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Connect the rudder servo to top connector.
Make sure the plugs go in the right way. Click on the
picture to the left to see what color wire should be on
what side. Run one of the extension cables that came with
the gyro from the middle connector marked 'To receiver 1-4'
to the rudder channel on the receiver (ch.4). Next run
the other extension cable from the bottom connector
marked 'To receiver aux' to ch.5 on the receiver.
NOTE: If you have the old style case, then the connector
on the gyro sensor box is used for factory programming
only. Do not connect anything to it. |
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Mount the Gyro on the back plate behind the
main shaft. Do NOT pay attention to the instructions for
gyro orientation. As long as you have the orange sticker
on top then you have it mounted in the right orientation.
I mounted mine with the arrows pointing left/right and
the cord coming out of the sensor box toward the back of
the helicopter (click on photo at the left). The gyro
comes with two pieces of foam tape that work really good.
I put one strip on the bottom left edge and the other on
the bottom right edge. If you need to replace the tape,
you can use the CSM tape part # CMLG150 |
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Before we continue it helps to understand the
characteristics of this gyro. You will notice that your
rudder stick only moves the servo for the first 75% to
the right and the first 25% to the left. The servo does
not move when the stick is past these positions. Also the
gain pot on the gyro sensor box does not work when you
use the remote gain. It does not matter what position the
pot is set to. The radio controlled gain takes priority.
Another thing to remember is that all heading hold gyros
have to initailize. This one takes about 9 seconds. Don't
move the helicopter during the first 9 seconds after you
turn it on. The gyro will let you know it's finished by
moving the servo just a little bit one way then back. It
will also turn on a red LED on the back of the gyro
sensor box. |
| Common misconception of all heading hold
gyros |
Another thing that a lot of people don't
understand is that the rudder travel adjust (ATV's /
EPA's) does not adjust how far the servo moves. You
cannot use this to prevent linkage binding. This
adjustment only effects how fast the tail moves (your
pirouette rate). |
| radio setup |
Disconnect the rudder link from the servo.
Turn on the radio and receiver. Wait 9 seconds for the
gyro to initialize. It will move the rudder servo a
little to let you know it's ready. Also you will notice a
red LED light up in the back of the gyro sensor box. |
| zero center position |
In the radio go to the 'SUBTRM' menu and the
rudder to 0 and gyro to 0. |
| trim step rate |
Go to 'TRIM' press the right arrow key until
you get to TRM-RU and use the +- keys to set the value to
1. |
| set limits to 100% |
Go to 'ATV' menu and use the right arrow to
select 'ATV-RU'. Hold the rudder stick to the left and
set the value to 100%, hold the rudder stick to the right
and set it to 100%. Go to 'ATV-GY' and make sure both
sides are also set to 100%. |
| dual rates to 100% |
Go to D/R menu and set all channels to 100%. |
| set the gyro gain |
Go to GYRO in the Advanced menu and look
under the word 'GYRO', if it does not say 'on' then press
the + key to turn it on. Press the right arrow, then set
the gain you want for Normal flight mode. I would start
off around 85. Press the right arrow and you will see IDL1,
set the gain value you want for flight mode 1. I would
start with 15. Press the right arrow and use the +- keys
to select SW-E. The concept is to use values below 50 and
above 50 to not only choose between HH or Normal, but
also to adjust the gain in each mode. For example if your
value is 80, that would put the gyro in normal mode with
60% gain. If you set the other side to 20 then it would
make the gyro operate in heading hold at 60% gain. The
further from 50 (high or low) the higher the gain will be.
