Futaba GYA431 User Manual

Page 2

LIMIT

GAIN

Servo

Preflight Adjustments

Flight Adjustment

Gyro Sensitivity and AVCS Switching

AVCS / NORMAL Modes

Servo Operation on the Ground

Link the servo in accordance with the kit instruction manual.

Adjust the linkage rod so that the trim amount is as small as pos-

sible.

Digital/Analog servo selection

Selection of an analog and digital servo is performed in a limit

trimmer's setting position.
A limit trimmer's motion is as follows.
Digital servo → A trimmer is adjusted by the Right rotation from

the middle point.
Analog servo → A trimmer is adjusted by the Left rotation from

the middle point.
The amount of limits -- the halfway point -- the minimum -- it will

become the maximum quantity if it is made to rotate to Max, re-

spectively. The check of operational mode is discriminable in the

display color of LED. The stability of digital-servo mode of a flight

increases in order to perform a high-speed control action.

Setup before a flight [ Remote gain use ]

Adjust the gyro sensitivity at the transmitter.

At S.BUS connection or when gyro port 2 and the gyro sensitivity CH

of the receiver are connected

Use the aileron/elevator selector switch to select aileron or

elevator. (Aileron: AIL Elevator: ELE)　　　　

Turn on your transmitter's power. Set the gyro sensitivity to about

50% at the normal side (minus rate side) in accordance with the

transmitter instruction manual. 50% of normal sensitivity will be -70%

at the rate of the sensitivity CH so that a next graph may be seen and

understood.

Turn on the receiver power. When the gyro starts the LED flashes

green and initialization begins. When initialization ends the servo

performs reciprocating operation to the left and right. This places the

Adjust the transmitter and gyro while repeatedly taking off and

landing and with the aircraft on the ground.

Transmitter adjustments must not be made while flying

because it is dangerous.

Fly the aircraft and trim it by turning off the gyro at 0% sensitivity
or in the

NORMAL mode. After trimming, switch the gain switch

between 0% sensitivity (or

NORMAL mode) and the AVCS mode three

times at an interval of within one second and then set the gain switch

to the AVCS mode position. This memorizes the AVCS mode neutral

trim position at the gyro. In the AVCS mode, do not perform trimming
during flight.

Adjust the gyro sensitivity so that hunting (deflection of the

aircraft in small increments) does not occur in the control axis

direction. The gyro sensitivity is different depending on the area of

the aircraft rudder, air speed, and gyro used. Initially try changing

the sensitivity in 5% steps. If hunting is excessive, the aircraft may be
damaged. Hunting tends to stop when the airspeed is lowered.

The gyro has two operation modes: NORMAL mode and AVCS

mode. In the AVCS mode, angle control is performed at the same

time as NORMAL mode rate (rotating speed) control. In the AVCS

mode, the neutral keeping force is stronger than the NORMAL

mode and the flight attitude of the aircraft is forcefully main-

tained. During knife-edge flying, idiosyncrasies of the aircraft

when climbing will be compensated automatically. On the other

hand since the rudder follows when the aircraft stalls, pay spe-

cial attention to the elevator axis. To be safe, switching to the

NORMAL mode when taking off and landing is recommended.

If the stick is moved when the airplane is on the ground, the ser-

vo will move to the limit position. In the AVCS mode, the servo

will not return to the neutral position even if the stick is set to

the neutral position, but this is normal.
If the stick is moved fully to the left or right three or more times

within one second, the servo will temporarily return to the neu-

tral position.

When the remote gain function is used normally and AVCS

mode switching is performed in accordance with the direction

of operation of the transmitter’ s remote gain channel. At the +

rate side, the AVCS mode is selected and at the – rate side, the

NORMAL mode is selected. The sensitivity is changed by adjust-

ing the end point rate. If the transmitter has a gyro sensitivity

setting mixing function, the sensitivity setting is performed di-

rectly.
When the remote gain function is not used, the clockwise di-

rection from the center of the sensitivity setting trimmer is the

AVCS mode (not used) and the counterclockwise direction is the

NORMAL mode. At the center position, the sensitivity becomes

zero. When the trimmer is turned fully to the left or right, the

sensitivity becomes 100%.
The sensitivity setting criteria by end point is shown in the

figure below. The sensitivity becomes zero between end point

-40% to +40% and becomes 100% at end point 100%.

