WOODCOMP KW-20 User manual

Vodolská 4
250 70 Odolena Voda
Czech Republic
Tel.: [phone]
e-mail:[e-mail]
http://www.woodcomp.cz
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Page 2 / Date of issue: 06.10.2023 Rev. 0
CONTENT
1. List of Valid Pages..........................................................................4
2. List of Revised Pages......................................................................5
3. Introduction ..................................................................................6
4. Manufacturer ................................................................................6
5. Type Certificate Holder ..................................................................6
6. Serial Number ...............................................................................7
7. General Information ......................................................................7
8. Operating Safety............................................................................7
9. Propeller Properties.......................................................................8
10. Technical Description.....................................................................9
10.1. Product Label................................................................................................................ 10
10.2. Propeller Designation System......................................................................................... 11
11. Basic Performance Data...............................................................12
12. Connection of KW-20 Propeller to Engine.....................................13
13. Propeller Unit Adjustment ...........................................................14
13.1. Adjustment before First Flight........................................................................................ 14
14. Operating Instruction...................................................................17
14.1. Mounting propeller on engine........................................................................................ 17
14.2. Starting engine and performing engine test..................................................................... 17
14.3. Taxiing ......................................................................................................................... 18
14.4. Taking Off..................................................................................................................... 19
14.5. Horizontal Flight............................................................................................................ 19
14.6. Aircraft Manoeuvres and Turbulence.............................................................................. 20
14.7. Maximum Flight Speed .................................................................................................. 20
14.8. Landing ........................................................................................................................ 20
14.9. Stopping the Engine ...................................................................................................... 20
14.10. Emergence Procedures .................................................................................................. 20
15. Transport, Handling, Storage........................................................ 22
15.1. Propeller Delivery ......................................................................................................... 22
15.2. Handling....................................................................................................................... 22
15.3. Storage ........................................................................................................................ 22
15.4. Transport ..................................................................................................................... 22
15.5. Responsibility for Transport ........................................................................................... 23
16. Inspections..................................................................................24
16.1. Pre-flight Inspection...................................................................................................... 24
16.2. After first 25 operation hours or after each new installation ............................................. 25
16.3. After 100 operating hours.............................................................................................. 25
16.4. Medium Repair............................................................................................................. 25
16.5. Overhaul ...................................................................................................................... 25

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17. Airworthiness Limitations Sections...............................................25
18. Special Inspections ......................................................................26
19. Repairs........................................................................................27
19.1. Blade Repairs................................................................................................................ 27
19.2. Repairs of Propeller Head and Metal Parts ...................................................................... 28
19.3. Repairs of Propeller Spinner........................................................................................... 28
19.4. Replacement of Polyurethane Protective Tape ................................................................ 28
20. Troubleshooting ..........................................................................29
21. Warranty Conditions....................................................................30
21.1. Warranty Period ........................................................................................................... 30
21.2. Warranty Conditions ..................................................................................................... 30
21.3. Responsibility ............................................................................................................... 30
21.4. Honoring the Claim ....................................................................................................... 30
WARRANTY CERTIFICATE.......................................................................32
KW-20 PROPELLER.................................................................................33

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1. List of Valid Pages
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2. List of Revised Pages
Changes or revisions to this manual may only be made by the manufacturer.
Any change should be recorded in the table below.
New or revised text on a revised page will be marked by a black vertical line on the
right side of the page. Date and number of the revision will be recorded on the bottom
edge of the page.
Revision
Date of issue
Revised pages
Date of insertion
Signature
0
06. 10. 2023
New issue

