B) Speed-Dependent Gain Control; C) Using The Flight Modes - PowerBox Systems Royal SRS Instruction Manual

b) Speed-dependent gain control

The PowerBox Royal SRS can be connected to an optional GPS sensor with the purpose of passing
speed data to the gyro.
The GPS Sensor supplies data regarding the model's speed to the iGyro at a rate of twice per se-
cond. This allows the gyro to adjust its gain constantly to suit the actual flying speed; an effect which
is particularly important when you are flying a model with a very broad speed range.
Gyro systems which are not speed-compensated in this way can only be set to a low gain setting,
because the model would otherwise tend to oscillate at high-speed. Reducing the gain to overcome
this problem reduces the gyro's stabilising effect at low speed, e.g. on the landing approach. Ho-
wever, fixed-wing model aircraft are particularly susceptible to gusts of wind and propeller torque
effects at low speed, so high gyro gain is desirable for precisely this reason.
The effect of the GPS sensor can be adjusted to any of six levels for each axis, so that maximum
gyro effect can be obtained in fast and slow flight alike.
Note: the GPS unit designed for use with the iGyro is also capable of detecting vertical
airspeed, which prevents the model oscillating even when the model is in a dive. The only fac-
tor which the GPS system cannot take into account when calculating the model's actual speed
is headwind and tailwind. However, that has such a small influence on the model's stability that
it can be neglected - even in very windy conditions.
If the GPS sensor briefly has poor or no reception during a flight, gyro gain is automatically reduced
to the minimum set value; this prevents the model oscillating regardless of its momentary speed.
In any case, the iGyro is capable of compensating for external influences on the model even when
gyro gain is set to a low value. GPS reception problems are rare, but in any case they are usually of
very brief duration, and are generally not even noticed when the model is flying.
The GPS Sensor does not require any particular orientation or position in the model. It can simply
be mounted using the double-sided adhesive tape supplied in the set. The location should not be
subject to vibration, and to ensure optimum reception the sensor must not be shielded by carbon
fibre or metallic parts in any direction.

c) Using the flight modes

The Flight Mode function can be assigned to any channel you wish, and gives the pilot the ability
to activate any of three different gyro settings for particular flight manoeuvres. The gyro is always
switched off in Flight Mode 1: control signals are passed 1 : 1 to the servo outputs. Naturally the Delta
or V-tail mixer remains active if that function is switched on.
The pilot is free to configure Flight Modes 2 and 3 in any way he wishes. In most cases the flight
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As can be seen from the diagram, gyro gain is sup-
pressed proportionally with increasing stick travel.
This reduces the tendency for the iGyro to counter-
act intentional control commands.
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