STEMME S10 Technical specifications

DOCUMENT NUMBER:
L400-912810 ISSUE AUG 20, 2016
FLUGPLATZSTRASSE F2, NR. 6-7 • GERMANY • 15344 STRAUSBERG
POWERED SAILPLANE
STEMME S10, VARIANT S12
DOCUMENT NUMBER • L400-912810
DATE OF ISSUE • AUGUST 20, 2016
FLIGHT MANUAL
AIRFRAME TYPE
TYPE CERTIFICATE
SERIAL NUMBER
REGISTRATION
: STEMME S12
: EASA.A.054
: 12-
:
AMENDMENT: 04
DATE: APR 04, 2022
CHAPTER-PAGE 0-1
COVER SHEET

This aircraft may only be operated in correspondence to
the instructions and operating limitations specied in
this manual.
CONTACT
STEMME AG
Flugplatzstrasse F2, Nr. 6-7
D-15344 Strausberg
Phone: [phone]
E-mail: [e-mail]
Web: www.stemme.com
All rights reserved.
Reproduction or disclosure to third parties of this document
any part there of is not permitted, except with the prior
and express written permission of STEMME AG.
DOCUMENT NUMBER:
L400-912810 ISSUE AUG 20, 2016
AIRCRAFT FLIGHT MANUAL STEMME S10, VARIANT S12
CHAPTER-PAGE 0-2
AMENDMENT: 04
DATE: APR 04, 2022

DOCUMENT NUMBER:
L400-912810 ISSUE AUG 20, 2016
AMENDMENT: 02
DATE: OCT 10, 2018
CHAPTER - PAGE 0-3
AIRCRAFT FLIGHT MANUAL STEMME S10, VARIANT S12
0.1 RECORD OF AMENDMENTS
Any revision of the present manual must be recorded in the following table,
with the exception of:
• Updated weight data,
• Changes to the arrangement of instruments on the instrument
panel.
• Data relating to the installation of supplemental or additional
equipment (section »9-2« and »9-3«).
The record of amendments in section »0.1«and the list of eective pages
in section »0.2«are assigned to an individual aircraft serial number. The
indicated amendment no. in the feed line of these pages does not change
with entries after delivery of the aircraft.
Revision of pages must be endorsed in the following list. Necessary amend-
ments, needs to be mandatory included in the present manual.
The new or amended text will be marked on the revised page by a black vertical
line on the right hand margin; the amendment number and the date will be
shown in the outside of the footer page.
The inspector certies by his signature the correspondence of this individual
Aircraft Flight Manual and the following list with the aircraft designated by
serial number.
Am.
No.
Removed
Pages
Inserted
Pages
Date of
Amend-
ment
Refer-
ence
Approval Date
of
Inser-
tion
Sig-
na-
ture
00 -- ALL AUG 20,
2016
P061-
2016-084
01 0-1, 0-3,
0-5,0-6,
2-20
0-1, 0-3,
0-5,0-6,
2-20
AUG 28,
2017
P061-
2017-094

DOCUMENT NUMBER:
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AMENDMENT: 04
DATE: APR 04, 2022
CHAPTER - PAGE 0-4
AIRCRAFT FLIGHT MANUAL STEMME S10, VARIANT S12
Am.
No.
Removed
Pages
Inserted
Pages
Date of
Amend-
ment
Refer-
ence
Approval Date
of
Inser-
tion
Sig-
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02 0-1, 0-2,
0-3, 0-4,
0-5, 0-7,
0-8, 1-1,
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1-8, 1-11,
1-13, 2-4,
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4-53, 6-1,
6-3, 6-6,
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OCT 10,
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2020
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2020-023
The technical
content
of this
document
is approved
under the
authority of
the DOA ref.
EASA.21J.250
04 0-1, 0-2,
0-4, 0-5,
0-7, 0-14,
4-33 ...
4-47
APR 04
2022
P061-
2022-001
The technical
content
of this
document is
approved
under the
authority of
the DOA ref.
EASA.21J.250
0-1, 0-2,
0-4, 0-5,
0-7, 0-14,
4-33 ...
4-47