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3. Introduction
Read this manual carefully before putting the product into service to get basic
information on operational safety.
If you do not understand the contents or if in doubt, always contact propeller
manufacturer –Woodcomp Propellers s.r.o.
We wish you many a pleasant flight with Aleš KŘEMEN –WOODCOMP propellers.
4. Manufacturer
Woodcomp Propellers s.r.o.
Odolena Voda, Dolínek, Vodolská 4,
okres Praha-východ, PSČ 250 70
Legal form: Limited Liability Company, registered in the Trade Register maintained by
City Court in Prague, section C, file 80616
Company ID: 26417693
VAT No: CZ26417693
Phone: [phone]
e-mail: [email protected]
http://www.woodcomp.cz
5. Type Certificate Holder
Woodcomp Propellers s.r.o.
Odolena Voda, Dolínek, Vodolská 4,
okres Praha-východ, PSČ 250 70
Legal form: Limited Liability Company, registered in the Trade Register maintained by
City Court in Prague, section C, file 80616
Company ID: 26417693
VAT No: CZ26417693
Phone: [phone]
e-mail: [email protected]
http://www.woodcomp.cz

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6. Serial Number
Please state the correct type designation and serial number of the propeller each time
you contact the manufacturer.
These data are specified on the first page of this User Manual, on Warranty Certificate
and on Product plate fixed on propeller blade No. 1
7. General Information
KW-20 propellers are reliable and field tested in long lasting operation, however
problems might occur as with any product.
Although it is impossible to eliminate all the risks involved just by reading the manual,
they can be minimized by applying the information presented and using the propeller
properly.
Information and descriptions in the manual are valid at the time of publication. Users
of Aleš Křemen propellers may be informed of changes or mandatory measures by
publication in the form of service bulletins at Woodcomp Propellers website
(http://www.woodcomp.cz).
Illustrations in this manual are for information only and do not replace drawings in
technical documentation.
Technical data are specified in SI metric system.
The manual may be translated from Czech to any other language, but the original
Czech text will held decisive validity.
.
8. Operating Safety
This propeller is subject to approval by aviation authorities, and is always operated
on users own risk!
Aerobatics and intentional spins with this propeller are prohibited!
Operation in icing conditions is not permitted!
❖Do not over speed the propeller to higher than maximum permitted rpm, with the
exception of emergency procedures detailed in Sect. 14.10.
❖Do not start the engine manually by the propeller.
❖Pulling/pushing the aircraft using the propeller is only possible when holding the
propeller root part closest to the hub.

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❖Before starting the engine, always check the condition of propeller and its
mounting.
❖Before starting the engine, always ensure that the propeller and its surroundings
are clear.
❖Record all data concerning propeller operation and repairs in the Propeller Log
Book.
❖Do not transport nor store the propeller standing on blade tips, even for short time!
❖Do not store the propeller in extremely damp environment, and do not leave it
outside in rain for extended periods.
9. Propeller Properties
Hydromechanical propellers KW-20 are equipped by automatic rpm governor
(Constant –Speed Propeller). This concept allows best possible use of engine power
while offering much better comfort when using the propulsion unit.
The pilot selects optimum propeller speed by engine controls as usual. Activation of
governor then ensures automatic control of engine throttle (or boost pressure) to keep
propeller speed constant, regardless of changes in cruise speed, descent, turbulence,
and flight manoeuvres, all without pilot´s intervention. Maximum permissible rpm of
propulsion unit will not be exceeded.
A plane with a propeller like this features a short takeoff run, high rate of climb to
reach its flight level, low fuel consumption for the flying range or endurance
demanded, and the possibility of a quick change to the maximum flight speed. The
propeller also improves aircraft’s service ceiling. A plane with this propeller performs
better in glider towing as well.
Constant speed propeller protects the propulsion unit from damage caused by
mishandling during operation.
KW-20 family propellers meet the requirements of standard airplane categories thanks
to their control stability and quick reaction.

