Futaba GY601 User Manual

AVCS GYRO

GY601

INSTRUCTION MANUAL

YAW-AXIS STABILIZER FOR MODEL HELICOPTER

(RATE GYRO)

2

Thank you for buying a GY601 AVCS gyro.
Before using your new gyro, please read this manual thoroughly and use the

gyro properly and safely. After reading this manual, store it in a safe place.

FOREWORD

The GY601 gyro is an AVCS (Angular Vector Control System) rate gyro
developed for model helicopter competition.

[GY601 Features]

•Super narrow pulse (760µs) drive system substantially improves servo

reresponse. An S9251 digital servo is used.

•Microcomputer high-speed arithmetic processing substantially improves
gyro response.

•High resolution 12-bit A/D accurately converts the sensor output to a
digital signal.

•Newest SMM (Silicon Micro Machine) and low-back aeroform case
improve vivibration resistance and neutral characteristic.

•Amp mounts an LCD that allows accurate data setting.

[S9251]

•Special servo for the GY601. Compatible with super narrow pulse (760µs)
drive.

•Operation speed 0.07sec/60º. High response realized.

•Alumite case w/heat sink effectively cools the motor heat.

Always use the special S9251 servo with the GY601.

The GY601 cannot operate with servos other than the S9251.
The servo may be destroyed.

Warning: This product contains a chemical known to cause cancer and
birth defects (or other reproductive harm).

•No part of this manual may be reproduced in any form without prior permission.

•The contents of this manual are subject to change without prior notice.

•This manual has been carefully written. Please write to Futaba if you feel that any
corrections or clarifications should be made.

TABLE OF CONTENTS

FOR SAFETY

•Meaning of Special Markings ---------------------------- 4

•Mounting/Operating Precautions ------------------------ 4

•Fuselage Maintenance Precautions ---------------------- 6

•S9251 Usage Precautions --------------------------------- 7

BEFORE USE

•Set Contents------------------------------------------------- 8

•AVCS Gyro ------------------------------------------------- 9

DATA SETTING

•Name and Function of Each Part------------------------12

•LCD Display and Edit Keys -----------------------------13

•Function Map ----------------------------------------------14

•GY601 Functions Setting --------------------------------15

•Remote Gain Function------------------------------------21

•Initialization------------------------------------------------30

INSTALLATION AND ADJUSTMENT

•Installing to Fuselage -------------------------------------32

•Flight Adjustments ----------------------------------------37

3

REFERENCE

•Specifications ----------------------------------------------40

•Definition of Abbreviations------------------------------41

•GY601 Parameters Sheet---------------------------------42

FOR SAFETY

4

FOR SAFETY

To ensure safe use, observe the following precautions.

Meaning of Special Markings

Pay special attention to the safety at the parts of this manual that are
indicated by the following marks.

Mark Meaning

Symbol: ; Prohibited ; Mandatory

Procedures which may lead to a dangerous condition and
cause death or serious injury to the user if not carried out
properly.

Procedures which may lead to a dangerous condition or
cause death or serious injury to the user if not carried out
properly, or procedures where the probability of
superficial injury or physical damage is high.

Procedures where the possibility of serious injury to the
user is small, but there is a danger of injury, or physical
damage, if not carried out properly.

Mounting/Operating Precautions

Insert the connectors fully and firmly.

If a connector works loose due to vibration during flight, control may be lost
and result in a dangerous situation.

Always use the GY601 with a PCM proportional system.

Using the GY601 with an FM proportional system, when noise enters, the
wrong neutral position may be memorized.

FOR SAFETY

Always use the accessory sensor tape to install the sensor to the fuselage.

This is necessary to securely fasten the sensor to the fuselage so that
operation of the gyro does not transmit unwanted fuselage vibrations directly
to the sensor.

When mounting the sensor, provide a little surplus so that the sensor
connection cables are not too taut.

If the sensor cables are too taut, the gyro will not display its full perfor­mance. If the sensor peels, control will be lost and result in a dangerous
situation.

Mount the sensor and control amp so that metals or other conductive
objects do not touch these cases.

The GY601 uses a conductive resin case to reduce electromagnetic interfer­ence. Because the surface of the case is conductive, metal objects may cause
a short circuit.

Mount the sensor and servo at least 2cm apart.
When using a GV-1 governor, mount the sensor and GV-1 amp at least

5cm apart.
When using the GY601 with a motor-driven helicopter, mount the

sensor and drive motor at least 10cm apart.

Noise from the servo motor, GV-1 amp and drive motor may cause the
performance of an erroneously operated gyro to drop.

Precautions When Turning on the Power Switch

During initialization, the message “-Hello-” appears on the GY601 LCD
screen.

Do not move the helicopter until this message disappears (in about 3
seconds).
Also, do not move the transmitter rudder stick from the neutral position
during this period.

5

Always check the direction of operation of the servos.

If you attempt to fly the model when a servo operates in the wrong direction,
the fuselage will spin in a fixed direction and enter an extremely dangerous
state.

6

FOR SAFETY

When the rudder neutral position was changed by the linkage, the
rudder neutral position in the AVCS mode must always be re-read
before use.

