BASIC SET UP for AIRCRAFT USING 2 CHANNELS and 2... AILERONS, ELEVATORS and RUDDER

BASIC SET UP for AIRCRAFT USING 2 CHANNELS and 2... AILERONS, ELEVATORS and RUDDER
BASIC SET UP for AIRCRAFT USING 2 CHANNELS and 2 SERVOS EACH for
AILERONS, ELEVATORS and RUDDER
What lies before you is an attempt to provide a set of written procedures to take you step-by-step through the
programming of a typical 30%-40% RC aerobatic aircraft. The programming steps are intended to address
the JR PCM 10SX, 10SXII, and 10X radio systems and today's IMAC style of aircraft that utilize 2
channels and servos each for ailerons, elevators and rudder. The Idea was to start at the very beginning with
servo installation and linkage set up, and then proceed step-by-step until the basic programming set-up was
complete. While in the process of describing some of the basic programming two things became
immediately apparent. First was the fact that these radio systems were so rich in useful programming
features that it would be difficult to exclude some of them even during basic set up. And second, it is a lot
easier to do the actual programming than it is to write about it.
On more than one occasion fellow modelers have been overheard saying things like; "This radio has so many
features that I don't know where to start learning about them" and "I can't use the manual because I don't
know which part to read first" and " I don't know anything about computers so programming is too difficult."
Well don't let the thought of programming intimidate you. Do you remember the first time you encountered
Cruise Control in an automobile? It had some buttons that were attached to some form of computer. How
long was it before you messed around with it and when you got it going you thought, "this is bad, cool, nifty,
slick, or maybe even far-out" – depending on how long ago it was. Each and every feature in the radio was
designed for a specific purpose – to help the aircraft fly better, easier, with more precision, faster, and
slower… and to make the job easier for the builder, mechanic and pilot. All it takes is some "messing
around" and perhaps a little guidance. Try to have some fun with it. Take your time, read and perform the
steps below, and if things get terribly messed-up you can just start over and perform the steps as many times
as you like.
Disclaimer: Owing to the number of variables that exist in each RC aircraft it cannot be guaranteed that
these instructions will work for every installation. Therefore the author assumes no responsibility for any
outcome including the proper operation of aircraft controls and functions, safety while testing and adjusting
parameters, and any other effect that may be associated with the material contained herein.
You may mount your servos now and plug them into the channels indicated below or wait until one of the
steps below instructs you to do so. However DO NOT ATTACH ANY LINKAGES TO THE SERVOS AT
THIS TIME.
Plug the servos into the receiver ports as indicated below.
SERVO LOCATION
RX CHANNEL
Throttle servo
Right Aileron servo
Right Elevator servo
Right Rudder servo
Left Aileron servo
Left Rudder servo
Left Elevator servo
Channel
Channel
Channel
Channel
Channel
Channel
Channel
1
2
3
4
6
7
8
(Throttle)
(Aileron)
(Elevator)
(Rudder)
(Flap, Aux1)
(Aux2)
(Aux3)
TIP: If we plug a DSC or Trainer cord (or just a pin plug with no wires attached) into the DSC receptacle in
the back of the transmitter it will turn on the display without transmitting and will enable us to program
without running the battery down so quickly.
By Len Alessi
1
All Rights Reserved © 5/24/02
1. Select a Model and Reset all Parameters (settings)
It is best to start with a fresh program that has all settings reset to factory defaults. This will ensure
that all previous sub trim and trim memory settings are set to zero and that all programmable mixes,
dual rates and other special functions are inactive. It will help to ensure the proper set up of all servo
linkages/throws and there should be no surprises after set up is complete.
a. Select a model using code 84. All programming for this model is going to be erased in the next
step. Touch ENTER when you have selected the model memory you want to use.
b. RESET the programming for the model by accessing code 28 and touching CLEAR to reset all
data for the model. Answer Yes to any questions regarding clearing or resetting the model and
touch ENTER when you are finished. We now have a “Fresh” set up to work with.
c. As a final step in this process, move all trim levers to their neutral or center positions.
2. Name The Model
Lets name the model to help get our fingers limbered-up for programming.
a. Access code 81 to select the appropriate letters/characters for the model name. Touch the SEL
key to change the selection of characters across the bottom of the display until we see the
character we want. Then touch the character. Touching it will move the character to the next
position in the model name. The cursor will automatically move one position to the right ready
for us to select the next character (the cursor is a pointer that shows us where the next letter is to
be inserted -- it only moves to the right and will wrap around to the beginning when it gets to the
end). If we want to leave a space, touch the arrow key to move the cursor one position to the
right. If we make a mistake and need to replace a letter or want to reposition the cursor just keep
touching the arrow key until the cursor gets to where we want it to be and select the character we
want. If we need to replace a character with a space, touch the arrow until the cursor is positioned
at the character to be replaced, touch SEL until we see a space character at the bottom of the
display and then touch the space character. Keep selecting characters until we have the model
name completed. Touch ENTER when finished to exit the Model Name function.
3. Set the Wing Type to FLAPERON
In order to use two channels/servos for the ailerons we will take advantage of the FLAPERON wing
type and its ability to control 2 aileron servos on two separate channels.
a. Access the Wing Type function using code 22.
b. Touch SEL under NORMAL until FLAPERON appears. Then touch ENTER to exit the Wing
Type function
4. Inhibit the FLAP, AUX2 and AUX3 Levers and Switches
We need to disable the FLAP, AUX2 and AUX3 levers and switches because we are going to use
these channels for primary flight controls (ailerons, elevators and rudder) and we no longer want the
levers and switches to control them.
a. Access TRIMMER FUNCTIONS or FUNCTION SELECT using code 17.
b. For the 10SX owner, touch CLEAR under FLAP, AUX2 and AUX3 until INH appears under
each indicating that the levers and switches are inhibited. For the 10SXII and 10X owner, touch
SEL under the 1st column that has FLAP in it until the little arrow is next to FLAP. Touch
CLEAR to inhibit the FLAP lever. Touch SEL again and the arrow will be next to AUX2 – touch
CLEAR again to inhibit the AUX2 switch. The arrow should already be next to AUX3 in the 2nd
column so just touch CLEAR under the 2nd column to inhibit the AUX3 lever.
c. Make sure that FLAP, AUX2 and AUX3 all have INH next to them before touching ENTER to
exit the function.
By Len Alessi
2
All Rights Reserved © 5/24/02
5. Set Up A Mixer for Dual Elevator Channels/Servos
At this point we will set up a mixer for the elevator channels/servos. For PCM 10SXII and 10X
owners this involves only 1 setting because these transmitters have a built-in function to handle dual
elevator servos. The PCM 10SX requires programming of a programmable mixer to control two
elevator servos on separate channels. By the way, using a separate servo and channel for each control
surface has the benefits of providing redundancy; ease of setting both servos to neutral; and the
ability to remove any differential throw that may be inherent in the linkages.
a. PCM 10SXII and 10X owners, return to the Wing Type function code 22 and touch SEL under
TAIL until D/ELEV appears. The radio will now automatically use a built-in mixer to control
channels 3 (Elevator) and Aux3 (channel 8) for the elevator servos. We are finished with this
step so touch ENTER to exit.
b. For PCM 10SX owners select the first programmable mixer using code 51 and continue with the
steps in this topic.
c. Touch number 3 to set the Elevator as the Master channel and then touch 8 to set channel 8 or
Aux3 as the Slave channel. Then touch ENTER to get to the next display. If you make a
mistake, touch CLEAR and touch 3 and 8 again before touching ENTER.
d. Hold the elevator stick in the up-elevator position and touch and hold the + key until the
percentage reads 100%. Now push and hold the elevator stick in the down-elevator position and
touch and hold the + key until the percentage reads 100%.
e. Touch the PAGE key to get to the next display.
f. Touch SEL under MASTER until INLC appears indicating that INCLUDE mixing is activated.
INCLUDE mixing tells the mixer to move the left elevator anytime the right elevator moves
regardless of where the input is coming from (stick, snap button, another program mix etc.)
Always activate INCLUDE mixing when mixing two channels for a primary flight control
(Aileron, Elevator, Rudder).
g. Now touch SEL under TRIM until ON appears so that the left elevator will move with the right
elevator when the elevator trim lever is moved. Always activate TRIM when using multiple
channels for a primary flight control.
h. Programming of the dual elevator mixer is now complete. Touch ENTER to exit the mixer.
6. Set Up A Programmable Mixer for Dual Rudder Channels/Servos
Now we’ll set up a programmable mixer for the Dual Rudder channels/servos.
a. Access the second programmable mixer using code 52.
b. Touch number 4 to set the Rudder as the Master channel and then touch 7 to set channel 7 or
Aux2 as the Slave channel. Then touch ENTER to get to the next display. If you make a mistake
touch CLEAR and then touch 4 and 7 again before touching ENTER
c. Hold the Rudder stick in the right-rudder position and touch and hold the + key until the
percentage reads 100%. Now push and hold the rudder stick in the left-rudder position and touch
and hold the + key until the other percentage reads 100%.
d. Touch the PAGE key to get to the next display (10SXII & 10X owners touch PAGE twice).
e. Touch SEL under MASTER until INLC appears indicating that INCLUDE mixing is activated.
INCLUDE mixing tells the mixer to move the left rudder servo anytime the right rudder servo
moves regardless of where the input is coming from (stick, snap button, another program mix
etc.) Always activate INCLUDE mixing when mixing two channels for a primary flight control
(Aileron, Elevator, Rudder).
f. Touch SEL under TRIM until ON appears so that the left rudder servo will move with the right
rudder servo when the rudder trim lever is moved. Always activate TRIM when using multiple
channels for a primary flight control.
g. Programming of the dual rudder servo mixer is now complete. Touch ENTER to exit the mixer.
By Len Alessi
3
All Rights Reserved © 5/24/02
7. Set Servo Directions For All Channels
It is important that all servos move in the proper direction before proceeding with any other
programming. Make sure all servos are mounted in their intended locations and plugged into the
channels indicated at the beginning of these instructions.
Temporarily install an output arm on each servo just for a visual reference – there is no need to install
the output arm screws yet as they will be moved and repositioned in subsequent steps. The servo
arms for both elevators should be pointing in the same direction (both up or down) and the servo
arms for the rudder servos should be pointing in the same direction (both up or down). DO NOT
ATTACH ANY LINKAGES TO THE SERVOS AT THIS TIME.
a. Turn on the transmitter and receiver and access the Reverse Servo function code 11.
b. Move the throttle stick from low to high and note the direction of travel relative to the throttle
arm on the carburetor. If moving the throttle stick to high will cause the carb to open once the
linkage is attached, then it is ok. Otherwise touch 1 on the bottom of the display to reverse the
throttle servo direction.
c. Move the aileron stick to the Right and note the movement of the Right aileron servo. If the servo
movement will cause the Right aileron to deflect upward once the linkage is attached then the
right aileron servo direction is ok, if not, touch the 2 at the bottom of the display to reverse the
direction of the right aileron servo. Now observe the Left aileron servo when the aileron stick is
moved to the Right. If its movement will cause the Left aileron to deflect downward it is ok,
otherwise touch 6 at the bottom of the display to reverse the direction of the left aileron servo.
d. Move the elevator stick to the Up-elevator position and observe the movement of the Right
elevator servo. If its movement will cause the Right elevator half to deflect upward once the
linkage is attached it is ok, otherwise touch 3 at the bottom of the display to reverse the direction
of the right elevator servo. Move the elevator stick to the Up-elevator position again and observe
the Left elevator servo. If its movement will cause the Left elevator to deflect upward then it is
ok, otherwise touch 8 at the bottom of the display to reverse the direction of the left elevator
servo.
e. Move the rudder stick to the Right and note the movement of the Right rudder servo. If the servo
movement will cause the rudder to move Right once the linkage is attached then it is ok,
otherwise touch the 4 at the bottom of the display to reverse the direction of the right rudder
servo. Now observe the Left rudder servo when the rudder stick is moved to the Right. If its
movement will cause the rudder to deflect Right it is ok, otherwise touch 7 at the bottom of the
display to reverse the direction of the left rudder servo.
f. Touch ENTER to exit the servo reversing function.
By Len Alessi
4
All Rights Reserved © 5/24/02
8. Set Up and Adjust the Throttle Linkage
Now we will set up the throttle linkage and adjust the servo travel for full throttle and idle. Note: Use
a non-conductive linkage such as a Ny-Rod if the engine has an ignition system! Using a nonconductive linkage greatly reduces the possibility of interference should the ignition develop a leak.
