That's simply not true, at least not in many cases. While Spektrum sets a throttle fail safe during binding it's really easy to Teach RC without having your throttle fail safe set at all on many systems. Even with Spektrum I've seen many people bind their receiver, then decide to reverse their throttle channel without rebinding. In this case if you simply perform teach RC you will be able to shut down your turbine on command while you have signal but if your system goes into fail safe not only will the turbine not shut down, it will go to full throttle and you won't be able to shut down your turbine from the transmitter at all.

Whether you care about logging an accurate shut down cause or not you should ALWAYS verify that your fail safes are set correctly and test that they work properly before flying any new model, especially turbine powered models.

IMHO, conflating a Rxer's failsafe and a ECU's failsafe above does NOT get you off the hook for confusing the OP's original question. KISS

To the above specific points, … The ECU failsafe has nothing to do with the Rxer's Failsafe. The ECU does not care if there is a Rxer failsafe. The ECU failsafe functions at a total loss of Throttle Signal, Hi/Low Turbine exhaust temp, etc. (e.g. like total loss of power to the RXer or the throttle harness disconnected from the ECU.) Even if the throttle is brought back to idle by a failsafe on an RXer, a throttle signal is still there. Even if the throttle channel was reversed and the RXer's failsafe was not reset, the throttle signal would still be there. Once RC learned, both of these signals would be above low trim, so even a normal shutdown would not be initiated, let alone a throttle based ECU failsafe!

First time turbine jet setups need to be face-to-face with someone who has experience with the particular radio and turbine and set them up on the bench together! Otherwise too many things get missed (e.g. flight modes, reasonable control throws & flap settings, CGs and wire routing, etc.) This type of collaboration is much more effective than trying to ferret out the useful information from a bunch of off-topic forum B.S. - KISS.

You are right about verifying that both failsafes work correctly though. Shut off the transmitter, and see what happens. A failsafe takes 2 seconds. A normal shutdown cycle will be immediate at low trim. Again, these are two different functions triggered by two or more different initiating conditions.

As far as knowing when a ECU failsafe has occurred, with the thousands of flights I have either done myself or observed on the flightline here, I can't recall anyone experiencing a failsafe. I personally don't think it is worth confusing a normal setup to maybe see a turbine message relating to an event that most-likely will never happen! Again - KISS. All you need to know is in the book!

Just an FYI the OP is using Futaba into a SmootheFlite with the failsafe set in the SmoothFlite.

Yea, that's the issue - no confirmation as to what type of shutdown you observed. The Jetcat setup is nice, just turn off the TX with the GSU attached, and if you have it setup correctly, you get a nice "F" on the display letting you know that the ECU recognized the RX failsafe.

Next time I get out the Cougar with the K-85, I'll have to look at it and see what I can see. I did verify that turning off the TX shuts down the turbine, but I can't recall if I timed it, or if I looked at it in the GSU display. I do know I wasn't really worried about it too much as I fly that little thing in so close I'm not worried about failsafes - just making sure that the turbine shuts down in any case. A bigger, heavier, more expensive airplane though like your F-16, and I would be.

Bob

ps. Len, we all know the difference between an RX failsafe and an ECU failsafe - the question is, getting the ECU to recognize an RX failsafe. Older ECUs, with the exception of Jetcat's, DID NOT have a mechanism for recognizing an "out-of-range" pwm signal from the RX as an indication of an RX failsafe. The whole debate is how do you *verify* that the Kingtech ECU DOES have that mechanism.

There is nothing for me to get "off the hook" for as I answered his original question completely accurately. While I provided more information than he needed, because it wasn't clear what he did and didn't know, everything I said was 100% correct, had been tested and I knew for a fact worked with the system in question. If someone chooses not to believe the truth because they couldn't verify it in the manual or it didn't appear to work for them for some unknown reason, it doesn't make it any less true.

As for your comment that The ECU Fail safe that shuts down the turbine on loss of signal has nothing to do with the Receiver fail safe, that is completely wrong as your receiver fail safe behavior is the only way for the ECU to know that your system no longer has contact with the airplane. This information is clearly spelled out in JetCats manual, at least the older ones and even page 64 of the Kingtech G2 manual says the same in a bit more round about way when they state the meaning of the warning message "RC SIGNAL LOST/INCORRECT: The signal received from the RX is wrong (outside calibration margin) or absent". That behavior is exactly what I described and makes the ECU totally dependent on the fail safe behavior of you receiver. While the turbine can shut down for all sorts of reasons, several of which you described, this is the one and only way the ECU knows that you have lost control of the model and it needs to shut down the turbine, which is what was being discussed here.

