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Setting failsafe in "Receiver"
- Thread starter 48thFleet
- Start date
G-man
Very Strong User
As reliable as our radio systems are generally, there are times when the signal from the transmitter to the receiver is lost.
The fail safe function determines what the model will do when commands from the transmitter are no longer available.
My thinking is we want the plane to land close by rather than fly far away.
For a glider, I set my fail safe with a little rudder deflection and a little up elevator, hoping the uncommanded plane
will spiral down to a gentle landing, shiny side up. For a motorized plane, same, with motor speed reduced.
You can test the effect of your fail safe setting by switching off the transmitter and observing the model.
Do this with sufficient altitude to turn the transmitter back on and recover control.
Most flights, we don't think much about fail safe settings.
But "that one time" you will be mighty glad you set the receiver fail safe.
// Dave
The fail safe function determines what the model will do when commands from the transmitter are no longer available.
My thinking is we want the plane to land close by rather than fly far away.
For a glider, I set my fail safe with a little rudder deflection and a little up elevator, hoping the uncommanded plane
will spiral down to a gentle landing, shiny side up. For a motorized plane, same, with motor speed reduced.
You can test the effect of your fail safe setting by switching off the transmitter and observing the model.
Do this with sufficient altitude to turn the transmitter back on and recover control.
Most flights, we don't think much about fail safe settings.
But "that one time" you will be mighty glad you set the receiver fail safe.
// Dave
Attachments
MikeB
Very Strong User
You may have the Tx sending the failsafe settings to the Rx, but choosing the option "Receiver" disables this, and then the failsafe values are whatever is set on the Rx. The Rx failsafe values may be set by holding the controls in the required position then pressing the "Bind/FS" button on the Rx.
Mike
Mike
thenated0g
Moderator
If you're using a flight controller, you want the receiver to stop sending any signal at all on fail safe
MikeB
Very Strong User
When setting failsafe on the receiver, ALL failsafe values are set at the same time.
When you set the failsafe on the receiver, the failsafe values are set when the button is pressed.
When using "CUSTOM" on the Tx, the failsafe values are sent every (about) 10 seconds, instead of actual control values. So, after changing the setting on the Tx, you need to wait at least 10 seconds before testing. Note that there is no guarantee the failsafe settings have been received by the Rx, The data packet containing failsafe values may not be received correctly sometimes, so even waiting 10 seconds may not always be enough, although it should get to the receiver eventually.
In the original implementation of openTx, The only setting on the Tx were "Hold", Custom, an "No Pulses", there was no "Not Set" or "Receiver" setting. This meant if nothing was done on the Tx, it sent "Hold", and this then became the setting, even if you set the failsafe on the Rx. Without the "Not Set" warning, you might think you have set the failsafe on the Rx, but this got changed to "Hold" without your knowledge. The "Receiver" setting was added first, and much later the "Not Set" warning was added.
Mike
When you set the failsafe on the receiver, the failsafe values are set when the button is pressed.
When using "CUSTOM" on the Tx, the failsafe values are sent every (about) 10 seconds, instead of actual control values. So, after changing the setting on the Tx, you need to wait at least 10 seconds before testing. Note that there is no guarantee the failsafe settings have been received by the Rx, The data packet containing failsafe values may not be received correctly sometimes, so even waiting 10 seconds may not always be enough, although it should get to the receiver eventually.
In the original implementation of openTx, The only setting on the Tx were "Hold", Custom, an "No Pulses", there was no "Not Set" or "Receiver" setting. This meant if nothing was done on the Tx, it sent "Hold", and this then became the setting, even if you set the failsafe on the Rx. Without the "Not Set" warning, you might think you have set the failsafe on the Rx, but this got changed to "Hold" without your knowledge. The "Receiver" setting was added first, and much later the "Not Set" warning was added.
Mike
doug35
Strong User
Just to be clear.... The failsafe values for each channel are individually set. When the receiver looses contact with the TX, the FS values are implemented. For example, my setting for fixed-wing aircraft is 50% left rudder, 0% throttle, and self-level mode = on. For a boat, you could have FS set to throttle to 10% and rudder to 25% left.
