Skyjib 6 Super with 5D Zenmuse and 1 motor fail (video)

[Quinton]

Had a motor fail on me before adding the Zenmuse, I thought I had it fixed (obviously not)
I have now replaced that motor and ESC tonight to be on the safe side (fingers crossed)

This is a Skyjib 6 Super with a 5D Zenmuse, I was out testing today and one of the motors went out, while I was testing.
Managed to bring it back, and videoed it on my iphone, so if you are ever wondering what happens to a HEX with 1 motor out, carrying 3kg gimbal here it is..

 

[rotorvista]

That's what we want to see!thanks for posting Quinton

 

[Benjamin Rowland]

Thanks for sharing this. Impressed that it managed to hover so well with one motor out.

 

[DucktileMedia]

Is that a WooChang or an A2? Impressive that it didnt even yaw.

 

[Quinton]

Is that a WooChang or an A2? Impressive that it didnt even yaw.

That is a Wookong with latest firmware.
When a motor stops you actually lose a lot of control on the yaw axis only, (you have some but very slow) the rest you can control as normal.

As part of my start up checks I actually full on yaw both ways for a few turns, as this is how it gets triggered.
I was trying out some rolling shutter tests against a few lamp posts when this happened, couldn't really notice any on the 5D, you would need to be going really quick to see it.

 

[sk8brd]

awesome- should put the 'loose 1 motor your done myth on a loaded hex to rest'- not awesome about your motor of course

 

[jes1111]

Very interesting... BUT...

What caused the motor to stop? I would regard this the same as a commercial aviation accident - we should ruthlessly track down the cause of the stoppage. Only that way can one be sure of avoiding repetition of the same problem. Motors themselves would rarely just "stop" - the issue is much more likely to be with the ESC or the wiring.

 

[Quinton]

Very interesting... BUT...

What caused the motor to stop? I would regard this the same as a commercial aviation accident - we should ruthlessly track down the cause of the stoppage. Only that way can one be sure of avoiding repetition of the same problem. Motors themselves would rarely just "stop" - the issue is much more likely to be with the ESC or the wiring.

I agree with you, the last time the ESC had a very slight cut, which I patched up...and it flew again well until yesterday.
Now I have a LOT of money hanging from underneath it I am taking no chances, so I simply replaced both.
If it happens again, then I know I have a major problem.

There was actually another post recently here regarding another person whos motor stopped on a quad, and SimonK piped in saying it sounded as though the ESC was out of synch (You had to download the video)
Mine actually sounded very similar, but I am not using simonK flashed ESCs (i will have to try and find the video)

Also if you look at these videos you will see that a motor could suddenly stop..
http://www.multirotorforums.com/sho...c-issues-(call-to-U5-owners)&highlight=simonk

 

[Quinton]

OK found it, it sounded exactly like this when it went out...problem is you have to download an mp4

http://www.multirotorforums.com/sho...-6-12S-HV-SimonK-ESC-working-on-6S-Good-Combi

 

[jes1111]

Worrying problem - and one that obviously no amount of like-for-like component replacement will solve. I'd follow Tiger's recommendation and stick with their own non-SimonK ESC until you can be 100% sure

Equally concerning was the way that guy's octo just folded up completely on what I'd call just a "hard landing".

 

[R_Lefebvre]

Wow, that's fantastic that it flew that well with the load.

Now, is this machine "overpowered"? ie: how much %throttle does it take to hover, do you know?

 

[Quinton]

Wow, that's fantastic that it flew that well with the load.

Now, is this machine "overpowered"? ie: how much %throttle does it take to hover, do you know?

I actually tested it in manual just before this happened, at 50% throttle it went down slightly, 1 notch on the ratchet above 50% throttle and it started to climb.

Just waiting to try it out with 16" Xoars later this week, I know the T-props have much more thrust, but they also make it more "twitchy"
This machine is 9.5 Kgs with the gimbal and 2 x 8300 Mah Lipos, everyone has been saying to me you need 8 motors to fly this, but I don't see a problem with it.

Here are some tests I did last week with the MT3515-15 and different props on a bench..


T-Motor 15x5 Props

25% 25.6W 1.11A 270g Thrust
50% 95W 4.2A 900g Thrust
75% 315W 14.0A 2000g Thrust
100% 480W 21.23A 2800g Thrust

Xoar 15x5 Props

25% 24.4W 1.05A 180g Thrust
50% 86W 3.75A 595g Thrust
75% 293W 13.11A 1600g Thrust
100% 434W 19.8A 2430g Thrust


T-Motor 16x5.4 Props

25% 25.5W 1.11A 355g Thrust
50% 110W 4.8A 1060g Thrust
75% 350W 15.3A 2370g Thrust
100% 536W 24.3A 3200g Thrust

 

[R_Lefebvre]

Ok, so there's some comments here like:

awesome- should put the 'loose 1 motor your done myth on a loaded hex to rest'- not awesome about your motor of course

The thing is, it's not about the payload, it's about the thrust reserve. In this case, it seems you have tons of thrust reserve even with the payload. If you had a more common thrust reserve of maybe only 30%, things would be different.

Not to take anything away from that controller. It's very impressive that it can do that at all. But some basic physics still apply to the situation.

 

[Carapau]

Rob, you are so right there. I see a lot of people flying heavy cameras- eg Reds on rigs that whilst seem perfectly powered with all motors working, would not last if a motor were to fail. The more expensive the camera the more need for redundancy and this is where too many people skimp out.

 

[jes1111]

at 50% throttle it went down slightly, 1 notch on the ratchet above 50% throttle and it started to climb

Small point - but I had this phenomenon - I disengaged the ratchet on the throttle (simple job on Futaba 8FG - YMMV) and now I can "trim it" to stay at my chosen altitude without constant "1-click" corrections.

 

[Quinton]

Small point - but I had this phenomenon - I disengaged the ratchet on the throttle (simple job on Futaba 8FG - YMMV) and now I can "trim it" to stay at my chosen altitude without constant "1-click" corrections.

Not sure what controller you use Jes, but I was talking about being in manual when I did that.
I would not fly around in manual unless I wanted to go upside down.
With the wookong, it will ALWAYS hover at the same altitude if you have it set at 50% in GPS/ATTI mode

 

[DucktileMedia]

Jess is saying if you have ratchets, you sometimes can't find a happy spot unless it's right between where the ratchets hold the throttle. I had this experience as well and decided to remove the metal tab that makes the ratchet work. But more than anything a gentle well tuned throttle curve is king. also good that you knew to test the percentage of lift in manual and not atti as a lot of pilots still dont know that most controllers apply throttle based on stick position and not percentage of stick movement.

 

[Benjamin Kenobi]

Hey Quinton,

This was my exact experience when a motor went out. You could hardly tell except the blade stopped. Still had full control, albeit slow to respond to yaw.

Brilliant that you got it on video!

 

[sk8brd]

if you build your rig right you should be around 50% throttle range at hover at your auw- anything higher your wasting amps. Due to the fact that this is a loaded hex coming in at 20lbs meaning auw weight not payload a wee bit heavier then most hex's out there Quinton's demonstration proves you can a heavy hex and still come out ok w/ a motor out. Clearly he built the thing to be efficient and picked the correct components to achieve an efficient setup at his weight. I have seen plenty of conversations of people saying the opposite regardless of how much power you got on tap. When my build is complete i will perform same test hopefully a2 reacts similar to wookong. i'm pretty sure w/out this type of software on the fc the results would be predictable.:nevreness: