Hi Buddies........im very new to RC...i have builded a quadcopter with kk 2.1.5. I tried to fly it but it was not stabilising, then i tried ti change p gain and i gain values..but never got any stable flight..in this process i broke down 3 motors and many propellers... Guys please do help me to get a stable flight....im from bangalore, electronic city....goli.vamsi2858@gmail.com   please do tell me a solution....quad fliers from bengaluru i need your support.

You shouldn't have tweaked the PID settings dude,it is pretty tuned normally. Its probably not the problem of your FC. Is your escs good?Are your props balanced, without vibrations? And, check CGreply after checking.

i got brand new ESC and Prop.....but i dint know how to check Centre of Gravity 

@goli vamsi,
Don’t expect a doctor to prescribe without knowing the symptoms, and your weight, height, bp, sugar etc.

Pl post details of your quad, ie, size, motors, escs, props, lipos etc and your kk 2.1.5 settings.
Then you can expect a meaningful answer from someone who has a similar setup.

E.g, I can share my kk 2.1.5 settings if you have an ST360 (mine is from Quadcopters)

Regards

Try to pick the quad up with a finger underneath, and find the place where you can do this without the quad falling to one side!

Warning: Do not fly any multirotor or airplane till you know where the CG is!

HI KK Iyer
I'm using kk 2,.1.5  1.9s firmware 30a ESC 450 sized frame 2.2Ah battery 1000KVA motors and prop of 10/4.5   p gain 50 i gain 20 for roll and pitch p gain 40 and i gain 20 for rudder    

Hi bro i found the CG point on my quad....what to do next?

Is it accurately in the centre of your quad?

no a bit away from it because my battery position was a bit sideways.... i mean by 2 cm away from centre

My equipment seems the same as yours (except quad size)
Will set it up in the evening and send you the PI settings.
Meanwhile you can see this kk 2.1.5 manual.
https://hobbyking.com/media/file/1026124741X1235859X24.pdf

Also correct your CG by moving the lipo. Or temporarily by adding some plasticine or solder wire to the lighter side.

@goli vamsi,

Here are the settings on my ST360:
Axis P gain P lmt I gain I lmt
Roll. 40.    100     40.    20
Pitch 40.    100.   40.     20
Yaw. 50.      20.    25.    10
Self level On (right aileron while arming)

Hope this helps. Best of luck.

Hi Bro i have tried with the values u have given.
The result is in this video


Dont know why it was fliping like that

@goli vamsi,

I have very little experience of quads. So I’ll avoid giving you suggestions that may be useless.
But I did learn quite a bit when setting up my ST360 some 4-5 years ago.

I think that by tackling PI settings to solve your problem (flipping), we missed the basic issues.

The first issue is configuration. Whether X or +.
The second is motor numbering.
The third is direction of motor rotation.
The fourth is CW or CCW prop.

Mine has X configuration
Top left motor is no 1, top right is 2, bottom right is 3, bottom left is 4
1&3 are CW, 2&4 are CCW

And, most important, the top of the kk 2.1.5 points to the direction of forward flight, ie, between 1&2.

Please check if yours is set up similarly.

Noticed that one motor speeds up, flipping the quad.
Becasuse the system thinks that arm is going down, when actually it isn’t.
So it is powering up the wrong motor.
Which indicates that the motors may be numbered incorrectly

Experts may laugh at these basic inputs, but I’m only sharing what I learnt by trial and error!

There’s one more important step. We’ll come to that after you verify the above basic issues.

Seems like you haven't calibrated the ESC. Have you done it?

yes bro i have many many times

surely bro ill try and let u know the result

hi bro i have checked my quad is X mode and motor-1 CW and its propeller CW motor-2 CCW and its propeller CCW motor-3 CW and its propeller CW motor-4 CCW and its propeller CCW.
my  kk 2.1.5 points to the direction of forward flight between 1&2 motors.
i have checked twice day r proper

Each separately?

