CAUTION - DJI NAZA V2 GPS Unexpected Take-Off Hazard – Mike

[DeweyAXD]

Re: CAUTION - DJI NAZA V2 GPS Unexpected Take-Off Hazard – M

Glad to here you got to the bottom of it Mike. Got there in the end . I agree that on an aftermarket TX with trim control it is very easy to knock it a notch and not even consider what that could lead to.

A bit of a battle but positives to be had all round from this thread in the end (especially to all us non stock TX owners).

Would be great if you re-do your video to highlight the dangers of trim nudging and its effects on RPA.

 

[Mike Mas]

Re: CAUTION - DJI NAZA V2 GPS Unexpected Take-Off Hazard – M

Thanks Dewey - hey this is what the hobby is all about, guys like us doing the R&D for the manufactures and making the products more fun to fly and most important safe!

Keep Warm!

 

[FatKevinSmith]

Re: CAUTION - DJI NAZA V2 GPS Unexpected Take-Off Hazard – M

So is this caused by the new feature Colin Guinn was referring to in the interview regarding the NAZA receiving a constant non-zero signal on one of the sticks, where it would go to failsafe mode?

http://www.youtube.com/watch?v=2bxjL7wFyb8#t=5m07s

EDIT: Fixed link

 

[OI Photography]

Re: CAUTION - DJI NAZA V2 GPS Unexpected Take-Off Hazard – M

So is this caused by the new feature Colin Guinn was referring to in the interview regarding the NAZA receiving a constant non-zero signal on one of the sticks, where it would go to failsafe mode?

http://www.youtube.com/watch?v=2bxjL7wFyb8“#t=4m23s

Correct.

 

[pawnmeister]

Re: CAUTION - DJI NAZA V2 GPS Unexpected Take-Off Hazard – M

I guess I picked the wrong week to stop sniffing glue...and buy a Vision! Forewarned: newbie here...no flying RC experience, powered paraglider experience only. Flyaways, corporate mischief, growing pains...will it be worth it or should I return this thing unopened? (It arrives tomorrow) Seriously, haven't looked forward to a purchase this much in quite some time, and trying to ramp up the knowledge base before it arrives. Do I understand this unintended lift-off phenomena to only involve modified or non-oem transmitters? Thanks guys
PS...thinking about heading to Maryland fly-in Sat. w/o the Phantom to get some perspective.

 

[LeoS]

Re: CAUTION - DJI NAZA V2 GPS Unexpected Take-Off Hazard – M

I guess I picked the wrong week to stop sniffing glue...and buy a Vision! Forewarned: newbie here...no flying RC experience, powered paraglider experience only. Flyaways, corporate mischief, growing pains...will it be worth it or should I return this thing unopened? (It arrives tomorrow) Seriously, haven't looked forward to a purchase this much in quite some time, and trying to ramp up the knowledge base before it arrives. Do I understand this unintended lift-off phenomena to only involve modified or non-oem transmitters? Thanks guys
PS...thinking about heading to Maryland fly-in Sat. w/o the Phantom to get some perspective.

The Phantom Vision is not affected.

If there is one advice to give to new phantom flyer, is to READ and read a lot. Manuals, forums, community advisory (even wrong ones), because the phantom is deceptively simple to fly but it's not completely foolproof... Yet.

 

[FatKevinSmith]

Re: CAUTION - DJI NAZA V2 GPS Unexpected Take-Off Hazard – M

because the phantom is deceptively simple to fly but it's not completely foolproof... Yet.

Truer words have not been spoken. I was a first time flyer last night. The Phantom will quickly lull you into believing you have a cybernetic connection to it where you can do anything. Then you back it into a fence and it goes flipping to the ground because you mistook forward for backward after spinning it in place like a top.

 

[750r]

Re: CAUTION - DJI NAZA V2 GPS Unexpected Take-Off Hazard – M

I for one have learned something on how Critical it is to do a preflight check on everything I am running a Futaba witch is new to me now I will go over everything before I power up the bird . I just wish this thread would have started a little different like if you don't make sure you are all set to 0 trim wise and stick wise your bird will take off on you . Something like that .
Anyhow thank you for the info .

 

[Colombus]

Re: CAUTION - DJI NAZA V2 GPS Unexpected Take-Off Hazard – M

I am very grateful for this post!!!!.

Now I can understand what happened to me few months ago. This was running on my head and worrying me from the back of my mind since then

I have an after market TX where the throttle is not self centered, this means that I have double yellow (ATTI) or double green (GPS) as soon as I power up my Phantom.

