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    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

Quote from: Goli Vamsi on April 07, 2018, 10:14:05 PM
i got brand new ESC and Prop.....but i dint know how to check Centre of Gravity 

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    

Quote from: K K Iyer on April 07, 2018, 10:40:18 PM

Quote from: Goli Vamsi on April 07, 2018, 10:14:05 PM
i got brand new ESC and Prop.....but i dint know how to check Centre of Gravity 

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

Is it accurately in the centre of your quad?

Quote from: AL HAM SHARI on April 07, 2018, 11:48:53 PM
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

Quote from: Goli Vamsi on April 07, 2018, 11:29:52 PM
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   

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.

Quote from: K K Iyer on April 08, 2018, 12:42:05 PM
@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?

Quote from: AL HAM SHARI on April 09, 2018, 08:27:30 PM
Seems like you haven't calibrated the ESC. Have you done it?

yes bro i have many many times

Quote from: K K Iyer on April 09, 2018, 08:11:05 PM
@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.

surely bro ill try and let u know the result

Quote from: Goli Vamsi on April 09, 2018, 10:12:44 PM

Quote from: K K Iyer on April 09, 2018, 08:11:05 PM
@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.

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

Quote from: Goli Vamsi on April 09, 2018, 10:12:01 PM

Quote from: AL HAM SHARI on April 09, 2018, 08:27:30 PM
Seems like you haven't calibrated the ESC. Have you done it?

yes bro i have many many times

Each separately?

Quote from: K K Iyer on April 10, 2018, 01:32:01 PM

Quote from: Goli Vamsi on April 09, 2018, 10:12:01 PM

Quote from: AL HAM SHARI on April 09, 2018, 08:27:30 PM
Seems like you haven't calibrated the ESC. Have you done it?

yes bro i have many many times

Each separately no I haven't done.....I don't know how to do that
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

Quote from: K K Iyer on April 10, 2018, 03:21:46 PM
@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!

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...