HELP motor runs on full throttle when I turn transmitter off

[kevin lane]

Being a newby this is causing me a real headache ,whilst trying to setup my servos I turned off the transmitter and the model went onto full throttle. I am aware of the need to turn on the transmitter first and to turn it off last, luckily I had removed the prop. I've tried binding the receiver again following advice from the net. I've also changed the ESC, receiver and li[po but all to no avail I can only assume the fault lies with the transmitter any suggestions would be very welcome.

Set ups tried: Hitec Optic 6 with 2.4 Fr sky module, Fr sky receiver - 8 chnl & 4 chnl

Motor brushless outrunner 1450 Kva drawing 10amps with no load

1200 mah lipo & 2200mah

Esc 12 amp mantis (now fried) and 20 amp mystere.

I've tried the transmitter on other models and it all works perfectly.

Kevin.

Edited By kevin lane on 23/02/2013 22:06:53

[Allan Bowker]

I read the title with horror, thank goodness you didn't have the prop on, many would have.

When you bind the receiver to the transmitter you need to set the throttle to the desired setting when signal fails (out of range or no power from transmitter). Most set the throttle to zero, this is for safety and to stop models flying away under power.

Your transmitter manual should explain about "throttle fail-safe" and might differ between manufacturers.

[WolstonFlyer]

I assume you are binding with the throttle fully down? Or is there some other failsafe setting that has been mixed up?

Can you delete the model memory and start again with a "clean" setup and then re-bind?

[kevin lane]

Thanks for prompt reply Allan but checked that failsafe is set to zero and that throttle is off when binding,I also deleted setup and started again.

Edited By kevin lane on 23/02/2013 22:18:39

[Tom Sharp]

I don't know about Hitec but with Futaba you have to reverse the throttle setting for electric powered applications.

 

 

 

 

 

Edited By Tom Sharp on 23/02/2013 22:19:03

[kevin lane]

Thanks Tom I was aware of that and I tried reversing the throttle just in case, no effect!

[Chris Bott - Moderator]

Kevin that sounds like classing failsafe operation. It sounds like it's set to full throttle for some reason.

It's the FR Sky instructions you need to be following, for setting the failsafe.

[Ruprect Spode]

FrSky Settings

2.2 Setting failsafe:

TF series receivers support failsafe function for all channels. Follow the steps below to set failsafe:
1) Bind the receiver first, and disable failsafe on the transmitter side;
2) Set all transmitter controls to the desired failsafe position;
3) Press briefly the F/S button of the receiver, the GREEN LED of the receiver will flash twice, indicating the failsafe is set up successfully.

If you do not need the failsafe function any more, just re-bind the receiver to set default failsafe mode.

Warning: Some transmitter manufacturers use a failsafe method that can interfere with that used by FrSky. Be sure to disable any transmitter failsafe settings before setting FrSky failsafe positions.

[Phil Green]

Sorry, quite a bit of misinformation there.

With a Frsky module the throttle setting at bind time is irrelevant, as are model memories and TF receivers. TFs are FASST and Futaba failsafe is a special case with throttle FS position on ch8.

Switch everything on, confirm its all working, close the throttle, dab the bind/fs button on the receiver.

Job jobbed. With the prop off, open the throttle just enough to run, switch off the tx and it will stop.

Hitec and Futaba will need ch3 reversing, low=1ms, high=2ms.

Cheers

Phil

Edited By Phil Green on 23/02/2013 22:53:37

[kevin lane]

Thanks everyone all fixed with one little press of the button on the RX

Hey Phil you dont need to reverse channel 3 on Hitec.

Boy do I feel STUPID!!!!!

Kevin

Edited By kevin lane on 24/02/2013 11:11:06

[Bill Brown 3]

I think it would certainly have had me guessing Kev, and a good many more, i admire you guys that have a natural grasp of what is going on within the technological devices we use now.

[Erfolg]

I guess the problem is solved?

I am sure that Ruprect is correct.

I am a little surprised that the failsafe would be set to full throttle.

In the past I have been a little blase with respect to the ESC, always believing that it would protect you from yourself, not having recognised this condition.

I have started setting the failsafe now when binding the Rx, as it is the easiest time. I then do all my setting up. From now on, testing the failsafe will be No. 2 on the Rx checks (No1 binding). Having first set up the reversed throttle on the Futaba Tx.

I have learnt an important piece of information today.

[Phil Green]

Posted by Erfolg on 24/02/2013 21:57:46:

I am sure that Ruprect is correct.

But Kevin was asking about a Frsky module & ACCST receivers, not TF receivers, the reply was correct for a Frsky TF FASST receiver which are different in that FASST handles failsafe in a unique way, sending the failsafe throttle position on channel 8, hence Frskys instructions to disable transmitter failsafe to stop it doing this when using TF FASST receivers. Kevins setup is ACCST rather than FASST.