Usually I take off very short after I power on engines, but now I remember one day I was doing something with my Fatshark goggles and suddenly my Phantom just took off suddenly. I've freaked out and finally managed to bring her back moving to ATT mode.

At that time I convinced to myself that I had inadvertently switched to Fails Safe , that was how I explained this to me.

Now I know what happened and I will take some precautions.

I agree with Mike, this is something that needs to be fixed by DJI, specially with many people having after market TX.

Imagine if you are working with your Phantom indoor with propellers on and this happen, having kids and people around. Very scary!!!!

 

[gmtx]

Re: CAUTION - DJI NAZA V2 GPS Unexpected Take-Off Hazard – M

"Imagine if you are working with your Phantom indoor with propellers on and this happen, having kids and people around. Very scary!!!!"

There's a video on YouTube about an indoor RTH and how the guy ended up in the ER with cuts on his hand from trying to get the Phantom back under control after a spontaneous takeoff in his house: http://www.youtube.com/watch?v=6Tpzz54xaIY

In his case it was caused by loose batteries in the remote control and the Phantom losing TX connection and taking off in RTH mode, but still, a scary situation. Quickly cured me of my urge to try a test flight indoors. :shock:

 

[ElGuano]

Re: CAUTION - DJI NAZA V2 GPS Unexpected Take-Off Hazard – M

There's a video on YouTube about an indoor RTH and how the guy ended up in the ER with cuts on his hand from trying to get the Phantom back under control after a spontaneous takeoff in his house: http://www.youtube.com/watch?v=6Tpzz54xaIY

In his case it was caused by loose batteries in the remote control and the Phantom losing TX connection and taking off in RTH mode, but still, a scary situation. Quickly cured me of my urge to try a test flight indoors. :shock:

Now there's a use case worth talking about! Is it demonstrated that a NAZA on the ground, once armed, will go into failsafe if the TX is shut off or loses power? If so, that's actually quite dangerous, since without a powered TX you can't regain control of it or disarm the motors. IMO, unlike OP's scenario of nonstandard subtrim config, this could happen without user error. This would also have nothing to do with RAP, it would be a pure failsafe issue.

 

[Colombus]

Re: CAUTION - DJI NAZA V2 GPS Unexpected Take-Off Hazard – M

"Now there's a use case worth talking about! Is it demonstrated that a NAZA on the ground, once armed, will go into failsafe if the TX is shut off or loses power? If so, that's actually quite dangerous, since without a powered TX you can't regain control of it or disarm the motors. IMO, unlike OP's scenario of nonstandard subtrim config, this could happen without user error. This would also have nothing to do with RAP, it would be a pure failsafe issue."

This case will happen of course, I was aware of that!!

El Guaro, If I well understood then the sub-trim use case is not necessary the only one, as in my case if you have a TX that throttle is not self centered, and your sticks are not centered by you manually, after a while that you has started the engine and you leave it without any input RAP will enter into action!!

I will try to reproduce....

 

[ElGuano]

Re: CAUTION - DJI NAZA V2 GPS Unexpected Take-Off Hazard – M

This case will happen of course, I was aware of that!!

El Guaro, If I well understood then the sub-trim use case is not necessary the only one, as in my case if you have a TX that throttle is not self centered, and your sticks are not centered by you manually, after a while that you has started the engine and you yleave it without any input RAP will enter into action!!

I will try to reproduce....

As far as RAP is concerned, under 100m height, throttle is excluded from the non-neutral condition for RAP, so you should be safe with non-self-centering throttle. If it doesn't perform as documented, that would be very important to know, so let us know what your testing yields!

 

[Colombus]

Re: CAUTION - DJI NAZA V2 GPS Unexpected Take-Off Hazard – M

I've made some test with my after market TX that do not have a self centered throttle.

Preconditions: TX is calibrated, trims are all set to 0, TX do not have a self centered throttle.
1.Powered on phantom and then engines and waited long time, fail safe did never kicked on.
2.I've set small trim on rudder, powered on phantom and then engines, fail safe kicked in after 30 seconds
3.I've set small trim on aileron, powered on phantom and then engines, fail safe kicked in after 30 seconds
4.I've set small trim on elevator, powered on phantom and then engines, fail safe did never kicked on.
5.I've set small trim on throttle, powered on phantom and then engines, fail safe did never kicked on.

In conclusion when small trim is activated (or TX is not calibrated properly) and even small values are set on rudder and aileron, once phantom is powered and then engines have been started, if you wait 30 seconds without giving any input to your TX, fail mode will kick in. To gain control back of your phantom you need to switch to fail safe switch and then ATT mode.

