Spektrum DX9 and WOT 4 that decided to do its own thing

[Nigel Finch]

Well my Discovery bit the dust and purchased a WOT 4 to replace. Guys at field set it up and trimmed and I had a fly and landed for the first time ( told it was a very nice landing). As it is my second model felt pleased with that even though a club member at my request had me on a wireless buddy link ( safety first ) just in case. No need as was very happy buzzing around.

Another battery in and lined up for take off this time on my own. Throttle open and climbed out at about 40 degrees. After about 10seconds it started to climb sharply. Applied elevator to stop climb and no response.

Took throttle down and still climb increased with no speed reduction? turned sharp to the left and applying aileron done nothing. Then went inverted and applied elevator but again no response.

graceful dive into the ground nose first.......

Upon looking spinner and prop had virtually no marks apart from the spinner nose on one side. Looked as though fail safe kicked in.

This was same receiver that was in Discovery when it crashed with friend at controls.

Its a AR400 receiver so any thoughts ? When we recovered the plane nothing worked until we unplugged power and servos and plugged it all back in.

[Masher]

Are you sure that wireless buddy was disabled on both Tx's?

Did you do a proper range check on the "suspect" receiver?

Edited By Masher on 22/07/2014 16:50:53

[Nigel Finch]

Hi Masher,

 

range check was a ok as this receiver has flown for four months faultless. I was near compared to flight on wireless buddy.

we done nothing to disable buddy as the DX9 was the master and other guys was a slave that I was flying on. Interesting as someone at field mentioned this ?

would this cause a issue as he did turn his TX on as I was taking off to sort his wot out

Edited By Nigel Finch on 22/07/2014 16:58:05

[Depron Daz]

Posted by Nigel Finch on 22/07/2014 16:57:42:

Hi Masher,

range check was a ok as this receiver has flown for four months faultless.

So am I right in thinking that since removing it from a crashed Discovery and replacing it inside the WOT4 you didn't conduct any further range checks? Do you do a pre-flight surface control check before every flight, ailerons, rudder and elevator? If not it is a must, not a maybe.

Any crashed equipment should be treated with extreme caution, and if it was mine I would conduct range checks fairly regularly or replace it, and perhaps use it in a small cheap shockie if you cannot face binning it.

[Chris Bott - Moderator]

Commiserations Masher, always sad to hear.

A few questions:-

Had you tested the failsafe before flying? If so did it cut the throttle? It sounds like throttle didn't cut at the time you lost control?

What was powering the receiver? BEC in the ESC, separate UBEC or a spearate Rx battery>

[Nigel Finch]

Hi,

no did not do a range check but I checked and the guy that flew it to trim also checked surfaces. I again checked before fatal flight.

did not re do a range check as first crash pilot said it could have been his error. My total error not to do this though !

this wireless buddy question interest me as after flight with me on his tx he powered it down. On me taking off he powered it on again but would that have caused a issue with my tx as it was the master ?

[Nigel Finch]

Was normal set up with power taken from esc into receiver

failsafe was checked before and worked. After initial Check I hink it cut in as marks on spinner was long ways from tip and if prop was spinning they would have gone round the spinner

[Masher]

TBH I have no experience of the wireless buddy system but it has to be on the suspect list I would think - things are getting very complicated and flexible, but humans make mistakes!

Hey Chris, it wasn't me on this thread - but I have destroyed a model this week

[Nigel Finch]

Can anyone help on the wireless trainer link question in this thread as it makes total sense. Other tx powered on andknocked out signal to receiver for a few seconds and fail safe kicked in ?

it says about the inhibit function but does not explain, should this be on all the time except when flying on buddy. 

Edited By Nigel Finch on 22/07/2014 17:36:47

Edited By Nigel Finch on 22/07/2014 17:37:16

[Chris Bott - Moderator]

Posted by Masher on 22/07/2014 17:22:21:

Hey Chris, it wasn't me on this thread - but I have destroyed a model this week

My apologies Masher - put it down to me loosing the plot, yet again...

Nigel I don't know anything about the wireless buddy system but I'm sure that only one Tx can be bound to the Rx in the plane, and that must have been yours surely? I take it that the instructor was using your Tx to fly the plane, and that you were later using your Tx to fly the plane? So only that one has ever been bound to the plane.