Re-reading method:

Turn on the transmitter in the AVCS mode, then turn on the
gyro . Or quickly switch (interval of within 1 second) the
remote gain channel switch between the AVCS mode and
Normal mode at least three times and switch the AVCS side
with the transmitter in the ON state. This memorizes the new
rudder position inside the GY601.

Avoid sudden temperature changes.

Sudden temperature changes will cause the neutral position to change. For
example, in the winter, do not fly immediately after removing the model
from inside a heated car and in the summer, do not fly immediately after
removing the model from inside an air conditioned car. Allow the model to
stand for about 10 minutes and turn on the power after the temperature
inside the gyro has stabilized. Also, if the gyro is exposed to direct sunlight
or is mounted near the engine, the temperature may change suddenly. Take
suitable measures so that the gyro is not exposed to direct sunlight, etc.

Check the remaining receiver/gyro/servo nicd battery operating time
during the adjustment stage and decide how many flights are remaining.

Never use the transmitter rudder trim in the AVCS mode.

When the rudder is trimmed during flight, the neutral position will change.

When using the GY601 in the AVCS mode, set revolution mixing to
OFF.

Fuselage Maintenance Precautions

Use a tale rotor drive tube or other part with a high torsion perfor­mance for the tail drive.
Take the strength of the tail into account during inspection and adjust­ment.

The amount of improvement of gyro performance has a considerable effect
on the fuselage vibration level or the size, type, linkage method, looseness,
etc. of the tail rotor.

FOR SAFETY

Since a higher gain than usual can be used then the tail rotor is more
effective, the load on the tail is also greater.

Always perform proper maintenance for ultimate performance.

The rigidity of the fuselage tail has a large effect on gyro performance.

Make the fuselage vibration as small as possible.

Fuselage vibration has an adverse affect on gyro operation.

S9251 Usage Precautions

Do not use the S9251 with applications other than the GY601 gyro.

The S9251 is designed to be used with the GY601 only, and will not operate
in other applications. Trouble may also occur.

Immediately after flight, do not touch the S9251 case.

The heat sink section of the case is extremely hot, and may cause burns.

When mounting in the fuselage, install the S9251 so that it does not
touch the servo case and metal parts of the helicopter frame.

The middle case has an aluminum heat sink construction, and will generate a
large amount of noise if touched. In this case, it will become impossible to
receive and is extremely dangerous.

Current Drain:

The S9251 is designed to be used with the GY601 gyro only, especially to
operate at high speed. Therefore, the servo starts, a correspondingly large
current flows and the current drain is, therefore, large. Constantly pay
attention to the remaining capacity of the Nicd battery and decide the
number of safe flights. Always pay attention to the following points:

•Always use an Nicd battery. A dry cell battery will not display the
spspecified performance.

•When using the S9251 in a system with a battery fail safe function,
the cut-off voltage is set to a high value. Shortening of the flight time
due to this must be included in calculation.

•Install the servo so that it does not get caught on the push rod or
does not loosen even when operated over its full travel. If unreason­able force is applied, the current drain will increase tremendously and
shorten the life of the servo and accelerate battery consumption.

7

BEFORE USE

8

BEFORE USE

Set Contents

After unpacking the GY601 set, first check if the following parts are
provided:

GY601 sensor (x1)

GY601 control amp
(x1)

Sensor tape (x3)

Mini screwdriver (x1)

S9251 servo (x1)

(Only a set w/servo)

BEFORE USE

• Drifting stop

Forward

Side wind

AVCS Gyro

Differences Between AVCS Gyro and Conventional Gyro

Compared to a convention gyro, the AVCS gyro has a substantially im­proved tail control capacity. Gyro operation also differs from that of
conventional systems in a number of ways.

The following sequentially describes the conventional gyro and the AVCS
gyro.

Conventional gyro

The conventional gyro detects movement of the helicopter's tail and controls
the rudder servo so that movement of the tail stops.

Now, consider hovering when the helicopter is exposed to a side wind, the
tail drifts. When the tail drifts, the gyro detects the tail rotation angular
velocity and operates the servo in the direction that stops the tail from
moving. Drifting of the tail is stopped by control from the gyro. When the
tail stops drifting, the control amount from the gyro becomes zero. Since the
helicopter is always exposed to side wind, even in this state, the tail starts to
drift again. When the tail drifts, the gyro tries to stop it again. The "drifting
stop" operation is repeated and the tail continues to drift in the wind
direction in this manner. The higher the gyro sensitivity, the smaller the
amount of this drift. However, if the sensitivity is high, hunting will occur
and, therefore, the sensitivity amp has a limit.

9

AVCS gyro

This following describes how the AVCS system works when the helicopter
is exposed to a side wind while hovering, the same as the preceding item.
When the helicopter is exposed to a side wind, the tail begins to drift. The

10

BEFORE USE

gyro controls the servo so that the movement of the tail stops, the same as a
conventional gyro. At the same time, a sensor is controlled so that the tail is
rotated in the opposite direction (returns to the original position). In short,
the conventional gyro performs an operation known as "drifting stop", but
the AVCS system performs an operation that "stops drifting and returns to
original position". The "return to original position" operation added to the
AVCS system improves rudder trim operation. In other words, the gyro can
automatically trim the rudder against side winds. This also applies to reverse
flight. When a helicopter is flying in the forward and reverse directions, the
rudder trim is changed to advance, but with the AVCS system, this trim
change is performed automatically and instantaneously so that the tail
remains extremely stable even during high-speed reverse flight.

