Sportine Aviacija LAK-17 2015 Technical specifications

Joint Stock Company "SPORTINĖ AVIACIJA ir Ko"
Pociūnų km., Ašmintos sen., LT-59327, Prienai, Republic of Lithuania
tel.: [phone] ● fax:[phone] ● e-mail: [email protected] ● www.lak.lt
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
FLIGHT MANUAL
For the
LAK-17BT sailplane
Type: LAK-17
Model: LAK-17BT
Sales Designation: LAK-17BT from Serial No. ...........
Serial Number: _______________
Registration: _______________
Date of Issue: _______________
It is a preliminary manual. The sailplane is not certified and has not shown
compliance with airworthiness requirements.

LAK-17BT Flight Manual

LAK-17BT Flight Manual
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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.
No.
Affected
Chapter
Affected
Pages
Date of
Issue
Approval
Date of
approval
Date of
Insertion
Signature

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LAK-17BT Flight Manual
Page v
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
WEIGHT AND 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

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LAK-17BT Flight Manual
Rev. No. 0 Date: 20 April 2015 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................................................................................. 1-6
1.6 Abbreviations .......................................................................................... 1-7
1.7 Unit conversion ....................................................................................... 1-7

LAK-17BT Flight Manual
Rev. No. 0 Date: 20 April 2015 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-17 BT
self-sustaining sailplane.
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,
5 March 2009.
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 by which is important or unusual.

LAK-17BT Flight Manual
Rev. No. 0 Date: 20 April 2015 Page 1-3
1.4 Descriptive data
The LAK-17BT is a modification of the single seat high performance self-
sustaining powered sailplane of FAI 15 m – 18 m class LAK-17AT 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 (see
Table 1-1).
Table 1-1
Max capacity of water ballast
15m
18m
21m
ltr
US gal
ltr
US gal
ltr
US gal
158
41,7
188
49,6
200
52,8
Inner wing tanks
158
41,7
158
41,7
158
41,7
Outer wing 21m tanks
–
–
–
–
42
11,1
Outer wing 18m tanks
–
–
30
7,9
–
–
Outer wing 15m tanks
0
0
–
–
–
–
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 retractable power-plant powered by 19,6 kW
(26,28 hp) two stroke two cylinder air cooled SOLO 2350 engine and LAK-P4-90
fixed pitch propeller. Power-plant is started by decompressing and then wind-
milling, and has no throttle control.
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 are described in Table 1-2.
Table 1-2
s [m]
c [m]
Airfoil
15 m
0,0
0,741
LAP7-150
1,2
0,711
LAP7-131/17
4,6
0,625
LAP7-131/17
6,7
0,38
LAP7-128/19
7,355
0,226
LAP93/148
18 m
0,0
0,741
LAP-150
1,2
0,711
LAP7-131/17

LAK-17BT Flight Manual
Rev. No. 0 Date: 20 April 2015 Page 1-4
s [m]
c [m]
Airfoil
4,6
0,625
LAP7-131/17
6,5
0,5
LAP7-128/18
8,0
0,38
LAP7-128/19
8,855
0,226
LAP93/148
21 m
0,0
0,741
LAP7-150
1,2
0,711
LAP7-131/17
4,6
0,625
LAP7-131/17
6,812
0,5
LAP7-128/18
9,157
0,38
LAP7-128/19
10,408
0,226
LAP93/148
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. 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-17BT 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.
Engine parameters are controlled by the instrument of type ILEC MCU
LAK-17BT. Power-plant extraction/retraction is operated automatically with the
extract/retract switch located on the MCU. Electronic safety devices are provided
to avoid misoperation.
Technical data of the LAK-17BT sailplane is shown in Table 1-3.

LAK-17BT Flight Manual
Rev. No. 0 Date: 20 April 2015 Page 1-5
Table 1-3
Wing span
15 m
(49.2 ft)
18 m
(59.06 ft)
21 m
(68.89 ft)
Fuselage length
6.555 m (21.5058 ft)
Height
1.29 m (4.23 ft)
Max gross weight
550 kg
(1212.5 lbs)
600 kg
(1322.8 lbs)
600 kg
(1322.8 lbs)
Mean aerodynamic chord
0.6281 m
(24.73 in)
0.6072 m
(23.905 in)
0.589 m
(23.19 in)
Wing area
9.18 m2
(98.81 ft2)
10.32 m2
(111.08 ft2)
11.58 m2
(124.65 ft2)
Wing loading (minimum)
41.5 kg/m2
(8.5 lbs/ft2)
36.47 kg/m2
(7.47 lbs/ft2)
33.96 kg/m2
(6.96 lbs/ft2)
Wing loading (maximum)
59.91 kg/m2
(12.27 lbs/ft2)
58.13 kg/m2
(11.90 lbs/ft2)
51,81 kg/m2
(10.61 lbs/ft2)

