AVCS GYRO

INSTRUCTION MANUAL
YAW-AXIS STABILIZER FOR MODEL HELICOPTER (RATE GYRO)

1M23N04302

Thank you for buying a GY501 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 Up to now, movement of the tail from side to side due to changes in the wind, flight posture, and other disturbances during model helicopter flights was minimized by increasing the sensitivity of the gyro. However, a bad effect is that the sensitivity may be increased too much so there was a limit on how much the tail could be controlled. Changes in F3C rules add forward and reverse flight aerobatics and demand various flight positions so that controlling the position of the tail has become more difficult. The GY501 gyro uses the Futaba AVCS system and makes it possible to theoretically correct this movement. This increases stabilization of the tail against disturbances. Since F3C contest fliers who use the GY501 gyro together with a high response servo, of course, achieve high stability against wind and other disturbances, it has a large effect also for helicopter novices.
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 -------------------------------- 6 - Setting Precautions -------------------------------------------- 7 - Operating Precautions ----------------------------------------- 8 - Fuselage Maintenance Precautions ------------------------- 10 BEFORE USE - Set Contents --------------------------------------------------- 11 - Name and Function of Each Part --------------------------- 12 - Description of GY501 Operation --------------------------- 13
ASSEMBLY AND ADJUSTMENT - Connections --------------------------------------------------- 29 - Mounting the Gyro Sensor ---------------------------------- 30 - Use -------------------------------------------------------------- 31
DATA SETTING - LCD Display and Edit Keys --------------------------------- 36 - Function Map -------------------------------------------------- 37 - Setting of Each Function ------------------------------------ 38
REFERENCE - Specifications ------------------------------------------------- 43 - Definition of Abbreviations --------------------------------- 44 - GY501 Parameters Sheet ------------------------------------ 45 - Repair Service ------------------------------------------------- 46

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 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. Symbol: ; Prohibited

; Mandatory

Setting Precautions
Connector Connection Insert the connectors fully and firmly. If vibration, etc. causes a connector to work loose during flight, the heli may crash.
Precautions When Turning on the Power Switch During initialization, the message **INIT* appears on the GY501 LCD screen. Do not move the helicopter until this message disappears (in about 5 seconds). Also, do not move the transmitter rudder stick from the neutral position during this period. Sensor Mounting Always use the attached sensor tape to mount the gyro sensor. Always reinstall the sensor tape if it has started to separate or tear. Do not get fuel, waste oil, etc. on the gyro sensor. The special paint may dissolve.
At linkage 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 with the transmitter in the ON state. This memorizes the new rudder position inside the GY501.

Operating Precautions

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.
FOR SAFETY Check the remaining receiver and 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 GY501 in the AVCS mode, set revolution mixing to OFF.
Fuselage Maintenance Precautions
Mounting 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. 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.

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

[GY501 Settings]

Select the gyro operation mode at the GY501 Mode screen. (AVC, NOR, or CMT)

[Transmitter Settings]

ATV function: Adjust both the RATE A and RATE B rates to 100% at the transmitter 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 GY501 G:1 and G:2 screen. The following shows the relationship between transmitter and gyro setting when GY501 sensitivity setting is 100% in both the G1 and G2 gain modes.
- Relationship between transmitter and gyro setting
Transmitter settings GY501mode settings GAIN1 GAIN2 NOR AVC CMT 0% 50% 100%
Normal mode AVCS mode Normal mode AVCS mode (G2) (G1) 100% 0% 100%

Actual gain

BEFORE USE (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 01. MODEL-01. NORML HEL : MODE PCM 0: 23: 17

85 % 15 %

: GAIN 1 : GAIN 2
Sensitivity rate Choose the GAIN1 or GAIN2 by the CH5 switch. Use the following values as the sensitivity setting standard:

CH5 switch Hovering

GAIN1 setting GAIN2 setting 85%

Flight

70% AVCS side

Normal side

The GY501 sensitivity is 0% at 50%. When set over 50%, the GY501 operates in the AVCS mode and when set under 50%, the GY501 operates in the Normal mode. When setting is changed 1%, the gyro sensitivity is changed 2%.
BEFORE USE When Using a T9Z Transmitter Programmable Mixing