Note: some carbs come equipped with a throttle-stop mechanism (usually an adjustable screw) that
can keep the throttle from closing all the way. Either adjust the screw so the carb can be closed tight
or remove it altogether as we want the throttle servo to be able to close the carb far enough to stop
the engine.
a. Turn on the transmitter and receiver and set the throttle stick at 1/2 throttle.
b. Move the throttle trim lever to its center detent and install a medium-length servo arm on the
throttle servo so that the arm is 90˚ or perpendicular to the throttle linkage.
c. Install the throttle linkage attaching one end to the servo arm (use the hole furthest from the
output shaft) and the other end to the carb lever that opens and closes the carb. Adjust the linkage
so that the carb is halfway open to correspond to the throttle stick being midway between high
and low throttle. Make sure there is no binding whatsoever in the linkage!
d. Access the TRAVEL function using code 12. PCM 10X owners should touch the “S” at the top
of the display to allow independent adjustment of the high- and low-end travel.
e. Move the throttle stick to the full-throttle position and observe the carb and linkage. If the carb is
fully open and the servo is buzzing and/or the throttle linkage is bending it is an indication that
there is too much travel. If this is the case, touch the "–" key under THRO to decrease the servo
travel until the servo stops buzzing and the linkage stops bending. If the carb is not fully open
with the stick at high throttle then there is not enough throw. In this case touch the + key Under
THRO to increase the travel until the carb is just fully open and no more. If the travel reaches
150% and the carb is still not fully open, then a longer servo arm is required or you must attach
the linkage closer to the pivot point at the carb lever.
f. Now move the throttle stick to the full-low position and observe the carb and linkage. If the carb
is closed tight and the servo is buzzing there is too much throw in this direction. If this is the
case, touch the "–" key under THRO until the servo stops buzzing and the carb just begins to open
about 1/32”. If the carb is not closed within about 1/32” then more throw is required and you
must touch the + key under THRO until the carb is just barely open. If you reach 150% travel
and the carb is still not within 1/32" of being closed there is probably differential built into the
linkage. Try removing the servo arm and rotating it 1 spline towards the low-end travel and
readjust the high-end again. If there just isn't enough travel, a longer servo arm is required or the
linkage must be attached closer to the pivot point on the carb lever.
g. Now move the throttle trim lever to the full-low position. It should completely close the throttle.
If there is excessive servo buzzing with the throttle trim at full low, then touch the"–" key under
THRO a few more times to reduce the throw a few more percentage points.
Note: Once you have finished setting the throws look at the percentages for low- and high-end
travel. If they are rather small (less than 60%) you may want to move the linkage inward on the
servo arm and perform all adjustments again from the beginning to provide better resolution.
h. Final adjustment of the throttle low-end travel should be performed with the engine running and a
helper securely holding the aircraft. Start the engine and run it until it gets up to normal operating
temperature.
i. Access TRAVEL code 12 (10X owners touch S) and position the throttle trim lever in its center
detent. If the engine idle gets too low and the engine quits when the trim lever is positioned in the
center, touch the "–" key under THRO to reduce the low-end Travel until the engine does not die
with the trim in its center detent.
j. Making sure the engine stays up to temperature, adjust the low-end travel using the + and – keys
under THRO until you get the lowest dependable idle with the throttle trim in it’s center detent
position. This completes the throttle servo adjustment so touch ENTER to exit.
By Len Alessi
5
All Rights Reserved © 5/24/02
SUB TRIM AND MECHANICAL ADVANTAGE
Sub Trims are intended for relatively minor adjustments to servo linkages and not for major trim
adjustments to the aircraft. Using excessive sub trim percentages can cause a loss in servo resolution
where the servo reaches its travel limit and stops moving before the control stick is fully deflected.
The diagram below illustrates an ideal servo/linkage setup when the servo is at neutral (no sub trim or
trim offset and digital trims centered). Notice that the servo arm is positioned at 90˚ or perpendicular to
the servo. Also note that the linkage or rod is attached at 90˚ to both the servo arm and the control
surface horn. This setup will result in the same amount of throw in both directions (0 differential throw).
If the servo cannot be mounted parallel to the linkage/rod then just make sure the servo arm is at 90˚ to
the control rod when the servo is at neutral.
Mechanical Advantage is a very important concept when dealing with larger aircraft. It refers to the
leverage that the servo can exert on the control surface. Since the control surfaces are rather large it is
important for the servo to have enough mechanical advantage or leverage to control them, regardless of
the servo's rated torque. A large amount of torque is of little value if there is not enough leverage to use
it. Insufficient leverage can lead to control surface flutter (usually a catastrophic event) and blow-back
where the air flow pushes the control surface backwards resulting in mushy or no control at higher
speeds.
There are two ways to increase the mechanical advantage of the servo. One is to make sure that the
control horn device, whether it be a horn as shown in the illustration above or a bolt with a Rocket Citytype fastener, is long enough. The horn is the lever that the servo uses to control the surface. The longer
the horn, the more leverage the servo has. It's like a Lug Wrench – when you can't get a lug nut loose
you put a piece of pipe over the end of the lug wrench to extend the handle and that gives you more
leverage to break the lug nut free. It's the same thing - the lug nut is the control surface and you are the
servo trying to move it. As a general rule-of-thumb, try to attach the linkage at the control surface so that
it is at least 1" away from the surface – longer is better.
The second way to increase the mechanical advantage for the servo is to attach the linkage at the servo
arm as far inward (towards the servo arm retaining screw) as possible while still providing enough throw.
It's the "lever thing" again, but in reverse, as we are trying to take leverage away from the control surface
by providing it with a shorter lever to work against the servo.
Ensure that the attach-point is the same distance from the hinge line for like surfaces (two ailerons, two
elevators and two rudder horns). If the attach points are not the same distance from the hinge line there
will be unequal throw and it will be more difficult to synchronize the surfaces for equal deflection. This
is especially critical for the rudder where two servos are attached to the same surface – unequal throw
will cause the servos to fight one another causing excessive battery drain, and in severe cases may cause
servo damage.
Always try to use the maximum amount of Travel (100%-150%) that the radio provides. If it is too much
travel don't reduce the percentage of travel in the radio, instead, move the linkage further away from the
hinge line at the control surface and/or move the linkage inward on the servo arm or use a shorter arm. If
you use high percentages of travel you maintain resolution (fine movements of the stick result in fine
positive movements of the control surface). When we decrease travel percentages we lose resolution.
By Len Alessi
6
All Rights Reserved © 5/24/02
9. Set Up and Adjust the Dual Elevator Servos and Linkages
The two elevator servos and linkages will be set up so they match one another at center (neutral) and
at full deflection up and down. The objective is to first get everything aligned as closely as possible
from a mechanical perspective by installing the servo arms correctly and mechanically adjusting the
linkages. Only then should the radio settings be adjusted to fine-tune everything. Remember, the
excessive use of Sub Trims is to be avoided, as it will result in dead band and a loss in resolution.
a. Turn on the transmitter and receiver and make sure the trim levers are centered. It is assumed
that all Sub Trims and Trim Offsets are still set to zero as a result of performing the RESET
operation at the beginning of these instructions. If you did not perform the RESET operation then
set all sub trims to zero using code 15 and reset all Trim Offsets (PCM 10SX and 10SXII only) to
zero using code 82 and touching CLEAR under AIL, ELEV and RUDD.
b. Install servo arms on the 2 elevator servos so that the arms are at 90˚ or perpendicular to the servo
cases (i.e. straight up or straight down). Rotate, swap and reinstall the arms or try different arms
if necessary to get them as close to 90˚ as you can. It is not unusual for the arms to be tilted
slightly and we will fine-tune them in a minute but get them as close as you can for now.
c. Access the Sub Trim function code 15 and touch the + and – keys under ELEV to adjust the Right
elevator servo so its arm is right at 90˚ to the case (straight up or straight down).
d. Touch PAGE to get to the next display of channels and touch the + and – keys under AUX3 to
adjust the Left elevator servo until its arm is right at 90˚ to the servo case.
e. We now need to set the Right elevator half to 0˚ incidence in relation to the wing. This can best
be accomplished by placing an incidence meter on the wing inboard of the ailerons and blockingup the tail until the wing incidence is at 0˚. Now install the linkage for the Right elevator half.
Put the incidence meter on the Right stab/elevator and adjust the Right elevator linkage to obtain
0˚ incidence (or as close to 0˚ as you can get). Now do the same for the Left stab/elevator and its
linkage.
f. If zero degrees incidence could not be obtained using the mechanical adjustments, use the SUB
TRIM function (code 15) and touch the + and – keys under ELEV to adjust the Right elevator
servo and touch the + and – keys under AUX3 (on the next PAGE) to adjust the Left elevator
servo to get both elevator halves at 0˚. When finished, both stab/elevator halves should be at 0˚
incidence relative to one another and to the wing.
g. Now its time to adjust the overall travel (up and down) of the two elevator servos. The elevator
travel should be set to the maximum that you ever intend to use for precision aerobatic flying. As
a general guideline, use as high a percentage of travel as you can (100%-150%) in order to
maintain maximum resolution. If a high percentage of travel results in too much throw do not
decrease the travel of the servo. Instead, move the linkage outward (away from the hinge line) at
the elevators or, move the linkage inward on the servo arm or use a shorter servo arm. This will
decrease the throw while increasing resolution and the mechanical advantage of the servo!
h. Access the TRAVEL function (code 12). (PCM 10X owners touch S). Hold the elevator stick in
the up-elevator position and touch the + and – keys under ELEV to set your maximum deflection
for the Right elevator half. Do the same while holding the elevator stick in the down-elevator
position. Now adjust the travel of the Left elevator by touching PAGE and touching the + and –
keys under AUX3 to exactly match the travel of the Right elevator in both directions. A degree
gauge works well for matching deflections. Dual elevator set up is now complete!
NOTE: Once the elevators have been adjusted as described above, use the TRACE RATE function
(code 14) to make future adjustments to overall elevator travel. Using TRACE RATE eliminates the
need to individually measure/adjust the throws of each servo when more than one channel is used for a
primary flight control (Elevator, Aileron, Rudder). It is used to make adjustments only after the
channels have been setup for equal throws.
By Len Alessi
7
All Rights Reserved © 5/24/02
10. Set Up and Adjust the Dual Rudder Servos and Linkages
The two rudder servos and linkages will be set up so they match one another at center (neutral) and at
full deflection left and right. The objective is to first get everything aligned mechanically and then
make fine adjustments with the radio. The excessive use of Sub Trims is to be avoided, as it will
result in significant dead band and a loss in resolution. It is very important that the servos don’t
“fight” one another as it may cause excessive battery drain and in severe instances may cause
servo damage.
a. Turn the transmitter and receiver ON and make sure the rudder trim lever is centered.
b. Install servo arms on the 2 rudder servos so that the arms are at 90˚ or perpendicular to the servo
cases (i.e. both straight up or both straight down). Rotate, swap and reinstall the arms or try
different arms if necessary to get them as close to this position as you can.
c. Access the Sub Trim function code 15 and touch the + and – keys under RUDD to adjust the
Right rudder servo so its arm is right at 90˚ to the case.
d. Touch PAGE to get to the next display of channels and touch the + and – keys under AUX2 to
adjust the Left rudder servo until its arm is 90˚ to the servo case.
e. We now need to set the Right rudder servo and linkage center point. Install the linkage for the
Right rudder servo and adjust the linkage so that the rudder is straight. If you cannot get it deadon with the linkage, get it as close as you can and then use Sub Trim code 15 and touch + and under RUDD to get it straight.
f. Now set the rudder throw in each direction by accessing TRAVEL code 12 (PCM 10X owners
touch S) and touching the + and – keys under RUDD while holding the rudder stick to the right
and then the left to establish the maximum desired throw in each direction. Make sure that the
servo is not trying to move the rudder past the physical limitations of hinges and hinge line bevel.
Excessive servo buzzing at the end points is an indication of binding and is undesirable.
g. Attach the linkage for the Left rudder servo BUT DO NOT MOVE THE RUDDER STICK!
Adjust the linkage so that it does not fight the Right rudder servo when the rudder stick is at
neutral. Get it as close as you can by mechanically adjusting the linkage. If the servos are
buzzing loudly it is an indication that they are fighting one another at neutral. If this is the case,
access Sub Trim code 15 and touch PAGE to get to the 2nd page of channels where you can touch
the + and – keys under AUX2 until the servos are no longer fighting each other – it should only
take a few percentage points to get them to stop fighting.
h. Disconnect the Left rudder servo linkage from the rudder but leave it attached to the servo.
Access TRAVEL code 12 and touch PAGE to get to the 2nd page of channels (PCM 10X owners
touch S). Now move the rudder stick all the way to the right and hold it there. Pick up the Left
rudder servo linkage and hold it up to the attach point at the rudder to see if it needs more or less
throw to properly attach and touch the + or – key under AUX2 until it looks like the linkage will
attach properly. Next move the rudder stick to the Left and adjust AUX2 throw in this direction
until it looks like the linkage will attach properly. Get these adjustments as close as you can!
i. Attach the Left rudder servo linkage to the rudder. Move the rudder stick all the way to the Right
and listen and look for signs of the servos fighting each other. Touch the + and – keys under
AUX2 until servo buzzing is at a minimum and the servos are not fighting each other. Now move
the rudder stick all the way to the Left and repeat the adjustment. Dual rudder servo set up and
adjustment is now complete!