The AVCS system requires a high-precision angular velocity sensor. The
GY601 realizes a high-precision angular velocity detection function and
extremely small output drift by using a new type of gyro sensor. This
minimizes rudder neutral position drift during flight and eliminates the need
to trim the rudder during flight.

• The tail remains extremely stable.

Forward

Side wind

Differences in rudder control method

The following describes the differences between conventional gyro and
AVCS gyro rudder control.

The conventional gyro sends the rudder control signals from the transmitter
to the rudder servo and starts to move the tail. When the tail moves, the gyro
detects this movement and generates a signal to stop it. If the tail continues
to move even in this state, a rudder control signal larger than the signal from
the gyro must be applied from the transmitter. That is, the difference
between the rudder control signal from the transmitter and the control signal
that attempts to stop this from the gyro becomes the actual amount of
movement of the tail. Ordinarily, the rudder control signal is amplified

BEFORE USE

several times over by the gyro amp and is balanced with the gyro control
signal so that the transmitter can be used at the normal steering angle.

The AVCS system uses a different rudder control method. As described in
the preceding section, it has additional functions that "attempt to return
movement by external force to the original position" and that generate an
angular velocity proportional to the rudder control signal. That is, it func­tionally controls the speed of rotation of the tail. The original AVCS
(Angular Vector Control System) came from this.

•In the AVCS mode, when the transmitter rudder stick is moved when
the helicopter was stopped, the rudder servo controls operation until
the tail reaches the specified rotational speed.

•Trim deviation of the rudder control signal also becomes a signal that
causes the tail to turn so that even a little trim deviation causes the
tail to move. Therefore, the rudder trim is made the same in all flight
states and must match the neutral reference signal at the gyro. The
method of reading the rudder neutral signal at the gyro will be
described separately.

•Since the rudder mixing signals from the transmitter also become a
tail rotation signal, all the rudder mixing functions must be disabled.

•In the AVCS mode, the gyro automatically trims the rudder so that
linkage changes cannot be verified. Initially, the GY601 trims the
rudder by flying in the Normal mode to take the rudder linkage neutral
position. This centers the linkage. At this time, this rudder neutral
reference point is read to the GY601.

Giving the gyro the rudder neutral reference signal and performing
tail operation by referring to this signal in the AVCS mode in this
way is how the AVCS system differs from the conventional system.

11

DATA SETTING

12

DATA SETTING

Name and Function of Each Part

GY601 control amp

LCD display

Displays the set data. (8 characters X 1 line)

(Input/output terminals)
Gyro sensor input
Rudder servo output

Edit keys

Used when setting data.
Operated by pushing with the
accessory mini screwdriver.

LCD contrast trimmer

Allows adjustment of the contrast so that the LCD display is easiest to see.
It is adjusted with the accessory mini screwdriver.

GY601 gyro sensor

Stick to the body using the accessory
sensor tape.

(Receiver connectors)
Remote gain input
Rudder input

To control amp

DATA SETTING

LCD Display and Edit Keys

LCD display

Set data display and operation
status monitoring are possible.

Edit keys
Setup screen call

The setup screens can be sequen­tially called with the FUNC+ or
FUNC- key. For the order in which
the setup screens are called, see the
function map.

Data setting

Perform data setting with the DATA+
or DATA- key. When setting a value,
the data is increased when the
DATA+ key is pressed and is
decreased when the DATA- key is
pressed. The mode can also be
selected using either the DATA+ or
the DATA- key.

13

DATA SETTING

14

FUNC ”-” key

Function Map

Normal screen display
(P15)

FUNC ”+” key

Gyro Reverse
(P16)

Gyro Gain Adjustment
(P16)

Rudder Control Gain
(P17)

Control Delay I
(P17)

Control Delay D
(P17)

Gain Tracking
(P18)

Power ON

Power on screen display
(P15)

Operation Mode Setting
(P18)

Flight Mode
(P19)

AVCS sense
(P20)

Linkage Limit Setting
(P20)

DATA SETTING

GY601 Functions Setting

Power on screen display

When the gyro power is turned on after the transmitter power was
turned on, -Hello- blinks for about three seconds to initialize the data
inside the gyro. During this period, do not move the transmitter
rudder stick or the helicopter. If the transmitter rudder stick or the
helicopter is moved by mistake, the rudder neutral data will not be
correctly read.

Normal screen display

15

•Actual gain (sensitivity)
display

•Operation mode display
N : NOR mode
A : AVCS mode

: Neutral offset

•Power supply voltage display

•During rudder neutral reset operation,
**** is displayed.

•During rudder servo reset operation by
rudder stick, ---- is displayed.

Low battery alarm

When the power supply voltage drops to 3.8V or less,
LOW Batt is displayed. When this message is displayed,
immediately stop use and recharge the Nicd battery.

16

DATA SETTING

Gyro Reverse

Initial value: NOR

Sets the gyro operation direction. NOR or REV can be selected.
Set so that when the helicopter is banked right, left correction rudder

is applied and when the helicopter is banked left, right correction
rudder is applied.