The Programmable Mixing (PMX) function lets operator perform a gain adjustment at each condition. Set the sensitivity at all conditions.
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.)
Transmitter settings GY501mode settings NOR AVC CMT -100% 0% +100%
Normal mode AVCS mode Normal mode AVCS mode (G2) (G1) 0% 100%

Actual gain 100%

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

01. MODEL-01. NORML HEL PCM ****** 0: 23: 17 ACTIVE : MODE ( ON) : MASTER GYR OFS : SLAVE : MIX TYPE TRIM:

MSTR MIX MODE: ******

SWT NXT END

LIN OFS HOV

Select the GYR.

Select the OFS.

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

+ 70 %

: RATE
Sensitivity rate Use the following values as the sensitivity setting standard: Hovering AVCS mode Normal mode Actual gain

+70% -70% 70%

+40% -40% 40%
When set over 0%, the GY501 operates in the AVCS mode and when set under 0%, the GY501 operates in the Normal mode.
BEFORE USE When Using a T8Usuper Transmitter
The Gyro Mixing (GYRO) function lets operator perform a gain adjustment at each Idle-Up switch position.
Gyro Mixing function: 1. Select the ON mode at the transmitter Gyro Mixing (GYRO) setup screen. 2. Select the Idle-Up switch for the sensitivity selection. 3. Set the NORM, IDL1 and IDL2 gains. (The following page shows a setting example in the CMT mode.)
Transmitter settings GY501mode settings NORM IDL1 IDL2 NOR AVC CMT 0% 50% 100%
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.

Switch position

Sensitivity rate

Set the NORM, IDL1 and IDL2 gains at each setup screen. Use the following values as the sensitivity setting standard:
Hovering AVCS mode Normal mode Actual gain

85% 15% 70%

70% 30% 40%
When set over 50%, the GY501 operates in the AVCS mode and when set under 50%, the GY501 operates in the Normal mode.
BEFORE USE When Using a Transmitter ATV Function
The ATV function lets operator perform a gain adjustment at each CH5 switch position.
ATV function: Set the ATV rates at the transmitter CH5 ATV function.
Transmitter ATV rates settings GY501mode settings NOR AVC CMT CH5 Switch CH5 Switch Forward side Front side 90% 0% 90% Normal mode Normal mode AVCS mode AVCS mode Normal mode AVCS mode (G2) (G1) 0% 100%
BEFORE USE When Using a GY501 Gyro Gain Adjustment Function
Adjust both the ATV rates to 90% at the transmitter Ch5 ATV function.
Operation Mode Setting function: Select the gyro operation mode at the GY501 Mode screen. (AVC, NOR, or CMT) Gyro Gain Adjustment function: Set the G:1 and G:2 gains at the GY501 G:x screen.
Transmitter ATV rates settings GY501mode settings NOR AVC CMT CH5 Switch CH5 Switch Forward side Front side 90% (Fixed) 90% (Fixed) Normal mode Normal mode AVCS mode AVCS mode Normal mode AVCS mode (G2) (G1) 0% 100%
BEFORE USE Initialization When the power switch is turned on, the GY501 automatically obtains the reference signal for AVCS function correction and initializes itself.
Precautions When Turning on the Power Switch During initialization, the message **INIT* appears on the GY501 LCD screen. Do not move the helicopter until this message disappears (in about 5 seconds). Also, do not move the transmitter rudder stick from the neutral position during this period.
BEFORE USE AVCS Mode Rudder Trim Reset Function When the GY501 is used in the AVCS mode only, the AVCS function automatically detects the rudder neutral position and rudder trim is essentially unnecessary. However, when the GY501 is used in the Normal mode, the neutral position is set by conventional rudder trimming. In the AVCS mode, the rudder stick position when the power was turned on is memorized as the neutral position and when the rudder is trimmed during flight, the neutral position will change. In the normal mode, when the rudder neutral position was reset, and the GY501 was switched to the AVCS mode in this state, the neutral position will change. To correct the difference in the neutral position in the Normal mode and the AVCS mode, the GY501 reads the rudder signal at the point at which it was switched from the Normal mode to the AVCS mode as the neutral reference point. Therefore, when switching the GY501 from the Normal mode to the AVCS mode, the following precautions are necessary: [At power ON] - When the power was turned on in the Normal mode, the rudder neutral position already memorized in the GY501 is used. - When the power was turned on in the AVCS mode, the rudder signal at that point is memorized and updated. [During use] - When using the GY501 in the AVCS mode, set revolution mixing to OFF. - When the rudder was re-trimmed in the Normal mode and the new trim position also affects the AVC mode, the rudder trim neutral position must be memorized in the GY501. 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 at