Hope this clarify.

M

 

[ElGuano]

Thanks M, interesting to note your findings on elevator. I'll try the test as well, but the documented operation should activate RAP with constant non-centered E input. Maybe your small trim was varying a bit and kept resetting the clock?

 

[Colombus]

Re: CAUTION - DJI NAZA V2 GPS Unexpected Take-Off Hazard – M

Thanks M, interesting to note your findings on elevator. I'll try the test as well, but the documented operation should activate RAP with constant non-centered E input. Maybe your small trim was varying a bit and kept resetting the clock?

It surprised me as well the result with elevator. I've tried with different values and strangely fail safe did never kicked in. If you try it out let me know.

M

 

[ElGuano]

Re: CAUTION - DJI NAZA V2 GPS Unexpected Take-Off Hazard – M

Thanks M, interesting to note your findings on elevator. I'll try the test as well, but the documented operation should activate RAP with constant non-centered E input. Maybe your small trim was varying a bit and kept resetting the clock?

It surprised me as well the result with elevator. I've tried with different values and strangely fail safe did never kicked in. If you try it out let me know.

M

Will do! I'll try it tonight, this could actually be a case where RAP isn't functioning as intended.

 

[Mike Mas]

Re: CAUTION - DJI NAZA V2 GPS Unexpected Take-Off Hazard – M

I've made some test with my after market TX that do not have a self centered throttle.

Preconditions: TX is calibrated, trims are all set to 0, TX do not have a self centered throttle.
1.Powered on phantom and then engines and waited long time, fail safe did never kicked on.
2.I've set small trim on rudder, powered on phantom and then engines, fail safe kicked in after 30 seconds
3.I've set small trim on aileron, powered on phantom and then engines, fail safe kicked in after 30 seconds
4.I've set small trim on elevator, powered on phantom and then engines, fail safe did never kicked on.
5.I've set small trim on throttle, powered on phantom and then engines, fail safe did never kicked on.

In conclusion when small trim is activated (or TX is not calibrated properly) and even small values are set on rudder and aileron, once phantom is powered and then engines have been started, if you wait 30 seconds without giving any input to your TX, fail mode will kick in. To gain control back of your phantom you need to switch to fail safe switch and then ATT mode.

Hope this clarify.

M

Colombus,

Thanks for taking the time and sharing your results with us!

Mike

 

[ElGuano]

Re: CAUTION - DJI NAZA V2 GPS Unexpected Take-Off Hazard – M

Thanks M, interesting to note your findings on elevator. I'll try the test as well, but the documented operation should activate RAP with constant non-centered E input. Maybe your small trim was varying a bit and kept resetting the clock?

It surprised me as well the result with elevator. I've tried with different values and strangely fail safe did never kicked in. If you try it out let me know.

M

Columbus,

I just ran a full suite of tests, and can confirm that elevator at constant non-centered position DOES trigger RAP. I would suggest hooking your Phantom up to the Assistant and see if you are inadvertently bumping the aileron a bit (or it may be drifting) when propping E for the test.

From my tests:

1. Throttle non-centered: RAP is NOT activated
2. Rudder non-centered: RAP activated
3. Elevator non-centered: RAP activated
4. Aileron non-centered: RAP activated.

X: TX off: RTH immediately triggered (note that this is pure failsafe, and is NOT Receiver Advanced Protection)

1-4 above is consistent with the documented functioning of RAP:

Case X is a bit more concerning--a battery failure of the tx upon arming the motors will instantly trigger failsafe regardless of RAP being enabled or disabled, and effectively leave you with no way to control the craft until it descends again on its own. It's not a bug, it's a consequence of the NAZA not knowing whether it's truly on the ground or just hovering very close to the ground.

 

[gmtx]

Re: CAUTION - DJI NAZA V2 GPS Unexpected Take-Off Hazard – M

So with Case X - loss of TX - the Phantom enters failsafe and returns home. But where is "home"?

One of the things I thought was interesting in the video I referenced was that the user said he thought his Phantom was trying to return to a previous "home" position from the last time he flew it. Is this possible - does the Phantom store home position in a non-volatile way that survives a battery pull/reboot? And what happens in Case X if you power on indoors and never get a GPS lock, hence no "home" position? No RTH, right? Would having S1 in ATTI prevent RTH from happening, even with GPS lock (or a "remembered" home positon)?

Sorry - I'm a newb with more questions than answers, but I really want to fly safely and unexpected (and potentially uncontrollable) takeoffs have me concerned.