Going above 50 tells the gyro to use standard rate mode
and going below 50 tells the gyro to use heading hold
mode. |
| set to normal mode |
While in Normal flight mode, move the rudder
stick to the right, then back to center, if the servo
does the same then you are in normal mode. If the servo
moves to one direction but does not move back to center
then you are in heading hold mode. If not, then reverse
the values in the GYRO menu. In other words set normal
mode to 15 and IDL1 to 85. Note: if you want to keep the
values above 50 for standard rate, then another
alternative is to go to the REVERS menu and select the
gyro channel and make it opposite of whatever it is set
to now. |
| servo direction |
Check the servo direction. Move the rudder
stick to the right and watch the servo arm. It should
move the servo clockwise which thereby should pull the
rudder control link forward. This will make the nose of
the helicopter rotate to the right (if you assembled the
hub the right way). If not, then go to the rudder channel
in the REVERS menu on your radio and change the direction. |
| gyro direction |
Rotate the helicopter so the nose goes to the
left and watch the rudder servo. The servo needs to
rotate clockwise. If not, then flip the reverse switch
located on the back of the gyro sensor box. |

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With the rudder link disconnected from the
servo. The first thing to do is make the link slide as
free as possible. Adjust the guides to acheive the least
resistance. I added a slight bent to the front section of
the rod as you can see if you click on the photo to the
left. I did this so as to stop the resistance the rod had
on the first frame guide due to being pulled down to the
servo. I also used a JR Ball link resizing tool to remove
unecessary resistance from the ball links. Once you get
the link as free from resistance as you can, turn on the
radio and receiver. Wait 9 seconds for the gyro to
initialize. It will move the rudder servo a little to let
you know it's ready. Set the rudder servo arm so that it
points a few degrees clockwise of straight up (pointed
toward the front of the heli) with the rudder stick and
rudder trim centered. The best position for tail
centering is to adjust the rudder link so that you have 4.5mm
between the pitch slider and the tail rotor casing with
the collective stick centered up/down and left/right.
Check that the front link is centered with the servo arm.
If it's not, turn the link clockwise to move it toward
the back or counter clockwise to move it forward. Once
the center of the ball link matches with the center of
the arm and you have the 4.5mm at the tail slider, then
you can move to the next step. |
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Hold the tail rotor stick full right and pull
the control rod all the way forward. Note: The servo will
only move during the first 75% of stick movement. This
does not mean something is wrong, this is the way it was
designed. Hold the link over the servo arm to see which
hole it will align with and install the ball in that hole.
Mine worked out to use the hole that is 9mm from the
center. You want to use the one that is furthest from
center that does not allow the servo to mechanically bind.
After you mount the ball, confirm that it does not try to
pull the link further than it can mechanically go either
right or left. Now you can snap the link on the ball. |
| Notes about this radio setup |
The above configuration lets the flight mode
switch select heading hold while in flight mode 1 or 2
and standard rate while in normal mode. It also allows
the gain for each mode to be set in the GYRO menu. Gain
values are 0-50 for heading hold and 50-100 for standard
rate. The further from 50, the higher the gain. |
Flight adjustments
with independent
normal/HH trims |
Go to OFST-1 and turn it on. This will allow
the trims to be independent between all flight modes.
While on the bench you need to set the HH center. If as
soon as the gyro enters HH mode, then the tail servo
immediately starts drifting until it reaches the limit on
one side or the other, this means the trim needs to be
adjusted. If the servo moves slowly, it will only need a
few clicks. So flip from normal to flight mode 1 and
watch the rudder servo. If it moves, then while in flight
mode 1, use the trim to stop it. Flip back to normal,
then to HH, you want to get it set so that when you
switch, the tail servo does not move. Note: This will get
you close, if not perfect, for actual flying, but you
should be aware that my experience has been that due to
vibration or whatever in flight, that the center position
is different. So when you flip the switch, the tail might
drift. Just adjust the trim to stop the drift.
Afterwards, you will see that on the bench, the tail will
drift when going from normal to HH, but that's okay,
since it will be right while flying.
The first time you hover you can set the trim for the
normal rate mode. Just use the rudder trim since you
don't have to be concerned about it interacting with the
HH mode.Gain settings:
For normal mode you want to increase the gain until you
see the nose of the helicopter wag (oscillate back and
forth), then back off the gain. That will be the highest
you can set the gain. Do the same for HH.
NOTE: If you can't get a gain in normal mode that is
close to 100% then you may have too much vibration or the
servo arm is too long.
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