"Just to be clear.... The failsafe values for each channel are individually set. When the receiver looses contact with the TX, the FS values are implemented. For example, my setting for fixed-wing aircraft is 50% left rudder, 0% throttle, and self-level mode = on. For a boat, you could have FS set to throttle to 10% and rudder to 25% left."
Yes, Got it. Thank you all.
Yes, Got it. Thank you all.
While on the topic - for many of my advanced gliders I actually set my failsafe to HOLD as anything else would probably result in the glider piling into the ground. HOLD has a decent chance of the glider flying to a smooth landing. These are planes that have much lower static stability. If a plane has flaps (normally do), then an argument can be made to apply the flaps and elevator into a landing condition.
For my power planes I usually have a default with NO throttle. Why no throttle? Well, my old flying buddy used to set his planes to 50% throttle for failsafe. He had a habit of forgetting to turn off his models, and when he would change model memories or switch off the transmitter the plane sitting on his work bench or in the pits would power up and attack people. (Poor guy did this many many times!)
For my power planes I usually have a default with NO throttle. Why no throttle? Well, my old flying buddy used to set his planes to 50% throttle for failsafe. He had a habit of forgetting to turn off his models, and when he would change model memories or switch off the transmitter the plane sitting on his work bench or in the pits would power up and attack people. (Poor guy did this many many times!)
thenated0g
Moderator
excellent point, i have had this happen before when the frsky units are too close to the radio when in my shop and the lose connection from too strong of a signal. Scared the crap out of me but didnt do any damage as the prop couldnt get spinning on the workbench.
Hawaii Sloper
Very Strong User
I do like the feature on ETHOS that tells you the plane is still on if you try to turn it off. I’ve done that a few times on the workbench when testing servos and radios.
Haoyang Wang
Very Strong User
HOLD may also result in the glider circling away.
MikeB
Very Strong User
LOL - Not the gliders I am referring too.
But yes.. Failsafe settings are always a debate for a pilot. I think it best to consider the options for each different model a pilot has. No one solution is perfect for all.
thenated0g
Moderator
If you have a simulator you could test all this and get kind of an idea whats going to happen
Just to clarify, to set the fail safe in the receiver, set the fail safe setting in the TX to should be set to what? Not Set, No Pulses, or Receiver. I assume the latter. Set the controls to the fail safe position on the TX and hold the bind button on the receiver. Then what?
Does the RX need to be shut off and then cycled? Does the TX need to be shut off and cycled?
My dilemma is that the servos do not shift to the pre-set position.
Thanks
Jonathan
Does the RX need to be shut off and then cycled? Does the TX need to be shut off and cycled?
My dilemma is that the servos do not shift to the pre-set position.
Thanks
Jonathan
Personally, I am not a fan of the "receiver" setting. That is sort of the only way you can do it on Spektrum, and I always thought it was lame. I prefer it on the transmitter for a couple reasons, first, I can see what it is. Second, if something changes, it will be picked up automatically. This second one was more important when I had a fuel burning engine, as I may adjust things on the throttle, which would change where its failsafe position needed to be.
I know Mike mentioned that there is a delay (I thought it was longer on OpenTx), but in my experience that hasn't been a problem. I setup where I like them, throttle to no signal and neutral for control surfaces, then I spin up the motor, deflect my sticks and turn off the tx, while someone is holding it obviously
, and I make sure things go where they are supposed to.
Oh, and sorry @48thFleet I haven't used "receiver" so I can't answer your question.
I know Mike mentioned that there is a delay (I thought it was longer on OpenTx), but in my experience that hasn't been a problem. I setup where I like them, throttle to no signal and neutral for control surfaces, then I spin up the motor, deflect my sticks and turn off the tx, while someone is holding it obviously
, and I make sure things go where they are supposed to.Oh, and sorry @48thFleet I haven't used "receiver" so I can't answer your question.
