New build test flight just crashed

[tombrown1]

View attachment 18863

Could really use you guys on this one.

CarbonCore 650 flat 6 converted to Y6
Tiger MN4014 -400KV
Tiger 15" props
WKM
Maytech 45A opto SimonK (preloaded)
Gryphon dist board
2x 8000mah nanotech lipos

Did its maiden about a week ago - very windy and jittery flight, but was ok - ran out 3 sets of lipos. Got home and realized I never calibrated the compass - stupid.

Fast-forward to today - I calibrated the compass - it was successful. Then went up. About 4 minutes in it was smooth as silk - amazing. No weird flashes or anything. About 20 feet up and it dove straight down. Didn't even have time for manual.
Lipos are perfect - all 12 cells are evenly drawn. There was some strange alarm going off that I've never heard before - it was a different sound than my lipo alarms. It must have been an esc. Does anybody know if these escs have alarms, and what would trigger them?

All 3 top motors were much hotter than 3 bottom motors - not burning my hand hot, but pretty hot. A few of the escs were also very hot - I assume the escs that went with the top motors.

I bought the WKM second hand, but having never been used several months ago - I was assured it was purchased new no earlier than last fall. So it shouldn't have been a FOD compass. I have the V2 upgraded IMU on it.

Manual mode was lifting it at about 53% power.

Wrecked up my brand new gimbal pretty good - though I didn't have a camera on it.

Really pissed right now. Every part of me wants to blame DJI and jump to SuperX, but I know that most of these crashes are caused by other things - and I think there's a good chance something else is going on.



Any help will be great. I'm devastated right now - spent all winter on this damn thing.



Thanks,

Tom

 

[kloner]

If i had to guess it's commutation errors between simonK firmware and high pole count motors.

take off all the props but one, fire it up, brace it and rev it really fast, low to high, does it lock up? make any chirping? smooth as ever?

 

[tombrown1]

Thanks Kloner. I'll try that next chance I get. What should I use with these 4014s? I thought Maytech Simonk was supposed to be a slam dunk.

 

[kloner]

try em out and see what there doing.... might be wrong, but i think is the case.

i'd get a matched set of whatever,,, if tiger motor then look into the tiger esc... they show 40a on there site.

 

[tombrown1]

OK, so I ordered Hobbywing Platinum 40A escs, installed them and put her up in the air today. Just to refresh, I'm running a 650mm frame at 6S with Tiger 4014s and 15" tiger props.

She flew great today - ESCs were all cool to the touch - great flight times.

Only problem was that all 3 top props were quite hot and all 3 bottom props were cool. Hover was around 45% with no load (ugh...).

So here's the question: What will happen if I put 14" props on top? Will that even out the temps of all 6 motors? Will it improve or degrade my hover %? Flight time?

I'm really trying to figure out of I need to scrap this entire project. I'll be using an extremely light gimbal with GH3. I'm guessing I'll be around 60% hover which isn't great, but how bad is that? Do I need to get a 800mm frame and different motors/props altogether, or is there a chance to make this work?

Thanks again to everyone who has given me a ton of help on this site. It is invaluable.

Best,

Tom

 

[Old Man]

It's possible to overload both an electric motor or a gas engine with too much prop. Over loading either makes them run hotter. If everything else was working as it should it may be worth the try of the 14" props. If the motors are good for the increase in RPM you'll probably find the throttle position for lift off increasing to a bit closer to that 50% sweet spot. If you go much past 50% before lifting you might consider aborting the test. Might consider using a ballast weight instead of a gimbal during the flight testing.

 

[tombrown1]

Thanks for the response. I think I really have no choice but to get the 14" props now. I just feel like I keep pouring money into something that might not ever even be functional.

I have to say that I'm really excited about the size of this thing. I would love to show up at a gig with a 650 that does just as good of work as our monster 1200 x8. The journey continues...

 

[jes1111]

It doesn't make much sense to runner SMALLER props on the top motors. Normally one would be putting higher pitch of the same diameter on the BOTTOM in order to even the workload. The higher temperature of the top motors and ESCs indicate that they are doing more WORK than the bottom ones in order to control yaw. That suggests an imbalance of some sort - a mechanical or electronic bias to yaw CW which needs to be countered constantly by the CCW props. The problem is to figure out why. Could be a mechanical alignment error, could be ESC calibration, could be an out-of-spec ESC, could be any number of things.

My first test would be to swap the top/bottom ESCs around, i.e. drive the top motors with the bottom ESCs and vice-versa - see if the problem now appears on the bottom motors.