Step 3: On the amplifier, locate the SV (Servo) receptacle. Plug the rudder servo into
this receptacle, noting the correct polarity as indicated by the shape of the plug, as
well as the wire color.
Tail Lock
™
Selection/Connection
The G550T offers several methods to access and use the tail lock function.
Note: If you’re using a 6- or 7-channel system, you must install the G550T as
detailed in Option 1.
Quick Star t
Option 1 is a quick way to get up and flying with your G550T, as it is the easiest
to set up. If you select the option to have the tail lock mode on, it will not be neces-
s a ry to use any form of tail rotor compensation, further simplifying the initial setup.
Option 1: Tail Lock Mode or Rate Mode Always On
If you choose to have the G550T function in either tail lock or rate mode only,
simply move the tail lock switch located on the amplifier to the desired position (On
for tail lock, OFF for rate mode). With this option, it is not necessary to connect the
Black SEL Aux 2 connector. Please note that with this method, it is not possible to
access both the tail lock and rate modes from the transmitter as only one Aux chan-
nel is being used.
Option 2: Remote Rate and Tail Lock Mode Access
Connect the black SEL Aux 2 connector from the amplifier to the following chan-
nel on your receiver:
JR PCM 10 series (9 and 10-channel systems): Gear (Channel 5)
JR XP8103 series (8-channel systems): Gear (Channel 5)
This option will allow both the standard rate and tail lock modes of the G550T to
be remotely selected during flight via the gear switch.
This method will also allow for the use of an optional program mix that will allow
the G550T’s modes to be selected via the Aux 3 gyro gain function. This method will
also enable the G550T’s modes to be linked to the flight mode switch.
INITIAL RADIO SETUP
The G550T Gyro is much more responsive than most standard gyros, and it can
sense and correct for rotation rates at over 720˚ per second. Because of this, the
travel adjust and exponential values can be much diff e rent than they are with other
g y ros to obtain the optimum feel and rotation rates.
Travel Adjust
Set the ru d d e r’s travel adjustment to maximum right and left. If you’re using a JR
PCM-10/10S/10SX, set the travel adjustment to 150% left and 150% right. These
values will be fine tuned in the Setup and A d j u s t m e n t s e c t i o n .
Dual Rates
The recommended starting points for dual rates are :
Flight Mode
M a n e u v e r
Dual Rate V a l u e
N o rm a l
H o v e r i n g
6 0 %
Flight Mode 1
540 stall turn s
1 0 0 %
Flight Mode 2
S t a n d a rd aero b a t i c s
6 0 %
Exponential
Because a very large stroke is used (150%), the control sensitivity around neutral
is high. Exponential is necessary to reduce the sensitivity around neutral. The re c-
ommended starting points of exponential are :
Flight Mode
M a n e u v e r
Exponential V a l u e
N o rm a l
H o v e r i n g
3 0 %
Flight Mode 1
540 stall turn s
4 0 %
Flight Mode 2
S t a n d a rd aero b a t i c s
4 0 %
N o t e : After you have gained some experience and flight time, you can alter travel
adjust, dual rate, and exponential values to suit your flying style.
SETUP AND ADJUSTMENT
Following is the step-by-step pro c e d u re that must be followed to achieve the
highest level of perf o rmance from your gyro system.
Step 1: Unhook the tail rotor linkage at the rudder servo and swing the servo arm
out of the way. Lightly grasp the tail rotor pushrod at the servo end and move the
tail rotor throughout its entire stroke. The tail rotor linkage should move through
its full range smoothly with very little friction and no rough spots. Work on the
linkage system until this is achieved.
Step 2: On your transmitter, reset all the rudder trimmers (sub-trim, trim offset,
stunt trim, mechanical trim lever, etc.) to zero or center. Set the throttle/pitch stick
at exactly the hover position (normally 50%). Turn off or zero out both the revolu-
tion mixing (up and down) and the acceleration mixing.
Step 3: Turn on your receiver and allow the helicopter to remain totally motionless
for three seconds. A bright LED light on the amplifier will come on after three sec-
onds, indicating the gyro has digitally stored the zero rotation value.