Gyro Gain Adjustment

Initial value: 100%

Adjusts the gyro gain. Setting range is 0 to 120%.
Two-point (G:1, G:2) gain adjustment is possible. When A is

displayed, the gyro is in the AVC mode and when N is displayed, the
gyro is in the NOR mode in accordance with the operation mode
setting.

DATA SETTING

Rudder Control Gain

Initial value : ACG: 120%, NCG: 130%

Adjusts the rudder stick operation gain. Setting range is 10% to
250%.

AVCS and NOR mode gain can be set independently. In the AVCS
mode, ACG is displayed and in the NOR mode, NCG is displayed.
The display automatically changes to A or B according to the
direction of the rudder stick and the gain of each direction can be set.
This function is used when tracking rudder operation gain between
the AVCS and NOR modes.

Control Delay I

Initial value : 0%

Sets the delay when the rudder stick was pushed operated. Setting
range is 0 to 100%. Rudder stick left and right can be set separately.

17

Control Delay D

Initial value : 0%

Sets the delay when the rudder stick was returned. Setting range is 0
to 100%. Rudder stick left and right can be set separately.

18

DATA SETTING

Gain Tracking

Initial value : +0%

Adjusts left and right tail braking tracking. Setting range is -20% to
+20%.

For example, when there is a sense of hunting when stopping left
pirouette or the helicopter drifts when stopping right pirouette, shift
Trk in the + direction. In the opposite case, shift Trk in the - direc­tion.

Operation Mode Setting

Initial : CMT

Sets the gyro operation mode. Settings are NOR, AVC, and CMT. In
the NOR mode, both G1 and G2 operate in the AVCS mode. In the
CMT mode, G1 operates in the AVCS mode and G2 operates in the
NOR mode. In the NOR mode, the GY601 operates the same as an
ordinary gyro. In the AVC mode, the GY601 always operates in the
AVCS mode. In the CM mode, the GY601 can be used in both the
AVCS and NOR modes.

DATA SETTING

Flight mode

Initial value : F3C

Switches the flight mode. Settings are F3C or 3D.
The F3C mode emphasizes tail suppression and stop. The 3D mode

slightly sacrifices tail suppression and stop, but lets you control
pirouette speed completely proportional with the rudder stick
operation amount and is suitable for 3D flight.

<3D mode steering angle setting>

During 3D mode setting, the transmitter rudder steering angle
is set to 100% and approximately 500º/second high pirouette
speed. Therefore, initially set the transmitter rudder steering
angle to a low value so that the tail can be safely controlled.
(About 70%)

The pirouette speed is proportional to the rudder steering
amount without regard to the gyro sensitivity.

19

20

DATA SETTING

AVCS Sense

Initial value : 100%

Adjusts the rudder control characteristic in the AVCS mode. Setting
range is 50 to 150%.

Check the rudder operation feeling and stopping characteristic and
adjust. When the flight mode (page 19) is the 3D mode, this value
becomes the pirouette standard value.

Linkage Limit Setting

Initial value : 100%

Sets the rudder servo travel limit.
Operate the rudder stick and adjust the rudder servo travel limit by

pressing the +/- key so that the servo moves to the maximum linkage
position. Use the same procedure to set both the left and right limits .
When setting, move the servo substantially so that the rudder angle
automatically becomes 200% and limit setting is easy. A or B is
displayed for the right and left directions.

Note: When this screen is displayed, the GY601 does not operate as
a gyro. To check operation, return to the initial screen, etc.

DATA SETTING

Remote Gain Function

The remote gain function lets operator perform AVCS mode and
Normal mode sensitivity adjustment and operation mode switching
from the transmitter. The channel used here is called the "remote
gain channel". (Channel 5 is used.)

21

(Remote Gain Function)

Transmitter

Gain/Mode Selection

• CH5 switch

• Idle-Up switch (T8Usuper)

• Flight condition (T9Z)

Gain Settings

• ATV function

• Gyro mixing (T8Usuper/T9Z)

• Programmable mixing (T9Z)

Receiver

GY601

Mode Settings

• Normal mode (NOR)

• AVCS mode (AVC)

• Selectable mode (CMT)

Gain Settings

• Gyro Gain Adjustment

Remote Gain Channel (CH5)

22

DATA SETTING

When Using a T9Z World Champion Model Transmitter
Gyro Sense Mixing

The Gyro Sense Mixing (GYR) function lets operator perform two-point gain
adjustment at each condition. Set the sensitivity at all conditions.

[GY601 Settings]

Select the gyro operation mode at the GY601 Mode screen. (AVC, NOR, or
CMT)

[Transmitter Settings]

ATV function:
Adjust both the RATE A and RATE B rates to 100% at the transmitter
5ch(GYR) ATV function setup screen.
Gyro Sense Mixing function:

1. Select the Dual Mode (DUO) at the transmitter Gyro Sense Mixing setup
screen.

2. Set the GAIN1 and GAIN2 gains.
(The following page shows a setting example in the CMT mode.)

[Sensitivity Display]

The gain display indicates the actual gain at the GY601 normal screen
display. The following shows the relationship between transmitter and gyro
setting .

- Relationship between transmitter and gyro setting

Transmitter

settings

GY601mode

settings

Actual gain

GAIN1
GAIN2

NOR
AVC
CMT

0% - 50% - 100%

Normal mode

AVCS mode

Normal mode AVCS mode

(G2) (G1)

100% - 0% - 100%

DATA SETTING

(Setting Example)

Adjust the gyro gain at the Gyro Sense Mixing setup screen at each
condition.
The following shows a setting example in the CMT mode.

