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Where do you set the throttle fail safe?

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Where do you set the throttle fail safe?

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Old 10-07-2018, 05:50 AM
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CARS II
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Default Where do you set the throttle fail safe?

I have always set mine to completely close the throttle killing the engine on my turbines when activated ( never had one happen yet ) reading the rules once again ( 510-a, 9. All radios must be equipped with fail safe and ECUs shall be configured to shut down the engine
within 2 seconds of fail safe activation ) I understand that I can set the radio fail safe to idle and if it goes to fail safe passed 2 sec then the ECU will shutdown the engine.

Yes? No?

Tks.

Last edited by CARS II; 10-07-2018 at 05:52 AM.
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Old 10-07-2018, 06:11 AM
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Dansy
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The KingTech that I used...are coming from the factory setup for 1.5 secs failsave, I also set my radio/RX for a 1.5 secs failsave...I test those on the bench prior to install.
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Old 10-07-2018, 06:41 AM
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Originally Posted by CARS II View Post
I have always set mine to completely close the throttle killing the engine on my turbines when activated ( never had one happen yet ) reading the rules once again ( 510-a, 9. All radios must be equipped with fail safe and ECUs shall be configured to shut down the engine
within 2 seconds of fail safe activation ) I understand that I can set the radio fail safe to idle and if it goes to fail safe passed 2 sec then the ECU will shutdown the engine.

Yes? No?

Tks.
This is something that I have mentioned before as I think it is often misunderstood.

If you set your radio failsafe to idle then, if the model goes into failsafe, then the receiver will output an idle signal. The ECU will see this as an idle signal and will just put the turbine to idle forever (i.e. it won't shut down as it doesn't know if this is you putting the throttle to idle or a failsafe condition). You need to use the failsafe setting procedure for your ECU to allow the ECU to control the idle/shut down process (or set the failsafe to shut off to force an immediate shut down if a failsafe occurs). This usually involves setting a failsafe position that is outside of the normal throttle travel so that the ECU knows it is a failsafe condition.
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Old 10-07-2018, 07:09 AM
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Yep! a little confusing ( al least for me ) since I'm doing some testing on my engine tomorrow, I will reset the fail safe to an idle condition, run the engine and then turn off the radio, I will post my findings tomorrow afternoon, this will be interesting .
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Old 10-07-2018, 07:16 AM
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Originally Posted by CARS II View Post
I have always set mine to completely close the throttle killing the engine on my turbines when activated ( never had one happen yet ) reading the rules once again ( 510-a, 9. All radios must be equipped with fail safe and ECUs shall be configured to shut down the engine
within 2 seconds of fail safe activation ) I understand that I can set the radio fail safe to idle and if it goes to fail safe passed 2 sec then the ECU will shutdown the engine.

Yes? No?

Tks.
You can keep doing it the same way if you want. If you set failsafe to instant shutdown by closing the throttle, ECU will think/act just like you shut it down in the pits.

The rule for 2 second delay was added if you felt you needed it......in case you got a quick failsafe and did not want the motor to shut down
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Old 10-07-2018, 07:17 AM
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To save repeated starts whilst trying to set things up you might be able to check the failsafe on the data terminal without running the engine.

On Jetcat the Failsafe icon will show on the HDT, when you turn off the transmitter, if the ECU failsafe has been activated (even without the turbine running). Xicoy ECUs will show ‘failsafe’ in the same way. I’m not sure about other ECUs.

If this doesn’t show then you are relying on the radio failsafe.
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Old 10-07-2018, 08:30 AM
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I hear you mr_Matt, I want to have that opportunity to not have the engine shutdown because a less than 2 sec fail safe.

Good idea siclic33, I will try that first, thanks for the tip

My engine is controlled by a Xicoy AU 303, it doesn't have all the functions that new ones have but we will see.
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Old 10-07-2018, 08:32 AM
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Len
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While some of the radios on the market automate a portion of this, the process of setting up failsafe in most radios is to set the throttle travel to the maximum in the radio, set the radio failsafe to the minimum of that travel, set the throttle travel to a lower amount ~75% of the previous travel, lastly teach the ECU the new ~75% travel. If the Tx signal abandons the Rx ie ‘Failsafe’ condition on throttle, the Rx will output the first maximum travel’s minimum setting which should then be 25% or 12.5% below the ECU’s expected idle setting thereby telling the ECU that there is no signal forcing the ECU’s failsafe condition which starts the (normally 2 second) clock, which without a re-established Tx signal, causes the ECU to shutdown the turbine. Once you fully understand the process it is fairly easy to add it to any of the popular radio brands. To my knowledge all the ECU’s out there have a screen that shows the pulse width sent from the Rx to the ECU. The pulse width must go below the idle setting and some ECU’s require it to be completely outside the useable area of the off/idle/max range. It is always safer to go outside that range if you cannot get the information on how your ECU reacts to a ‘failsafe’ setting which is above the shutdown pulse width but below the idle pulse width. Muddied up enough yet?
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Old 10-07-2018, 01:23 PM
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I understand it, just have to see it on the GSU and radio to get it.
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Old 10-08-2018, 04:23 PM
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I've been reading the radio manual, ECU manual and from postings on RCU regarding fail safe.
Most of it is clear now, I turn on the radio and airplane and tried to make it to failsafe but it didn't then I run the engine a little higher than idle then turned the radio off, two seconds later the engine quit, here is a picture from the GSU right after that event ( top ) and a picture after turning the airplane off then on.

Thinking about what changed from before the first flame out that happened about a month ago to before that, the only thing that changed was that I had swapped the radio's battery from a 10 years old 3 cell LIPO that was still good but it was starting to show weakness during charges to a 3 cell LIFE, first I didnt like the LIFE voltage displyed of 9.9v, compared to the 3 cell LIPO of 12v right after been charge, this may not have to do anything with the problem but, that has been the only thing that changed, I now have a new fresh 3 feel LIPO back in the radio, .

Last edited by CARS II; 10-08-2018 at 04:44 PM.
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Old 10-08-2018, 04:45 PM
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Here is the pic of the GSU after the second flame out when I was testing at the field.
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Old 10-08-2018, 06:44 PM
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I think I found the last piece of the puzzle.

This is what Len was saying.

Thank you.

Setting up JetCat Failsafe on Futaba 14mz

I think I now understand fail safe set up.

Last edited by CARS II; 10-08-2018 at 06:47 PM.
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Old 10-08-2018, 08:14 PM
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Ok then, my fail safe is now set up at140% and my learn rc is at 100%

Tomorrow I go flying, with the new adjustments if I get a fail safe shutdown I should get a fail safe shutdown massage from the ECU on the GSU as the cause of the shutdown.

Will see.
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Old 10-09-2018, 05:01 PM
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Fail safe is correctly set up now, I'm still chasing the why the engine quit on me twice.

Thank you to all the for the info on fail safe posted here.

Last edited by CARS II; 10-09-2018 at 05:05 PM.
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Old 10-10-2018, 10:52 AM
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look for RPM undershoot on (throttled) deceleration. Sometimes a pump that has sat awhile can get gunky and cause undershoot. Swap the pump or clean it.

IMHO, extra pumps should be in one's box like glo plugs in the old days.
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Old 10-10-2018, 02:29 PM
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This pump had been working on a regular basis for the last 2 years, cleaning it is a great suggestion, I will do that.
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Old 10-10-2018, 06:55 PM
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The pump has been cleaned now and checked for leaks, all good to go there.

I was able to turn it with a 1.5 v AAA batt.

Last edited by CARS II; 10-11-2018 at 02:42 PM.
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