I also built a quad , flies pretty stable had to add a bit trim to get it tuned perfectly. PLZ DO NOT FLY USING SELF LEVEL MODE IT IS NOT PRECISE AND MAKES THE QUAD UNSTABLE.

You can refer to this link to get details of the pie and other settings.
Do we have to do anything else after shifting CG to the center ??

I did not know anything about the CG in quads before reading this.   Can you plz elaborate about the CG ?

@goli vamsi,
First disconnect lipo from quad, then:
1. Remove all props for safety
2. Disconnect all Escs from FC
3. Disconnect Rx channel 3 from FC
4. Plug lead of motor 1’s ESC into ch 3 of Rx

5. Switch Tx on
6. Move throttle stick to full
7. Connect lipo to quad

You should hear a long beep indicating that full throttle position has been registered. (Beep sound may differ from make to make, check your ESC programming details if you have them)

8. Move throttle immediately to idle. Beep will indicate idle position registered.
9. Disconnect quad lipo

10. Reconnect quad lipo. You should hear the normal start up tone and beeps indicating number of cells
11. Check response of motor to throttle
12. Disconnect quad lipo
13. Unplug ESC number 1 from Rx ch 3

14. Plug ESC of motor number 2 into Rx ch 3
15. Repeat all steps from step 6 onwards.

Calibrate ESCs 3 & 4 the same way.
Best of luck!

@kk iyer
Dear sir need help in this :http://www.rcindia.org/multirotors/cg-balancing-in-quadcopter-need-help/msg286911/#msg286911

so after calibrating individually again i have to connect to fc and then i have to calibrate all esc together right?

Don’t remember, but most probably will not be needed...

i didnt get u r point bro

Once the ESCs are calibrated individually, i think it will probably not be necessary to calibrate again after connecting to the FC.
Anyway, if reqd, it will take only a minute...

Waiting eagerly to see if the flipping has stopped!

Hi bro i have tried the way u told. That is calibrating ESC's individually. I found that one of the ESC is not working fine. The motor connect to dat ESC is spinning faster and casing quad to flip. So i have ordered for new ESC . After getting that i ill let u know the result.
Thanks in Advance bro...u helped a lot

you can calibrate ESCs individually by connecting them to rx one by one and then you can calibrate all together by FC.

Found simple video showing ESC calibration process with FC

Needs a recheck.
We were only trying to get each ESC to recognise full throttle and idle positions.
You said “The motor connect to dat ESC is spinning faster and casing quad to flip.“
How did you reach that conclusion?

Why you ordered a new ESC, since it's working fine? If you calibrated that ESC, it would be good again.

guys check dis links for my prob with ESC
part1   

part2   

1) Could you do the above repeated thing once more. Now , After you put the throttle down, wait for a few seconds. There will be another sound too.Then It will work properly.
2) when you toggle a channel, the motor starts spinning. It's not the problem of ur quad. It is a very simple thing to solve. It's the problem of your TX. Kindly find that option and turn it off. Could you reply after this?

1.i checked your first point still it wasn't responding...i waited for almost 2 minutes.
2. i don't know how to check the thing u mentioned in your second point

2)I am useless for you bro, I don't remember how to turn off the second thing. I have done it, but don't remember. It's called some arming switch or something like that. Look in ur settings.
1)could you remove all wires from receiver except the one from the ESC and connect the ESC directly to the battery and try again?

i have soldered all the things together..u mean to test dat esc alone with its own supply and only that esc connected to receiver

Could you put the throttle up for some time? Let me know if it's beeping.

yea tried now but its not calibrating

Did it show any other sound?

No bro...No sound nothing happen 

Then I think there is a problem, but don't lose your hope. Your connection with the rx may be weak. Make sure you have a good connection with the pins and try.

Did you connect the ESC to rx firmly??

yea bro all those connections are proper

Then its sure that it has a problem

even if you are going to buy a new esc, you will remove the solder joint of this esc. so try removing the esc and try the thing one last time with the power directly to the esc. then you can know whether it is the problem of esc or the pdb. regards.

ha ok bro surely i ill try......i got my new esc so today i ill check the things u said