations..........................................................................................1-6
1.7 Unit conversions......................................................................................1-6

LAK-17B FES Flight Manual
Rev. No. 0 Date: September 23, 2014 Page 1-2
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-17B
FES sailplane with Front Electric Sustainer 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.
Warning:
Means that the non-observation of the corresponding
procedure leads to an immediate or important degradation of
the flight safety.
Category of Airworthiness: Utility.
1.3 Warnings, cautions and notes
The following definitions apply to warnings, cautions and notes used in the
flight manual.
Caution:
Means that the non-observation of the corresponding
procedure leads to a minor or to a more or less long term
degradation ofthe flight safety.
Note:
Dra s the attention on any special item not directly related
to safety by hich is important or unusual.

LAK-17B FES Flight Manual
Rev. No. 0 Date: September 23, 2014 Page 1-3
1.4 Descriptive data
The LAK-17B FES is a modification of the single seat high performance
sailplane of FAI 15m - 18m class LAK-17A designed according to CS-22,
category “U” specifications. It is a mid-wing self-sustaining glider with flaps, T-
tail, retractable main landing gear and water ballast tanks of 188 ltr /49.6 US gal
capacity (inner wings-158 ltr / 41.7 US gal, outer (18m) wings- 30 ltr / 7.9 US
gal). 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 poured out through the hole at the bottom of the outer wing.
Sailplane is equipped with Front Electric Sustainer system.
Main parts of the FES system are:
– Brushless electric motor,
– Controller for motor,
– Foldable propeller,
– FES BATTERY PACK GEN1 or GEN2 with internal BMS(Battery
Management System),
– Charger (one 1200W or two 600W),
– 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).
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:
18 m -
0.0
1.2
4.6
6.5
8.0
8.855
0.741
0.711
0.625
0.5
0.38
0.226
LAP7-150
LAP7-131/17
LAP7-131/17
LAP7-129/18
LAP7128/19
LAP93/148
S (m) c (m) Profile
The cockpit is of monocoque construction. The manually controlled seat
back and an adjustable head rest together with optimally arranged controls offer
notable comfort for the long flights. The one piece Plexiglas canopy hinges
forward.

LAK-17B FES Flight Manual
Rev. No. 0 Date: September 23, 2014 Page 1-4
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 semi-automatically. Towing hooks are mounted:
near the main landing gear (C.G. / winch / auto-tow 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 fork-type spar tips, joined with two pins.
The T-tail (fixed stabilizer with elevator) of the LAK-17B 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-17B FES
Wing span..............................................................18 m (59.06 ft)
Fuselage length......................................................6.555 m (21.5058 ft)
Height....................................................................1.29 m (4.23 ft)
Max gross weight..................................................600 kg (1322.8 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(11.90 lbs/ft2)

LAK-17B FES Flight Manual
Rev. No. 0 Date: September 23, 2014 Page 1-5
1.5 Three-view drawing

LAK-17B FES Flight Manual
Rev. No. 0 Date: September 23, 2014 Page 1-6
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 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.
1.7 Unit conversions

LAK-17B FES Flight Manual
Rev. No. 0 Date: September 23, 2014 Page 2-1
Appr.
Chapter 2
LIMITATIONS
2.1 Introduction.............................................................................................2-2
2.2 Airspeed.................................................................................................. 2-2
2.3 Airspeed indicator markings................................................................... 2-4
2.4 Power-plant information and operation limitations................................ 2-4
2.4.1 Power-plant..................................................................................2-4
2.4.2 Batteries....................................................................................... 2-5
2.5 Mass (weight)..........................................................................................2-5
2.6 Center of gravity..................................................................................... 2-6
2.7 Approved manoeuvres.............................................................................2-6
2.8 Manoeuvring load factors........................................................................2-6
2.9 Flight crew.............................................................................................. 2-6
2.10 Kinds of operation...................................................................................2-7
2.11 Minimum equipment...............................................................................2-7
2.12 Aero tow, winch and auto tow launching................................................2-8
2.13 Other limitations......................................................................................2-8
2.14 Limitation placards..................................................................................2-9

LAK-17B FES Flight Manual
Rev. No. 0 Date: September 23, 2014 Page 2-2
Appr.
2.1 Introduction
Chapter 2 includes operation limitations, instrument markings and placards,
necessary for safe operation of the LAK-17B FES sailplane with Front Electric
Sustainer 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:
Warning:
LAK-17B FES is a self-sustaining powered sailplane and is
prohibited from taking off solely by the means of it’s own
power.
Speed Remarks
IAS; km/h / (kts)
18 m
VNE Never exceed speed
275 / (148)
260 / (140)
245 / (132)
220 / (119)
195 / (105)
Do not exceed this speed in
any operation and do not use
more than 1/3 of control
deflection at:
0 - 4 000 m (0 - 13 100 ft)
up to 5 000 m (16 400 ft)
up to 6 000 m (19 680 ft)
up to 8 000 m (26 250 ft)
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. Rough air is in lee
wave rotor, thunderclouds, etc.