As far as I know, the pupil Tx would have been bound to a Rx inside the instructor Tx? In which case, when he turned his back on, I'd hope it wouldn't control the plane until the trainer button is held down on the instructor Tx - i.e. yours?

It may be worth testing just this scenario again, if you can get him to help you test the sequence of events with you.

[Chris Bott - Moderator]

OK, not sure where we got to on the diagnosis.

I can't see it being the other transmitter switching on that caused it, but that is worth persuing I guess.

If the motor stopped when you lost control, then this begs the question - did the battery move in the model and become unplugged?

Another possibility is an overheated BEC, if that was the Rx supply.
In this scenario, it could have got quite hot on the previous flight, and then the second flight pushed it over the edge.

Often a BEC will shut down when overheated, and then work perfectly again once it's cooled down.

[Nigel Finch]

Looks like it's the receiver in some way from replies. Still going to look into wireless trainer as think its worth following to see if it could affect the signal

[Chris Barlow]

From what I understand on the DX6 the Instructor/Pupil bind has to be re-established whenever either of the transmitters are turned off/on again.?

Edited By Chris Barlow 1 on 22/07/2014 23:46:24

[Romeo Whisky]

I have a DX9 and I am assuming the DX9 was the master. If so then my understanding is that it is imperative that your club trainer with the DX9 master must inhibit the Trainer on the DX9 Model Memory used for the training flight when the training session is finished. If not, and he leaves his DX9 set to your model then if he turns his DX9 on while you are flying, his DX9 will potentially have control of your model (and you won't) unless he presses the trainer switch on his DX9 to give you control (just as in the training session). If he hasn't inhibited the wireless trainer facility and switches on the DX9 in the pits when you are flying solo, I believe this could cause your apparent loss of control and he might be completely unaware that his TX has taken control of your model.

It is a good idea also for the DX9 owner to set up a specific model memory for the specific wireless-buddied model and then after the training session to both inhibit the Trainer feature and also change to a different model memory before switching off. This is because in wireless buddying the Master is bound to the model and the slave is bound to the Master. For the same reason, for wireless buddying the slave TX should use an unused spare model memory and not the same memory slot he normally flies solo on.

To quote the warning panel on Page 20 of the DX9 manual:- CAUTION! Select Inhibit when you aren't using the wireless trainer function. Failure to select Inhibit may result in loss of control of the aircraft.

Hope this helps.

[Glenn Philbrick]

I think Romeo has the answer. If the other guy switched on his transmitter that has been used as a trainer to yours and operated any of the control functions then that could well have taken the control from your Tx he would have to operate the trainer switch to hand control back to you. When ever we do wireless training using Spektrum I always set a specific memory for the trainer, this also has the advantage that any trim changes are saved.

[SkippyUK]

Chris Barlow 1 - I use a DX8 as slave and DX9 as master setup with a switch for transferring control (and the voice) and the auto facility for taking back control i.e. master waggle sticks and control is automaitically back to the master.

Both the DX9 and the DX8 retain the binding through multiple power cycles.

Romeo Whisky - the master must have been bound to the plane and the slave to the master - if the master was switched off then the slave would not control the plane as the binding is incorrect however (and you might have been alluding to this), if the slave changed model from 'Training' to the correct model but the master was left on the plane model then you may (can't confirm) have 2 tx's with the correct binding to a model so when the master was switched on - trouble ensued.

I have experienced that rare coincidence that I bound a plane at the same time as another was doing his (indoors in a hall) and although both TX's claimed binding, neither of us had proper control.

A slightly different scenario may have been that the master was Nigels and the slave was the trainers and I can confirm that if, while wireless buddying, the slave is switched off then control properly goes to the master.

However when the slave is powered on again it will take control if the button or switch is re-activated (will not if defined switch is not re-activated) - found this out when newbie turned off slave TX by mistake...

Not sure how the master was setup but this is definitely one scenario where a 2nd TX can take over a plane.

I always change model OFF buddy model when finished to avoid this.

Skippy (sorry for War & Peace reply)