NOTE: Once the rudder servos have been adjusted as described above, use the TRACE RATE function
(code 14) to make future adjustments to overall rudder travel. Using TRACE RATE eliminates the need
to individually measure/adjust the throws of each servo when more than one channel is used for the
Elevator, Aileron, or Rudder. It is used to make adjustments only after the channels have been setup for
equal throws.
By Len Alessi
8
All Rights Reserved © 5/24/02
11. Set Up and Adjust the Aileron Servos and Linkages
The two aileron servos and linkages will be set up so they match one another at center (neutral) and at
full deflection up and down. The objective is to first get everything aligned mechanically by
installing the servo arms correctly and adjusting the linkages. Only then should the radio settings be
adjusted to fine-tune everything. The excessive use of Sub Trims (high Sub Trim percentages) is to
be avoided, as it will result in significant dead band and a loss in resolution.
a. Make sure the aileron trim lever is centered.
b. Install servo arms on the 2 aileron servos so that the arms are at 90˚ or perpendicular to the
control rods. Rotate, swap and reinstall the arms or try different arms if necessary to get them as
close to this position as you can.
c. Access the Sub Trim function code 15 and touch the + and – keys under AILE to adjust the Right
aileron servo so its arm is right at 90˚ to the linkage.
d. Touch PAGE to get to the next display of channels and touch the + and – keys under FLAP to
adjust the Left aileron servo until its arm is right at 90˚ to the linkage.
e. Set the ailerons at neutral so that they are in line with the wing root trailing edges. Install the
linkages for the both ailerons. Adjust the linkages so that the aileron trailing edges are in line
with the trailing edges at the roots of the wings. Get them as close as you can.
f. If exact alignment could not be obtained with the mechanical adjustments, use the Sub Trim
function code 15 and touch the + and – keys under AILE to adjust the Right aileron servo and
touch the + and – keys under FLAP (touch PAGE to get to the 2nd display) to adjust the Left
aileron servo to get both aileron trailing edges aligned with the wing.
g. Now its time to adjust the overall travel (up and down) of the two aileron servos. The aileron
travel should be set to the maximum that you ever intend to use for precision aerobatics. As a
general guideline, use as high a percentage of travel as you can (100%-150%) in order to maintain
maximum resolution. If a high percentage of travel results in too much throw then move the
linkage inward on the servo arm (closer to the servo arm screw) or use a shorter servo arm, and/or
move the linkage outward (away from the hinge line) at the ailerons.
Note: Ailerons are large long control surfaces and as such are more prone to flutter than
elevators and rudder. It is therefore very important that the linkage set-up provide enough
mechanical advantage for the servo to keep the ailerons under control. Mechanical advantage is
increased when you attach the linkage closer to the servo screw on the servo arm and when you
attach further away from the hinge line at the aileron. As a general rule-of-thumb, try to attach
the linkage at the aileron at least 1" from the surface of the aileron and preferably more. If the
horns/screws aren't long enough – get longer ones!
h. Access the TRAVEL function (code 12). (PCM 10X owners touch S). Hold the aileron stick in
the full Right-aileron position and touch the + and – keys under AILE to set your maximum
deflection for the Right aileron. Do the same while holding the aileron stick in the full Leftaileron position. Make sure the deflection is the same in both directions.
i. Now adjust the travel of the Left aileron by touching PAGE and touching the + and – keys under
FLAP to exactly match the travel of the right aileron in both directions. A degree gauge works
well for matching deflections. Dual aileron set up and adjustment is now complete!
NOTE: Once the ailerons have been adjusted as described above, use the TRACE RATE function (code
14) to make future adjustments to overall aileron travel. Using TRACE RATE eliminates the need to
individually measure/adjust the throws of each servo when more than one channel is used for the
Elevator, Aileron, or Rudder. It is used to make adjustments only after the channels have been setup for
equal throws.
By Len Alessi
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12. Setting Dual Rates and Exponential Curves.
Dual Rates and Exponential curves can be very effective in setting up an aircraft to "feel" the way
you would like it to feel when performing different types of maneuvers. You can essentially change
the aircraft's personality just by flipping a switch, causing the aircraft take on traits that make certain
maneuvers easier for the pilot. At times you may want the aircraft to feel very crisp such as when
performing point rolls and sided-loops and then feel softer for other maneuvers such as rolling circles
and consecutive rolls and yet other times when you would like the aircraft to be very crisp but
without a the tendency to be over-controlled like in performing snap rolls. Dual Rates and
Exponential curves can be combined to produce these traits for most any aircraft. When
programming a Dual Rate and Exponential curve always think about what kind of maneuver or flying
style you plan to accomplish with it.
Dual Rates (D/R) limit how far a control surface travels. Without dual rates your control surfaces
deflect to their full travel – the travel that you previously established with the TRAVEL function and
linkage set-up. When a D/R is programmed it limits the amount of deflection that occurs when the
stick is moved to its extremes. For example if you set an elevator D/R to 75% the elevator will only
deflect 75% or 3/4 of its full travel, if set to 50% it will be limited to ½ of its full travel and so forth.
A D/R setting of 100% results in full travel again as though there were no D/R programmed at all.
An example of programming a D/R for the ailerons would be to set up an aileron D/R for flying
consecutive rolls by setting the aileron D/R to 25% (actual percentage will vary). At this setting
moving the aileron stick full left or full right would result in a roll rate of about 1 roll per second.
This allows you to deflect the aileron stick all the way and just hold it there while concentrating on
elevator and rudder inputs – flying consecutive rolls just became easier.
EXPONENTIAL (EXP) does not limit the total deflection of a servo/control surface – the surface
still moves 100% of its travel. It does however determine how the surface
reaches its full travel, or how the control surface moves relative to the stick.
When Exponential is not used, the servo response is said to be linear. That is,
every movement of the stick causes the same movement in the servo--if the stick
moves 20%, the servo moves 20% and the control surface follows the stick
throughout the entire travel range. When plotted on a graph where the X-axis
(left and right) = stick movement and the Y-axis (up and down) = servo No Exponential
movement, the result is a straight line that is at 45 degrees.
When using Exponential, a positive (+) exponential percentage causes the servo to move less when
the stick is close to the neutral point, and to move more as the stick moves further from the neutral
point. For instance, the stick is moved from neutral to 20% and the servo only moves from neutral to
10%. As the stick is moved further from center (from 20% to 40%) the servo moves further and faster
(from 10% to 35%) The further the stick is moved away from center, the higher the rate of servo
movement. The larger the positive (+) Exponential percentage, the further the
stick must be moved from center before the servo rate increases, and the faster the
servo rate becomes when it gets close to the end of its travel. When stick travel
(left and right) versus servo travel (up and down) is plotted on a graph, the result
is a “curve”. The curve stays close to the X-axis at the center (small servo
movement) and moves away from the X-axis at a greater rate (more servo
Exponential
movement) as the stick is moved further off center.
By Len Alessi
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Exponential is typically used to reduce sensitivity or otherwise dampen movements around the
neutral stick position without sacrificing full servo travel. This provides the pilot with very smooth
and precise control of the aircraft while allowing relatively large movements in the control stick. It
becomes easier to make very smooth and precise corrections that are difficult to detect.
The PCM 10SX and SXII allow 3 D/R and EXP settings each for Aileron, Elevator and Rudder. The
10X allows 3 D/R & EXP settings when Flight Modes are not activated and up to 5 D/R & EXP
settings if all Flight Modes are activated.
In our example we will use the POS0 switch positions (switches in the UP position) for normal
flying, POS1 (middle switch positions) for snap rolls and POS2 (switches all the way down) for
consecutive rolls, slow rolls and rolling circles. If you are already familiar with Dual Rates and
Exponential curves and have you own settings in mind, then please feel free to substitute your own
settings. It is recommended however that you set rates and curves for each of the 3 switch positions
for each control surface. It is also recommended that you use POS0 (switches in the upper position)
for normal flying because of some Flight Mode considerations that will be introduced later.
NOTE: The percentages provided below are only starting points and serve mostly to convey the
concept of Dual Rate and Exponential curves. You will need to test-fly the aircraft using the
various switch settings to determine if percentages need to be increased or decreased.
a. AILERON D/R & EXP. Access the DR/EXP function 13. The Aileron D/R EXP display
appears. If you move the Aileron D/R switch through its 3 positions you will notice the display
changing to POS0, POS1 and POS2.
b. Position the Aileron D/R switch in its upper position (POS0). We will use this position for
normal flying. Decrease the D/R percentage to 75% by touching – under D/R. This will limit
aileron deflection to ¾ of full travel and set a moderate amount of exponential by touching +
under EXP until it is +30%. Touch SEL under TYPE until NORMAL appears to select a normal
exponential curve.
c. Now put the Aileron switch in the POS1 or middle position. We'll use this position for snap rolls
where we want full Aileron deflection and perhaps less exponential so the Ailerons will be more
responsive around neutral. Leave the D/R percentage at 100% and set the EXP percentage to +20
by touching + under EXP. Now touch SEL under TYPE until NORMAL appears.
d. To set the 3rd Aileron D/R EXP combination for consecutive rolls, slow rolls and rolling circles,
set the Aileron D/R switch to its lower or POS2 position. Reduce the Aileron D/R percentage to
25% by touching – under D/R to give us a nice slow roll rate. Lets also set the EXP to +30% and
set the TYPE to NORMAL.
You now have 3 aileron rates/curves defined – POS0 (upper position) gives ¾ Aileron travel and
moderate exponential for normal flying, POS1 (middle position) provides full Aileron travel and
has less Exponential for snap rolls, and POS2 (lower position) has significantly reduced aileron
deflection for consecutive rolls and slow rolls. After test flying them, you can come back into
D/R EXP code 13 and adjust them by PAGING to the Aileron display, moving the aileron D/R
switch in the desired position (POS0, POS1, POS2), and adjusting the D/R and EXP percentages.
e. ELEVATOR D/R & EXP. Touch PAGE until the Elevator D/R EXP settings are displayed.
Position the Elevator D/R switch in its upper position (POS0). We will use this position for
normal flying. Lets leave the D/R percentage at 100% to provide full Elevator travel and set a
moderate amount of exponential by touching + under EXP until +30% is obtained. Touch SEL
under TYPE until NORMAL appears to select a normal exponential curve.
By Len Alessi
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f. Now put the Elevator D/R switch in the POS1 or middle position. We'll use this position for snap
rolls where we want to reduce Elevator deflection to help us avoid "burying" the snaps. We also
want less exponential so the Elevators will move off center quickly. Decrease the D/R percentage
to 50% by touching – under D/R. This will limit Elevator deflection to ½ of full travel. Lets also
set the EXP percentage to +20 by touching + under EXP. Now touch SEL under TYPE until
NORMAL appears.
g. To set the 3rd Elevator D/R EXP combination, set the Elevator D/R switch to its lower or POS2
position. Reduce the Elevator D/R percentage to 75% by touching – under D/R to give us enough
Elevator authority, and lets set the EXP to +45% to give us ultra-smooth control for Elevator
input during rolling maneuvers. Touch SEL under TYPE until NORMAL appears to obtain a
normal exponential curve.
You now have 3 Elevator rates/curves defined – POS0 gives full Elevator travel and moderate
exponential for normal flying, POS1 has the Elevator travel reduced by ½ and has less
Exponential for snap rolls, and POS2 has ¾ deflection and increased exponential for smooth
inputs during rolling maneuvers such as consecutive rolls, slow rolls and rolling circles. After
test flying them, come back into D/R EXP code 13 and adjust them by PAGING to the Elevator
display, moving the Elevator D/R switch in the desired position (POS0, POS1, POS2), and
adjusting the D/R and EXP percentages.
h. RUDDER D/R & EXP. Touch PAGE until the Rudder D/R EXP settings are displayed. Position
the Rudder D/R switch in its upper position (POS0). We will use this position for normal flying.
Lets leave the D/R percentage at 100% to provide full Rudder travel and set a moderate amount
of exponential by touching + under EXP until +35% is obtained. Touch SEL under TYPE until
NORMAL appears to select a normal exponential curve.
i. Now put the Rudder D/R switch in the POS1 or middle position. We'll use this position for snap
rolls where we want to reduce Rudder deflection to help us avoid "burying" the snaps. We also
want less exponential so the Rudder will respond quickly around neutral. Decrease the D/R
percentage to 45% by touching – under D/R. This will limit Rudder deflection to less than ½
travel. Lets also set the EXP percentage to +25 by touching + under EXP. Now touch SEL under
TYPE until NORMAL appears.
j. To set the 3rd Rudder D/R EXP combination, set the Rudder D/R switch to its lower or POS2
position. Keep the Rudder D/R percentage at 100% and lets set the EXP to +50% to give us
ultra-smooth control for Rudder input during rolling maneuvers. Touch SEL under TYPE until
NORMAL appears to obtain a normal exponential curve.