Also, also be aware that Frsky offer two rom versons A & B:

A sets failsafe from the bind/fs button on the receiver as described above

B sets failsafe from the bind/fs button on the transmit module & can therefore be set in flight.

A is the default but on a set bought 2nd hand its as well to check which version you have as the previous owner may have updated it.

Cheers

Phil

Edited By Phil Green on 25/02/2013 02:17:59

[Steve Hargreaves - Moderator]

Posted by kevin lane on 24/02/2013 11:08:42:

Thanks everyone all fixed with one little press of the button on the RX

Hey Phil you dont need to reverse channel 3 on Hitec.

Boy do I feel STUPID!!!!!

Kevin

Edited By kevin lane on 24/02/2013 11:11:06

A lesson learned whilst still retaining the use of all your fingers is a good thing Kevin.....we all have to learn....

[Tony Smith 7]

Posted by Erfolg on 24/02/2013 21:57:46:

I am a little surprised that the failsafe would be set to full throttle.

I wonder whether it might default to zero, output centred. That would be 1/2 throttle which of course isn't what you want by any means. It seems a bit more likely than +100%, bearing in mind that an add-in module like this doesn't "know" which channel is throttle or anything about the model either. Defaulting to -100% would be power off for most aircraft, but could be full speed in reverse for a car or a boat, or full power downwards for an aerobatic helicopter.

[Phil Green]

Frsky failsafe is well documented and works exactly as described so theres really no need to make any assumptions, in fact, since its a requirement under CAP658 that failsafe is set correctly, familiarity with the Frsky failsafe options is pretty much essential!  

If the failsafe is not set, it defaults to "hold last position" on every channel. To select this option manually, simply rebind but dont subsequently set F/S.

To set the failsafe, switch everything on and make sure everything is working, then position all the channels to the required failsafe settings. Then dab the F/S button on the rx. Thats it.

To set the failsafe where the RomB option has been loaded, then switch everything on and make sure everything is working, then position all the channels to the required failsafe settings. Then dab the F/S button on the tx module. You can do this in flight, trimming for say a descending power-off circle, then locking the failsafe to those settings.

"No pulses" is another failsafe option which can be chosen manually if required by dabbing the F/S button on the rx whilst the tx is OFF. This is a safe option for electrics as an ESC will shut down with no signal pulse. Some Lost Model Finders and dual receiver adapters need a 'no pulses' option as they cant distinguish a failsafe pulse from a controlled pulse.

Frsky is a very capable and advanced system, when you think how many other sets offer such a variety of failsafe options on all channels? The downside is that to get the best from it, until you're completely familiar with it you really do need to keep a copy of the manual handy!

Cheers

Phil

Edited By Phil Green on 25/02/2013 16:17:17

[Tony Smith 7]

Thanks for the full explanation of the Frsky fail safe options, I wasn't aware of the "no pulse" option which sounds quite useful in some scenarios - it sounds as if that would act as "hold last position" for everything except the ESC. In an ideal world that would probably be the best default until fail safe is explicitly set.

In the case of the original poster where the motor powered up after the transmitter was switched off, that's not holding last position nor no-pulse, so that implies that failsafe must have become set to an inappropriate value. Is there any way that fail-safe can become set other then by pressing the button?

[Phil Green]

Not really Tony - the only time I can imagine this is if the rx had been previously used on an IC model where the throttle needed to be reversed, or a glider where throttle stick would be flaps or brakes, and failsafe had been set to 2ms on the throttle channel. It is intriguing. Whats the history of the Frskyfied Optic 6 please Kevin?

Cheers

Phil

[kevin lane]

Hi Phil looks like I've stirred up a hornets nest, hopefully all the discussions may save someone being "stung".

History: The rx was used on another model but the throttle was not reversed, I always change the motor wiring to reverse direction, I try to avoid reversing channels where possible I find it less confusing! The original simple model was using just ailerons chs1 & 2 and the throttle channel ch 3. It worked perfectly straight out of the box and I;m certainly not experienced enough to think about using flaps or brakes, incidently I also used the same 12 amp Mantis ESC prior to me accidentally frying it.

Kevin

[Erfolg]

I am not following thisvery well.

To reverse the direction of the motor, isn't this done normally via the ESC, where the feature is provided, or switching two of the feeds with brushless motors, or the switching the polarity with a brushed motor.

Reversing the throttle lever, isn't this associated with the Tx manufacturer, to alter how the ESC sees high and low throttle?

I suspect as others have suggested, the issue is due to missetting the failsafe on the Rx, on loss of signal.