[techcoast]

I've flown this CC3D with Libre and had a lot of success. But, now I'm running into an issue and I don't know why that is. The issue is, I calibrated the entire thing, each ESC was tested and confirmed with the wizard, then I put props on it and try to spool it up but I get nothing out of No 4 until the throttle is up pretty far and the rest of the props are already screaming.

Now, as I type this I figure I better test the Tx for throttle position and low and behold it now throttles up. I put it down and now the motors start doing strange things like accelerating on their own causing the bird to tip.

I'm a little frustrated now, has anyone else encountered such issues?

Help is GREATLY appreciated. 

[jbarchuk]

I think once you made variations in the Tx that you need to calibrate ESCs again to account for the new throttle endpoints. Maybe not but couldn't hurt to try.

Following the pic in the vehicle wizard, confirm rotation directions of each prop, and that each ESC is plugged into the correct servo port.

Confirm props are mounted right side up (letters up.)

When you start spinning props and something seems 'weird,' stop trying right there. The FC is already confused and needs to be reset (cycle power) or it will remain confused. Then try something to fix it and try spinning props again, but always cycle power between tries to reset the whole FC.

[hwh]

You mean accelerating on their own while sitting on the ground armed with the motors spinning lower than takeoff speed?  That's normal, you can't sit on the ground with the bird armed, you should take off or disarm.  On the ground armed the cc3d will start trying to level the bird and also noise on the sensors makes it try to change attitude.  As the error accumulates and the bird doesn't move it speeds up the motors trying to get control of the attitude.

The one engine not working right and magically starting to work correctly sounds more like a loose connection.

[techcoast]

Yup, verfified everything and started from scratch.. still the same. Wondering if the ESC's took a dump. SomonK 20A..

[techcoast]

I barely touch the throttle and it just quickly accelerates into a high throttle. I understand to take off quickly and get it in the air, but this thing just flips.

[hwh]

Flipping as you try to takeoff sounds like what jbarchuk was saying, a wrong prop (cw/ccw) on an engine, an engine turning the wrong way, or the engines not plugged in in the correct order.  Has this bird flown before or is it a new build?

Please check the above things and if it's not one of them post a copy of your settings, file -> export uav settings while the board is connected.  That allows much faster checking of settings than asking what's this set at, what's that set at, etc...

And don't be frustrated, someone here will help you figure out what's wrong and get you in the air again. 

[techcoast]

This bird has flown with this FC. I verified rotation and props. I switched out FC tonight and still had the same issue.  Im thinking it's an ESC issue

[techcoast]

I appreciate the help

[techcoast]

Here's the UAV file from when this whole thing started. The second one is the current settings with the new FC that still gives me the same behavior.

[Mateusz]

Some ideas

• Recalibrate ESCs (without props) using wizard easy way. Manual way is to set max (usually 2ms pulses), then connect battery, wait for beeps, turn to min (usually 1ms pulses) wait for beeps, disconnect battery.
• Calibrate neutral points again (without props) connect battery use wizard.
• Check length of the screws if they don't penetrate motors stator. I had case which was hard to believe, and I even made a movie of it. ESC was fine, but motor once accelerated, could never stop. The cause was too long screws penetrating stator and shorting some windings. Removing just one motor screws was fixing the problem (100% repeatable issue same result 5-6 times).
• Do the motors spin the same way or get same neutral point when you are doing it via vehicle wizard ? If so, then ESC/FC/Motors combination is fine, and it must be your transmitter.

[techcoast]

Hearing about the possibility of a TX problem prompted me to check the cables from the RX to the FC. Sure enough there was a nick in one of the control cables. I switched out the cable with another and re-calibrated. Now, I can hover, but it needs a lot of input from the tx to get there. I check the orientation on Libre and it's 0 all around, but as soon as I manually rolled the bird the horizon rolled and was offset about 25-30 degrees from 0. It also shows a slow pirouette to the left on the lower screen.

[techcoast]

And yet even more puzzling. Now, I re-connected the bird to Libre, and it's all zero'd out. Everything looks good. I do a quick hover and it's perfect.    Go figure. Anyway, I'm going to keep an eye on this thing but I have to admit I'm rather skeptical of this FC now.  Any ideas why this would be happening??

[Mateusz]

And yet even more puzzling. Now, I re-connected the bird to Libre, and it's all zero'd out. Everything looks good. I do a quick hover and it's perfect.    Go figure. Anyway, I'm going to keep an eye on this thing but I have to admit I'm rather skeptical of this FC now.  Any ideas why this would be happening??

Sometimes changing some settings requires rebooting flight controller. I am not sure what you mean by "all" zero'd out. Hope you didnt lose your configuration ? That would not be normal behaviour, unless you erased it explicitly. But I am glad it works and flies nice for you

[techcoast]

All zero'd out meant that the horizon was level. I understand that the quad needs a chance to re-boot, and maybe that was the final thing that made the difference. It just makes me very cautious to do anything with this FC now.. I just wish I had a more definitive answer.