MultiWii / NAZE / SP Racing F3 Multiwii 328p Thottle problem!!

[JLawrence]

Hey guys,

I am using a Multiwii 328p FC that I picked up from hobbyking. I installed the multiwii 2.3 firmware on it and uncommented what I needed to. After calibrating the ACC and MAG on the GUI, I still have problems. 1) The motors do not seem to power up evenly, and the quad ends up flipping over backward when I try to hover. 2) While holding the throttle constant (say at 20%) two out of the four motors will slowly start to speed up to full throttle.

Does anyone have any suggestions?? It is starting to drive me crazy..

Thanks,
John

 

[mattjb]

Hi John,

I have this same problem. I have used Multiwii v2.2 and v2.3 and have the same problem. I'm using Turnigy Plush ESC flashed with BLHeli firmware (setup for quadcopter), and Multiwii Pro board with the Atmel2560.

My Quad is flyable, but my PID settings are quite low.

I wonder if this is normal behaviour though because the quad can't adjust while on the ground and is slowly trying to.

Any other experts that can shed some light on this would be much appreciated.

I'm having trouble getting my Quad "dialled" in, but think this may be due to some really crappy bearings in my motors.

Matt.

 

[Raldan]

I'm no expert by any stretch, but here's a few thoughts...

JLawrence: 1) The motors do not seem to power up evenly, and the quad ends up flipping over backward when I try to hover. 2) While holding the throttle constant (say at 20%) two out of the four motors will slowly start to speed up to full throttle.

My throttle problems were due to uncalibrated escs. Search for info on that.
If you have a good combination of motors/prop/batt/weight, you should be able to hold hover at about 50% throttle. See ecalc.ch for help with your config.

Check to be sure when starting on the ground that Baro is NOT turned on. That was my mistake early on. The Baro is trying to maintain altitude (at present ground level) so it was fighting my quad lifting off. Also be sure to starting from as level a surface as possible.

The modes to fly in are viewable and configured using the MultiWiiConf app.

I have horizon on all the time on my board and I then add Baro to Horizon once I am in the air. I use a small black foam pop screen from a headset microphone I wasn't using and positioned it, covering the baro chip (the one with the pinhole in the center). That chip dislikes both light and gusts of wind (prop wash). A microphone pop filter's foam can do just the trick. Search for ways to secure it to your board. Since I have a copper clad pc board over my flight board on standoffs, I wedge the pop screen under the board and secure it using a small loose cable tie. The pc board serves as a base for my gps chip.

View attachment 17702

I'm on my mac operating system, so I don't have access to my PID settings at the moment, but I can dig them up if needed. I'm still getting the bugs out of my quad. With an AUW of 1.5kg, I can hover in the wind for 12-13 mins using a 5000mah 30C 3S. My hover seems okay (waiting for a windless day here in SoCal) but the GPS toilet bowls in a 15 foot diameter circle. It also jitters considerably. The baro oscillates up and down about 4 feet when on. With the wind, that could be atmos conditions.

mattjb: I'm having trouble getting my Quad "dialled" in, but think this may be due to some really crappy bearings in my motors.

I had some issues with poor motor mounting, using cable ties to secure them to the wood booms. Once I tightened things down, I got rid of some wobbling on one motor.

Keep at it guys, it definitely gets better. At the least you're learning.

 

[JLawrence]

So I finally was able to get mine flying without problems. Well besides my horrible piloting skills. I just reflashed all of my ESC's and eeprom cleared the FC twice and reloaded the firmware. Took it outside and it seemed to fly great!

 

[mattjb]

Nice going!

Great reply from Raldan.

I'm going to reflash my Plush ESCs with the latest version of BLHeli and try a new set of motors with bearings that don't sound like they are rotating on broken biscuits! My motors are secured to DJI arms directly so there isn't a vibration problem there. I'll find a use for the crappy NTM motors in plane somewhere.

I'll work on one fix at a time and try to learn, and eliminate the problems.

 

[JLawrence]

So all in all, my quad is flying okay. The only thing is the controls seem to be incredibly touchy. The slightest roll or pitch and the thing is gone. Is this normal? Anyway to make this a softer transition for a beginner pilot like myself?

 

[Raldan]

So all in all, my quad is flying okay. The only thing is the controls seem to be incredibly touchy. The slightest roll or pitch and the thing is gone. Is this normal? Anyway to make this a softer transition for a beginner pilot like myself?

What mode you in?

Once you release the stick, does the copter stop and try to level itself or just keep going?

 

[SoCal Blur]

So all in all, my quad is flying okay. The only thing is the controls seem to be incredibly touchy. The slightest roll or pitch and the thing is gone. Is this normal? Anyway to make this a softer transition for a beginner pilot like myself?

You can set up Expo in your radio to make curves for Pitch and Roll that will ease you into each.

 

[kraftybrett]

Hi there. Regarding you control sensitivity, Using the GUI or the android App just increase the RC EXPO until your happy with sensitivity.
HAPPY TUNING