Select the Dual Mode (DUO).

GYRO SENCE

DUAL : MODE

85 %

15 %

Use the following values as the sensitivity setting standard:

01 . MODEL-01. NORML HEL PCM 0: 23: 17

: GAIN 1

: GAIN 2

0 20 40 60 80 100

END

Sensitivity rate
Choose the GAIN1 or GAIN2 by the CH5 switch.

23

CH5 switch

Hovering Flight

GAIN1
setting

GAIN2
setting

Actual gain

85%

15%

70% 40%

70%

30%

AVCS side

Normal side

The GY601 sensitivity is 0% at 50%. When set over 50%, the GY601
operates in the AVCS mode and when set under 50%, the GY601
operates in the Normal mode. When setting is changed 1%, the gyro
sensitivity is changed 2%.

DATA SETTING

24

When Using a T9Z Transmitter Programmable Mixing

The Programmable Mixing (PMIX) function lets operator perform a gain
adjustment at each condition. Set the sensitivity at all conditions.

[GY601 Settings]

Select the gyro operation mode at the GY601 Mode screen. (AVC, NOR, or
CMT)

[Transmitter Settings]

Function Control:
Set the CH5 (GYR) switch to “NUL” at the transmitter Function Control
(FNC) setup screen.
ATV function:
Adjust both the RATE A and RATE B rates to 120% at the transmitter ATV
function setup screen.
Programmable Mixing function:

1. Select the “ACTIVE” mode (ACT) at the transmitter Programmable Mixing
setup screen.

2. Set the mixing type to “OFS”.

3.Set the slave channel to “GYR”.

4. Set the sensitivity rate (RATE).
(The following page shows a setting example in the CMT mode.)

[Sensitivity Display]

The gain display indicates the actual gain at the GY601 normal screen
display. The following shows the relationship between transmitter and gyro
setting.

- Relationship between transmitter and gyro setting

Transmitter

settings

GY601mode

settings

NOR
AVC
CMT

Actual gain

-100% - 0% - +100%

Normal mode

AVCS mode

Normal mode AVCS mode

(G2) (G1)

100% - 0% - 100%

DATA SETTING

(Setting Example)

Adjust the gyro gain at the Programmable Mixing setup screen at each
condition. The following shows a setting example in the CMT mode.

Select the “ACTIVE”.

PROG MIX 1

ACTIVE : MODE ( ON) TRIM:

GYR

OFS

LIN

OFS

01 . MODEL-01. NORML HEL PCM 0: 23: 17

*** : MASTER

: SLAVE

: MIX TYPE

MSTR MIX MODE:

HOV CRV CTL

******

******

SWT
NXT
END

25

Select the “GYR”.

PROG MIX 1

Select the “OFS”.

01 . MODEL-01. NORML HEL PCM 0: 23: 17

: RATE+ 70 %

0 20 40 60 80 100

END

Sensitivity rate

Use the following values as the sensitivity setting standard:

Hovering Flight

AVCS mode
Normal mode

Actual gain

+70%

-70%

70% 40%

+40%

-40%

When set over 0%, the GY601 operates in the AVCS mode and when
set under 0%, the GY601 operates in the Normal mode.

26

DATA SETTING

When Using a T8Usuper Transmitter

The Gyro Mixing (GYRO) function lets operator perform a gain adjustment at
each Idle-Up switch position.

[GY601 Settings]

Select the gyro operation mode at the GY601 Mode screen. (AVC, NOR, or
CMT)

[Transmitter Settings]

Gyro Mixing function:

1. Select the “ON” mode at the transmitter Gyro Mixing (GYRO) setup
screen.

2. Select the Idle-Up switch(SW-E) for the sensitivity selection.

3. Set the “NORM”, “IDL1” and “IDL2” gains.
(The following page shows a setting example in the CMT mode.)

[Sensitivity Display]

The gain display indicates the actual gain at the GY601 normal screen
display. The following shows the relationship between transmitter and gyro
setting.

- Relationship between transmitter and gyro setting

Transmitter

settings

GY601mode

settings

NORM

IDL1
IDL2

NOR

AVC
CMT

Actual gain

0% - 50% - 100%

Normal mode

AVCS mode

Normal mode AVCS mode

(G2) (G1)

100% - 0% - 100%

DATA SETTING

(Setting Example)

Adjust the gyro gain at each the Idle-Up swtch position at the Gyro Mixing
setup screen. The following shows a setting example in the CMT mode.

Select the “ON”
mode.

Select the Idle-Up
switch(SW-E).

27

Switch position

Sensitivity rate

Set the “NORM”, “IDL1” and “IDL2” gains at each setup screen.

Use the following values as the sensitivity setting standard:

（NORM）（IDL1）（IDL2）

SW-E

AVCS mode

Normal mode

Actual gain

Hovering

85%
15%

70% 40%

Flight

70%
30%

When set over 50%, the GY601 operates in the AVCS mode and when
set under 50%, the GY601 operates in the Normal mode.

28

DATA SETTING

When Using a Transmitter ATV Function

The ATV function lets operator perform a gain adjustment at each CH5
switch position.