You now have 3 Rudder rates/curves defined – POS0 (upper position) gives full Rudder travel
and moderate exponential for normal flying; POS1 (middle position) has the Rudder travel
reduced by more than ½ and has less Exponential for snap rolls; and POS2 (lower position) has
full deflection and increased Exponential for smooth inputs during rolling maneuvers such as
consecutive rolls, slow rolls and rolling circles. After test flying them, come back into D/R EXP
code 13 and adjust them by PAGING to the Rudder display, putting the Rudder D/R switch in the
desired position (POS0, POS1, POS2), and adjusting the D/R and EXP percentages.
k. D/R EXP Notes. As you touch SEL under TYPE you will notice that there are a number of
Exponential types available—NORMAL, EXP/LIN, LIN/EXP, and VTR%. Repeatedly touching
SEL under TYPE will cycle through all of the available types.
EXP/LIN results in the servo following the stick in an exponential fashion for the first ½ of
stick movement and then it switches to a linear progression (straight line) from ½ stick to full
stick deflection.
By Len Alessi
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LIN/EXP results in the servo following the stick in a linear fashion for the first ½ of stick
movement and then it switches to an exponential progression (curved line) from ½ stick to
full stick deflection.
VTR (Variable Trace Rate) is used in conjunction with Dual Rate and acts like a Double
Dual Rate. When VTR is active, servo response follows the Dual Rate response line (smaller
percentage gives a flatter line and less movement like a high EXP percentage) until the VTR
point is reached (VTR point can be set at 50%, 60%, 70%, 80%, 90%). When the VTR point
is reached, the servo rate increases, and the servo follows a higher linear rate. VTR is
selected by touching SEL under TYPE until the desired VTR percentage appears. VTR can
be used to produce a very versatile response curve. If for instance, an aileron Dual Rate is set
relatively low (30%-60%) and the VTR point is set at 70%-90% the resulting response is
moderately flat for the majority of travel and then increases dramatically toward the end of the
travel. With this type of curve the response is docile around center for slow rolling; crisp in
the middle for point rolls; and full at the ends for vertical rolls or crisp rolls at low speed.
PCM 10SXII owners have the ability to program 1 customized response curve for each
control (Aileron, Elevator, Rudder). The curve is established by setting and moving points
just like in programming a multi-point mixer. This feature allows you to tailor the response
for both sides of neutral (i.e. one response for up-elevator and a different response for downelevator). If you need a customized response curve and you are not familiar with
programming multi-point mixers then wait until you cover multi-point mixing and then return
to this section to program a custom response curve.
PCM 10X owners have the ability to set different D/R and EXP values in both directions for
all 3 switch positions of each control (5 positions if 5 Flight Modes are activated). I.e.
different D/R and EXP settings for up-elevator and down-elevator, right- and left-aileron, and
right-and left-rudder. Just hold the stick in the desired direction while setting D/R and EXP
values for POS0, POS1 and POS2 (and optionally POS3 & POS4)
By Len Alessi
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13. Set Up Exponential for the Throttle
The larger engines typically employ a carburetor such as Walbro, Tillitson and Delorto. In many
instances these carbs do not produce a linear throttle response where ¼ throttle stick movement
results in ¼ engine RPM. Instead, they will cause engine RPM to increase very rapidly from low
throttle up to about ½ throttle and then very slowly from ½ throttle to full throttle. When the carb is
open ½ way the engine may be running at 75%-90% of its maximum RPM. Obviously this is not an
ideal situation.
What we would like to have is a linear throttle response where the engine RPM follows our throttle
stick so that at ¼ throttle the engine is running at ¼ RPM and at ½ throttle the engine is running at ½
RPM etc. This can be accomplished by causing the throttle servo to move in an EXPONENTIAL
fashion which means that the servo will move very little for the first ¼ - ½ of stick movement and
then move more rapidly as the stick is advanced further. Ideally, there should be a noticeable RPM
change with each click of throttle stick movement.
a. PCM 10SX and 10SXII owners access the D/R EXP function 13. Touch PAGE 3 times to get
to the Throttle Exponential display
b. Touch SEL under TYPE NORMAL until LO BASE appears. Now touch the + key until you
obtain a percentage of approximately 30% - 40%. This is a good place to start. Some engines
may require up to 70% exponential to achieve a linear throttle response while others may
require less than 30%. Once your aircraft is all set up, run your engine and adjust the
percentage until the engine RPM follows the throttle stick. If the engine RPM is still ahead of
the stick position increase the percentage – if it lags behind the stick position then decrease
the percentage. PCM 10SX and 10SXII owners are now finished with this step.
c. PCM 10X owners have the ability to program 2 separate throttle curves in order to finely tune
the Exponential that is applied to the throttle and to set up specialty curves. We will program
only one basic curve here.
d. Access the Throttle Curve function code 18. Touch YES at the Throttle Servo Hold question
(it's a good habit to get into in the event you make adjustments with the engine running).
Now touch SEL under EXP until ON appears.
e. Move the throttle stick to the full-low position. Now advance the throttle stick slowly while
watching the bottom of the center of the display. When the word STORE appears, touch
STORE and it will store a point on the 45-degree line. Advance the stick slowly again and
each time you see STORE touch it to store a point on the line. When you finish you will have
5 or 6 points along the 45-degree line.
f. At this time, the 45-degree line represents a linear servo response (move the stick ½ way, the
servo moves ½ way). Each of the points on the line PLUS each end of the 45-degree line can
be adjusted by positioning the cursor (the vertical line that moves across the graph as you
move the throttle stick) over a point and touching the + and – keys.
g. Position the cursor (vertical line) over point# 1 by moving the throttle stick. Touch the "-"
key to drag the point down some. Do the same to points 2-4 until your curve
looks something like the one to the right. This is a good place to start. Final
adjustments need to be made while running the engine with a helper securely
holding the aircraft. If the engine still accelerates to quickly (relative to the
Throttle stick position) pull points 1, 2, 3 and maybe 4 down further making
the line more curved at the bottom and middle. If the engine accelerates too slowly move
points 1, 2, 3 and 4 up a little at a time making the line straighter at the bottom and or middle
until a linear throttle response is achieved.
By Len Alessi
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All Rights Reserved © 5/24/02
14. Set Up and Adjust the Idle-Up Mixer
Idle-Up is a very useful function for larger aircraft because it allows you to set up a very slow idle to
produce a breaking effect for landing and at the flip of a switch provide a higher idle that is very
dependable for flying. It is especially useful in the thinner air of higher altitudes.
Our Idle-Up function will use the AUX5 knob/channel to set how much the engine idle increases.
PCM 10SXII and 10X owners will use the Retract switch to turn Idle-Up on and off whereas PCM
10SX owners will use the Brake switch. Actually, any of the available switches can be used.
NOTE: It is very important that the throttle linkage be Completely Free of binding and contain no
slop for the Idle-Up to work properly.
a. Access the next Program Mix, code 53.
b. Touch 10 to select Aux5 as the Master and touch 1 to select channel 1 (throttle) as the Slave.
Now touch ENTER to get to the next display.
c. Touch PAGE to get to the switch selection display. PCM 10SXII and 10X owners touch SEL
under GER or GR to select the Retract Gear switch. PCM 10SX owners touch SEL under SW
until BRK appears under SW, and also touch SEL under MASTER until ORIG appears.
d. Now touch PAGE to get back to the first display (SXII and 10X owners touch PAGE twice).
e. Rotate the Aux5 knob all the way Counter Clockwise and touch STORE under OFFSET.
This should result in an OFFSET percentage of approximately -86%. This offset will limit
the Aux5 knob so that it can only increase the idle and not decrease it. It will safeguard
against accidentally killing the engine by switching on Idle-Up.
f. Flip your new Idle-Up switch back and forth and notice the display changing from POS-0 to
POS-1 just above the percentages.
g. Position your Idle-Up switch in the position (forward or back) where you would like the IdleUp to be turned "ON". Touch the + key until the percentage is 10%. This represents the total
percentage that will be mixed into the throttle when the Idle-Up switch is turned on and the
Aux5 knob is rotated fully clockwise.
h. Turn the transmitter and receiver ON. Rotate the Aux5 knob fully clockwise. Flip the IdleUp switch on and off and check to make sure the throttle is moving in the correct direction. It
should move towards the high throttle direction when turned "ON". If it is moving in the
wrong direction, touch TURN under the percentages to change direction. Check the direction
again with the knob still fully clockwise.
i. Make these final adjustments with the engine running. Rotate the Aux5 knob fully
Counter Clockwise and set the Idle-Up switch to OFF. Start the engine and get it up to
normal operating temperature – this is important.
j. Access TRAVEL code 12 (10X owners touch S ) and position the throttle trim lever in its
center detent. If the engine idle gets too low and the engine quits when the trim lever is
positioned in the center, touch the "–" key under THRO to reduce the throw on the low-end
until the engine does not die with the trim in its center detent.
k. Making sure the engine stays up to temperature, adjust the low end travel using the + and –
keys under THRO until you get the lowest dependable idle with the throttle trim in it’s center
detent position.
l. Now turn on the Idle-Up using your Idle-Up switch and slowly turn the Aux5 knob
Clockwise to get the desired RPM increase (if the Aux5 Knob is too sensitive or insensitive,
go back into mix 53 and adjust the mix percentage down or up respectively). Don't set the
Idle-Up too high, or you may not be able to enter a spin but make sure it is set high enough so
that the engine does not quit during a spin or tail slide.
By Len Alessi
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m. Once you have the correct amount of Idle-Up, kill the engine and inspect the throttle linkage
to ensure that the addition of throttle for Idle-Up does not stall the throttle servo at the highthrottle position. Advance the throttle stick to full high and turn on the Idle-Up. If the throttle
servo is trying to drive the carb past full open and/or the throttle servo is buzzing, access
TRAVEL code 12, (PCM 10X owners touch S) and touch the “-“ key until the throttle servo
is not trying to drive the carb past full open when the throttle stick is in the full high position.
n. Using the Idle-Up. Prior to your take-off roll or just after take-off, turn the Idle-Up on. Turn
the Idle-Up off when you are ready to enter the landing pattern.
Sometimes the engine will be hotter/leaner at the end of the flight and the idle will be too high
or too low with Idle-Up turned off. If this happens, keep the throttle trim lever in its center
detent position and readjust the low-end travel (code 12) for the lowest dependable idle right
after landing when the engine is still hot. The low-idle should be adjusted to provide the
lowest dependable idle for landing at the end of the flight rather than for taxi and take-off at
the beginning of the flight. You should be able to turn the Idle-Up off at the end of a flight
and have confidence that the engine is running slow enough to provide good braking effect
without quitting.
You may find that on some days the idle is too fast or too slow with the trim lever in its center
detent (air changes & pushrods sometimes expand/contract). You can adjust the low-end
travel in function 12, or, you can simply move the throttle trim lever off center a few clicks
and leave it there after the engine is warmed-up to operating temperature. The Idle-Up will
increase RPMs from whatever point the throttle trim lever is set. Normally, once you have
the Aux5 knob set for the desired increase in RPM, it does not require further adjustment
provided that the low-idle is set properly. Remember to turn Idle-Up OFF before attempting
to land or you may sail right on by!
15. Set Up Fail Safe
Now that the throttle is all set up it's a good time to set your Fail Safe. We will set Fail Safe such that
all controls hold their last good inputs except for the throttle – it will go to high idle.
a. Access Fail Safe code 77.
b. Touch 1. This puts the Throttle in Fail Safe mode while all other channels remain in HOLD
mode.
c. Lower the Throttle Stick to full-low, put the Throttle Trim Lever in its center detent, and turn on
your Idle-Up switch. If you have not programmed an Idle-Up switch, set the Throttle Trim Lever
just a bit above low idle so that going into Fail Safe does not kill the engine completely.
d. Now touch STORE to store the throttle position. The system is now set so that only the throttle
will be affected if the RX encounters interference. It will go to idle while all other servos hold
their last position.
e. In the event that you do encounter interference there is a chance that you will fly right through it
without knowing it except for hearing the engine hesitate for a split second as it is lowered to idle
and then back to the present throttle setting.
By Len Alessi
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16. Set the Count Down Timer (PCM 10SX, SXII & 10X)
It's always a good idea to use a timer to help avoid running out of fuel. It is typical to fly 10-15
minutes on 32 ounces of fuel when running a gas engine in the 100 CC range. Set the timer so that it
will give you an adequate safety margin before running out of fuel.
a.
b.
c.
d.
e.
Access the Timer function code 87.
Touch ACT to activate the Count-Down Timer.
Touch the + and – keys to the left to set the number of minutes in 1 minute increments.
Touch the + key to the right to set the number of seconds in 10 second increments.
Look at the integrated Timer. It is showing you how long the TX has been turned on since the
RESET function was performed way back at the beginning of this document. Touching CLEAR
under the Integrated Timer will reset it to zero.
f. Activating the Count-Down Timer causes ST/SP and CLEAR to appear on the power-up display
(the screen that is displayed when the system is powered-up). To use the Count-Down Timer,
Touch ST when you are about to take off. When the timer counts down close to zero, it will beep
several times indicating that it is time to land.
