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Old Jan 01, 2013, 05:45 PM
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Originally Posted by gbmarsh View Post
Or use 3 servo 'Y' cables and do all 4 together

Cheers,
Geoff
It is suggested in most forums that it is best to do them individually...I have never done more than 1 at a time so I cannot confirm or deny how well that works.
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Old Jan 01, 2013, 08:58 PM
Wait...what?
gbmarsh's Avatar
Canada, BC, Abbotsford
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Originally Posted by Flying By View Post
It is suggested in most forums that it is best to do them individually....
Really, why is that? All you are doing is letting the esc read and store the full pulse range from your rx throttle channel. So if you do this with the 'Y' cable setup, all 4 escs get that info at the same time. I've done it this way many times and can confirm it works and saves time

Cheers,
Geoff
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Old Jan 01, 2013, 09:55 PM
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Originally Posted by gbmarsh View Post
Really, why is that? All you are doing is letting the esc read and store the full pulse range from your rx throttle channel. So if you do this with the 'Y' cable setup, all 4 escs get that info at the same time. I've done it this way many times and can confirm it works and saves time

Cheers,
Geoff
Not exactly sure why many say to do them individually...but if you can do all 4 at once that is awesome. I will have to try that next time.
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Old Jan 02, 2013, 01:08 AM
Wait...what?
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Originally Posted by Flying By View Post
Not exactly sure why many say to do them individually...but if you can do all 4 at once that is awesome. I will have to try that next time.
Ah, I think when they say individually they mean independent of the flight controller.
The reason for this is so that sensor/motor mix data does not effect the calibration.

Some references:
http://www.rcgroups.com/forums/showt...l#post22431364
http://www.rcgroups.com/forums/showt...l#post17011223
http://www.rcgroups.com/forums/showt...l#post21457545

Hope that helps

Cheers,
Geoff
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Old Jan 02, 2013, 08:09 PM
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Joined Oct 2012
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My Quad Wants to Flip

I've calibrated my ESCs and everything in the GUI. Now the first time I put the props on and power it up the quad wants to flip over.

As I slowly increase the throttle, I see 2 front motors start spinning first then the rear-right and lastly the rear-left. Also, the motors sound like they're revving up and down. Finally, if I give enough throttle to try to take off the quad will just flip (either forward or backward).

Attached is my config and I'd appreciate it if anyone could help.

Thanks.
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Old Jan 02, 2013, 09:54 PM
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I had similar behaviour on my quad, turn on the tx, plug in the battery, throttle up to take off, and at not even a quarter throttle one or two random motors would be revving high enough to flip the thing before I could react and shut it down. It turned out I needed to recalibrate the gyros. Try this order, tx on first, quad on ground, does not need to be perfectly level, just still, plug in battery, let receiver see the tx, give it a second, disarm motors just to be sure, throttle down yaw left and hold, now pull the pitch stick down, the board flashes to show it's calibrated, now try to take off.
looking back I may or may not have been holding the quad while fiddling with the connector, probably confusing the hell out of the gyro, oops.
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Old Jan 02, 2013, 11:49 PM
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Originally Posted by Gregco10 View Post
I had similar behaviour on my quad, turn on the tx, plug in the battery, throttle up to take off, and at not even a quarter throttle one or two random motors would be revving high enough to flip the thing before I could react and shut it down. It turned out I needed to recalibrate the gyros. Try this order, tx on first, quad on ground, does not need to be perfectly level, just still, plug in battery, let receiver see the tx, give it a second, disarm motors just to be sure, throttle down yaw left and hold, now pull the pitch stick down, the board flashes to show it's calibrated, now try to take off.
looking back I may or may not have been holding the quad while fiddling with the connector, probably confusing the hell out of the gyro, oops.
I tried what you suggested to calibrate the gyro. After that it was a little better but still flipped over if I applied too much throttle. I think it's because of the uneven throttle. If I gradually decrease the throttle I can actually see RL and RR props stop spinning (or barely) while FL and FR are still going. This is consistent to the attached pic.

What should I do to make the motor output in sync? I've tried to calibrate all 4 ESCs individually and all at once (using ESC_CALIB_CANNOT_FLY in the config.h) but to no avail.
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Old Jan 03, 2013, 12:12 AM
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Originally Posted by notlkk View Post
I tried what you suggested to calibrate the gyro. After that it was a little better but still flipped over if I applied too much throttle. I think it's because of the uneven throttle. If I gradually decrease the throttle I can actually see RL and RR props stop spinning (or barely) while FL and FR are still going. This is consistent to the attached pic.