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10. Technical Description
KW-20 family of propellers are designed for aircraft with piston engines coupled with
reducing gearbox.
Vrtule KW-20 propellers are constant speed propellers of hydro-mechanical design. In
rest position (without oil pressure), propeller blades are set to minimum angle (pitch),
secured by a mechanical stop.
Down pitching of blades is controlled by mass and aerodynamic effects acting on them
and by means of an auxiliary screw spring in the propeller axis. Up pitching is controlled
by increasing oil pressure in the propeller servomechanism, which keeps the system in
equilibrium.
Control is exerted by hydraulic governor which increases oil pressure when the
propeller speed goes up (“increase” type). Pressurised oil flows through propeller shaft
axis into hydraulic servomechanism located in hub attachment. It consists of a cylinder,
whose bottom end contacts propeller flange on the engine. Inside the cylinder, there is
a piston and piston rod on which a swinging link is mounted, acting via brass stones on
eccentric pins placed in blade root bushes. Blade angle down stop is located at the
piston rod´s front end.
The propeller hub itself and its load carrying parts are made of aluminum alloys.
Propeller blades are made of resonation fir wood core, connected to blade root by
slashing and gluing. Blade roots are made of hardened wood. Blade surface is made of
glass or carbon laminate, protected by gelcoat layer. This structure has exceptional
mechanical parameters, low weight, great resistance and perfect look.
Blade root is precisely machined, inserted into duraluminum hub, and secured by steel
screws with special thread. Blade outboard leading edges are protected against
damage with a layer of cast polyurethane (PU), their inboard part (near the propeller
centre) with a self-adhesive polyurethane tape
Blade root is fixed to the hub by nut with packing to prevent lubricant leak from the
bearings, with PTFE ring and 40% bronze inset. Blade root is held in two axial needle-
type bearings and supporting nut.
The blade tips are painted red to improve visibility when in motion.
Composite spinner is also a part of the propeller.

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10.1. Product Label
Hub
The hub is marked at the outer surface with self-adhesive label with propeller
designation (see chapter 10.2) and serial number.
example:
Blades
At the rear of each blade root there is self-adhesive label with the following data
imprinted on it:
example:
H - Blade for hydraulic propeller
39377 - Serial number of propeller
A - Order of blade in set A, B, C
10/2014 - Date of blade manufacture –October / 2014
R - Marking of propeller after inspection by manufacturer. Not
present on new propeller.
KW-20-A-H-2-0-0-F/
R-171-031 S/N:39377
H 39377 A 10/2014 R

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10.2. Propeller Designation System
HUB / BLADES
KW –xx –( ) –( ) –( ) –( ) –( ) –( ) / ( ) –( ) –( )
1 2 3 4 5 6 7 8 / 9 10 11
Hub
1KW Propeller type
2No. of propeller model
3Code letter for propeller category: A - Automatic Propeller
F - Fixed Pitch Propeller
G - Ground Adjustable Propeller
V - Variable Pitch Propeller
4Code letter for blade pitch change system: H –Hydraulic
E –Electric
M –Mechanical
5Number of blades installed
6Code letter for feathering system: F –Feather position installed
0 –No feather position possible
7Code letter for reverse provision: R –Reverse position installed
0 –No reverse position possible
8Code letter for flange type listed in Aleš KŘEMEN Service Bulletin No. 4
Blades
9Code letter for blade design and installation: R - Right-hand tractor
RP - Right-hand pusher
L - Left-hand tractor
LP - Left-hand pusher
10 Propeller diameter in v cm
11 Blade type identification (contains design configuration and aerodynamic data)
according to the certified hub/blade-combinations.

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11. Basic Performance Data
Propeller model
KW-20
Number of blades installed
2
Blade type
- 031 („W“)
- 033 („C“)
- 034 („B“)
Diameter
right: 1707 ±4 mm
left: 1683 ±4 mm
1695 ±4 mm
1715 ±4 mm
Min. angle setting
5°
Max. angle setting
50°
Max. engine power output-Nmax
115 HP
Max. propeller RPM - nmax
2550 ot/min
Temperature Service Rate
-25°C / +45°C
Moment of mass inertia
0,4 kgm2
Mass of complete propeller
cca 8 kg acc. to type of blades and spinner
Mass of Jihostroj governor
0,90 kg
Lifetime
Propeller lifetime is not specified if every mandatory
periodical inspection are performed in specified
intervals
KW-20 has been tested in operation of aircraft equipped with ROTAX 912/914 engines
ROTAX 912 and ROTAX 914 engines must be equipped for KW-20 propellers:
ROTAX engine version 3 is equipment for hydraulic constant speed use from factory.
- Reducing gearbox with governor drive,
- Propeller shaft supplying pressure oil to the propeller,
- Hydraulic governor, see Service Bulletin No. 03 as amended,
- Governor control from cockpit.