17. Setting Trim Offsets (PCM 10SX & 10SXII)
After test flying your aircraft and using the trim levers for trimming you should store the trims so that
you can move the Trim Levers back to their center detents for future flying.
Note: Do not activate this function while flying!!
a. PCM 10SX and SXII owners Access Trim Offset code 82.
b. Touch STORE at the lower left of the display.
c. The display will now tell you to SET TRIM & ENTER. At this point move all trim levers to their
center detents and touch the ENTER key to store trims for Aileron, Elevator and Rudder. The
throttle trim is not stored in this function.
d. Touch ENTER to exit Trim Offset.
18. Adjusting the Trim Rates (PCM 10SX, SXII & 10X)
After test flying our aircraft and storing our trims (10SX & 10SXII) it is a good idea to reduce the
trim rates so that we can make very fine adjustments to trim. Reducing the trim rates will also
eliminate the condition where one click (beep) of trim is either too much or not enough. Reducing
the Trim Rate on the PCM 10SX and SXII reduces the travel that can be obtained with a trim lever
(0-30 degrees). With the PCM 10X the travel of the analog throttle trim is reduced but the travel of
the digital trims on aileron, elevator and rudder is not. Instead the travel on these digital trims is
divided-up into smaller (finer) increments so that each beep of the trim results in a smaller movement
of the servo.
a. Access Trim Rate code 83.
b. PCM 10SX and SXII owners touch – under AILE, ELEV and RUDD until the trim rate is 30%.
If the next time you need to trim the aircraft you find that the trims are still too sensitive where a
click in one direction is too much and a click in the other direction is not enough, return to this
function and reduce the rates further.
c. PCM 10X owners touch – under AILE, ELEV and RUDD to obtain a setting of 1. This will
provide us with maximum trim resolution for keeping our aircraft in trim. If we find that our
throttle trim is to sensitive (one click down is too low and one click up is too fast) then touch –
under throttle to reduce the throttle trim rate until the throttle trim is no longer too sensitive.
d. Touch ENTER to exit Trim Rate.
By Len Alessi
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All Rights Reserved © 5/24/02
Mixing Out or Eliminating Pitch- and Roll-Coupling
Most aerobatic aircraft exhibit both pitch and roll coupling with the application of rudder. It is most
noticeable when flying the aircraft in a knife-edge attitude. Normally, when we put the aircraft in a
knife-edge and apply rudder to hold it there two things happen. First, the plane usually tries to roll out of
the knife-edge. When it rolls in the same direction as the rudder input it is called Proverse roll (most
common) and when it rolls in the opposite direction of the rudder input it is called Adverse roll. The
second thing that happens is that the aircraft "pitches" as though elevator input were being applied. It
pitches either towards the landing gear (most common) or towards the canopy with application of rudder.
Ideally we would like to be able to roll the aircraft to the knife-edge position and only apply rudder to
have the aircraft maintain a straight line. The next few pages explain how to set up mixers in your PCM
10SX, 10SXII and 10X to eliminate Pitch- and Roll-Coupling so that the aircraft will do just that.
19. Mixing Out Roll-Coupling with the PCM 10SX
We are going to set up a programmable mixer that will automatically provide aileron input when we
move the rudder stick. The aileron movement will counteract any roll coupling that is induced by the
rudder. If we have Proverse roll coupling then we want the ailerons to move in the opposite direction of
the rudder and if we have Adverse roll coupling we want the ailerons to move in the same direction as
the rudder.
a. Test fly your aircraft in both the right and left knife-edge attitude to determine if it has Proverse
roll coupling (aircraft rolls in the same direction as the rudder input) or Adverse roll coupling
(aircraft rolls in opposite direction as the rudder input). You will need to know this before
programming the mixer.
b. Access the next programmable mixer 54.
c. Touch 4 to select the rudder as the master and touch 2 to select the ailerons as the slave. Then
touch ENTER to get to the next display. If you make an error touch CLEAR and touch 4 and 2
again before touching ENTER.
d. Mixing is typically so slight that it can be left on all of the time. However, if you would like to be
able to turn the roll-coupling mixer on and off proceed with "e" below. If you do not want to
turn the mixer on and off skip to "f" below.
e. If you would like to be able to turn the roll-coupling mixer on and off then touch PAGE to get to
the next display. Touch SEL under SW until the desired switch is displayed under SW. If you
have already used the BRK switch for the Idle-Up mixer, then do not select BRK – use a different
switch instead. Set the switch to the position where you want the mixer to be turned ON. (If after
test flying and adjustment you would like to have the roll-coupling mixer on all of the time, write
down the percentages you have programmed for each direction; come back to this display and
touch SEL under SW until FIX appears.)
f. Move the rudder stick to the Right and hold it there. Touch the + key to set the percentage to 3%.
Now move the rudder stick to the Left and while holding it there touch the + key to set the
percentage to 3%. Since roll coupling is typically very slight we are starting with small
percentages.
g. Turn on the transmitter and receiver. Move your rudder stick to the Right and note the movement
of the Right aileron. If your aircraft exhibits Proverse roll-coupling then we want the right
aileron to deflect downward with right rudder, just like applying a small amount of left aileron
input. If your aircraft has Adverse roll coupling then we want the right aileron to deflect upward
when right rudder is applied. If the aileron is not deflecting in the proper direction touch the
TURN key to reverse its direction while still holding the stick to the right.
By Len Alessi
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h. Now hold the rudder stick to the Left and note the movement of the Right aileron. If your aircraft
exhibits Proverse roll coupling then we want the right aileron to deflect upward just like applying
a small amount of right aileron input. If your aircraft has Adverse roll coupling then we want the
right aileron to deflect downward. If the aileron is not deflecting in the proper direction then
touch the TURN key to reverse its direction while holding the rudder stick to the Left.
i. The ailerons should now be deflecting a small amount with the application of full Right and Left
Rudder. They typically only need to deflect about the ½ the thickness of the trailing edge to mixout roll-coupling. If your ailerons are deflecting a lot more or a lot less than this, then change the
percentages from 3% to something greater or less by touching the + and – keys while holding the
rudder to the right and to the left.
j. If your aircraft has Proverse roll-coupling then your ailerons should be deflecting in the opposite
direction of the rudder input i.e. left aileron when right rudder is applied and right aileron when
left rudder is applied. If your aircraft has Adverse roll coupling the ailerons should be deflecting
in the same direction as the rudder input. If the ailerons are moving in the wrong direction touch
TURN while holding the rudder stick to the right and/or left.
k. Now it is time to test and adjust our roll-coupling mixer. With the mix turned on roll the plane to
the Right knife-edge and apply Left rudder. Note if the aircraft tries to roll out of the knife-edge
to the Left. If it does and the aircraft has Proverse roll then you need to increase the percentage
in the mixer for Left rudder input so that it results in more Right aileron. If it tries to roll out to
the Right and you have Proverse roll then you need to decrease the percentage of mix for Left
rudder input to decrease the amount of Right aileron coming out of the mixer.
Now roll the plane to the Left knife-edge and apply Right rudder. Note if the aircraft tries to roll
out of the knife-edge to the Right. If it does and you have Proverse roll then you need to increase
the percentage in the mixer for Right rudder input so that it results in more Left aileron. If it tries
to roll out to the Left and you have Proverse roll then you need to decrease the percentage of mix
for Right rudder input to decrease the amount of Left aileron coming out of the mixer.
The same tests apply for Adverse-roll coupled aircraft and the adjustments are just the opposite of
those described above for Proverse roll.
l. Keep testing and adjusting the 2 mix percentages until the aircraft does not try to roll out of knife
edge with either right or left rudder input and your roll-coupling mixer programming is complete.
By Len Alessi
19
All Rights Reserved © 5/24/02
20. Mixing Out Roll-Coupling with the PCM 10SXII and 10X
We are going to use a built-in mixer that was specifically designed to eliminate roll coupling by
generating aileron input with the application of rudder. The aileron movement will counteract any roll
coupling that is induced by the rudder. The built-in mixer provides for both pitch and roll coupling
however, we will be using only the roll coupling portion at this time so be sure that mixing is set while in
the Aileron portion of the display.
a. Test fly your aircraft in both the right and left knife-edge attitude to determine if it has Proverse
roll coupling (aircraft rolls in the same direction as the rudder input) or Adverse roll coupling
(aircraft rolls in opposite direction as the rudder input). You will need to know this before
programming the mixer.
b. Access the built-in Rudder-to-Aileron/Elevator mixer code 64. The Aileron display will appear.
c. Roll coupling is typically so slight that it is usually not a problem to leave it on all the time.
However, if you would like to turn the mixing on and off, touch PAGE twice and select a switch
that you would like to use to do so. Then touch PAGE again to return to the Aileron mixing
display.
d. In this step you will need to enter percentages either under POS0 if you did not select a switch to
turn the mix on and off, or under POS1 if you did select a switch. Hold the rudder stick to the
Right and touch + under POS0 if you did not select a switch, or touch + under POS1 if you did
select a switch until you obtain 3%. Hold the rudder stick to the Left and do the same. Since roll
coupling is typically very slight we are starting with small percentages.
e. Turn on the transmitter and receiver. Turn on the mix if you selected a switch. Move your rudder
stick to the Right and note the movement of the Right aileron. If your aircraft exhibits Proverse
roll coupling then we want the right aileron to deflect downward with Right rudder, just like
applying a small amount of left aileron. If your aircraft has Adverse roll coupling then we want
the right aileron to deflect upward when Right rudder is applied. If the aileron is not deflecting in
the proper direction touch TURN to reverse its direction while still holding the stick to the Right.
f. Now hold the rudder stick to the Left and note the movement of the Right aileron. If your aircraft
exhibits Proverse roll coupling then we want the right aileron to deflect upward just like applying
a small amount of right aileron. If your aircraft has Adverse roll coupling then we want the right
aileron to deflect downward when Left rudder is applied. If the aileron is not deflecting in the
proper direction then touch TURN to reverse its direction while holding the rudder stick to the
left.
g. The ailerons should now be deflecting a small amount with the application of full Right and Left
Rudder. They typically only need to deflect about the ½-¾ the thickness of the trailing edge to
mix-out roll-coupling. If your ailerons are deflecting a lot more or a lot less than this, then
change the percentages from 3% to something greater or less by touching the + and – keys while
holding the rudder to the right and to the left.
If your aircraft has Proverse roll-coupling then your ailerons should be deflecting in the opposite
direction of the rudder input i.e. left aileron when right rudder is applied and right aileron when
left rudder is applied. If your aircraft has Adverse roll coupling the ailerons should be deflecting
in the same direction as the rudder input. If the ailerons are moving in the wrong direction touch
the TURN key while holding the rudder stick to the right and/or left.
h. Now it is time to test and adjust your roll-coupling mixer. With the mix turned on roll the plane
to the Right knife-edge and apply Left rudder. Note if the aircraft tries to roll out of the knifeedge to the Left. If it does and the aircraft has Proverse roll then you need to increase the
percentage in the mixer for Left rudder input so that it results in more Right aileron. If it tries to
roll out to the Right and you have Proverse roll then you need to decrease the percentage of mix
for Left rudder input to decrease the amount of Right aileron coming out of the mixer.
By Len Alessi
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All Rights Reserved © 5/24/02
Now roll the plane to the Left knife-edge and apply Right rudder. Note if the aircraft tries to roll
out of the knife-edge to the Right. If it does and you have Proverse roll then you need to increase
the percentage in the mixer for Right rudder input so that it results in more Left aileron. If it tries
to roll out to the Left and you have Proverse roll then you need to decrease the percentage of mix
for Right rudder input to decrease the amount of Left aileron coming out of the mixer.
The same tests apply for Adverse-roll coupled aircraft and the adjustments are just the opposite
of those described above for Proverse roll.
i. Keep testing and adjusting the 2 mix percentages until the aircraft does not try to roll out of knife
edge with either right or left rudder input and your roll-coupling mixer programming is complete.
By Len Alessi
21
All Rights Reserved © 5/24/02
21. Mixing Out Pitch-Coupling With the PCM 10SX, SXII and 10X using a Multi-Point Mixer.
Pitch coupling is usually more severe than roll coupling and is typically non-linear in nature so we
will use a Multi-Point mixer to mix-out pitch coupling. It will allow you to fine-tune the mixing to
provide the right amount of elevator output for all amounts of rudder input.
a. Access the first multi-Point programmable mixer code 56.
b. Touch 4 to select the Rudder as the Master and touch 3 to select the elevator as the Slave. If you
make a mistake touch CLEAR and the touch 4 and 3 again.
c. Touch SEL under TYPE NORMAL until CURV appears. Now touch ENTER to get to the
mixing display. Yikes!
d. An Explanation of the display. Don't panic! While the display looks complicated it is actually
pretty simple if we know what we are looking at. Slowly move the rudder stick left and then right
while observing the graph. A vertical line moves across the graph as you move the rudder stick.