[GY601 Settings]

Select the gyro operation mode at the GY601 Mode screen. (AVC, NOR,
or CMT)

[Transmitter Settings]

ATV function:
Set the ATV rates at the transmitter CH5 ATV function.

[Sensitivity Display]

The gain display indicates the actual gain at the GY601 normal screen
display. The following shows the relationship between transmitter and gyro
setting.

- Relationship between transmitter and gyro setting

CH5 Switch CH5 Switch

Transmitter

settings

GY601mode

settings

ATV rates

NOR
AVC
CMT

Forward side Front side

90% - 0% - 90%

Normal mode Normal mode

AVCS mode AVCS mode

Normal mode AVCS mode

(G2) (G1)

Actual gain

100% - 0% - 100%

DATA SETTING

When Using a GY601 Gyro Gain Adjustment Function

[Transmitter Settings]

Adjust both the ATV rates to 90% at the transmitter Ch5 ATV function.

[GY601 Settings]

Operation Mode Setting function:
Select the gyro operation mode at the GY601 Mode screen. (AVC, NOR, or
CMT)
Gyro Gain Adjustment function:
Set the G:1 and G:2 gains at the GY601 G:x screen.

- Relationship between transmitter and gyro setting

CH5 Switch CH5 Switch

Transmitter

settings

ATV rates

Forward side Front side
90% (Fixed) 90% (Fixed)

29

GY601mode

settings

NOR
AVC
CMT

Actual gain

Normal mode Normal mode

AVCS mode AVCS mode

Normal mode AVCS mode

(G2) (G1)

100% - 0% - 100%

30

DATA SETTING

Initialization

AVCS mode operation is based on the rudder neutral data stored in
the GY601. When using the GY601 for the first time, or when the
internal reference data and the transmitter neutral position differed
when the transmitter neutral trim was adjusted, etc., the rudder
neutral data must be read again.

[At power ON]

When the power switch is turned on, the GY601 automatically
obtains the reference signal for AVCS function correction and
initializes itself.

•When the power was turned on in the Normal mode, the rudder
neutral position already memorized in the GY601 is not updated.

•When the power was turned on in the AVCS mode, the rudder signal
at that point is memorized and updated.

Precautions When Turning on the Power Switch

During initialization, the message “-Hello-” appears on the GY601
LCD screen.

Do not move the helicopter until this message disappears (in
about 3 seconds).
Also, do not move the transmitter rudder stick from the neutral
position during this period.

DATA SETTING

[During use]

When the rudder was re-trimmed in the Normal mode and the new
trim position also affects the AVCS mode, the rudder trim neutral
position must be memorized in the GY601.

Re-reading method

In this case, quickly switch (interval of within 1
second) the transmitter remote gain switch between the
Normal and AVCS sides at least three times and
switch the AVCS side at the neutral trim position set in
the Normal mode. This memorizes the new rudder
neutral position in the GY601.

When the transmitter has a function that allows trim
setting for each flight condition, such as the T9Z, the
AVCS mode trim position is fixed and this operation is
unnecessary.

Never use the transmitter rudder trim in the AVCS mode.

When the rudder is trimmed during flight, the neutral position will
change.

31

When using the GY601 in the AVCS mode, set revolution mixing
to OFF.

When the rudder neutral position was changed by the linkage,
the rudder neutral position in the AVCS mode must always be
re-read before use.

32

INSTALLATION AND ADJUSTMENT

INSTALLATION AND ADJUSTMENT

Install and adjust the GY601 as described below.

•When making GY601 adjustments, always
use the accessory miniature screwdriver
and do not apply excessive force.

Installing to Fuselage
1 Installing sensor and amp

GY601 sensor

Frame gyro bed

Install the GY601 sensor to the fuselage using the accessory sensor
tape. Also routinely check the sensor tape and replace the tape if it is
saturated with oil or partially peeled.

*Oil on the sensor bottom and the part installed to the frame can be

wiped off with cleaner, etc.

Sensor installation precautions

•Always use the accessory sensor tape to install the sensor. Install the
sensor to the center of the sensor tape.

•Depending on the vibration from the helicopter, the sponge may tear
near the corners of the sensor tape. If the helicopter is flown in this
state, vibrations will not be sufficiently absorbed and the sensor may
fall off. Before flight, always check the sensor installation state. If the
sponge is torn, replace it.

•Install the sensor so that the
bottom of the gyro is perpendicu­lar to the main rotor shaft axial
direction. Offset of this axis will
also react in the roll and pitch
directions.

Installing control amp

•When installing the control amp, after the end of sensitivity adjust­ment, vibration-proof the amp by wrapping it in sponge, the same as
the receiver.

2 Connections

Connect the GY601, receiver
and servo as shown below.

•Connect the sensor to the
amp sensor input ("GYRO").

INSTALLATION AND ADJUSTMENT

33

Insert the connectors
fully and firmly.

If a connector works loose
due to vibration during
flight, control may be lost
and result in a dangerous
situation.

(S9251 only)

•Connect the rudder servo to
the amp servo output ("SX").

•Connect the amp rudder
input ("RX,1-4") input
connector to the receiver
rudder channel (ch4).