DOCUMENT NUMBER:
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AMENDMENT: 04
DATE: APR 04, 2022
CHAPTER - PAGE 0-5
AIRCRAFT FLIGHT MANUAL STEMME S10, VARIANT S12
PAGE APPR. AM.
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CHAPTER 0
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0-2
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0-4 04 APR 04, 2022
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CHAPTER 1
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0.2 LIST OF EFFECTIVE PAGES
This list is valid only for the aircraft serial no. specied on title page.
APR 04, 2022
04

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AMENDMENT: 01
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DOCUMENT NUMBER:
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AMENDMENT: 04
DATE: APR 04, 2022
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DOCUMENT NUMBER:
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AMENDMENT: 03
DATE: SEP 14, 2020
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CHAPTER 6
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EQL -- --
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DOCUMENT NUMBER:
L400-912810 ISSUE AUG 20, 2016
AIRCRAFT FLIGHT MANUAL STEMME S10, VARIANT S12
AMENDMENT: 00
DATE: --
CHAPTER - PAGE 0-13
3.9.4.4 Yellow Low Fuel Caution Light........................................ 3-25
3.9.4.5 Yellow TCU-Caution Light Flashes................................... 3-26
3.9.4.6 Red Battery Charge Warning Light for
the External Alternator Illuminated................................. 3-27
3.9.4.7 Yellow Caution Light for the internal
Generator Illuminated. ................................................. 3-28
3.9.4.8 Total Electrical Failure................................................... 3-29
3.9.4.9 Loss of RPM-Indication. ................................................ 3-30
3.9.4.10 Sudden Decrease of MAP and RPM.................................. 3-30
3.9.4.11 Sudden Increase of MAP and RPM....................................3-31
3.9.4.12 Oscillating of RPM, Increase and Decrease....................... 3-32
3.9.4.13 Exceedance of Maximum Allowed
Cylinder Coolant Temperature (CCT)............................... 3-33
3.9.4.14 Exceedance of Maximum Allowed Oil Temperature............ 3-34
3.9.4.15 Oil Pressure below Minimum During Flight. ...................... 3-35
3.9.4.16 Oil Pressure below Minimum on Ground........................... 3-35
3.9.4.17 Exceedance of Maximum Allowed Engine RPM.................. 3-36
3.9.4.18 Loss of Propeller Pitch Control........................................ 3-36
3.9.4.19 Propeller Vibrations...................................................... 3-37
3.9.4.20 Landing Gear Malfunction - Emergency Gear Extension. .... 3-38
3.9.5 Flight in Icing Conditions...............................................3-40
4. Normal Operating Procedures.......................................... 4-1
4.1 Introduction.................................................................. 4-1
4.2 Aircraft Assembly........................................................... 4-1
4.2.1 Rigging and Derigging.................................................... 4-1
4.2.1.1 Fuselage....................................................................... 4-1
4.2.1.2 Wing............................................................................ 4-1
4.2.1.3 Horizontal Tail. ..............................................................4-3
4.2.1.4 Fuselage Fairings. ..........................................................4-3
4.2.2 Fueling.........................................................................4-4
4.3 Daily Inspection.............................................................4-5
4.3.1 Engine..........................................................................4-5
4.3.2 Wing Connecting Area....................................................4-7
4.3.3 Propeller, Nose-cone and Front Gear................................ 4-8
4.3.4 Landing Gear. ............................................................. 4-10