This is called the Cursor and it shows us the position of the rudder stick.
Also note that there is a single point in the middle of the graph labeled 1. The 1 is positioned at
0% or midway (up and down) on the graph which indicates that there is 0 movement of the slave
(elevator) at this point. It is also midway 50% (right and left) on the graph and since the rudder
stick centers itself when released, it is right under the cursor when the rudder stick is at center.
For our purposes we can keep this point right where it is, at 0%.
The X-axis (left and right direction) on the graph represents the position of the master channel
stick and that is why we see the cursor moving right and left as we move the rudder stick Rudder
input is represented as Left and Right on the graph. The Y-axis (up and down direction) on the
graph represents the movement of the slave channel – in this case our elevators. Elevator Servo
position is represented as Up and Down on the graph. When a point on the line has a positive (+)
percentage it indicates travel of the slave channel (elevator) in one direction like down-elevator
and a negative (-) percentage represents movement in the other direction like up-elevator. The
greater the percentage, the greater the movement of the slave servo (in our case elevator). A
percentage of 0 indicates no movement. When we let go of the rudder stick it returns to the
center over point #1 which is set to 0% so there is no movement of the slave (elevator) servo
when the stick is centered. The point at which the cursor intersects the mixing line shows us the
deflection of the master stick and the movement of the slave servo (both direction and % of
deflection).
IN represents the position of the rudder stick (in percentages) in relation to the graph. At the
extreme left of the graph the rudder stick is 0%, at the extreme right it is 100% and in the middle
is 50%. The IN percentage is displayed to the right of IN.
OUT represents the position of the slave channel, in our case the elevators, also represented in
percentages. Only this time it is represented by + and – percentages. A positive (+) percentage
indicates movement in one direction (i.e. Down elevator) while a negative (–) percentage
indicates movement in the other direction (i.e. Up- elevator). 0% indicates no elevator
movement. The top of the graph represents +100% of servo movement (in one direction) while
the bottom of the graph represents a –100% (in the other direction). We will be watching the
OUT percentage closely while programming.
P-1 is the point number and it appears under PAGE when the cursor is positioned over point #1
and the percentage to the right shows you where point #1 is located relative to the rudder stick
position. If you move the rudder stick all the way right and left, P-1 will change to P-L and P-H
representing the Low and High points at the ends of the mixing line (the points are invisible at the
ends of the mixing line – but they are there, and they can be moved). The point number will
appear under PAGE any time the cursor gets close to, or is positioned over a point.
By Len Alessi
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+ and - are located at the bottom of the display. They are used to move a point up and down on
the graph. Touching + moves a point upward while touching – moves a point downward. To
move a point, we move the rudder stick until the cursor is positioned over the point and hold the
stick there while touching the + or – keys.
CL located between the + and – keys is used to delete a point on the line. This is not to be
confused with CLEAR below. Note, the + and – keys and CL are replaced by STORE any time
the cursor is moved to a position where a new point can be added to the line. Touching STORE
when it appears adds a point to the line where the cursor is positioned.
0 The shaded 0 to the right of the + and – keys is used to quickly reset a point to 0%. It is a form
of shortcut. To use it, position the cursor over a point using the rudder stick and while holding
the cursor over the point touch the 0. The point will be immediately moved to 0% or midway up
and down on the graph which represents 0 movement of the slave channel.
EXP smoothes the line between points resulting in curves or one large curve. If EXP is left off
the points are connected by straight lines. EXP can be turned on and off to fine-tune mixing
response.
POS0 indicates which position the Mixer is in. Each Multi-point mixer can be programmed to
have 2 mixing curves which are switch selectable (the PCM 10SX and the 10X can also switch
between the 2 curves using the throttle stick). If one of these curves is programmed such that no
mixing occurs then we can effectively turn the mix on and off.
CLEAR is in the lower left of the display. It us used to cancel the entire program mixer. If you
touch CLEAR you must start programming of the mixer from the beginning (well almost, some
of the old settings will remain in effect but the master and slave channels will be gone and the
mixer will no longer function).
OKAY, LETS GET ON WITH IT!
e. If you have any Dual Rates programmed, set your D/R or Flight Mode switch to the position that
gives you full Rudder throw.
f. Touch SEL under EXP until ON appears so that we will have smoothed lines connecting our
points.
g. Touch PAGE to get to the next display for a moment. We should select a switch to turn the mixer
on and off. If the aircraft exhibits severe pitch coupling with full rudder input then it will
probably be a good idea to turn the mixer off when performing some low-speed maneuvers that
require large rudder deflections such as Hammerheads. If the mixing is left on when doing a
Hammerhead the resulting elevator mixing may cause the aircraft to pitch during the pivot,
spoiling the maneuver.
PCM 10SX owners can select a switch to turn the mixer on and off by touching SEL under SW
until the desired switch is displayed, or the throttle stick can be used to turn the mixer on and off
when the throttle stick is moved below say ¼ throttle. If you would like to use the throttle touch
SEL until STK appears. Then position the throttle stick at about ¼ throttle and touch STORE.
Touch PAGE to get back to the mixing display.
PCM 10SXII owners touch SEL under the switch that you would like to use to turn the mixer
ON. Touch PAGE twice to return to the mixing display.
By Len Alessi
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h.
i.
j.
k.
l.
m.
PCM 10X owners touch SEL under the switch that you would like to use to turn the mixer ON,
or, if you would like to use the throttle to turn the mix on and off then touch SEL under STK;
position the throttle stick at ¼ throttle and touch STORE. Touch PAGE twice to return to the
mixing display.
If you have decided not to use a switch or the throttle to turn the mixer on and off and have not
selected any switches or the throttle stick, then proceed with step k below. If you have selected a
switch to turn the mix on and off, set the switch to what you want to be the OFF position. If you
have selected the throttle to turn the mix on and off, then position the throttle stick at the full-low
position. We are going to set the OFF position of the mixer so that no mixing occurs when it is
turned off.
Make sure there is no mixing with the mixer turned to the OFF position. Move the rudder stick
all of the way to the Right and hold it there. Touch the 0 (shaded 0 key) just to the right of the +
and - keys to reset (if not already at 0) the end of the mixing line to 0%. Now move the rudder
stick all of the way to the Left and hold it there. Touch the 0 to reset this end of the line to 0%.
There should now be a straight horizontal line across the graph. The straight line indicates that
there is 0% mixing (no mixing – no elevator input) when the rudder stick is moved right and left.
You can turn on the TX and RX to verify this.
If you have selected a switch to turn the mix on, set the switch to the ON position. If you have
selected the throttle to turn the mix on and off then position the throttle stick at ½ throttle or
above. Be sure to leave this setting in tact while programming. We are going to set the ON
position of the mixer to 0% before we program it further.
Move the rudder stick all of the way to the Right and hold it there. Touch the 0 key just to the
right of the + and - keys to reset (if not already at 0) the end of the mixing line to 0%. Now move
the rudder stick all of the way to the Left and hold it there. Touch the 0 key again to reset this
end of the line to 0%. There should now be a straight horizontal line across the graph. The
straight line indicates that there is 0% mixing (no mixing – no elevator input) when the rudder
stick is moved right and left.
Slowly move the rudder stick to the Right until the cursor is about ½ way between point 1 and the
left side of the graph and hold it there. STORE appears at the bottom of the display. Touch
STORE to add a new point to the mixing line while holding the rudder stick in position. Release
the rudder stick and then slowly move it to the Left until the cursor is about ½ way between point
2 and the right side of the graph and hold it there while you touch STORE again. Another point is
added to the line and the points are re-numbered left to right 1, 2 and 3.
Now lets program some percentages and check to make sure we are going in the right direction.
Move the rudder stick all the way to the Right and hold it there. The cursor will move all the way
to the end. Touch the – key until the OUT percentage is –10%. Move the rudder stick all the way
Left and hold it there and touch the – key until the OUT percentage is –10% again.
Turn on the Receiver and watch the elevators. Move the rudder stick all the way to the right and
the elevators should deflect upward some. Move the rudder stick all the way to the left and the
elevators should again deflect upward some. If your aircraft pitched toward the gear in knifeedge flight and the elevators are moving upward when the rudder stick is moved full right and full
left then we have programmed the percentages in the proper direction.
If the elevators are moving downwards instead of upwards and the aircraft pitches towards the
gear in Knife-edge, we need to reverse the percentages. Move the rudder stick to full Left and
touch the + key until +10% is achieved. Now move the rudder stick full Right and touch the +
key until +10% is achieved for this end of the mixing line.
By Len Alessi
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All Rights Reserved © 5/24/02
The elevators must move in the opposite direction of the pitching that occurs when the aircraft is
in knife-edge. If the aircraft pitches towards the gear then we need Up-elevator, if it pitches
towards the canopy we need Down-elevator. (+) Percentages move the elevator in one direction
and (–) percentages move the elevator in the other direction. If the elevators are moving in the
wrong direction change the percentages from + to – or – to + buy touching the + or – keys to
move the points above or below the 0% line.
n. Now we can program the two intermediate points. Position the cursor over point #1 by moving
the rudder stick. While holding the cursor over point #1 touch the + or – key until the OUT
percentage is 4%. Use the same percentage sign (+ or -) as was used for the end points. I.e. if the
end points are a (–) percentage then touch the – key until –4% is achieved, if the end points are a
(+) percentage touch the + key until +4% is achieved.
o. Set the other intermediate point. Position the cursor over point #3 by moving the rudder stick.
While holding the cursor over point #3, touch the + or – key to get the same + or – 4% as was set
for point #1. The graph should now look like one of the following:
2
1
3
1
2 3
p. Move the rudder stick side-to-side and check the elevator movement again to confirm that the
elevators are moving in the proper direction to mix-out the pitch coupling of your aircraft.
Elevator direction can be changed by moving the points up or down until their signs change from
+ to – and vise versa.
Note: Air-foiled tail surfaces are very efficient and require only a small amount of movement to
effect a change. For this reason we start with small percentages for points #1 and #3. These two
intermediate points control the amount of mix required for relatively small rudder deflections
such as those used during point rolls. However pitch-coupling can become quite severe with full
rudder deflections such as those required for knife-edge loops. The percentages at each end of
the line control mixing when full deflection is used. Keep this in mind when testing and making
adjustments.
q. Test fly and adjust the multi-point mixer. Have a helper standing by to take notes. Turn on the
mixer and roll the aircraft to each knife-edge and apply just enough rudder to maintain altitude.
Note how much pitching occurs in each direction. If the aircraft is still pitching in the direction it
was before mixing was applied then the percentages at points #1 and #3 should be increased
(more + or more -, in other words, moved further from the 0% center line) to provide more
elevator mixing. If the aircraft is now pitching in the opposite direction, then the mix percentages
are too great and they should be reduced (moved closer to the 0% center line). It is not unusual to
have different percentages for right and left rudder and the multi-point mixers were designed for
just this purpose.
Now test the full rudder mix by rolling the aircraft to each knife-edge position and applying full
rudder. Again note the pitching that occurs. Adjust the percentages at each end of the line by
moving the rudder stick full right and full left and touching the + and – keys. The further positive
and the further negative you go the more elevator mix you get.
Keep performing these tests and adjusting the percentages until there are no pitch changes with
the application of rudder in Knife-edge.
By Len Alessi
25
All Rights Reserved © 5/24/02
r. Additional Notes Regarding Multi-Point Mixers. We have only used 5 of the possible 8 points
that can be set/programmed for mixing. It is possible to establish 6 points along the mixing line.
Each of these 6 points PLUS each end of the line can be moved up and down for a mixing
percentage. A new point can be set on the line any time STORE appears at the bottom of the
display. Typically 5 points (2 to the left of center and 2 to the right of center) are sufficient to
provide a very fine-tuned mixing curve that will supply the proper mixing for all inputs.
If you really need to get all 6 points onto the curve, start by deleting all points, even point #1 that
appears when the mixer is first initiated. To delete a point, position the cursor over the point and
touch the CL between the + and – keys. After all points have been removed, move the stick to
the full Left position. Slowly let the stick come back towards center until STORE first appears
and touch STORE to add the point. Gradually let the stick move towards center again until
STORE appears again and then touch STORE. Do this one more time and you should have 3
points defined. Now move the stick all the way to the Right and repeat this procedure.
There is almost no limit to what can be done with the points by positioning the cursor over a
point and touching the + and – keys to move it up and down. Here are few examples of multipoint curves:
1
2 3 4 5
4
2
6
1
1
2
3
1
2
3
4
3
At times you may notice that the cursor does not go all the way to the ends of the mixing line.
This usually happens when you have a dual rate or Flight Mode selected that is using less than
100% of the rudder throw. Always set your dual rate switches or Flight Modes so that you have
your maximum rudder (or whatever the Master channel happens to be) rate selected when
programming a Multi-Point mixer.
By Len Alessi
26
All Rights Reserved © 5/24/02
FLIGHT MODES (PCM 10SXII & 10X)
What is a Flight Mode? For our discussion a Flight Mode represents an aircraft configuration
(Rates/Curves, mixes, Differential, etc.) that is designed and optimized to assist the pilot and the aircraft in
performing a specific type of maneuver.