BEFORE USE the neutral trim position set in the Normal mode. This memorizes the new rudder neutral position in the GY501. 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. Note: The rudder neutral position is memorized inside the GY501. 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 with the transmitter in the ON state. This memorizes the new rudder position inside the GY501.
BEFORE USE 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.

Drifting stop

Forward

Side wind

BEFORE USE 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 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 GY501 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.

ASSEMBLY AND ADJUSTMENT

Connections

Gyro Sensor (GYRO)

Rudder Servo (SX)

Rudder Channel (RX.1-4)

Remote Gain Input (RX.AUX)
Connect to receiver sensitivity setting channel (normally ch5).

Mounting the Gyro Sensor

The gyro sensor is extremely sensitive to vibrations. Always use the attached sensor tape to mount the gyro sensor. Stick the sensor tape to the center of bottom of the sensor and firmly stick the sensor to a flat part of the helicopter frame so that it does not touch the frame. Mount the sensor so that the bottom of the sensor is level with the rotating surface of the tail.
Gyro Sensor Sensor Tape Flat part
Always use the attached sensor tape to mount the gyro sensor. Always reinstall the sensor tape if it has started to separate or tear. Do not get fuel, waste oil, etc. on the gyro sensor. The special paint may dissolve.
The following describes basic use of the GY501. Note that in the AVCS mode, operation is somewhat different than that of a conventional gyro. Initial setting 1) Set the gyro operating direction at the GDir screen.
(See page 39 for setting method)
2) Set the servo operation limit range at the Lmtx screen.
(See page 42 for setting method) - Adjust the servo travel so that it is within the linkage range.
3) Set the gyro operation mode at the Mode screen.
(See page 42 for setting method) - To use the GY501 in the Normal mode only, set to "Nor". To use the GY501 in the AVCS mode only, set to "AVC". When switching between the AVCS mode and Normal mode, set to "CMT". - When using the GY501 in the "CMT" mode, the AVCS and Normal mode sensitivities must be set while hovering and during flight. Therefore, a transmitter (T9Z, T8UHsuper, etc.) with a gyro mixing function is necessary.
The following shows how to use the GY501 in the CMT mode. 4) Adjust the gyro gain.
(See page 39 for setting method) - The GY501 initial sensitivity is 100% for both the G1 and G2 gains.
ASSEMBLY AND ADJUSTMENT When using a T9Z transmitter, set the sensitivity at the transmitter without changing the 100% reference value. Use the following values as the sensitivity setting standard:
- Call the T9Z GYR setup screen. - Adjust the sensitivity when hovering to 85% at the AVCS side and 15% at the normal side. - Set the sensitivity during flight to 70% and 30% in the AVCS and normal modes, respectively. - At this time, 70% is displayed on the GY501 sensitivity display when hovering and 40% is displayed on the GY501 sensitivity display during flight. *1: The GY501 sensitivity becomes 0% at 50%. When set over 50%, the GY501 operates in the AVCS mode and when set under 50%, the GY501 operates in the Normal mode. When setting is changed 1%, the gyro sensitivity is changed 2%.

