My motor reversed in flight- please help

[DattaGroover]

During a normal flight with my P2, using a Taranis controller, it had red & green lights on normally, when it started a return to home run, completely out of my control. No big deal, but I wanted to land it myself, and get the camera angle right. My controller was 100% unresponsive, so I turned it off, then back on. At which point one of the motors did a full reversal.

It tumbled down to a very hard landing, ruining the shell. After replacing the shell (and one of the ESCs) I got it all back together, re-calibrated, but one of the motors still spins the wrong way.

Any idea what could possibly cause this, and how do I fix it?

Many thanks!

 

[ianwood]

Do you have any video you can post? I assume your props came off in the crash, no?

 

[syotr]

During a normal flight with my P2, using a Taranis controller, it had red & green lights on normally, when it started a return to home run, completely out of my control. No big deal, but I wanted to land it myself, and get the camera angle right. My controller was 100% unresponsive, so I turned it off, then back on. At which point one of the motors did a full reversal.

It tumbled down to a very hard landing, ruining the shell. After replacing the shell (and one of the ESCs) I got it all back together, re-calibrated, but one of the motors still spins the wrong way.

Any idea what could possibly cause this, and how do I fix it?

Many thanks!

Check the wiring to the motor from the ESC you replaced. You likely have two wires swapped.
If a prop came off in flight, it does not mean the motor reversed. If an ESC fails and the motor comes to a sudden stop, then the inertia in the prop may spin it off.

 

[Hughie]

My controller was 100% unresponsive, so I turned it off, then back on. At which point one of the motors did a full reversal.

How do you know this ?

If you have changed the ESC since the incident, it is possible that you have the windings swapped over so that it now runs in reverse. This is not the same as it running in reverse during the incident.

Do you have some footage?

 

[DattaGroover]

Do you have any video you can post? I assume your props came off in the crash, no?

I will see if I can find that video. My hard drive crashed 2 days ago, so I have to find my original.

Interestingly, no, the props didn't come off. One prop totally smashed when it hit. And only 1 motor reversed.

When I tried to fire it up yesterday (with a new shell) the prop on the backwards motor came right off.

 

[ianwood]

If a motor reversed, the prop would most assuredly come off. Self-tightening would become self-removing. The prop would have to be tightened to several foot/lbs. of torque tight to keep it from not coming off right away.

 

[DattaGroover]

My controller was 100% unresponsive, so I turned it off, then back on. At which point one of the motors did a full reversal.

How do you know this ?

If you have changed the ESC since the incident, it is possible that you have the windings swapped over so that it now runs in reverse. This is not the same as it running in reverse during the incident.

Do you have some footage?

It did a very high speed tumble
I do have the footage - just rendering it now (it's over 2Gig originally) I was extremely careful to connect the ESC up the same way, and I checked it afterwards.

 

[DattaGroover]

If a motor reversed, the prop would most assuredly come off. Self-tightening would become self-removing. The prop would have to be tightened to several foot/lbs. of torque tight to keep it from not coming off right away.

That makes sense. I have no idea why the prop didn't come off. However, notice from the video (once I get it rendered & uploaded) how fast the tumble is.

 

[DattaGroover]

If a motor reversed, the prop would most assuredly come off. Self-tightening would become self-removing. The prop would have to be tightened to several foot/lbs. of torque tight to keep it from not coming off right away.

Here is the crash:

[vimeo]115021350[/vimeo]

 

[DattaGroover]

Do you have any video you can post? I assume your props came off in the crash, no?

Just posted video.

 

[sergekouper]

Scary! Though I can't imagine and engine reversing. That is just out of my knowledge and comprehension... However, I think you are going down very quickly and I don't like much the noise of these engines reving up and down... I would think that you "lost" an engine, or an ESC maybe. Clearly a mechanical failure.

 

[ianwood]

Agreed. Losing a motor, losing altitude, other motors trying to stay level could probably do what is in the video. Looks like an ESC failure. In order to get the motor to reverse, the wiring would have to be changed or shorted.

 

[Hughie]

Sounds to me like an ESC failure too. Note that if an ESC fails it is likely to lose drive to one or all of the motor phases. That *wont* cause a reversal of the motor.

 

[DattaGroover]

Agreed. Losing a motor, losing altitude, other motors trying to stay level could probably do what is in the video. Looks like an ESC failure. In order to get the motor to reverse, the wiring would have to be changed or shorted.

Right you are. It probably was an ESC failure. When I replaced it, I looked at the adjacent motors, not the one across, and revers-wired it. Easy fix!

And it probably was an ESC failure originally.

Thanks!

 

[DattaGroover]

Sounds to me like an ESC failure too. Note that if an ESC fails it is likely to lose drive to one or all of the motor phases. That *wont* cause a reversal of the motor.

Yep, you are right. Also, as mentioned earlier in this thread by Ianwood and others, if it had actually reversed, the prop would have spun off.

 

[Hughie]

Sounds to me like an ESC failure too. Note that if an ESC fails it is likely to lose drive to one or all of the motor phases. That *wont* cause a reversal of the motor.

Yep, you are right. Also, as mentioned earlier in this thread by Ianwood and others, if it had actually reversed, the prop would have spun off.

Correct.

 

[DattaGroover]

Sounds to me like an ESC failure too. Note that if an ESC fails it is likely to lose drive to one or all of the motor phases. That *wont* cause a reversal of the motor.

Here's a new thought: what if it was my Taranis? I have noticed it hiccuping from time to time when it sends weird signals and my phantom bucks for a half Second before it settles down.

I love the features of the Taranis, but am having doubts about its reliability.

 

[Prophecies]

Have you ever crashed before minor or not? Any tipovers at all? Have you fiddled with the motors and/or ESC's in the past? This definitely looks like an ESC failure, though I'm not sure how simply turning the controller off and on again would have triggered this...

 

[DattaGroover]

Have you ever crashed before minor or not? Any tipovers at all? Have you fiddled with the motors and/or ESC's in the past? This definitely looks like an ESC failure, though I'm not sure how simply turning the controller off and on again would have triggered this...

No fiddling, yes to minor crash.

Only because I'm noticing the Taranis now doing occasionally weird things, I'm suspicious that it was to blame. It COULD have been a coincidence, but it failed the instant I turned the controller back on.

 

[Mako79]

During a normal flight with my P2, using a Taranis controller, it had red & green lights on normally, when it started a return to home run, completely out of my control. No big deal, but I wanted to land it myself, and get the camera angle right. My controller was 100% unresponsive, so I turned it off, then back on. At which point one of the motors did a full reversal.

It tumbled down to a very hard landing, ruining the shell. After replacing the shell (and one of the ESCs) I got it all back together, re-calibrated, but one of the motors still spins the wrong way.

Any idea what could possibly cause this, and how do I fix it?

Many thanks!

Check the wiring to the motor from the ESC you replaced. You likely have two wires swapped.
If a prop came off in flight, it does not mean the motor reversed. If an ESC fails and the motor comes to a sudden stop, then the inertia in the prop may spin it off.

If a motor comes to an immediate stop, would the props continue in the same direction and tighten further? A prop would only come off if the motors spin in reverse - correct me if im wrong..