The Objective of programming Flight Modes is to provide us with the ability to flip a switch to select a
collection of settings that make it easy to perform a maneuver. For example; positioning our Flight Mode
switch in its 1st position sets the aircraft up for normal precision flying; positioning the switch in it's 2nd
position sets the aircraft up for snap rolls; positioning the switch in its 3rd position sets the aircraft up for
consecutive rolls, slow rolls, and rolling circles; while the 4th position gives us a set up for 3D, and the 5th
position gives us a setup for performing Torque Rolls.
If you have been following along from the beginning you are probably thinking that we have already done a
significant amount of programming to help the aircraft in performing specific types of maneuvers (remember
setting up the Dual Rates and Exponential curves?). Now what we need to do is group them together into
Flight Modes so that we can select them with a single switch (well almost, we can select between 3 Flight
Modes with a single switch but selecting between 5 Flight Modes involves 2 switches).
At this point we want to adjust our thinking with regard to programming. Instead of worrying about
individual features provided by the radio and how to program them, we need to think about what we want to
accomplish with the aircraft and what the radio can do to help us. If we approach programming in this
fashion we not only have a better chance of using the radio to its full potential, but it will be easier for us to
fly maneuvers because the radio will be helping us. Obviously this will require "stick time" because only by
flying the aircraft will we be able to determine where we and the aircraft need help. For instance, if in
performing snap rolls we discover that we have a problem with the aircraft over-rotating because we are
using too much rudder input, then we need to make sure that we don't use too much rudder. How do we get
the radio to help us do that? We reduce the amount of rudder travel that is available while we are in the Snap
Roll Flight Mode -- problem solved!
The PCM 10SXII and 10X contain a number of functions that are easily incorporated into Flight Modes.
They include:
•
•
•
•
•
•
•
•
•
•
Dual Rates and Exponential curves for aileron, elevator, and rudder
Flap positions with Elevator Trim correction
Trim settings for primary flight controls (aileron, elevator, and rudder)
Servo Speed for all 10 channels
Gyro Gain
Aileron Differential
Snap Roll settings for primary flight controls (rate/direction)
Aileron to Rudder mixing
Rudder to Aileron and Rudder to Elevator mixing
Up to 8 Programmable Mixers (includes 3 multi-point mixers)
As a general rule, any function in the radio that provides a switch selection option can usually be assigned to
1 or more Flight Modes. While the majority of the items listed above pertain to specific functions, the fact
that 8 program mixers are included provides us with an unlimited number of other possibilities in
determining the aircraft’s behavior when a Flight Mode is selected.
By Len Alessi
27
All Rights Reserved © 5/24/02
FLIGHT MODE PROGRAMMING (10SXII & 10X)
It is not practical to program all Flight Mode settings at one time, especially for a new aircraft. This
approach would be difficult, time-consuming, risky, and would probably result in less-than-optimum Flight
Mode configurations. Therefore, the recommended procedure is based upon a phased approach that involves
programming and adding functions to Flight Modes one at a time. This allows us to program a function, testfly the function with minimal risk, and fine-tune the settings for optimal performance before adding the
function to Flight Modes.
Note: The PCM 10SXII and 10X provide the option of having 3 Flight Modes (FM-0, FM-1, FM-2) or 5
Flight Modes (FM-0, FM-1, FM-2, FM-3, FM-4).
Note: When Flight Modes are activated only one function is automatically associated with Flight Modes. It
is the Dual Rate (D/R & EXP) function (code 13), which effects the movements of the three primary flight
controls (aileron, elevator, and rudder). All other functions and features are optional and can be assigned
to Flight Modes at the pilot’s discretion. The PCM 10SXII requires a preliminary step to get the D/R EXP
settings to function properly with Flight Modes whereas the 10X takes care of this automatically.
22. Activate Flight Modes PCM 10SXII & 10X.
We are going to activate Flight Modes and choose the switch that we are going to use as our Flight
Mode switch. We have 3 choices for the Flight Mode switch: the Aileron D/R switch, the Elevator
D/R switch or the Rudder D/R switch. Once we select one of the switches the other 2 D/R switches
become inoperative and can no longer be used -- not even for selecting Dual Rates because all D/R
activity is transferred to the Flight Mode switch.
a. To activate Flight Modes access Function Select (code 17).
b. Touch PAGE to get to the 2nd display.
c. Touch SEL under D/R SW to select one of the switches to use as your Flight Mode switch
(Aileron, Elevator, or Rudder). Touching SEL repeatedly cycles through the 3 switches.
Selecting a switch is what activates Flight Modes. To turn Flight Modes off, touch SEL under
SW until INH appears indicating that Flight Modes are inhibited.
d. PCM 10X owners -- Unless you think that you will need to re-trim the aircraft for each Flight
Mode (should only occur if you are going to use flaps or something else that will result in
sustained control deflection) then leave the FM TRIM inhibited. Otherwise touch ACT under
TRIM INH to activate Flight Mode Trims where you will need to re-trim the aircraft for each
Flight Mode.
e. Now decide if you would like to have 3 Flight Modes or 5 Flight Modes (it might be best to start
out with just 3). If you would like to have 5 Flight Modes then touch ACT under EXTRA INH to
turn on the other 2 Flight Modes.
f. Flight Modes are now activated. If 3 Flight Modes have been activated they are FM-0, FM-1 and
FM-2. If 5 have been activated they are FM-0, FM-1, FM-2, FM-3, and FM-4. The switch you
selected is now the Flight Mode Switch. The upper switch position is always Flight Mode 0 or
FM-0 and can be thought of as HOME BASE because it never changes. Since it never changes it
is the ideal Flight Mode to use for normal flying, as you will be able to instantly switch to it in
case of an in-flight emergency.
g. Touch ENTER to exit Function Select.
By Len Alessi
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23. Selecting Flight Modes with the Flight Mode Switch.
Selecting Flight Modes can be different depending on whether 3 Flight Modes have been activated or
5 Flight Modes have been activated. The manuals contain good explanations and diagrams of Flight
Mode switch operation. See page 32 of the PCM 10SXII manual and page 20 of the 10X manual.
If 3 Flight Modes have been activated then only the Flight Mode switch is used to select between
Flight Modes where the Upper position of the switch is FM-0, the Middle position is FM-1 and the
Lower position is FM-2.
If 5 Flight Modes have been activated then we must use 2 switches to select Flight Modes. The
second switch that is used is the MIX switch, which is located on the top of the transmitter at the
right rear corner. When the MIX switch is in its upper position (away from you) then the Flight Mode
switch behaves normally where the Upper position is FM-0, the Middle position is FM-1 and the
Lower position is FM-2. When the MIX switch is in the lower position (towards you) the Flight
Mode switch behaves a little differently. The Upper position is still FM-0 (remember HOME
BASE), but the Middle position selects FM-3 and the Lower position selects FM-4.
24. Assigning D/R and EXP Settings to Flight Modes – PCM 10SXII ONLY!
PCM 10SXII owners must perform this preliminary step to assign our D/R EXP settings to Flight
Modes. Remember that we have already programmed 3 D/R EXP settings for each control (aileron,
elevator and rudder). Now we are going to assign them to the Flight Mode switch.
a. Access the FM Rate Function (code 23). FM-0 appears to the left of the display. This indicates
that the 1st Flight Mode, FM-0 is selected. At the bottom of the display is AILE, ELEV and
RUDD. Below each of these is a 0 followed by a colon ":" and then a percentage. The zeros
indicate that position POS0 of our D/R EXP settings are assigned to each control -- remember we
programmed POS0, POS1 and POS2 for each control surface earlier. The percentages indicate
the D/R percentage that is associated with POS0.
b. We are going to leave the POS0 D/R EXP settings assigned to FM-0 so just Touch MODE to get
to the next Flight Mode -- (FM-1) should now be displayed to the left of the screen.
c. Touch SEL under AILE until 1 appears next to the percentage under AILE. Touch SEL under
ELEV until 1 appears next to the percentage under ELEV. Touch SEL under RUDD until 1
appears next to the percentage under RUDD. We have just assigned the POS1 D/R EXP settings
for each control (AILE, ELEV, RUDD) to the 2nd Flight Mode (FM-1).
d. Touch MODE to get to the FM-2 settings -- FM-2 will appear to the left of the display.
e. Touch SEL under AILE, ELEV and RUDD until 2 appears next to each percentage. We have just
assigned the POS2 D/R EXP settings to the 3rd Flight Mode (FM-2).
f. For our example we are going to leave the 4th and 5th Flight Modes set to use the POS0 rates for
each control so just touch ENTER to exit this function.
Note: the 4th and 5th Flight Modes automatically default to the POS0 settings even if only 3
Flight Modes have been activated.
We now have all of our D/R EXP settings (POS0, POS1, POS2) for each control (AILE, ELEV,
RUDD) assigned to Flight Modes. The D/R EXP settings are sill accessible and still adjustable
by using the Flight Mode switch to select them while in the D/R EXP function (code 13).
The PCM 10SXII has 3 D/R EXP settings for Ailerons, 3 D/R EXP settings for Elevator, and 3
D/R EXP settings for Rudder that can be distributed among 3 or 5 Flight Modes. If you wish to
assign a different D/R EXP setting to a Flight Mode, come back into this function (23), select the
desired Flight Mode, and then select the desired D/R EXP setting (0, 1, 2) under the desired
control(s) (AILE, ELEV, RUDD).
By Len Alessi
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25. Test the Flight Mode Switch Operation (PCM 10SXII and 10X)
Lets test our Flight Mode switch to see how it selects between the various D/R EXP settings.
While PCM 10SXII owners had to assign the D/R settings to Flight Modes, 10X owners will see
that the POS0, POS1, and POS2 D/R settings for each control were automatically assigned to
FM-0, FM-1, and FM-2 respectively when Flight Modes were activated.
a. Put the Flight Mode switch in the Upper position (FM-0, or HOME BASE). If you have
activated 5 Flight Modes, put the MIX switch in its upper position (away from you).
b. Access the D/R EXP function 13.
c. The display begins with the Aileron D/R settings. You are now looking at the Aileron POS0
settings. Put the Flight Mode switch in its Middle position (FM-1) and you will see the Aileron
POS1 settings. Put the Flight Mode switch in its Lower position (FM-2) and you will see the
Aileron POS2 settings. You can adjust any of the settings that are displayed and from now on,
this is how you select an Aileron D/R EXP setting in order to make adjustments.
d. Put the Flight Mode switch back to its Upper position (FM-0). Touch PAGE and the display
switches to the Elevator settings. Cycle the Flight Mode switch through is positions and you will
see the POS0, POS1, and POS2 elevator settings just like you did with the ailerons.
e. Touch PAGE again and you can see the Rudder settings by cycling the Flight Mode switch
through its positions. Touching PAGE again on the PCM 10SXII brings up the Throttle
Exponential settings whereas the 10X will loop back to the Aileron Settings. PCM 10SXII
owners must touch PAGE 1 more time to get back to the Aileron settings.
If you have been following along from the beginning you will keep the Flight Mode switch in its
Upper position (FM-0 – HOME BASE) for normal precision flying; when you want to perform
snap rolls you will put it in the Middle position (FM-1); and when you want to perform
consecutive rolls, slow rolls and rolling circles you will put it in its Lower position (FM-2).
f. If 5 Flight Modes have been activated on the PCM 10SXII put the Flight Mode switch in its
center position (FM-1) -- POS1 appears. Now put the MIX switch in its lower position (towards
you) and notice that POS1 changes to POS0 -- You have just selected the 4th Flight Mode
(remember we left the 4th and 5th Flight Mode set to the 0 positions for each control while we
were in Function 23). Now put the MIX switch back to its upper position and put the Flight
Mode switch in its lower position to select the 3rd Flight Mode (FM-2) and POS2 appears. Now
put the MIX switch in its lower position and it changes from POS2 back to POS0 again because
you have selected the 5th Flight Mode. Remember when 5 Flight Modes are activated the MIX
switch causes the 2nd and 3rd Flight Modes (FM-1 & FM-2) to become the 4th and 5th Flight
Modes (FM-3 & FM-4). The Upper position (POS0) is HOME BASE and it never changes!
With this set up if you inadvertently turn on the 4th and 5th Flight Modes the aircraft will fly as
though you have your Normal rates (POS0 rates) selected. While it may seem useless for the 4th
and 5th Flight Modes to use the same D/R settings as the 1st Flight Mode, it is not. There are
many more things that we can make happen when the 4th and 5th Flight Mode are selected that do
not happen when the 1st Flight Mode is selected. For instance, we could set up program mixers
that mix elevator to elevator, rudder to rudder and aileron to aileron in order to increase control
throws to maximum for 3D maneuvers and assign them to the 4th and 5th Flight Modes (FM-3 &
FM-4). We could also set up a multi-point mixer that mixes the throttle to the throttle to provide
a very steep curve to quickly get the throttle up to the point to provide enough power to hover and
then have it progress very slowly upward to provide precise throttle control for the torque rolls. If
we assigned this mixer to the 5th Flight Mode then we could use the 4th Flight Mode for 3D and
the 5th Flight Mode for Torque Rolls! While we're at it we could program a gyro and assign it to
the Torque Roll Flight Mode as well.