DOCUMENT NUMBER:
L400-912810 ISSUE AUG 20, 2016
AMENDMENT: 04
DATE: APR 04, 2022
CHAPTER - PAGE 0-14
AIRCRAFT FLIGHT MANUAL STEMME S10, VARIANT S12
4.3.5 Wings......................................................................... 4-10
4.3.6 Empennage..................................................................4-11
4.3.7 Fuselage......................................................................4-11
4.4 Pre-Flight Inspections................................................... 4-13
4.4.1 Checks Before Entering Cockpit. .................................... 4-13
4.4.2 Check of Flight Controls and Pressure Probes. .................. 4-15
4.4.3 Checks Before Engine Start............................................ 4-16
4.5 Normal Operating Procedures and
Recommended Airspeeds. ............................................. 4-17
4.5.1 Engine Start, Warm-Up and Taxi Procedures..................... 4-17
4.5.1.1 Engine Start................................................................ 4-17
4.5.1.2 Engine Warm-Up. ........................................................ 4-20
4.5.1.3 Taxiing. ...................................................................... 4-21
4.5.2 Take-O and Climb...................................................... 4-22
4.5.2.1 Checks before take-o. ................................................ 4-22
4.5.2.2 Interpretation of the Three T/O Procedures. ..................... 4-26
4.5.2.3 T/O and Climb............................................................. 4-28
4.5.3 Cruise and Cross-Country Flying. ................................... 4-31
4.5.3.1 General Remarks. ........................................................ 4-31
4.5.3.2 Powered Flight............................................................. 4-31
4.5.3.3 Gliding Flight............................................................... 4-35
4.5.3.4 Change of Aircraft Congurations
(Powered , Gliding Flight).............................................. 4-37
4.5.3.5 Flying in Strong Turbulence............................................ 4-43
4.5.3.6 Cold Weather Operation. .............................................. 4-43
4.5.4 Approach....................................................................4-44
4.5.5 Landing, Taxi and Parking. ............................................4-48
4.5.5.1 Landing......................................................................4-48
4.5.5.2 Taxi and Ground Operation............................................4-49
4.5.5.3 Parking and Shut-Down................................................ 4-49
4.5.6 High Altitude Flight...................................................... 4-53
4.5.7 Flight in Rain............................................................... 4-55
4.5.8 Aerobatics. ................................................................. 4-55
5. Performance. ................................................................ 5-1
5.1 Introduction.................................................................. 5-1

DOCUMENT NUMBER:
L400-912810 ISSUE AUG 20, 2016
AMENDMENT: 04
DATE: APR 04, 2022
APPROVED SECTION - PAGE 4-33
AIRCRAFT FLIGHT MANUAL STEMME S10, VARIANT S12
• Flaps AS REQUIRED (depending on airspeed)
• Throttle SET (max 5500 RPM, recommended
4300 - 5000 RPM)
• Fuel selector switch Fuel management as required
(right, left, or both tanks)
CAUTION
The S12 tends to y slightly right wing low during high speed cruise, due to
high engine torque caused by a high power setting, combined with a small
rolling moment due to sideslip at high airspeeds.
For power settings, speeds, fuel consumption and other data refer to section
5.3.1 Performance in powered-conguration.
WARNING
Engine RPM will increase at constant power setting with altitude at constant
airspeed! Above about 2000 m/6600 ft altitude (ISA) engine RPM could exceed
the max. continuous limit of 5500 RPM for 100% engine power. Engine power
must be reduced as necessary to maintain engine RPM below max. 5500 RPM.
DESCENT IN POWER FLIGHT
Procedure with more than 50% MCP (Fast Speed Descent):
• PPC switch T/O or CRUISE AS REQUIRED
(depending on airspeed)
• Throttle More than 50 %
• Flaps AS REQUIRED (depending on airspeed)
• Cowl-Flaps AS REQUIRED (depending on engine
temperature)
• Attitude DOWN to achieve desired descent prole
and airspeed