While is true that the old 72Mhz system would generally stop sending a servo pulse if signal was lost, the vast majority of modern systems (all of them?) have a fail safe behavior that is either set automatically during binding or needs to be configured in order to work. I don't believe Spektrum even has the ability to stop sending a servo pulse on the throttle channel and as long as there is power to the receiver it will output a valid servo pulse on the throttle channel, The only way the ECU can tell there is no RC control is if this servo pulse changes to a value outside the range learned during teach RC or stops being sent completely. I don't know of any modern systems that stop sending servo pulses on fail safe by default, which some such as Jeti can be configured to do this. If you bind a Spektrum receiver with a throttle setting that will be used to shutdown the turbine, it will stop on loss of control, if you bind with throttle set to the idle position it will go to idle on loss of control and not stop, if you reverse the throttle channel after binding it will go to full throttle on loss of control. I've seen this happen first hand.

As for never having seen a loss of signal at an event, I've seen it first hand. The airplanes fail safe wasn't set correctly, turbine went to full throttle I've also seen people have what they thought were flame outs because they were had a hold just long enough to send them into fail safe which immediately stopped the turbine due to their fail safe setting. They were baffled because ECU logs indicated normal shut down and were chasing electrostatic discharges, blocked fuel filters, replacing UATs, etc.The signal loss was brief and due to having a Cortex Pro installed, the hold condition wasn't even noticed other than the turbine stopping in flight. Until I looked at their transmitter and pointed out they were having multiple holds on every flight it never occured to them it was a radio issue that was causing the flame outs. They moved their remote receivers around, the holds went away and no more in flight shut downs.

I completely agree that it's best to get face to face help for these types of things and I have nothing against keeping things simple or ignoring the shut down cause as long as you have verified that your fail safe settings are correct and your turbine shutdown on loss of RC signal. However saying you don't need to do anything or is has noting to do with your fail safe setting is completely wrong and if believed to point of not verifying fail safe works, potentially dangerous.

Having seen these issues first hand is why I simply couldn't ignore a statement saying that you don't need to worry about your fail safe because it has nothing to do with anything and your turbine will simply shut down on it's own if you lose signal.

I think the diagnostic menu is only accessible on the first reboot (power down and up) of the ECU after a run cycle which is similar to the old Xicoy ECU's. As for the summary menu I just checked. I only have four runs total on the engine and the 3rd was the one where I turned the TX off while the engine was running to simulate a F/S. Other than every run having different numbers in the "AbNor" row, under the "AbNor" line each run there is another row that just says "User Off". All four of my runs just say "User Off". On Pg 57 of the manual they mention a PC terminal interface available in the future that would be able to give more detailed info. I don't see a PC interface cable on the Kingtech website.

By the way the old Xicoy ECUs record the number of Rx errors and the error time in seconds and is displayed on the GSU. The Xicoy instructions also say to program the fail-safe less than the stop signal, ex. 100% vs 125%
.
With the new KingTech the difference between 100% and 125% was not enough to trigger the fail-safe with my Jeti on the bench not running. I'm not going to try to reprogram different throttle settings to find what will work because my fail-safe is set to "OFF" for throttle which indicates no signal on the GSU. All of this was discussed on the other thread in the Turbine Clinic.

It will be a while before I can test this with the engine running.

How did you set the Fail-safe in the SmoothFlite?

Basically it's the same as setting it in the radio. There's a failsafe screen with bar graphs for the first ten channels. I set the radio end point throw on the low end all the way out to -140% go to the smoothflite display and touch the throttle channel bar graph which turns it from blue(hold position) to green( failsafe set position) and then save. Smoothflite recommends setting the FS in their unit and warns not to set both the radio and their unit as it can cause "jitters"

Tbh I prob have learned something and could do a "relearn" on my turbine with throttle trim at middle for off and full up for idle and could set failsafe to trim completely down and see if I can get the turbine to operate normally but have a delayed shutdown on throttle signal "out of margin" tolerance.

Still not sure if I would rather just have a instant shutdown than a 2 second delay but in the event of having random shutdowns it could be a good diagnostic tool.

It would take 101 lost frames and 0.9s before my receiver would even go into failsafe, feel that margin is already long enough for "freeflight" and would be noticeable in most cases.