LAK-17B FES Flight Manual
Rev. No. 0 Date: September 23, 2014 Page 2-3
Appr.
Warning:
At higher altitudes the true airspeed is higher than the
indicated airspeed , and VNE is reduced with altitude.
* Warning:
select your motor start/stop speed correctly:
- flaps must be at +2 position;
- 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.
Speed Remarks
IAS; km/h / (kts)
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:
-1 up to 0
+1 up to L 275 / (148)
190 / (102)
Do not exceed these speeds
with the given flap setting
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 205 / (110) 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

LAK-17B FES Flight Manual
Rev. No. 0 Date: September 23, 2014 Page 2-4
Appr.
2.3 Airspeed indicator markings
Airspeed indicator markings and their color code significance are shown
below:
Marking Significance
IAS value or range
km/h / (kts)
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 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-17B FES is equipped with Front Electric Sustainer system and is
prohibited from taking-off solely. Therefore use of the power-plant has some
limitations which needs to be observed:
– start motor only at the speed range VPO = 80…160 km/h (43…86 kts);
– do not fly glider with motor running at the speed higher as VPE = 160
km/h (86 kts).
2.4.1 Power-plant
Motor:
Motor manufacturer: “Sportinėaviacija ir Ko”
Motor model: FES-LAK-M100
Out runner BLDC brushless synchronous permanent magnet motor with
electronically controlled commutation system 3 phase, air cooled.
– Up to 23kW for shorter time.

LAK-17B FES Flight Manual
Rev. No. 3 Date: October 20, 2017 Page 2-5
Appr.
– Diameter 180 mm, length 100 mm
– Weight of motor – 7.3 kg.
– Efficiency more than 95%
Maximum power: max power 23 kW (30 hp), at 4500 RPM
Continuous power: 16kW continuous power at 116V
Max motor RPM: 4500 RPM
Recommended RPM: 3000 RPM for horizontal flight;
Propeller:
Propeller: diameter 1.0 m (3.28 ft.)
Manufacturer: “Sportinėaviacija ir Ko”
Model: FES-LAK-P10-100
2.4.2 Battery packs
LAK-17B FES has two Battery packs wired in serial. Each battery pack
has 14 cells, so altogether 28 cells.
Nominal capacity of each cell is 40Ah, at middle voltage 3.7V (minimum
3.2, maximum 4.2V).
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:
–External FES-BMS-7R for GEN1 battery packs
–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,
v1.19.
2.5 Mass (weight)
Maximum take-off mass of the LAK-17B FES is:
with water ballast: 600 kg (1322.8 lbs)
without water ballast: 455 kg (1003 lbs)

LAK-17B FES Flight Manual
Rev. No. 1 Date: December 02, 2014 Page 2-6
Appr.
Maximum landing mass: 600 kg (1322,8 lbs).
Note:
When landing on a rough and hard surface always dump all
water ballast before landing.
Maximum mass of all non lifting parts: 276.3 kg (609.14 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:
– rear limit:
206 mm aft of wing root rib leading edge;
328 mm aft of wing root rib leading edge.
Warning:
he sailplane may be safely operated only when loaded in the
range defined in the Chapter 6 ofthis 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.
2.8 Manoeuvring load factors
Limit load factors are:
– for VA=190 km/h (102 kts) airspeed
– for VNE=275 km/h (148 kts) airspeed
– for VNE=275 km/h (148 kts), air brakes extended
– for VF=160 km/h (86 kts), flaps +1, +2, L
2.9 Flight crew
LAK-17B FES is a single seat motor-glider. Load in a pilot seat must be as
follows:
Max load in the seat: 110 kg (242 lbs.);
Min load in the seat: see placard in cockpit and weighing report.
+5.3 / -2.65;
+4.0 / -1.5;
+3.5 / 0;
+4.0 / 0.