Couple Newbie Questions / Observations from my DJI F550

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plasticjoe

Member
I am a total newbie to multirotor... flown planes and electric planes for 10+ yrs tho... I purchased a DJI F550 and so far, I have about 50 flights on it and am getting pretty good at fast forward flight and turns.
I am flying stock motors and esc's. Naza only... no GPS yet.. and 4 cell 4000 and gemfan 10 inch props.

1. I have monitored the temps on the esc's and motors and they come down lukewarm on the motors and the esc's... totally cool ( I heard that 4 cell = 8 inch props... but saw many posts with guys flying 4c on the stock ones ) Just curious if I am pushing the edge on this.. high temp = bad things.. and these are totally cool.

2. I have had this happen 2x so far... and I think it might be an initialization issue ? What is happening is this... I plug in the battery... hear the chimes... then when I go to spool it up... it flips over. Had this happen 2x in the grass so far with no damage. I unplug the battery... plug it back in.. and no issues. Comments ? Ideas ?

3. I have noticed that there is one motor that is a little slower on spool up than the others... but once it's up and running there is no issue with it drifting other than with the wind direction. Not sure if that has anything to do with #2 above .

4. There is a little "oscillation" when hovering... but I think that could be due to no GPS ? The balance is right on... or maybe I need to balance motors or props ?

5. Also I noticed that when I go from Attitude mode to Manual mode... the rotor speed picks up about 30%+ just from the flip of the switch. I know it's alot more manuuverable in that mode.. and am going to test some slow flight with it... but the sudden increase in speed is almost like when my son has his throttle/pitch curves on his helis off on the normal to idle up mode switch. Just curious if this is a normal reaction when the mode is switched.


As I said... I am totally new to all of this... and so far everything seems OK... just had some observations that I'd like to ask about. Thanks in advance for your replys :)
 
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jforkner

jforkner

Member
Had an incident similar to Item #2 yesterday with my Naza-based quad. I flew briefly (2-3 min.), landed, unplugged the battery, then plugged it back in for a second flight. During arming, I noticed the #1 motor lagging during spool-up; decided to give it a go anyway. Upon applying power it flipped over the front right-side. Three more attempts resulted in the same thing. Very frustrating since it had flown fine just prior.

I'll be monitoring this thread to view responses and/or troubleshooting ideas.


Jack
 

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Chalagi

Member
Sounds like a bad bullet connection. I had the same thing but mine never flipped. One motor was very slow at getting started so I redid the bullets on that motor and everything was fine.
 

Benjamin Kenobi

Benjamin Kenobi

Easy? You call that easy?
Chalagi said:
Sounds like a bad bullet connection. I had the same thing but mine never flipped. One motor was very slow at getting started so I redid the bullets on that motor and everything was fine.
Click to expand...

Agreed. At least bullets are easy to solder!:02.47-tranquillity:

1. I have monitored the temps on the esc's and motors and they come down lukewarm on the motors and the esc's... totally cool ( I heard that 4 cell = 8 inch props... but saw many posts with guys flying 4c on the stock ones ) Just curious if I am pushing the edge on this.. high temp = bad things.. and these are totally cool.


Oh no! Not totally cool! :) Totally cool= Good things. So keep at it. There's no reason for heat on this setup. The motors draw 12A and you have 30A ESC's so expect coolness, as long as you have a good lipo of course...

4. There is a little "oscillation" when hovering... but I think that could be due to no GPS ? The balance is right on... or maybe I need to balance motors or props ?

That simply sounds like you need to adjust your gains in the assistant software. What are your settings? I use 130% on the 4 basic gains (pitch, roll, yaw and vertical), and 90% on the attitude gains (this is the important one for stability). The basic gains determine the Naza's response to your stick inputs. The attitude gains determines the Naza's reponse to non-commanded inputs (Wind for instance:cold:). PS- on the Assistant software the first line is Basic gains and second is Attitude gains, it does say on the left of the screen.

5. Also I noticed that when I go from Attitude mode to Manual mode... the rotor speed picks up about 30%+ just from the flip of the switch. I know it's alot more manuuverable in that mode.. and am going to test some slow flight with it... but the sudden increase in speed is almost like when my son has his throttle/pitch curves on his helis off on the normal to idle up mode switch. Just curious if this is a normal reaction when the mode is switched.

The motors do work a bit harder in ATTI mode. The Naza is giving many precise inputs and works the system a little harder. 30% is probably about right. So once again, totally cool.