Black Red

To receiver

•Connect the amp remote
gain input ("RX,AUX")
connector to the receiver
sensitivity setting channel
(normally ch5).

Always use the special S9251 servo with the GY601.

The GY601 cannot operate with servos other than the S9251.
The servo may be destroyed.

3 Gyro operation mode selection

When using the gyro only in the NOR mode,
select NOR. When using the gyro only in the
AVCS mode. select AVCS. When using the
gyro in both the AVCS and NOR modes,
select CMT.

34

INSTALLATION AND ADJUSTMENT

*However, when using the gyro in the CMT mode, since the AVCS

and NOR mode gain must be set during hovering and in flight, a
transmitter with a gyro mixing function (T9Zwc series, T8Usuper
series) is necessary.

•For a description of transmitter setting, see the remote gain function
(p21).

4 Rudder servo linkage check

Make the initial linkage connections in the NOR mode. In this case,
make adjustments mechanically and make minimum trimmer
adjustments at the transmitter.

In the NOR mode, make the following linkage checks:

•In the rudder neutral position, connect the linkage at the position at
which the servo horn and control wire are perpendicular.

Perpendicular

Control wire

Set the servo horn length based on the
helicopter manufacturer's instructions.

Move the rudder stick to the right and left and check the direction of
operation of the tail rotor. If the tail rotor turns in the wrong direc­tion, reverse the direction with the transmitter reverse function.

5 Gyro operation direction check

If the rudder servo moves to the left when the nose of the helicopter
moves to the right, the gyro direction is correct.

If the rudder servo moves to the right, switch
the direction using the GDir screen.

*If you try to fly the helicopter while the gyro direction is incorrect,

when the rotor rotates clockwise, the helicopter nose will yaw to
the left and cause an extremely dangerous situation.

INSTALLATION AND ADJUSTMENT

6 Limit setting

Move the rudder stick to the left and right and
perform adjustment at the Lmt screen so that
the servo operation angle becomes the maxi­mum value at which the servo horn does not
strike the linkage.

*When flying, the servo horn does not move beyond this set angle,

thus protecting the linkage. However, if the limit setting is too low,
gyro performance will be effected.

*In this mode, only the stick operates; the gyro does not operate.

7 Gyro gain setting (tentative setting)

The initial gain of the GY601 is 100% for
both G1 and G2. When setting the gain from
the transmitter, leave it at the 100% reference
gain.

Make the following value the gain setting criteria.
A setting example when a T9Zwc series transmitter was used is

described below. When using another transmitter, see "Remote gain
function" on page 21.

(T9Zwc transmitter setting)

•Call the transmitter GYR setting screen.

•Adjust the gain when hovering to 90% at the AVCS side and 10% at
the normal side on the transmitter screen.

•Set the gain in flight to 80% and 20% for the AVCS and NOR mode,
respectively, on the transmitter screen.

•At this time, the GY601 gain display becomes 80% for hovering and
60% for flight.(*1)

(*1) In the case of the T9Zwc GYR function, GY601 gain is 0% for a

transmitter setting of 50%. When the gain is set above 50%, the
GY601 operates in the AVCS mode and when the gain is set below
50%, the GY601 operates in the normal mode. The gyro gain
changes 2% for every 1% gain change.

35

36

INSTALLATION AND ADJUSTMENT

When using a transmitter without a gyro gain switching function,
connect the gain setting connector to an idle channel and set the
GY601 G1 and G2 gains using this gain setting screen. Gain can be
trimmed by means of the transmitter ATV function.

8 Transmitter setting check

Checks the transmitter setting in the ACVS mode. Check that the
transmitter is not set so that the neutral position has shifted.

(Transmitter setting)

•Set all rudder mixings to INH.

•Set all hovering and flight rudder trims to the same position.

•Set rudder ATV to 100% under all conditions.

•Also set the T9Z condition delay function to INH.

If the normal screen operation mode display is “A” under all usage
conditions, neutral offset is OK. If “ ” is displayed, display “A” by
operating the rudder trimmer for that flight condition.

9 Rudder neutral position check

In the AVCS mode, the rudder servo neutral position is unknown.
Check the neutral position by switching the GY601 to the NOR
mode, or by moving the rudder stick to the left and right at least
three times at high speed and immediately returning the stick to the
neutral position. This temporarily resets the rudder servo.

INSTALLATION AND ADJUSTMENT

Flight Adjustments
1

In the AVCS mode, turn on the transmitter power, then turn on
the gyro and receiver power. This reads the rudder neutral signal at
the GY601.

•Never move the helicopter or rudder stick during the approximately
three seconds that the -Hello- display blinks.

2 Hover in the Normal mode and adjust the rudder neutral position.

•In the AVCS mode, the rudder neutral position is automatically set,
and linkage changes cannot be verified. First, perform rudder neutral
adjustment in the Normal mode.

•Move the transmitter trim lever and reset the neutral position. When
the rudder servo neutral position has changed considerably, readjust
the linkage.

3 When the transmitter rudder trim was adjusted, the rudder neutral

data must be read to the GY601. Therefore, always perform the
following operations:

•Switch the transmitter sensitivity switch quickly (internal of within 1
second) between AVCS and Normal at least three times. "****" is
displayed on the LCD screen to show that data is being memorized.
During this operation, never move the transmitter rudder stick from
the neutral position for at least 1 second immediately after switching
the switch in the state in which the model is on the ground. Memori­zation and updating is executed only when the sensitivity switch is in
the AVCS mode position.

