G-20
The JR R921 receiver features two types of fail-safe:
SmartSafe and Preset Fail-safe.
SmartSafe
This type of fail-safe is especially ideal for most types of
electric aircraft and is also recommended for most types
of gas- and glow-powered airplanes and helicopters.
Here’s how SmartSafe works.
Receiver Power Only
When the receiver only is turned on (no transmitter signal
is present), all servos except for the throttle are driven to
their preset fail-safe positions, normally control surfaces
at neutral and the landing gear down. These fail-safe
positions are stored in the receiver during binding. At this
time the throttle channel has no output, to avoid operating
or arming the electronic speed control. In glow-powered
models, the throttle servo has no input so it remains in its
current position.
After Connection
When the transmitter is turned on and after the receiver
connects to the transmitter, normal control of all channels
occurs. After the system makes a connection, if loss of
signal occurs, SmartSafe drives the throttle servo only
to its preset fail-safe position (low throttle) that was set
during binding. All other channels hold their last position.
When the signal is regained, the system immediately (less
than 4 ms) regains control.
Preset Fail-Safe
Preset fail-safe is ideal for sailplanes and is preferred by
some modelers for their glow- and gas-powered aircraft.
Receiver Power Only
When the receiver only is turned on (no transmitter signal
is present) all servos except for the throttle are driven to
their preset fail-safe positions, normally control surfaces
at neutral and the landing gear down. These fail-safe
positions are stored in the receiver during binding. At this
time the throttle channel has no output, to avoid operating
or arming the electronic speed control. In glow-powered
models, the throttle servo has no input so it remains in its
current position.
After Connection
When the transmitter is turned on and after the receiver
connects to the transmitter, normal control of all
channels occurs. After the system makes a connection,
if loss of signal occurs preset fail-safe drives all servos
to their preset fail-safe positions. For sailplanes,
it’s recommended that the spoilers/flaps deploy to
de-thermalize the aircraft, preventing a flyaway. Some
powered modelers prefer to use this fail-safe system to
program a slight turn and low throttle to prevent their
aircraft from flying away. When the signal is regained, the
system immediately (in less than 4 ms regains control).
Programming SmartSafe
(All Spektrum Aircraft Receivers)
During the binding process the bind plug is left in
throughout the process and is removed only after the
receiver connects to the transmitter. After the connection
is made, confirmed by operating the servos, the bind plug
can be removed. The receiver is now programmed for
SmartSafe.
Fail-Safe Functions