DOCUMENT NUMBER:
L400-912810 ISSUE AUG 20, 2016
AMENDMENT: 04
DATE: APR 04, 2022
CHAPTER - PAGE 4-34
AIRCRAFT FLIGHT MANUAL STEMME S10, VARIANT S12
Procedure with less than 50% MCP (Deeper Descent):
• Airspeed Reduce by pitching up and slowly reduce
engine power to max. 140 kph/76 kt
• PPC switch T/O or CRUISE AS REQUIRED
• Throttle 50 % or less
• Flaps AS REQUIRED (depending on airspeed)
• Cowl-Flaps AS REQUIRED (depending on engine
temperature)
• Attitude DOWN to achieve desired descent prole
and airspeed of max. 140 kph /76kt
• Airbrakes Extend as required
and/ or
• Landing Gear Extend as required
CAUTION
Flying with less than 50 % MCP and at the same time a higher airspeed than
140 kph/76kt will signicantly increase the wear and the temperature of the
clutch and its friction pads.
NOTICE
Glider conguration is recommended for long time descents. For gliding ight
refer to the corresponding chapter.
SLOW FLIGHT AND STALL BEHAVIOR IN POWERED CONFIGURATION
Approach to stall speed in powered conguration is indicated by an acoustic
warning, set about 5-8 kph/ 3-7 kt above stall speed.
Speed should be increased immediately at acoustic stall warning onset.
Minimum speeds are given in section 5.2.2.1 Stall and minimum speeds in
powered-conguration for unaccelerated straight and level ight.
Procedures to recover from unintended stall or spin are given in section
3.4 Stall Recovery and 3.5 Spin Recovery.

DOCUMENT NUMBER:
L400-912810 ISSUE AUG 20, 2016
AMENDMENT: 04
DATE: APR 04, 2022
APPROVED SECTION - PAGE 4-35
AIRCRAFT FLIGHT MANUAL STEMME S10, VARIANT S12
4.5.3.3 GLIDING FLIGHT
GLIDER CONFIGURATION
With the engine stopped, propeller blades folded and nose-cone closed the
S12 is a normal glider with aps.
The S12 has good balanced ight characteristics and well harmonized ight
controls. Bank can be changed from +45° to -45° within about 4,8 seconds
without side-slipping (110 kph/ 59 kt, MTOW).
The speed-polar (envelope curve for optimal ap settings) is given in section
5.3.3 “Gliding Flight Polar”.
HIGH SPEED
Up to VNE = 270 kph/146 kt the S12 is well easily controllable.
Above V
A
= 180 kph/97 kt ight controls can not be deected fully or abruptly.
At VNE = 270 kph /146 kt the control is limited: Not more than 1/3.
Limit load factors are given in section 2.9.
If strong turbulence are anticipated such as in rotors of mountain waves, in
thunderstorms or when passing mountain ridges, the maximum airspeed in
rough air VRA = 180 kph/97 kt must not be exceeded.
Airbrakes should be deployed up to VNE = 270 kph/146 kt.
Flight path during steep decent at VNE = 270 kph / 146 kt, airbrakes fully ex-
tended, is -30°.
WARNING
The airbrakes should be deployed carefully above VA= 180 kph / 97 kt. A high
deceleration rate results with airbrakes extended at high airspeeds. The
seat belts need to be well tightened and objects in cockpit area need to be
properly secured.

DOCUMENT NUMBER:
L400-912810 ISSUE AUG 20, 2016
AMENDMENT: 04
DATE: APR 04, 2022
APPROVED SECTION - PAGE 4-36
AIRCRAFT FLIGHT MANUAL STEMME S10, VARIANT S12
SLOW FLIGHT AND STALL BEHAVIOR IN GLIDER CONFIGURATION
Gliding and searching for thermals often requires ying at low speed.
When ying at mid and forward CG, minimum airspeed should be limited by
the aft stop of the elevator and only dynamic stalls (rapid pull-up) should
be possible. Indication of stall in glider conguration is by aerodynamic buf-
feting (in level ight and in turns), when vortices of separated airow from
the wing root area impinge on the tail surface. This aerodynamic bueting
occurs about 5-8 kph / 3-7 kt above stall speed. At rst indication of stall
warning (aerodynamic bueting) reduce elevator back pressure to reduce
angle-of-attack and increase airspeed.
If speed is not increased at stall warning onset and reduced further, the
aircraft may stall with a wing drop. Up until wing drop, aileron and rudder
are eective and correct; controllability is restored immediately, even during
stall, when elevator is released forward. An uncontrollable tendency to spin
has not been observed.
WARNING
Altitude loss for recovery from stall in level ight should be up to 30 m/100 ft,
out of a turn up to 40 m/130 ft and for a delayed reaction up to 60 m/200 ft.
Minimum speeds are given in section 5.2.2.1 Stall and minimum speed in
glider congurationfor unaccelerated straight and level ight. During turns,
depending on bank angle and corresponding g-load, minimum speeds are
higher.
Example:
Minimum speed and stall during steady turns with 60° of bank and a g-load
of 2, are expected to be higher by a factor of 2  1.4 compared to unaccel-
erated level ight.
Procedures to recover from unintended stall or spin are given in section
3.4 Stall Recovery and 3.5 Spin Recovery.