What should I do to make the motor output in sync? I've tried to calibrate all 4 ESCs individually and all at once (using ESC_CALIB_CANNOT_FLY in the config.h) but to no avail.
Hi notlkk, looking at all the GUI screen shots you have posted I notice you are getting LOTS of I2C errors which would indicate their is a problem with one of the sensors on your board.

Cheers,
Geoff
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Old Jan 03, 2013, 01:21 AM
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Originally Posted by gbmarsh View Post
Hi notlkk, looking at all the GUI screen shots you have posted I notice you are getting LOTS of I2C errors which would indicate their is a problem with one of the sensors on your board.

Cheers,
Geoff
Geoff, thanks for the response. I forgot to comment out GPS in config.h and that's why you see a lot of I2C errors. I've since commented it out and those errors are gone. However, the problem still exists. When I gradually throttle up my RL motor is still not spinning while the other 3 are.
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Old Jan 03, 2013, 01:37 AM
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Originally Posted by notlkk View Post
Geoff, thanks for the response. I forgot to comment out GPS in config.h and that's why you see a lot of I2C errors. I've since commented it out and those errors are gone. However, the problem still exists. When I gradually throttle up my RL motor is still not spinning while the other 3 are.
I had something similar. Make sure the propeller configuration is *exactly* as it show in the manual and I mean exactly. I had the inverse on each one so out of desperation I changed my motor wiring to match the manual and now it flies ok...
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Old Jan 03, 2013, 01:45 AM
Wait...what?
gbmarsh's Avatar
Canada, BC, Abbotsford
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Originally Posted by notlkk View Post
Geoff, thanks for the response. I forgot to comment out GPS in config.h and that's why you see a lot of I2C errors. I've since commented it out and those errors are gone. However, the problem still exists. When I gradually throttle up my RL motor is still not spinning while the other 3 are.
Right then, how about posting a list of gear on your quad i.e motor/ esc specs and brands, prop size, frame dimensions and all up weight to give us a baseline to start troubleshooting from.

Cheers,
Geoff
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Old Jan 03, 2013, 01:56 AM
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Originally Posted by rcmonster99 View Post
I had something similar. Make sure the propeller configuration is *exactly* as it show in the manual and I mean exactly. I had the inverse on each one so out of desperation I changed my motor wiring to match the manual and now it flies ok...
Yes. I think I have them correctly configured. FL and RR are CW, FR and RL are CCW. Again, I think the main problem is the motor output is not even. I've tried to trim my Tx to make them go even but it's almost impossible.
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Old Jan 03, 2013, 01:57 AM
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Originally Posted by gbmarsh View Post
Right then, how about posting a list of gear on your quad i.e motor/ esc specs and brands, prop size, frame dimensions and all up weight to give us a baseline to start troubleshooting from.

Cheers,
Geoff
Frame: cloned F450
Motors: F4006 950kv
Prop: Gemfan 11x4.7
ESC: Skywalker 20A
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Old Jan 03, 2013, 02:44 AM
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Originally Posted by notlkk View Post
Frame: cloned F450
Motors: F4006 950kv
Prop: Gemfan 11x4.7
ESC: Skywalker 20A
Looks good, what are your MINTHROTTLE & MINCOMMAND settings in config.h ?
Also have you tried calibrating all 4 esc at the same time using the servo 'Y' cable setup?
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Old Jan 03, 2013, 10:14 AM
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Originally Posted by gbmarsh View Post
Looks good, what are your MINTHROTTLE & MINCOMMAND settings in config.h ?
Also have you tried calibrating all 4 esc at the same time using the servo 'Y' cable setup?
Here's what I have in my config.h:

#define MINTHROTTLE 900
#define MINCOMMAND 800


I didn't use the servo Y cable to calibrate my ESCs but I did calibrate them individually by connecting the ESC cable to my Rx throttle channel. Also tried the

//#define ESC_CALIB_CANNOT_FLY // uncomment to activate

in config.h to calibrate all of them together.

UPDATE:

I did ESC_CALIB_CANNOT_FLY to calibrate all ESCs again. Now when I connect the battery and arm all 4 motors/props seem to spin at the same speed. However, the problem is they start spinning right after I armed without even moving up the throttle. Also, when I increase the throttle the quad will flip forward so it seems the rear motors are spinning faster than the front ones.
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Last edited by notlkk; Jan 03, 2013 at 11:01 AM.
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