LAK-17BT Flight Manual
Rev. No. 0 Date: 20 April 2015 Page 1-6
1.5 Three-view drawing

LAK-17BT Flight Manual
Rev. No. 0 Date: 20 April 2015 Page 1-7
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 conversion
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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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......................................................................................... 2-5
2.4.2 Fuel tank and fuel................................................................................ 2-5
2.5 Mass (weight).......................................................................................... 2-6
2.6 Center of gravity...................................................................................... 2-6
2.7 Approved maneuvers............................................................................... 2-7
2.8 Maneuvering load factors ........................................................................ 2-7
2.9 Flight crew............................................................................................... 2-7
2.10 Kinds of operation ................................................................................... 2-8
2.11 Minimum equipment ............................................................................... 2-8
2.12 Aero tow, winch and auto tow launching ................................................2-9
2.13 Other limitations...................................................................................... 2-9
2.13.1 Crosswinds...................................................................................... 2-9
2.13.2 Water ballast ................................................................................. 2-10
2.14 Limitation placards................................................................................ 2-10

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2.1 Introduction
Chapter 2 includes operation limitations, instrument markings and placards
necessary for safe operation of the LAK-17BT self-sustaining powered sailplane,
its engine, standard systems and standard equipment.
The limitations have been approved. Compliance with these limitations is
mandatory.
Warning:
LAK-17BT is a self-sustaining powered sailplane and is
prohibited from taking off solely by the means of its own
power.
Note:
due to high noise when engine is running, it is highly
recommended to wear headset during powered flight
2.2 Airspeed
Airspeed limitations and their operational significance are shown in Table
2-1.
Table 2-1
Speed
IAS [km/h / (kts)]
Remarks
15 m & 18 m & 21 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), 220*/(118)*
260 / (140), 205*/(111)*
245 / (132), 190*/(103)*
220 / (119), 165*/(89)*
195 / (105), 140*/(76)*
0 – 4000 m (0 – 13100 ft)
up to 5000 m (16400 ft)
up to 6000 m (19680 ft)
up to 8000 m (26250 ft)
up to 10000 m (32800 ft)
VPE
Maximum
operation with
power-plant
extended
160 / (86)
Do not exceed this speed
with the power-plant
extended (at any power
setting or propeller
stopped)

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Appr.
Speed
IAS [km/h / (kts)]
Remarks
15 m & 18 m & 21 m
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.
VA
Maneuvering
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
+1 up to L
275 / (148), 220*/(118)*
190 / (102)
VW
Maximum winch
and auto-tow
launch speed
140 / (76)
Do not exceed this speed
during winch or auto-tow-
launching
VT
Maximum aero
towing speed
160 / (86)
Do not exceed this speed
during aero towing
VLO
Maximum
landing gear
operation speed
205 / (110)
Do not extend or retract
the landing gear above
this speed
VPO min
Minimum speed
to extend or
retract the
power-plant
90* / (49*)
Do not extend or retract
the power-plant below this
speed
VPO max
Maximum speed
to extend or
retract the
power-plant
110 / (60)
Do not extend or retract
the power-plant above this
speed
*- airspeed limitation for 21m wing configuration.
Warning:
At higher altitudes the true airspeed is higher than the
indicated airspeed, and VNE is reduced with altitude.

LAK-17BT Flight Manual
Rev. No. 0 Date: 20 April 2015 Page 2-4
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*Warning:
Select your power-plant extension/retraction speed
correctly:
Flaps must be at +2 position;
Make sure your selected speed for power-plant
extension/retraction is at least 8…10 km/h (4…5 kts)
higher than a stall speed for your flight configuration
2.3 Airspeed indicator markings
Airspeed indicator markings and their color code significance are shown in
Table 2-2.
Table 2-2
Marking
IAS value or range
[km/h / (kts)]
Significance
White arc
102…190 / (55…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)
190…220* /(102…118*)
Maneuvers must be conducted with
caution and only in smooth air.
Red line
275 / (148), 220*/(118)*
Maximum speed for all operations
Blue line
95 / (51)
Speed for best climb Vy, flaps in
position “+2”
Yellow triangle
95 / (51)
Approach speed at maximum weight
without water ballast
*- airspeed limitation for 21m wing configuration.