DOCUMENT NUMBER:
L400-912810 ISSUE AUG 20, 2016
AMENDMENT: 04
DATE: APR 04, 2022
APPROVED SECTION - PAGE 4-37
AIRCRAFT FLIGHT MANUAL STEMME S10, VARIANT S12
4.5.3.4 CHANGE OF AIRCRAFT CONFIGURATIONS
POWERED , GLIDING FLIGHT
CHANGE FROM POWERED TO GLIDER CONFIGURATION
• PPC switch T/O
• Throttle IDLE
• Air speed REDUCE to approx. 100 kph/ 54 kt
• Cowl aps FULLY OPEN
CAUTION
With cowl aps fully open, the engine cools down fast and the risk of unin-
tentionally overheating engine after engine stop is reduced.
• Engine temperature WAIT for cool-down
(CCT and oil temperature < 100°C/212°F).
• Ignition OFF (switch position OFF, tachometer
reads “0” RPM).
WARNING
If the engine is operated under load, a sudden shutdown can result in over-
heating and damage to the turbocharger system.
CAUTION
If the engine is shut-down without a sucient cool-down period prior to
shut-down, this can result in local overheating of the engine and coolant
overow.To avoid this, engine should be cooled down at idle power until engine
temperatures are <100 °C/212 °F (CCT and oil temperature) before shutdown.
• Propeller-brake PULL until propeller stops.

DOCUMENT NUMBER:
L400-912810 ISSUE AUG 20, 2016
AMENDMENT: 04
DATE: APR 04, 2022
APPROVED SECTION - PAGE 4-38
AIRCRAFT FLIGHT MANUAL STEMME S10, VARIANT S12
CAUTION
To avoid excessive wear of the centrifugal clutch, avoid extended periods of
propeller windmilling with engine not running.
• Propeller positioning PULL handle very slowly and
smoothly to its stop.
NOTICE
If the handle is pulled too fast,the propeller unit will turn over neutral position
and cause structural damage to the propeller and/or nose-cone.
CAUTION
If the propeller positioning handle is pulled too fast, the propeller should
be driven past the correct position for nose-cone closure. If the nose-cone
cannot be closed, the propeller positioning must be repeated; never pull
handle for closing nose-cone quickly. If unsure of correct propeller position,
repeat positioning.
• Fuel shut-o valve CLOSE
• Electric equipment AS REQUIRED for gliding.
• Cooling of engine bay WAIT for at least for 3 minutes.
CAUTION
Before cowl aps are closed with the nose-cone,the engine should cool down
for three minutes after shutdown, cowl aps fully open, to avoid overheating
of areas in engine bay.
• EXT ALT OFF
• Engine Switch OFF
• Nose-cone handle CLOSE and LOCK
(red alternator warning light OFF).

DOCUMENT NUMBER:
L400-912810 ISSUE AUG 20, 2016
AMENDMENT: 04
DATE: APR 04, 2022
APPROVED SECTION - PAGE 4-39
AIRCRAFT FLIGHT MANUAL STEMME S10, VARIANT S12
NOTICE
When closing and locking nose-cone, all engine and electrical instruments
except for comm radio, soaring computer and variometer are switched o
by the electrical logic.
CAUTION
Operate only minimum essential electric or electronic equipment when soaring
for extended periods. Engine restart and electrical landing gear operation are
impossible with the battery discharged.
CHANGE FROM GLIDER TO POWERED CONFIGURATION
• Airspeed < 140 kph/ 76 kt
(recommended 100 kph/ 54 kt).
• Fuel shut-o valve OPEN
• Engine switch ON
• Nose-cone OPEN and LOCKED
(engine instruments on).
• Cooling air aps FULLY OPEN
• Propeller T/O position (green light)
• Fuel selector switch BOTH tanks
• Choke ON for cold engine
OFF for warm engine.
• Throttle IDLE if choke on
Max. 10% for warm engine.
• Ignition START (for a minimum of three seconds).
• Engine tachometer Check for indicated RPM.