Step 4: Install the servo arm 90˚ to the tail rotor pushrod (see diagram). You may
find that the splines are slightly offset on your servo, not allowing an exact 90˚
positioning. If so, rotate the
servo arm to another ar m
position and try again.
Secure the arm in place with
the screw provided. Attach
the pushrod to the arm at
approximately 16 mm out
from the center. Later, we
will optimize this distance
through flight testing.
Step 5: Be sure the rudder
servo is moving in the cor-
rect direction. A right servo command should move the nose of the helicopter to
the right. (If you’re unsure, seek help from someone with more experience.)
Reverse the servo direction in the transmitter’s programming if necessar y.
Step 6: Give a right rudder command and note the direction the rudder servo
moves (clockwise or counterclockwise). Then pick up the helicopter and quickly
rotate the nose to the left. The servo should move in the same direction as it did
when you applied right rudder (clockwise or counterclockwise). If the rudder servo
rotates in the opposite direction, move the reverse switch located on the amplifier
in the opposite direction.
Step 7: With the G550T in tail lock mode (green LED), check to insure that the
servo will remain in the neutral (centered) position. If the servo "creeps" or slowly
moves in either direction, enter the sub trim function of your radio system and add
a sub trim value as needed until the servo will remain in the neutral position, with
no tendency to creep in either direction.
TAIL ROTOR LINKAGE ADJUSTMENT
With the servo arm positioned at 90° degrees to the control rod, adjust the over-
all length of the tail control rod so that the tail pitch mechanism is at the center of its
travel limits. It’s also necessary to insure that the tail rotor blades have the pro p e r
d e g ree of pitch in the neutral position to maintain a stationary hover. A p p ro x i m a t e l y
5° is a good starting point. The final pitch of the tail blades will need to be fine tuned
during test flights by adjusting the tail linkage mechanically.
Servo Travel Adjustment
With the G550T in rate mode, adjust the overall left/right travel of the servo
through the travel adjust function of your system so that there is no binding of the
linkage/tail pitch mechanism at full left/right travel.
Note: You will notice that with the travel adjusted, it appears that the rudder stick
only works the servo throughout half its stroke. This is normal! During flight, the
g y ro provides feedback to the servo that combines information about its ro t a t i o n
rate and the gain setting that gives pro p o rtional rotation rates throughout the ru d-
d e r’s stick travel.
I m p o rt a n t : When properly adjusted, it’s normal for the rudder stick to only aff e c t
the ru d d e r’s position around the center half of its stroke. During flight, the gyro
senses the rotation rate of the helicopter, and the rudder servo works norm a l l y
t h roughout its total stro k e .
R AT E / TAIL LOCK MODE SELECTION
T h e re are two set up options available when installing the G550T.
N o t e : While in tail lock mode,
a slight change in the neutral
position of the servo may occur
while the model is in a station-
a ry position. In addition, when
the servo is moved to the
e x t reme left/right position and
released, the servo will slowly
move back to the neutral posi-
tion.
These movements are com-
pletely normal and are caused
by the Angular Velocity Command Control System of the G550T. These movements
only occur while the model is stationary. In flight, these movements do not occur.
O P T I O N 1: Tail Lock or Rate Mode Always On
( M a n d a t o r y with 6-channel systems)
Step 1: Locate the tail lock switch on the gyro amplifier and move to the desire d
position (ON for tail lock mode, OFF for rate mode).
Step 2: Tu rn the radio system ON and confirm that the G550T is in the desired mode
( red LED: rate mode, green LED: tail lock mode).
N o t e : If the tail lock mode is selected, make sure that all tail rotor mixing values
in the radio program have been reset to the factory default (0) position.
p rocede to gyro gain settings.
Rudder Servo
90°
16mm
Control Ball
Attach Control
Ball to Arm
16mm from
Center.
Off/On
Rev.
LED Indicator
Red: Rate Mode
Green: Tail Lock Mode
Tail Lock System
