Futaba GYA440 Rate Gyro for Airplanes

Features of GYA440

• Dedicated airplane setting
• Compatible with elevator or rudder control
• Remote gain function: Trimmer (Limit/GAIN) (Digital/Analog servo function)
• Monitor LED
• Elevator/Rudder selector switch
• Port 1 (S.BUS input/Elevator/Rudder servo input)
• Port 2 (Gyro sensitivity input)
• Port 3 (Elevator/Rudder servo output)
• Gyro direction switch
• Integrated type, compact size and light weight
• Easy setup
• Supporting the S.BUS/S.BUS2 connection

Set Contents

• GYA440
• Mini screwdriver
• Extension cord: (Black)
• Sensor tape
• Accessory connector (Red)
• Magic strap (for clamping the wiring)

Connection

S.BUS Connection

S.BUS connectivity minimizes wiring. The GYA440 and GYA441 can be connected by one 3-way hub. The aileron, elevator, and rudder servos are output from the gyro. Standard servos can also be used.

When an R6303SB is used, the CH switching mode is set to group 7. The normal group 7 CH outputs are CH3, CH11, and CH12. CH3 is the throttle channel and CH11/CH12 are spare channels.

The transmitter function settings are shown below. A total of 9 channels are used with 3-axes gyro control.

S.BUS 3-axes Connection Example

This is a three axes connection example. The aileron uses a GYA441 and the receiver is an R6303SB.

At S.BUS/S.BUS2 operation, the channels are fixed as shown in the table below. Match the transmitter channels to these.

Mounting to the Chassis

The gyro is very sensitive to vibration. Securely mount it with the included double-sided sponge tape at a position where vibration is minimal and the gyro is perpendicular to the axis to be controlled. Since double-sided tape will not stick to balsa, make a smooth surface by cementing a smooth plastic sheet to the frame and securely attach the gyro with double-sided tape. Provide a surplus in the wiring and bundle the wiring with the included magic strap so that it will not interfere with the rod.

The turning direction which fixes the gyro can be any direction up to 360° relative to the pitch axis.

Diagram Description:

• Elevator Mounting: Shows the GYA440 mounted to the elevator control surface. The gyro is positioned perpendicular to the elevator's axis of rotation.
• Rudder Mounting: Shows the GYA440 mounted to the rudder control surface. The gyro is positioned perpendicular to the rudder's axis of rotation.
• Sensor Tape Application: Illustrates degreasing a flat surface of the fuselage and applying the sensor tape. Notes that sensor tape does not stick to balsa.

Name and Function of Each Part

• Port 1 (S.BUS input/Elevator/Rudder servo input): Connects to the receiver's S.BUS port or directly to the elevator/rudder servo.
• Port 2 (Gyro sensitivity input): Connects to the receiver's gyro gain channel for remote gain adjustment.
• Port 3 (Elevator/Rudder servo output): Connects to the elevator or rudder servo.
• Elevator/Rudder selector switch: Selects whether the gyro controls the elevator or rudder.
• Gyro direction switch: Reverses the direction of gyro correction.
• Trimmer (Limit/GAIN): Adjusts the servo limit or gyro gain depending on the connection and mode.
• Monitor LED: Indicates the operating status of the gyro.

Preflight Adjustments

Setup before a flight [Remote gain use]

1. Adjust the gyro sensitivity at the transmitter. Use the Elevator/Rudder selector switch to select elevator or rudder (ELE/RUD).
2. Turn on your transmitter's power. Set the gyro sensitivity to about 30% at the normal side (minus rate side) in accordance with the transmitter instruction manual.
3. Turn on the receiver power. The LED will flash green during initialization (approx. 3-5 seconds). Once initialized, the servo will perform a slight reciprocating operation. If the neutral position has changed, the LED will slowly blink orange; restart the gyro. Move the stick and check servo operation.
4. Move the stick to the maximum left and right. Adjust the gyro limit trimmer so that the servo operating angle is at the maximum position without linkage interference.
5. Trimmer Operation: Make trimmer adjustments gently using the included mini screwdriver. Adjust to the maximum operation of the linkage.

Gyro sensitivity and AVCS Switch

When the remote gain function is used, AVCS mode is selected at the + rate side and NORMAL mode at the - rate side of the transmitter's remote gain channel. Sensitivity is adjusted by the endpoint rate. If the transmitter has a gyro sensitivity setting mixing function, sensitivity is set directly.

When the remote gain function is not used, the clockwise direction from the center of the sensitivity setting trimmer is AVCS mode, and counterclockwise is NORMAL mode. At the center, sensitivity is zero. Sensitivity becomes 100% at the full extent of the trimmer.

Sensitivity Setting Criteria (End Point):

• Sensitivity is zero between -40% to +40% endpoint rate.
• Sensitivity becomes 50% at +70% endpoint rate.
• Sensitivity becomes 100% at +100% endpoint rate.

AVCS/NORMAL Modes:

• AVCS Mode (LED: RED): Performs angle control simultaneously with rate control. Offers stronger neutral keeping and forcefully maintains flight attitude. Recommended for situations like knife-edge flying.
• NORMAL Mode (LED: GREEN): Performs rate (rotating speed) control. Switching to NORMAL mode is recommended for takeoff and landing.

Trimmer Movement (Remote Gain Function Not Used):

• AVCS 50%
• AVCS 100%
• 0%
• NORMAL 50%
• NORMAL 100%

Recommendation: When using AVCS, set the sensitivity CH to a 3-position switch. If using a 2-position switch, ensure 0% sensitivity (NORMAL mode) and 0% sensitivity (AVCS mode) are set to inhibit the gyro.

[When remote gain function is off]

Adjust the gyro sensitivity with the GYA440 trimmer. Do not use AVCS mode. Remote gain is inhibited if Port 2 is not connected. In this case, the limit trimmer functions as the gyro sensitivity setting trimmer. The servo is fixed to analog mode.

Diagram Description: Shows trimmer adjustments for gain.

Flight Adjustment

Adjust the transmitter and gyro while repeatedly taking off and landing, or with the aircraft on the ground. Transmitter adjustments must not be made while flying.

1. Fly the aircraft and trim it by turning off the gyro (0% sensitivity or NORMAL mode). Switch the gain switch between 0% sensitivity (or NORMAL mode) and AVCS mode three times within one second. Set the gain switch to AVCS mode. This memorizes the AVCS mode neutral trim position. Do not perform trimming during flight in AVCS mode.
2. Adjust the gyro sensitivity to prevent hunting (small, rapid movements of the aircraft in the control axis direction). Adjust sensitivity in 5% steps. Excessive hunting can damage the aircraft. Hunting tends to stop when airspeed is lowered.

Servo Operation on the Ground

When the stick is moved while the airplane is on the ground, the servo will move to the limit position. In AVCS mode, the servo will not return to neutral even if the stick is at neutral, which is normal. If the stick is moved fully left or right three or more times within one second, the servo will temporarily return to the neutral position.

GYA440 Ratings

• Gyro sensor: MEMS vibrating structure gyro
• Operating voltage: DC4.0V to 8.4V
• Current drain: 30mA (excluding a servo)
• Operating temperature range: -10ºC to +45ºC
• Dimensions: 20.5 x 20.5 x 11.0mm (except protrusion)
• Weight: 3.7g
• Functions: (1) Gyro sensitivity trimmer, (2) Monitor LED, (3) CH change elevator or rudder, (4) S.BUS/S.BUS2 compatibility, (5) Digital/Analog servo function

Monitor LED Display

Warnings

• Failure to follow these safety precautions may result in severe injury to yourself and others.
• Check that there is sufficient transmitter battery capacity for flight.
• Determine the operating time of the receiver, gyro, and servo battery in advance.
• Analog servos cannot be used while in "digital servo" mode.
• Do not operate the airplane and transmitter sticks for about 3-5 seconds after turning on the GYA440 (When shared with the receiver).
• Always check the direction of operation of the gyro by moving the servo to the left and right (a little).
• Do not strike the gyro with a hard object. Do not drop it onto a concrete surface or other hard floor. The sensor may become damaged during strong impacts.
• Do not use trims or mixing in AVCS mode. In the AVCS mode, all corrections are made by the gyro. Therefore, if trimming and mixing are used, it may cause unexpected operation.
• Do not use the GYA440 for applications other than RC airplanes. This gyro is designed for RC airplanes only.
• Do not place gyro near heating equipment (engine, motor, ESC, battery, servo, etc.). The gyro is sensitive to heat and may cause operational issues.

Servo Adjustments

Digital/Analog servo selection

Selection of an analog and digital servo is performed by the limit trimmer's setting position.

• Digital servo: Trimmer adjusted by right rotation from the middle point.
• Analog servo: Trimmer adjusted by left rotation from the middle point.

The LED display color indicates the operational mode. Digital-servo mode increases flight stability for high-speed control actions.

Diagram Description: Shows trimmer positions for digital and analog servo selection, with corresponding LED colors (Orange for Digital, Green for Analog).

Preflight Adjustments [Remote gain use]

1. Adjust the gyro sensitivity at the transmitter. Use the Elevator/Rudder selector switch to select elevator or rudder.
2. Turn on transmitter power. Set gyro sensitivity to approx. 30% on the normal side (minus rate side).
3. Turn on receiver power. Wait for initialization (LED flashes green). Servo performs slight reciprocating motion upon completion. If neutral position changes, LED blinks orange; restart gyro. Move stick and check servo operation.
4. Move stick to maximum left and right. Adjust gyro limit trimmer for maximum servo operating angle without linkage interference.

[When remote gain function is off]

Adjust gyro sensitivity with the GYA440 trimmer. Do not use AVCS mode. Remote gain is inhibited if Port 2 is not connected. The limit trimmer automatically changes to gyro sensitivity setting trimmer. Servo is fixed to analog mode.

Diagram Description: Shows trimmer adjustments for gain when remote gain is off.

Gyro Sensitivity and AVCS Switching

When remote gain is used, AVCS mode is selected at the + rate side and NORMAL mode at the - rate side of the transmitter's remote gain channel. Sensitivity is adjusted by endpoint rate.

When remote gain is not used, clockwise from the center of the sensitivity trimmer is AVCS mode, counterclockwise is NORMAL mode. Sensitivity is zero at the center.

Sensitivity Setting Criteria: Sensitivity is zero between -40% to +40% endpoint rate, 50% at +70%, and 100% at +100%.

AVCS/NORMAL Modes: AVCS mode provides stronger neutral keeping and maintains flight attitude. NORMAL mode provides rate control. Switching to NORMAL mode for takeoff and landing is recommended.

Diagram Description: Illustrates sensitivity settings based on endpoint rates and shows the difference between AVCS and NORMAL modes in crosswind conditions.

Flight Adjustment

1. Trim the aircraft with the gyro off (0% sensitivity or NORMAL mode). Switch the gain switch between 0% and AVCS mode three times within one second. Set to AVCS mode to memorize the neutral trim position. Do not trim in AVCS mode during flight.
2. Adjust gyro sensitivity to prevent hunting. Adjust in 5% steps.

Futaba Corporation Contact Information

FUTABA CORPORATION
3-4 Kandakajicho, Chiyoda-ku, Tokyo 101-0045, Japan
TEL: +81-3-4316-4820, FAX: +81-3-4316-4823

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