DOCUMENT NUMBER:
L400-912810 ISSUE AUG 20, 2016
AMENDMENT: 04
DATE: APR 04, 2022
APPROVED SECTION - PAGE 4-40
AIRCRAFT FLIGHT MANUAL STEMME S10, VARIANT S12
WARNING
If OAT is extremely low, i.e. at high altitudes or in cold areas, battery capacity
after longer soaring time might be too low for engine restart. Successful engine
restart might only be possible at higher temperatures and lower altitudes.
This must be taken into account for ight and route planning.
CAUTION
In ight engine start: The propeller may continue turning with the engine
not running (following an unsuccessful engine re-start), because engine and
propeller are isolated by a centrifugal clutch. A running engine is indicated
only by the engine tachometer, not by observing propeller turning.
CAUTION
After the starter is actuated an automatic electronic device inhibits the igni-
tion with a time delay of three seconds. The starter must be operated always
for at least three seconds. The time delay allows the propeller blades to be
fully extended before the engine starts, and consequently reduces the loads
for the propeller blades and their corresponding stops.
CAUTION
If the engine res before the expected time delay of three seconds is over, i.e. in
case of a malfunctioning electronic device, system checks must be performed
before the next ight in accordance with the S12 Aircraft Maintenance Manual.
CAUTION
During a cold engine start-up, the power lever must be fully pulled back to its
”IDLE power” stop. In case of a warm engine start-up, it is possible to open
the throttle slightly (add up to 10% power) to improve the engine start-up
behavior.

DOCUMENT NUMBER:
L400-912810 ISSUE AUG 20, 2016
AMENDMENT: 04
DATE: APR 04, 2022
APPROVED SECTION - PAGE 4-41
AIRCRAFT FLIGHT MANUAL STEMME S10, VARIANT S12
CAUTION
If the drive system was not operated for > 5 minutes, propeller blades are in
T/O-position regardless of actual switch position. If switch is in cruise position,
the pitch control mechanism begins to change the propeller pitch when the
engine starts.
CAUTION
If engine starter does not operate for restart, refer to section 3.7.3.
NOTICE
As soon as the engine res up, release the starter key to disconnect the starter
motor. If the engine does not re after 10 seconds of starter operation, stop
and wait for at least 2 minutes for the starter to cool down, then try again.
• Ignition BOTH
• Throttle about 2000 RPM
• Oil pressure GREEN ARC after max. 10 seconds.
WARNING
If the minimum oil pressure is not indicated within 10 seconds, stop engine
immediately.
NOTE
Minimum oil pressure 1.5 bar / 22 psi; with cold engine at low RPM, up to
7.0 bar/102 psi are normal.

DOCUMENT NUMBER:
L400-912810 ISSUE AUG 20, 2016
AMENDMENT: 04
DATE: APR 04, 2022
APPROVED SECTION - PAGE 4-42
AIRCRAFT FLIGHT MANUAL STEMME S10, VARIANT S12
• Fuel selector switch Fuel management as required
(right, left, or both tanks).
• Warning and
caution lights OUT
• EXT ALT ON
• Electrical systems ON as required
• Choke OFF with increasing engine temperature
(1-2 minutes should be sucient).
• Engine warm-up At approximately 2500 RPM if the engine
is cold.
WARNING
The engine must be warmed-up at a reduced power setting. If either the
power setting of a cold engine is too high, or the choke is still applied, the
engine may run rough, splutter or even quit.
CAUTION
During engine warm-up, oil temperature and CCT have to be monitored
continuously. In case of a malfunction of the cowl aps, a danger of
overheating and engine damage exists.