Futaba GY611 User Manual

Page 10

EFORE

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 re-

mains extremely stable even during high-speed reverse ﬂight.
The AVCS system requires a high-precision angular velocity sensor. The

GY611 realizes a high-precision angular velocity detection function and ex-

tremely 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 con-