When using a transmitter that does not have a gyro sensitivity switching function, connect the sensitivity setting connector to a vacant channel and display the GY501 sensitivity setup screen and set the G1 and G2 gains. Sensitivity can also be fine adjusted using the transmitter ATV function. 5) Check the transmitter settings in the AVCS mode.
- Set all the rudder mixing functions to INH. - Set the hovering and flight rudder trimmers to the same position. - Make the rudder ATV 100% at all conditions. - Set the T9Z condition delay function to INH.
ASSEMBLY AND ADJUSTMENT Flight Adjustments 1) Turn on the transmitter power, then turn on the receiver power.
- Never move the model or rudder stick during the 5 seconds the "INIT" 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 GY501. Therefore, always perform the followingoperations:
- 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.
4) Set the sensitivity to the position at which hunting does not occur during hovering and flight.
- In the AVCS mode, when the sensitivity is lower than the suitable sensitivity, operation that resembles conventional hunting or operation that seems to be the opposite of operation of a conventional gyro, such as a slight drifting of the tail when the sensitivity is high may occur. Therefore, use a method that finds the suitable value by checking neutral suppression and pirouette stopping by raising and lowering the sensitivity.

ASSEMBLY 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 GY501 rudder control linkage.
(See page 40 for setting method) - 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 andtracking.
(See page 40 for setting method) (See page 41 for setting method)
- 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) 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.

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.
Low Battery Alarm When the power supply voltage drops to 3.8V, "LOW Batt" is displayed. When this message is displayed, quickly stop operation and charge the Nicd battery.

Function Map

Power ON
Initial screen at power on (P38)
Power supply voltage display (P38)

FUNC - key

FUNC + key
Gyro Gain Adjustment (P39) Gyro Reverse (P39) Rudder Control Gain (P40) Control Delay (P40) Gain Tracking (P41) Servo Frame Rate (P41) Operation Mode Setting (P42) Linkage Limit Setting (P40)

Setting of Each Function

Initial screen at power on
This is the initial screen at power on. When the transmitter power is off, "*IDLE**" is displayed until the transmitter power is turned on. After the transmitter power is turned on, "*INIT***" blinks for about 5 seconds to read the reference data. During this period, do not move the transmitter rudder stick or the helicopter. If the transmitter rudder stick or helicopter is moved by mistake, the rudder neutral position will change.
Operation screen display / Power supply voltage display Normal mode operation Low battery alarm Rudderneutralmemorizationupdating AVCS mode operation Rudder neutral deviation display
DATA SETTING Displays the receiver power supply voltage.When the voltage drops to 3.8V, "LOW BAT" is displayed. In the AVCS mode, "A" is displayed. When the rudder neutral full reset operation was performed, the "****" mark, which indicates execution, is displayed. In the AVCS mode, when there is a difference between the transmitter rudder neutral position and the GY501 neutral data, the " " mark is displayed.

Gyro Gain Adjustment

Initial value: 100%
Performs gyro sensitivity adjustment. Two-point gain adjustment is possible. The setting range is 0 to 100%. When "A: or "N" is displayed in accordance with operation mode setting, the GY501 operates in the AVC mode and Normal mode, respectively. The gain display indicates the actual gain, and changes with transmitter remotegainadjustment.

Gyro Reverse

Initial value: NOR
Sets the direction of operation of the gyro.
DATA SETTING Rudder Control Gain
Initial value: ACG:100%, NCG:100%
Sets the rudder stick operation gain. The gain can be set independently for the AVCS mode and Normal mode. When the operation mode is AVCS, "ACGX" is displayed. In the Normal mode, "NCGX" is displayed. The display is automatically changed to "A" or "B" depending on the direction of the rudder stick. The gain of the set direction can be set. This setting is used in tracking the rudder operation sensitivity between the AVCS and Normal modes. The setting range is 30% to 200%.

Control Delay

Initial value: 0%
Sets the rudder stick operation delay. The delay amount can be set independently for left and right operation of the rudder stick. Adjust by checking the left and right directions pirouette stopping state. For instance, when pirouette stopping resembles hunting, increase the CDI of that direction. On the other hand, to stop drifting, decrease CDI. The setting range is 0 to 100%.
DATA SETTING Gain Tracking

Initial value: +0%

Adjusts left and right tail stopping. It is used at 0% as standard, but use this adjustment when pirouette stopping cannot be adjusted using the CDI parameter. For example, when pirouette stopping resembles hunting, or right turn pirouette stopping drifts, shift Trk in the + direction. In the reverse case, shift Trk in the - direction. If Trk is large, a left and right pirouette speed difference will be produced. Therefore, adjust gain tracking with the smallest possible value. The setting range is -20% to +20%.