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12. Connection of KW-20 Propeller to Engine
Dimensions correspond to ROTAX 912 engine flange–part number 837 282.
Dia. 13 mm holes on dia. 101.6mm circles are used to attach KW-20 propeller.

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13. Propeller Unit Adjustment
Propeller unit consists of a propeller and a governor. Connection between the
governor and pilot forms a part of aircraft fuselage, can differ in each particular case,
and as such, is not detailed in this text.
CAUTION!
Adjustment of propeller unit by persons not authorized by the
manufacturer is strictly prohibited.
Although the adjustment of propeller unit on aircraft is simple, improper modification
of settings may be dangerous to propulsion unit and operating safety.
13.1. Adjustment before First Flight
This chapter discusses propulsion unit setting before first flight and/or after mounting
of new propeller, or repair of the propeller or its governor.
The manufacturer supplies units already factory-adjusted and ready for installation on
to aircraft and engines of serial production, which are are well-known to the propeller
unit manufacturer. In this case, simply fit the unit, bleed the air, and conduct pre-flight
tests followed by test flight.
Propeller unit must be set correctly to work properly and to be “fail safe”. KW-20
propeller units, i.e. the propeller with the governor, are very reliable; however,
regulations for higher category aircraft, according to which this propeller unit is built,
require that a plane should be able to fly, albeit with limited flight envelope, even after
the propeller control has been damaged. This effectively means that the plane must be
able to keep flying in case its propeller remains fixed at the minimum pitch (take-off
position) while the governor is off, if the propeller remains fixed at maximum pitch
angle, and also when it becomes stuck in any in-between position.
The regulations also require that propeller unit must not require any pilot intervention
(change of controls set before the takeoff) during takeoff and initial climb phases of the
flight.
To meet these requirements, the propeller unit has a number of setting elements. All
speed and angle settings are determined by the manufacturer. You should require
these to be changed, always consult the issue with the manufacturer.

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13.1.1. Propeller Governor Adjustment
Governor maximum speed is the only setting to be made. Minimum governed speed is
determined by governor design, and usually these are 50-60% of maximum speed.
In case of failure of pilot-governor control link, the governor will set takeoff regime
(minimum pitch) automatically.
Adjustment procedure:
1. Loosen propeller low pitch stop (self locking nut) by 2 turns, this moves piston rod
deeper inside the propeller. This nut is located at front part of the hub, and as such it is
accessible after removal of aerodynamic spinner.
This adjustment of the moment when propeller governor actually starts to reduce
engine speed allows you to adjust lower maximum speed allowed by the governor.
2. Start the engine.
3. Slowly and carefully increase the power output of the engine by acting on the gas
lever, while observing the engine rpm.
The engine speed will go up to 5730 to 5750rpm (ROTAX 912 engine). Speed increase
should stop at this moment.
If the speed settles at lower rpm than given above, stop the engine and adjust the lever
stop of the governor speed selector so as to extend the lever movement in the
direction in which it is pulled by the return spring.
If the speed increases above this value, shorten the lever travel by adjusting the stop.
4. Repeat steps 2 and 3 until you reach desired maximum governed speed.
5. Secure governor speed selector lever stop.
13.1.2. Propeller Low Pitch Angle Stops Adjustment
This adjustment is performed after governor adjustment (see Chapter 13.1.1 above) as
follows:
1. Screw in propeller low pitch stop nut by 2 turns. (This moves piston rod out of the
propeller.)
2. Check that the governor speed selector remains in the takeoff position, i.e. on the
stop to which it is pulled by the return spring.
3. Start the engine.
4. Increase engine power output up to its maximum.
Rpm must increase smoothly, up to full throttle without governor intervention. At full
throtle, rpm must be lower than the maximum allowed by propeller manufacturer. For
instance, ROTAX 912 engine in planes climbing at lower speed (ca 80–90km/h) should

