One motor starting slightly slower. Vid in slo-mo

[Pumpkinguy]

I have 1 hour flying time on my new rig. It's been flawless. I noticed from the first flight that #6 starts a little slower than the rest. It's hard to see in real time so I filmed in 240fps and slowed 20x.
What causes this? Kde motors and esc's.

 

[Old Man]

Hope you get an answer. I have a similar start up condition with one motor.


Sent from my iPhone using Tapatalk

 

[Pumpkinguy]

I'm just editing a clip in flight. I think # 6 is going slower than all the others. 1-5 May be compensating so without slomo I would have never known.

 

[Pumpkinguy]

#6 is on the right. looks slower to me.

 

[Hexacrafter]

It looks like #6 in both the start and while flying. My first bet is lazy ESC. You will need to perform some tests. You can do it props off. Swap #5 and #6 servo plugs on the FC start motors over and over.... Did the lazy motor stay #6 or is #5 now lazy... If #5 then you know it is not the FC. If#6 then the FC may have issues.....but I am betting against that. So let's go back to #5 is then lazy....it is either a motor or ESC. So put things back correctly at the FC with #5 and #6. Now swap ESC to motor connections. If the problem follows the motor..#6. Then it is a motor with issues. Again betting against that. If #5 then it is a lazy ESC. Then replace the ESC. We have seen about 1 of every 50 ESC act this way. This is my bet.. Please advise of the outcome.
Andrew

 

[Pumpkinguy]

Thanks Andrew. I was thinking esc. I am gonna test tomorrow. Then toss a spare in if necessary. I have all the luck in the world. I have emails into kde. I know Patrick will take care of me. Cheers.

 

[Pumpkinguy]

It's the motor. 100%. Switched esc wires. Still #6. Switched servo cables still#6.

 

[SleepyC]

Man, I had the same issue with a rig I had. Andrew from @Hexacrafter and I spent months trying to figure out the problem and we couldn't figure it out. 2 sets of ESC's, 3 flight controls... ended up we replaced the motor and the rig flew like glass.

If you can, see if you can swap #5 and #6 motors and see if the slow motor changes places.

 

[Pumpkinguy]

Man, I had the same issue with a rig I had. Andrew from @Hexacrafter and I spent months trying to figure out the problem and we couldn't figure it out. 2 sets of ESC's, 3 flight controls... ended up we replaced the motor and the rig flew like glass.

If you can, see if you can swap #5 and #6 motors and see if the slow motor changes places.

You were probably posting when I was. It's the motor.

 

[Hexacrafter]

Great! I am very happy you have this sorted.... Lost the bet, but at least helped with the investigation....
Bad motors are pretty rare.... but it happens..
SleepyC and I had to have a few beers sorting out his bad motor.... and more beers... and more beers..

 

[SleepyC]

Funny enough, we found the problem in the same way by mistake. I did an iPhone slo-mo simply to show the rocking I was seeing in the rig and when we played it back we were like.. WOAH SLOW MOTOR!

 

[Pumpkinguy]

I'm wondering if it was always like that or if I damaged it in the gryphon crash. Physically it was not touched in the crash. I carefully inspected every motor.
It is obviously electrical and not mechanical.

 

[Pumpkinguy]

I think we learned here that slow motion is an amazing tool. I could have flown with this for months and never known.

 

[Hexacrafter]

I think you would have found out sooner than later......
As it progressively gets worse, you try and tune it out with gains and then again and again until it is not tunable. Then it start flying like a "drunken sailor".... This I have seen a few too many times....

 

[Pumpkinguy]

Well, I just had to know. Here is a slowed down start up vid of my Gryphon maiden flight. There would only be 2 flights for a total of less than 10 minutes before I had a crash. Total loss of frame and other components totalling $3000. Looks like the motor on the right is doing the same thing. That must be the one. Obviously I couldn't tell it was spinning slower. But this vid confirms this motor was not damaged in the crash. It came defective from the factory.