Refer to the transmitter instruction manual and set the end

point. When AVCS is used, setting the 3-positions switch to the

sensitivity CH (there are types which cannot be set by transmit-

ter) and setting it as shown above is recommended. In the case

of a 2-positions switch, inhibiting the gyro at 0% sensitivity such

as NORMAL mode and sensitivity 0% and AVCS mode and 0%

sensitivity is safe.

Trimmer movement when the

remote gain function is not used

(when S.BUS is not used and port

2 is not connected) . Please do not

use AVCS, when you do not use re-

mote gain. Because, neutral memo-

ry cannot be performed. And taking

off and landing being dangerous.

LIMIT

GAIN

Tilt the airplane to the left on

the ground and check that the

ailerons operate to the right. (In

the case of aileron control)

Tilt the airplane to the

left on the ground and

check that the ailerons

operate to the right.

(In the case of aileron

control)

It is good for carrying

out a knife edge.

It is good for carrying

out a beginners and

taking off and landing.

<2nd servo operating direction>

During aileron mode operation

the 2nd aileron servo

moves in the

same direction as the

aileron servo. In the elevator

mode, the 2nd elevator servo

moves in the opposite direc-

tion of the elevator servo.

Mount the servos as left and

right objective linkage.

LIMIT

GAIN

In the case of aileron control, switch the gyro direction switch and

adjust the direction of operation of the gyro so that the ailerons

move all the way to the right when the airplane is tilted to the left.

In the case of elevator control, switch the gyro direction switch and

adjust the direction of operation of the gyro so that the elevator servo

moves in the down direction when the airplane is moved in the up

direction. If the direction of operation of the gyro is incorrect, flight

will become impossible so make the settings positively.

Gyro sensitivity zero --- LED OFF

AVCS side --- LED red

NORMAL side --- LED green

LIMIT

GAIN

＜

A gain trimmer's work ＞

First,we recommend to

start with NORMAL30%.

＜

GAIN CH ＞

LIMIT

GAIN

LIMIT

GAIN

When a remote gain function is off, it becomes only analog servo

mode. A trimmer becomes only for gain.
(Digital-servo use is possible)

*When you use an analog servo, please be sure to set to ana-

log servo mode. If it sets to digital-servo mode and it is op-

erated, there is a danger that a servo will be destroyed.

gyro into the ready state. During initialization secure the fuselage

so that it will not move and fix the transmitter stick at the neutral

position. Initialization takes about 3-5 seconds after the receiver

operates. After initialization the LED lights green. If the neutral

position has changed, the LED will light orange. In this case, restart the
gyro. Move the stick and check that the servo operates.

Move the stick to the maximum left and right and adjust the gyro

limit trimmer so that the servo operating angle is at the

maximum position at which there is no interference with the linkage.

FUTABA CORPORATION

1080 Yabutsuka, Chosei-mura, Chosei-gun, Chiba-ken, 299-4395, Japan

Phone: +81 475 32 6982, Facsimile: +81 475 32 6983

[ When remote gain function is off ]

Adjust the gyro sensitivity with the GYA431 trimmer.
Do not use the AVCS mode.

All remote gains are effective at S.BUS connection. When port 2 is not

connected when S.BUS is not used remote gain is inhibited. In this case,

the limit trimmer is automatically changed to gyro sensitivity setting

trimmer.

(Limit position is fixed at operating angle left and right 55. A servo is

fixed to analog mode.)

In this case,

gain setup with a transmitter and

limit adjustment

of differing in a procedure are lost. And as shown in a figure, gain is

adjusted of the trimmer of GYA431.

● Trimmer operation

*Make trimmer adjust-

ments gently by using the

included mini screwdriver.