Servo Frame Rate

Sets the servo output frame rate. The transmitter frame rate (Nor) or 1/2 the transmitter frame rate (High) can be set. Normally, use at "Nor".
DATA SETTING Operation Mode Setting

Initial value: CMT

Sets the gyro operation mode. In the "NOR" mode, both G1 and G2 operate in the Normal mode. In the "AVC" 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 Normal mode. In the "Nor" mode, the GY501 operates the same as conventional gyros. In the "AVC" mode, the GY501 always operates in the AVCS mode. In the "CMT" mode, the GY501 can be used in both the AVCS and Normal modes.

Linkage Limit Setting

Sets the rudder servo travel limit. The linkage limit can be adjusted by pressing the + and - keys so that the rudder stick is operated and the servo operates up to the maximum linkage position. When setting, rudder ATV automatically becomes 200% and the servo deflection becomes large so that limit setting can be easily performed. A or B is displayed depending on the right or left direction.

REFERENCE

Specifications
* Specifications are subject to change without prior notice.
GY501 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: 60mA (@4.8V, including sensor) Operating temperature range: -10 to +50 degree C Operating humidity range: 10 to 90%RH (no condensation) Dimensions: 56.5 x 30.5 x 16mm (body) Weight: 34g (body) + 55g (sensor)
S9205 Ratings Speed: 0.11sec/60degree (@4.8V) Torque: 5.5kg-cm (@4.8V) Dimensions: 40.5 x 20 x 37.5mm Weight: 53g

Definition of Abbreviations
The following defines the abbreviations and symbols used in this manual in alphabetical order. The function names are given on the descriptionpages.
A ACGA/B Rudder control gain (AVCS) p40 AFR AFR function. ATV ATV function. Steering angle adjustment function. AVC AVCS mode. AVCS AVCS system. AVCS mode. C CD1A/B Control delay. p40 CMT Normal/AVC switching mode. D D/R DUO F Frm Dual rate function. T9Z dual gain control mode. Servo frame rate. p41 I IDLE INH INIT
Transmitter power OFF state. p38 Use inhibited state. Initialize. Initialization. p38
L LCD Liquid crystal display screen. LmtA/B Linkage limit setting. p42 LOW BAT Low battery error display. p38 M Mode Operation mode setting. p42
N NCGA/B Rudder control gain (Normal) p40 NOR Normal mode. Normal side. P PMIX R REV T Trk Programmable mixing. Reverse side. Tracking. p41
G G:1A/N Gyro gain 1 side. p39 G:2A/N Gyro gain 2 side. p39 GDir Gyro reverse. p39 GYRO T9Z gyro sense mixing. H High High side (frame rate 1/2 side).

GY501 Parameters Sheet

* Copy and use.
Helicopter: Date: Parameter G:xx
Gyro Gain Adjustment G:1 G:2

Initial value

100% 100%

Set value

Remarks

0-100% 0-100%

NOR ACGA ACGB NCGA NCGB CD1A CD1B 100% 100% 100% 100% 0% 0%
NOR/REV 30-200% 30-200% 30-200% 30-200% 0-100% 0-100%

ACGx,NCGx

Rudder Control Gain

Gain Tracking

-20-+20%

NOR/High

Operation Mode Setting

CMT/NOR/AVC

LmtA LmtB

Repair Service

Before requesting repair, read this instruction manual again and recheck your system. Should the problem continue, request repair service as follows: Describe the problem in as much detail as possible and send it with a detailed packing list together with the parts that require service.
Symptom (Including when the problem occurred) System(Transmitter, Receiver, Servo's and model numbers) Model (Model name) Model Numbers and Quantity Your Name, Address, and Telephone Number. Dated Proof of Purchase (For Warranty Claims)
Please read the warranty card supplied with your system. When requesting warranty, please send the card along with some type of dated proof of purchase. If you have any questions regarding this product, please consult your local hobby dealer or contact the Futaba Service Center. The address and telephone number are listed below. (For U.S.A.) (Telephone inquiries are accepted from 8:30 AM to 5:00 PM PST daily, except on Saturday, Sunday and Holidays.) Address(For U.S.A.) Futaba Corp. of America 4Studebaker Irvine, CA 92618 (949) 455-9888