Flipping over is not normal! Obviously!:nevreness: Nor is a slow starting motor. Listen to the sequence at the ESCs start-up and memorise it. They should act the same every time, same pitch and timing etc. Check bullets as mentioned by Chagali. And just check the connections in general. Which way did it flip? Same each time. You've found your motor/esc then. It flips towards the affected side.

Phew, long post for me!


 


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plasticjoe

Member
Cool wow... now I know I have some things to check tomorrow evening... today's my birthday and just got home. Thanks for the updates on my questions. I'll pop into the Naza and get the gains and let you guys know. And I'll re-solder the bullets on the offending motor as well.
As far as the "oscillation" when I was flying it with the 8 inch props... it was not there. But with the 10 inch props... it's shown up. But... the Hexa is sooo much more stable and solid feeling with the 10 inch props. Maybe lowering the gains would solve that. As I said.. I'll post the gains tomorrow evening.
thanks for the help !
Joe
 

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plasticjoe

Member

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Chalagi

Member
I fly the F550 with 10-4.7 props on 3S 5000Mah batteries with 30Amp esc. Mu gains are 170-170-135-170 bottom gains are 100-100. The 550 is very quick at responding to stick inputs. No slow delay at all with quick stick movements. I gradually moved my agins from 100 up to where they are now and they feel like they are spot on.
 

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plasticjoe

Member
I feel comfortable flying it. actually it seems a tad "draggy" and you have to "push" it around to get it to move. so would moving the gains up cause it to be more draggy or less ?
 



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bigmoebbq

Member
I just ordered my 55 from Altitude Hobbies. I hope to get the controller in a few weeks. I think I am going to go with a Naza. I have pretyy much anything rc related. Planes, Helis, cars, etc. I am just a really slow builder..lol
 

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plasticjoe

Member
here's a video of the motors spooling up and the 2 that spool up slower are the top red one and the bottom lime green one.
The top red one I re-soldered the bullet connectors on it tonight before I shot the video. http://www.youtube.com/watch?v=x6zvHs5HRI8
please forgive the shakiness and orientation on the video. a tad hard to shoot with an iphone and starts one LOL
 

Mrtarango32

Mrtarango32

Member
I'm having the same issue but with just one motor. I connected to another esc still same issue. (Tried the esc with another motor also and ran fine) The bullet connectors seem pretty solid on the bad? Motor
 

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plasticjoe

Member
the only thing that can go bad on these brushless motors is the bearings or a magnet loose. If it were a magnet... the esc would fry pretty quickly ( had that happen on an electric plane once ) So I guess I might look into what size the bearings are and pick up a few sets of them.
 

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Chalagi

Member
All I know is that at default gains mine was slow and not responsive to fast stick movements. After reaching the gains that I use right now its quick and responds fast to the sticks. I can give it a quick hard right cyclic and release the stick and it pops very fast back to level. It will not hurt to try the higer gains. But if your heli starts to wobble very fast or slow then back the gains down 10 to 15%.
 

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plasticjoe

Member
It happened again to me today at lunchtime... Flew one flight no issues. Landed... changed batteries.. did the CRC and then it flipped quicker than $(*%&#*(%&) broke 2 props... didn't hurt anything else. It Flipped backwards. The 2 from ( red leg ) motors revved faster at start up than the others. The ESC's chimed in unison like always... nothing different. Ideas ? what's happening ? concerns me when I get my GPS in... this happens avery 20 or so flight... it's gonna slap the crap outa that GPS
 
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Chalagi

Member
Do you think it might be your naza? If your ESC's are programmed correctly and you IMU is programmed correct it just might be your naza. Kinda hard to blame the motors with that many good flights and then a bad one. As you said not much to go wrong on a motor. So that narrows it down to 3 items. Do uou have another naza or flight control to test?
 

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plasticjoe

Member
I don't know... it's weird.. almost like something isn't initializing correctly. I'm posting here to see if anyone else has had this happen to them and if they were able to find a solution.
 

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Chalagi

Member
About 2 months ago I spooled up my F550 after rotating the bottom plated 180 degree so that my landing gear would fit properly. I guess that by doing that it messed up the motor sequence and at spool up it wobbled very bad and then flipped upside down. It did that 2 times before I finally figured out what was causing it ti wobble and flip. I also had 1 motor that was really bad at stating up with the other motors and I re-solder on the bullet connections and its been fine since. Well your initializing comes from the esc's and your naza. So I really thinks that where your problem will be found.
 

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