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reach about 20rpm less than the governor setting. In planes climbing at higher speed
(ca 110 - 120km/h), this engine should reach about 120 - 150rpm less.
If you need lower rpm, tighten propeller down pitch stop nut. Loosen it to obtain
higher setting.
5. Repeat steps 2 to 4 until you reach desired governed speed.
6. Install spinner back onto propeller. Position spinner so that red dot on spinner
external surface meets red dot on backplate (withal blade No. 1). Fasten spinner
using 8 screws and washers, with Loctite 243 applied.
Remark:
Propeller adjustment must be performed with clean propeller blades, as any soiling
(e.g. insects) influences its aerodynamic properties, leading to misadjusted governor.
Do not adjust the propeller at strong winds or gusts. It is not recommended to set the
propeller at extreme temperatures.
Low pitch stop location

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14. Operating Instruction
14.1. Mounting propeller on engine
1. Put a vessel beneath front part of engine to contain the oil which may escape from
propeller reducer shaft or from propeller servo-system.
2. Check flange contact surfaces of reducer shaft and propeller and/or clean them to
make them dry, clean and rust free.
3. Fit centring bushes (dia 13mm) into six flange holes at reduction gearbox side.
4. Put rubber sealing O-ring 46 x 2,5 P/N A-1015-01 onto 47mm centering piece. It is
recommended to use new O-ring at each assembly.
5. Check that aerodynamic spinner holding plate is mounted on the propeller hub.
6. Mount propeller on flange and fix it using six self-locking nuts; torque the nuts to
22Nm.
7. Start the engine and perform engine test according to Chapter 14.2; observe the
joints to ensure that oil is not leaking.
9. Mount spinner on the propeller and fix it with screws. Use new screws at each
assembly.
14.2. Starting engine and performing engine test
Always observe the following procedure:
1. Check propulsion unit according to its mnufacturer´s instructions.
2. Check propeller integrity.
3. Set speed selector to takeoff regime, i.e. to minimum pitch. This position of the
speed selector corresponds to maximum rpm of propulsion unit.
4. Start the engine.
On starting the engine the propeller will achieve its idle speed. Observe engine warm-
up instructions and gradually increase the speed using throttle lever. Propeller
remains at the down blade pitch stop; the governor usually does not intervene. It
may intervene if weather conditions differ considerably from standard and near
engine’s maximum power output. Under standard conditions ROTAX 912 engine will
run at 5400 to 5500rpm depending on the plane type, with the governor limiting the
speed at 5730 to 5750rpm.

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5. Bleed the control system
If engine test is carried out after installation of new propeller, after oil change, or
after a long period when the propeller was out of operation, it is necessary to bleed
propeller control system. To carry out bleeding, set full throttle and set speed
selector to maximum propeller speed (same position as when warming up engine).
Then, move the selector gently toward lower propeller spee, i.e. toward higher pitch.
When the propulsion unit speed decreases by 50–100rpm (without any manipulation
with throttle lever), put the selector back to maximum speed position. Repeat these
steps five times.
It is a serious mistake to decrease propeller speed further toward minimum value
during this procedure, as the blade angle will become too high for this regime and the
blades operate at too high pitch. The propeller will sustain this mishandling, but its
life will be shortened.
Presence of air in the control system translates to “softness” of constant speed
during flight, but this should cease soon and the propeller will finish bleeding on
itself.
6. Verification of governor function
During engine test, which is part of normal operation of aircraft, it is not necessary to
bleed the system. Checking the operation of control system will suffice. The method
is the same as during bleeding; simply check the rpm dropping and recovering once.
14.3. Taxiing
Leave the speed selector in takeoff position i.e. minimum pitch and maximum speed
during taxiing. Control the aircraft speed using throttle lever or brakes, as necessary.
Propeller speed will be controlled by throttle lever, with governor not intervening.
Constant speed propeller usually allows finer control of aircraft speed during taxiing,
compared to fixed or ground adjustable propeller. However, higher rpm may be
required to achieve the same ground speed; engine rpm will be higher, but actual
power required will be lower.

