The DSX9 and RD921 are capable of 2 different types of Failsafe.

SmartSafe Failsafe

The RD921 features a SmartSafe failsafe option.  With SmartSafe, when signal is lost the throttle channel only is driven to its preset failsafe position (normally low throttle) while all other channels hold last command. Here’s how SmartSafe works:

Receiver power only
When the receiver only is turned on (no transmitter signal is present), all servos except for throttle are driven to their preset failsafe positions, normally control surfaces at neutral and the landing gear down. These failsafe 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 signal 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 failsafe position (low throttle) that was set during binding. All other channels hold their last commanded position. When the signal is regained, the system immediately (less than 4ms) regains control.

SmartSafe:

• Prevents unintentional electric motor response on start-up.

• Eliminates the possibility of over-driving servos on start-up by storing preset failsafe
positions.

• Establishes low-throttle failsafe and maintains last-commanded control surface position
if the RF signal is lost.

Note: Failsafe positions are stored via the stick and switch positions on the transmitter during binding.

 

Preset Failsafe

With Preset Failsafe, if the signal is lost all channels are driven to their preset failsafe positions. Here’s how Preset Failsafe works:

Receiver power only
When the receiver only is turned on (no transmitter signal is present), all servos except for throttle are driven to their preset failsafe positions, normally control surfaces at neutral and the landing gear down. These failsafe 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 signal 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 Failsafe drives all servos to their preset failsafe positions that were set during binding. When the signal is regained, the system immediately (less than 4ms) regains control.

Preset Failsafe:

• Prevents unintentional electric motor response on start-up.

• Eliminates the possibility of over-driving servos on start-up by storing preset failsafe positions.

• Establishes preset failsafe servo positions for all channels if the signal is lost.

Note: Failsafe positions are stored via the stick and switch positions.

Setting SMARTSAFE

During the binding process, the bind plug is left in throughout the process and is only removed after the receiver connects to the transmitter. Once the connection is made (confirmed by operating the servos), the bind plug can be removed and safely stored. The receiver is now programmed for Smartsafe.

Setting PRESET FAILSAFE

During the bind process, the bind plug is inserted into the bind port (or in the charge jack) and then the receiver is powered up. The LED's in each receiver should blink indicating that the receiver is in bind mode. Before the receiver is bound to the transmitter, remove the bind plug, adjust the stick (and switch) positions of the transmitter to their failsafe positions. Press the bind button on the rear of the transmitter and power the DSX9 on. The system should connect within 15 seconds and the receiver is now programmed with the new preset failsafe positions.

 

ALWAYS test the failsafes before proceeding to fly !

If you have a twin engine system where the 2nd engine is on the AUX1 port (for example) then if using SMARTSAFE, then in the event of a lost signal your aircraft will only cut the single throttle !

Therefore if using a twin system, use the PRESET FAILSAFE as this will adjust both engines to your throttle failsafe position.