Heavy Lift Project Setbacks & Moving Forward

Blayne Chastain

Blayne Chastain

MR, Heli & Sailplanes
Hey guys. Some of you might have followed along with my build of our Gryphon Dynamics X8 over at www.gimb.al

Initial test flight was successful but we had what we believe to be ESC failure during a 15lb weight lift test.

ESCs were Maytech 75amp with Simon K. Motors: Tmotor u7 490kv.

Not meaning to draw folks over to our website specifically, it's just where we log our builds.

I received a note (after-the-fact) from Maytech that they ended up finding that SimonK wasn't playing nice with some of the TMotor U-Series. I also have a friend who experienced similar issues - his theory was more that the U7 490's were drawing more power than on the spec sheet and that the ESCs simply weren't designed to handle the Wattage even though everything falls within published specs.

While that may be true, there's also probably something to the the simonK / tMotor compatibility issues. TBH, I've been off the forums for the last couple months as I've been caught up between other projects and summer travel. That said, I'm not as "up" on the current state of affairs in MR land :)

So now I'm ready to move forward and reconsider both my ESCs and Motors.

This platform was designed to produce roughly 80lbs max thrust with 18" props.

Would be interested in your thoughts - those of you with heavy-lift build experience.

Build Outline for Reference

Intro
http://gimb.al/build-log-gryphon-x8-day-1/

Power Distro
http://gimb.al/build-log-gryphon-x8-day-2/
http://gimb.al/gryphon-x8-day-3/

Component Planning
http://gimb.al/gryphon-x8-day-4/

ESC & Motor / Arm Assembly
http://gimb.al/gryphon-x8-day-5/
http://gimb.al/gryphon-x8-day-6/
http://gimb.al/gryphon-x8-day-7/

Final Assembly
http://gimb.al/gryphon-x8-day-8/

Successful Test Flight
http://gimb.al/gryphon-x8-day-9/

Nav Light Installation
http://gimb.al/gryphon-x8-day-10/

Crash Video with Wookong Flight Log Download
http://gimb.al/gryphon-x8-crash/

After analyzing flight log data, it's pretty clear that the WKM was doing all the right things. Most of my peers have pointed to the ESCs as the first place to start.

Looking forward to our discussion here on this.

Thanks in advance,
 

kloner

kloner

Aerial DP
you need the t-motor 80 amp esc's for those.....

hear that metalic sound that comes and goes, that's your motors/esc in commutation error,,,
 

Blayne Chastain

Blayne Chastain

MR, Heli & Sailplanes
Thanks for the insight Kloner. So, you're saying it wasn't an issue of power spec but of firmware yes? Are folks staying away from SimonK for these motors that you know of?

kloner said:
you need the t-motor 80 amp esc's for those.....

hear that metalic sound that comes and goes, that's your motors/esc in commutation error,,,
Click to expand...
 


kloner

kloner

Aerial DP
absolutely.... do this, take off all but one prop, pin the rig to the ground and rev the throttle from 25-100% as fast as you can, your gonna hear/see this


go to t-motors website and lookup the description on the u7....
 
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stevemaller

stevemaller

Heavy Lifter
If I was going true heavy lift right now, I'd go with the KDE motors and ESCs. They're very technical folks, based in the USA, and extremely responsive to support questions. U7 motors seem to be extremely tweaky and I've seen tons of horror stories with them over the past few months.
 





Blayne Chastain

Blayne Chastain

MR, Heli & Sailplanes
Thanks Steve. We have considered this route but wanted more headroom than what the Hercules III offers (30amp cont / 60amp burst from what I recall). Have heard nothing but great reviews and have almost pulled the trigger a couple of times.

baja-king said:
Hi Blayne,

I would seriously look at the Hercules III if you want a bullet proof ESC and as already suggested KDE motors...

http://www.andreasbaier.de/index.php/en/herkules-iii-generation-3

http://kopterworx.com/shop/powerboards-esc/herkules-iii/herkules-iii-3-6s-brushless-esc-okto-xl.html

Steve
Click to expand...
 

Blayne Chastain

Blayne Chastain

MR, Heli & Sailplanes
Thanks Steve. I have an email in with KDE - looking forward to chatting with them.

When you say that you've heard horror stories - I'm assuming this is with SimonK equipped ESCs?

stevemaller said:
If I was going true heavy lift right now, I'd go with the KDE motors and ESCs. They're very technical folks, based in the USA, and extremely responsive to support questions. U7 motors seem to be extremely tweaky and I've seen tons of horror stories with them over the past few months.
Click to expand...
 


stevemaller

stevemaller

Heavy Lifter
Blayne Chastain said:
Thanks Steve. I have an email in with KDE - looking forward to chatting with them.

When you say that you've heard horror stories - I'm assuming this is with SimonK equipped ESCs?
Click to expand...
Nobody I know is using those ESCs on heavy lifters.
Here's an interesting video that you might appreciate from KDE where they test the responsiveness of their ESC with both their new big motor and a Tiger U7.

 
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Blayne Chastain

Blayne Chastain

MR, Heli & Sailplanes
At the time that I was building this rig initially, many were using SimonK but things move fast and sometimes you're penalized for being an early adopter :) It wasn't until after we had our issues that folks were reporting similar issues - some reporting much greater losses with full camera payloads on board so I consider ourselves relatively "lucky"...

I did see that video earlier today - really impressive.

Much appreciated.

stevemaller said:
Nobody I know is using those ESCs on heavy lifters.
Here's an interesting video that you might appreciate from KDE where they test the responsiveness of their ESC with both their new big motor and a Tiger U7.
Click to expand...
 

kloner

kloner

Aerial DP
commutation error, i can hear it trying in your video and i can see that shake it does when it's not shutting off the motor..... flight controllers hate the incompatible esc thing, there not tunable and it'll crash sooner or later.
 

kloner

kloner

Aerial DP
It has been the gold standard for red lifting for the last 2 years.... up untill fall of last year, it was the way we all built em.... i still fly one now, and it's awesome



stevemaller said:
Nobody I know is using those ESCs on heavy lifters.
Here's an interesting video that you might appreciate from KDE where they test the responsiveness of their ESC with both their new big motor and a Tiger U7.

Click to expand...
 
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Blayne Chastain

Blayne Chastain

MR, Heli & Sailplanes
Sorry, I meant on your video that you posted with your rig with the 60amp Maytech - was that also a comm error?

kloner said:
commutation error, i can hear it trying in your video and i can see that shake it does when it's not shutting off the motor..... flight controllers hate the incompatible esc thing, there not tunable and it'll crash sooner or later.
Click to expand...
 

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