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14.4. Taking Off
Set full throttle and keep the speed selector in the takeoff position. As the plane
gathers speed, during takeoff run and initial climb, propulsion unit rpm rise
automatically till they reach maximum value set by the governor. Then the governor
intervenes, keeping rpm constant.
After finishing the initial climb, it is advisable to go from the takeoff power output
(limited to 5 minutes with ROTAX 912 engine) to maximum constant power (full
throttle and 5500rpm for ROTAX 912 engine). The most convenient and safe transition
to maximum constant power is to decrease engine speed using propeller speed
selector, while keeping throttle fully open. On reaching required altitude, throttle
down according to required air speed.
Any attempt to decrease engine rpm during flight by closing throttle is serious mistake,
resulting from misunderstanding of how constant speed propeller works. On an engine
fitted with a constant speed propeller, throttle lever actually controls propeller thrust,
not rpm. Closing throttle during flight will reduce engine rpm near idle speed, where all
propeller thrust is lost. Inexperienced pilot closing throttle during climb is in danger of
getting into risky second regime of flight.
14.5. Horizontal Flight
Constant speed propeller offers the most economical operation in the horizontal flight
–minimum fuel consumption for a given range or endurance. High flight speed can be
obtained without overloading the engine load, and acoustically comfortable engine
operating regime can be selected.
Calculation of propeller unit setting to achieve the most economical operation is
complicated, requiring input of multiple performance characteristics of aircraft, engine,
and propeller. However, virtually the same result can be obtained experimentally
through test.
It is advisable to perform this test as follows:
1. At your preferred flight level, set throttle and speed selector to achieve normal flight
regime (e.g. 4800 to 5500rpm); allow this regime to stabilize.
2. Use speed selector to achieve engine speed recommended by its manufacturer, e.g.
4300rpm, NOT TOUCHING the throttle lever.
3. Do not touch speed selector and adjust engine throttle to arrive at flight speed
selected in step 1.
If propeller and engine load is too high after this adjustments (keep checking engine
exhaust and oil temperature and pressure), reduce engine load by lowering propeller
pitch (by setting governor control to 4800, 5200rpm and so on) and always correct

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flight speed using throttle lever. If aircraft manufacturer recommends other procedure
in aircraft operation manual, such procedure should prevail. In most flight regimes,
lower engine rpm means lower fuel consumption per hour, and higher higher
propulsion efficiency of propeller.
14.6. Aircraft Manoeuvres and Turbulence
The propulsion unit keeps set speed without pilot´s intervention.
14.7. Maximum Flight Speed
Some aircraft do not achieve maximum horizontal flight speed at maximum propeller
speed, but at full throttle and slightly reduced propeller speed. A suitable setting
should be found according to procedure in Chapter 14.5.
The governor will protect the engine from over-speeding up to aircraft’s never exceed
speed plus a small safety margin (vNE).
14.8. Landing
During landing, speed selector must be set to takeoff position no later than after the
final turn. This makes the recovery of speed and height easier in critical situation
(wrong landing calculation, obstacle on runway). You need not be afraid of fast opening
engine throttle from idling to maximum power, as the governor will protect the
propulsion unit from overspeed.
14.9. Stopping the Engine
Before stopping the engine, set speed selector to takeoff position and keep it in this
position when not airborne, too.
14.10. Emergence Procedures
KW-20 propellers are reliable, but as the possibility of failure can never be completely
eliminated, all pilots must know correct procedures allowing safe completion of flight
in case of a failure.
Propeller governor failure usually results in blocking of certain propeller pitch between
the stops or at one of the stops. Propeller then effectively becomes fixed-pitch
propeller. In this case, propulsion unit can only be controlled by throttle lever. The
other type of failure includes loss of control stability due to e.g. impurities in oil
entering the governor or the propeller. Depending on the position in which the blades
have locked and depending on the flight regime, the pilot should act as follows:
A) Propeller blades locked in small pitch range
The failure is indicated by increased rpm at flight speed higher than the optimum
speed of climb.