By Len Alessi
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g. If 5 Flight Modes have been activated on the PCM 10X put the Flight Mode switch in its
center position (FM-1). Now put the MIX switch in its lower position (towards you) and notice
that FM-1 changed to FM-3. You have just selected the 4th Flight Mode. Put the Flight Mode
switch in its Lower position and you have selected the 5th Flight Mode (FM-4). Remember when
5 Flight Modes are activated the MIX switch causes the 2nd and 3rd Flight Modes (FM-1 & FM-2)
to become the 4th and 5th Flight Modes (FM-3 & FM-4). The Upper position (POS0) is HOME
BASE and it never changes!
Also notice that when the 4th and 5th Flight Mode are selected that fresh displays are presented
ready to be programmed with new D/R and EXP percentages. Set up your rates and curves for
these 2 additional Flight Modes to help you perform specific types of maneuvers. If you really
have no use for these 2 additional Flight Modes at this time, it might be best to inactivate them by
returning to function 17, touching PAGE, and Inhibiting EXTRA to turn them off in order to
avoid selecting them by mistake. You can always re-activate them later when you have thought of
a specific use for them.
h. Put some additional flights on the aircraft to become familiar with your Flight Mode switch(s),
and the rates/curves that are active in each Flight Mode. If you need to make adjustments to the
rates and curves for any Flight Modes come back into the D/R EXP function 13, select the
appropriate Flight Mode using the Flight Mode Switch, select the appropriate control surface by
touching PAGE, and then make your adjustments.
Preliminary Flight Mode programming is now complete. When you are comfortable with flying
the aircraft in this basic Flight Mode configuration, proceed with programming, test flying, and
adjusting the settings for the next function (if any) that you would like to be incorporated into
Flight Modes.
By Len Alessi
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26. Aileron Differential
When ailerons are deflected the aileron that deflects downward creates more drag than the aileron
that deflects upward. If the amount of drag is great enough it will cause the aircraft to yaw in the
direction of the down aileron, i.e. a roll to the right will case the aircraft to yaw to the left because the
left aileron deflects downward. This, of coarse, is an undesirable tendency that will result in nonaxial rolls and a loss of heading when rolls are performed on vertical and 45 degree lines. But there
is good news! The PCM 10SX, SXII and 10X radio systems provide a Differential function that
allows you to decrease how far each aileron deflects downward (or upward) without affecting the
aileron that travels upward (or downward) and therefore enables you to eliminate yaw tendencies in
rolling maneuvers. The Differential function allows us to have 2 differential settings that are switch
or Flight Mode selectable. We can have one setting that is on all of the time or we can have one
setting that is on and one that is off (0 differential) or we can have 2 different amounts of differential
-- maybe one for normal flying and another for flat spins.
NOTE: There is another factor that can cause the aircraft to roll in a non-axial fashion. If the mass
of the aircraft is mostly above or below the thrust or datum line it can cause a pendulum effect and
the aircraft will appear to wobble as it rolls. Aileron differential may help to straighten out the rolls,
however it will not be able to eliminate it. If the aircraft still wobbles after trying differential
adjustments in both directions there is a chance that the aircraft is out of balance vertically. Try
raising and lowering batteries and other radio gear to eliminate the wobble and then proceed with
differential adjustment again.
a. Access the Wing Type function (code 22).
b. If you would like a single aileron differential setting to be in effect all of the time (recommended
for now), touch + to set a small percentage of differential and touch TURN if necessary to obtain
the proper direction (less Down deflection than Up deflection or less Up deflection than Down
deflection). Programming is complete -- touch ENTER to exit the Wing Type function. Test fly
the aircraft and return to this function (22) to make adjustments until the yaw tendency has been
reduced or eliminated.
c. At this point it is assumed that you would like to switch between two aileron differential values.
If one of these values is set to zero, you will be able to turn aileron differential OFF by selecting
the position that has the 0 value.
PCM 10SX owners touch SEL under SW to select the switch that will be used to toggle between
the 2 differential values. Put the switch in one position and touch + to set the amount of
differential and touch TURN if necessary to obtain the proper direction. Now put the switch in
the other position and touch + to set the amount of differential for this position (if one of the
positions is left at zero (0) then selecting this position turns the differential OFF). Touch ENTER
to exit the Wing Type function and test fly the aircraft. Return to this function (22) to make
adjustments until the yaw tendency has been eliminated.
PCM 10SXII and 10X owners touch PAGE to obtain the switch selection display. Touch SEL
under each Flight Mode or switch where you would like aileron differential turned ON. Leave all
other FMs and switches set to P-0. Put the switch in the ON position and touch + to set the
amount of differential for this position and touch TURN if necessary to obtain the proper
direction. Now put the switch in the other position and touch + to set the amount of differential
for this position (if this position is left at zero (0%) then selecting this position turns the
differential OFF). Touch ENTER to exit the Wing Type function and test fly the aircraft. Return
to this function (22) to make adjustments until the yaw tendency has been eliminated.
By Len Alessi
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27. Servo Speed
If less-than-normal servo speed is desired for one or more channels then the Servo Speed function is
for you. The Servo Speed function allows the pilot to decrease the speed of any servo. A practical
application of this function is to reduce the speed of the throttle servo so that “jamming” the throttle
stick (high or low) will not cause the engine to flood and die. Another application may be when two
servos/channels are used for a common control (like dual elevators) and for some reason one servo
seems to move a little faster than the other servo. We could slow the faster servo down until it
matches the speed of the slower servo.
Servo speed is displayed in degrees per second and may actually show a value that is greater than the
rated speed of the servo. Therefore, decrease the value until you can start to see a noticeable
difference in speed.
Note: Use extreme caution if you decrease the speed of primary flight control servos (Aileron,
Elevator, Rudder)!! You may not be able to control the aircraft properly if the servos move too
slowly.
a. Access the Servo Speed function (code 24).
b. PCM 10SX owners touch – under the desired channel to decrease the speed of the servo(s)
plugged into that channel (touch PAGE to see all channels). Touch – until you can see a
noticeable decrease in the servos speed. Touch ENTER to exit the Servo Speed function.
Ground test the servo speed settings and then test fly the aircraft. Make adjustments until the
desired results are obtained.
c. PCM 10SXII and 10X owners. If Flight Modes are Not activated adjust the speed as described in
"b" above.
If Flight Modes are activated we must set the speed for each Flight Mode where we want the
servo(s) speed decreased. Touch – under the desired channel to decrease the speed of the servo(s)
plugged into that channel (touch PAGE to see all channels). Touch – until you can see a
noticeable decrease in the servos speed (take note of the speed you end up with). To set the speed
of the servo for the next Flight Mode touch MODE and set the servo(s) speed to the same value as
noted previously. Keep touching MODE and setting the servo speed until the speed is reduced
for all intended Flight Modes. Touch ENTER when finished to exit the Servo Speed function.
Ground-test the servo speed settings to ensure that the proper settings are activated with the
intended Flight Modes. Make adjustments as appropriate.
Fly the aircraft to become familiar with this additional Flight Mode feature.
By Len Alessi
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28. Programmable Mixing and Flight Modes – General Concept (PCM 10SXII & 10X)
This section presents a general guide to the steps involved in setting-up a programmable mixer and
assigning it to one or more Flight Modes. It is not intended to accomplish any specific function or
flight task, but rather to provide a form of checklist for setting up a mixer and getting it assigned.
There are 8 programmable mixers (51-58) that can be assigned to Flight Modes. Each programmable
mixer can be programmed to have 2 sets of mix percentages and we can assign one of two sets to
each Flight Mode. If one set of mix percentages is set to zero, we will be able to turn the mixing on
and off using the Flight Mode switch (ON for one or more Flight Modes and OFF for the remaining
Flight Modes).
It is assumed that Flight Modes are already active and the D/R&EXP settings have been established.
It is recommended that you initially leave 1 set of percentages (POS0) set to zero and only program
mix percentages into the 2nd set (POS1). This will allow us to turn the mix on (POS1) and off
(POS0) with the Flight Mode switch for initial test flying and adjustment.
a. Access a programmable mix function (code 51-58).
b. After selecting the master and slave channels touch ENTER. Note: select NORM or CURV
before touching ENTER if a multi-point mixer is being used (56-58).
c. Touch PAGE until the switch/position display appears. Identify a non-critical Flight Mode (FM0 – FM-4) that will be used to test the program mix. Touch SEL under this Flight Mode to
indicate that it will use POS1 settings. Leave all other Flight Modes set to POS0. Now mixing
will be activated only when this Flight Mode is selected.
d. Touch PAGE and select the type of mix (Normal, Include, Origin) and whether or not the Trim
feature is to be enabled.
e. Touch PAGE until the mixing percentage screen is displayed. Move the Flight Mode switch to
the ON position (POS1 appears over the percentages indicating that the mixer is in the ON
position).
f. Set the mix OFFSET (if any) and set the mixing percentages as may be appropriate for the desired
mixing activity. Thoroughly ground-test the mixer.
g. Fly the aircraft and test the mixer by selecting the Flight Mode that was selected as using POS1.
Adjust the mixing parameters in the Function Code that was used in step 1 to obtain the desired
results.
h. You may now return to the programmable mix (51-58) to program the POS0 settings and/or to
assign the mixing values to other Flight Modes. Remember, in order to be able to turn mixing
off, either POS0 or POS1 values must be set to zero.
By Len Alessi
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All Rights Reserved © 5/24/02
29. Programming Down Elevator for Vertical Down Lines (PCM 10SX, 10SXII & 10X)
Some aircraft exhibit the tendency to "pull out" towards the canopy on vertical down lines. This trait
can easily be eliminated with a program mix that applies just a little down-elevator when the throttle
stick is brought all the way back to the full-low stick position.
a. Access an unused programmable mixer (code 51-58).
b. Touch 1 to select the throttle as the master and touch 3 to select the elevator as the slave. If you
make a mistake, touch CLEAR and then touch 1 and 3 again.
c. If you are using a Multi-point mixer (56-58) make sure that the type of mix is NORM and not
CURV and then touch ENTER to get to the mixing display.
d. It may be desirable to turn the mixer ON and OFF so that there is no mixing when landing. If you
do NOT want to turn down-elevator mixing on and off then proceed with "e below.
At this point we're assuming that we want to turn the mix ON and OFF. Touch PAGE to get to
the switch selection display. If you have programmed an Idle-UP function then the ideal switch
to use for turning the mix on and off is the Idle-Up switch. When we turn Idle-Up off we can
also have the switch turn the down-elevator mixing off.
PCM 10SX owners touch SEL under SW until the Idle-Up switch is selected (we used the BRK
switch in our example). If Idle-Up has not been programmed then select the switch of your
choice, but do not use STK. Put the switch in the ON position and proceed with "f" below.
PCM 10SXII and 10X owners touch SEL under the Idle-Up switch (we used GER or GR in our
example). If Idle-Up has not been programmed, touch SEL under the switch of choice, but do not
use STK. Put the switch in the ON position and touch PAGE to get to the type of mix display and
then proceed with "f" below.
e. PCM 10SX owners touch PAGE once while 10SXII and 10X owners touch PAGE twice to get to
the type of mix display.
f. Touch SEL under MASTER until ORIG appears so that mixing will be based only on the
physical position of the throttle stick and will ignore any exponential that may be associated with
the throttle channel. Touch PAGE to return to the mixing display.
g. Move the throttle stick to the full-low position. Now move it 1 click upward. Touch STORE
under OFFSET with the throttle stick in this position. This sets the mixer's center point or offset.
h. Move the throttle stick back to the full-low position. Touch + until the percentage is about 3%.
We are setting the mixing percentage that occurs when the throttle stick is moved below the offset
or the full-low position.
i. Now test the mix direction by turning on the RX and watching the elevators. If you are using a
switch to turn the mix on and off, make sure the switch is in the ON position. Moving the stick to
the full-low position should cause the elevators to deflect downward slightly. If you see no
movement, touch + to increase the percentage while holding the throttle stick in the full-low
position until you see the elevators move a little.
If the elevators move in the wrong direction (up elevator) touch TURN while the stick is in the
full-low position and the elevators should now deflect downward when the throttle stick is moved
to the full-low position.
If you are using a switch, turn the switch off and the elevators should no longer move when the
throttle stick is brought to the full-low position.
Test fly the aircraft and return to this mixer to adjust the amount of down elevator required to
eliminate the "pulling-out" tendency. Increase down-elevator by touching + and decrease it
by touching – while holding the throttle stick in the full-low position with the switch (if used)
in the ON position.
By Len Alessi
35
All Rights Reserved © 5/24/02
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