37

4 Set the sensitivity to the position at which hunting does not occur

during hovering and flight.

•When the helicopter tail hunts, set the gyro sensitivity to a lower
value. When adjusting the gyro sensitivity, increase and decrease the
sensitivity gradually while checking.

•When the sensitivity is low even when the gyro sensitivity is 100%,
make the rudder servo horn position longer. The sensitivity can be
increased (up to 120%) at the GY601 gyro gain adjustment screen, or
by increasing the ATV amount of the transmitter sensitivity setting
channel. The actual sensitivity can be checked on the GY601 normal
screen display.

38

INSTALLATION AND ADJUSTMENT

5 Adjust the hovering and flight rudder effect using the transmitter's

D/R or AFR function.

•Do not adjust with the ATV function. If the ATV function is used,
trimming may change.

(If necessary)

6 When you sense a difference in the rudder effect between the

AVCS and Normal modes, adjust using the GY601 rudder control
gain.

•Adjustment method
When the rudder effect in the AVCS is different from the rudder effect
in the Normal mode after adjustment was performed using the
transmitter's D/R or AFR function, adjust the difference using the
NCGx parameter.

7 Adjust the left and right pirouette stopping state by control delay

and tracking.

•Adjustment using the delay function of the T9Z transmitter is also
possible. Since the gyro gain also has a large effect on the stopping
state, make this adjustment after adjusting the sensitivity.

8 Adjust the rudder operation feel using the GY601 AVCS sense in

the AVCS mode.
(Steering angle, neutral suppression, and pirouette stopping)

INSTALLATION AND ADJUSTMENT

9 When you want to use rudder mixing in the Normal mode, set the

transmitter so that rudder mixing is applied only during Normal
mode operation. Never use rudder mixing in the AVCS mode.

39

40

REFERENCE

REFERENCE

Specifications

GY601 Ratings

Yaw-axis stabilizer for helicopter (rate gyro)
Display device: 8-character dot matrix liquid crystal display
Operating voltage range: DC 3.8V to 6.0V
Current drain: 70mA (@5.0V, including sensor)
Dimensions: 57 x 32 x 15mm (amp), 34 x 34 x 18mm (sensor)
Weight: 34g (amp) + 24.5g (sensor)

S9251 Ratings

Dimensions: 40 x 20 x 36.6mm
Weight: 57g
Speed: 0.07sec/60º (at 4.8V)
Torque: 3.7kg-cm (at 4.8V)

* Specifications are subject to change without prior notice.

REFERENCE

Definition of Abbreviations

The following defines the abbreviations and symbols used in this
manual in alphabetical order. The function names are given on the
description pages.

41

3D 3D mode. p19

A
ACGA/B Rudder control gain

(AVCS) p17
AFR AFR function.
ATV ATV function. Steering angle

adjustment function.
AVC AVCS mode.
AVCS AVCS system. AVCS mode.
AVS AVCS sense. p20

C
CMT Normal/AVC switching mode.

D
D1DA Control delay. p17
D1IA Control delay. p17
D/R Dual rate function.
DUO T9Z dual gain control mode.

F
F3C F3C mode. p19
Fmod Flight mode. p19

G
G:1A/NGyro gain 1 side. p16
G:2A/NGyro gain 2 side. p16
GDir Gyro reverse. p16
GYRO T9Z gyro sense mixing.

H
Hello Power on screen display.
High High side.

I
IDLE Transmitter power OFF state.
INH Use inhibited state.

L
LCD Liquid crystal display screen.
LmtA/B Linkage limit setting. p20
Low Low side.
LOW BAT Low battery error

display.

M
Mode Operation mode setting. p18

N
NCGA/B Rudder control gain

(Normal) p17

NOR Normal mode. Normal side.
P

PMIX Programmable mixing.
R

REV Reverse side.
T

Trk Gain tracking. p18

42

REFERENCE

GY601 Parameters Sheet

* Copy and use.

Helicopter:

Date:

Parameter value value Remarks
GDir

Gyro Reverse

G:xx

Gyro Gain Adjustment

ACGx,NCGx

Rudder Control Gain

D11x

Control Delay I

D1Dx

Control Delay D

Initial Set

NOR NOR/REV

G:1 100% 0-120%
G:2 100% 0-120%

ACGA 120% 10-250%
ACGB 120% 10-250%
NCGA 130% 10-250%
NCGB 130% 10-250%

D1IA 0% 0-100%
D1IB 0% 0-100%

D1DA 0% 0-100%
D1DB 0% 0-100%

Trk

Gain Tracking

Mode

Operation Mode Setting

Fmod

Flight Mode

AVS

AVCS Sense

Lmtx

Linkage Limit Setting

+0% -20-+20%

CMT CMT/NOR/AVC

F3C F3C/3D

100% 50-150%

LmtA 100%
LmtB 100%

REFERENCE

43

Makuhari Techno Garden Bldg., B6F 1-3 Nakase, Mihama-ku, Chiba 261-8555, Japan

FUTABA CORPORATION

Phone: [phone] Facsimile: [phone]

©FUTABA CORPORATION 2000, 11