i have the following setup
Quad F450 frame
5000mah battery
1400 kv motors
10*4.5 props
APM 2.6 Clone
Neo-6m gps/compass
HLW XXD 30A ESC
turnigy 5x transmitter

i have followed all the steps from loading firmware to calibrating ...
first test flight worked fine ..

but for second test flight after arming 1 motor is not spinning and rest 3 are spinning correctly..
After giving little throttle the motor which was not spinning starts spinning ,but with less speed as compared with the other 3 motors..
I Have checked each of the motors during calibration and they work fine.


i have gone through setup once again but the problem persists... please help..

Are you sure you have done the calibration through the fc correctly?
Please post a link to the apm2.6 clone

Maybe the esc is not functioning properly ... Try to connect the esc on any other output to confirm that the fc is giving inputs or another motor to the same output as the presumably faulty esc , this would confirm that the fault is with the esc or the fc . After all this also check the motor by plugging it into any other esc currently on the fc . Best of luck ..

ya i have done manual esc calibration.....

here is link to fc kit

http://robokits.co.in/quadrotors-hexarotors/flight-controllers/arducopter-apm-2.6-full-kit-gps-power-module-telemetry

Try doing the calibration through the flight controller
http://copter.ardupilot.com/wiki/esc-calibration/

Try to calibrate all ESC's at once with the APM.

1. Remove the props
2. connect APM to PC via USB cable
3. Go to CONFIG/TUNING->Full Parameter List and find ESC (either use Search or find it manually), the default value should be 0
4. If it is 0 than change it to 1. Start-up in ESC Calibration mode and Write Parameters to APM
5. Disconnect USB cable from PC
6. Turn on your Handset (Turnigy 5X) and move the throttle stick all the way up (full throttle)
7. Connect the battery to the Quad, you should here few beeps (depending on ESC's you have), i have Turnigy motors and Q-Brain ESC so when it beeps twice i know i can lower the throttle (refer to your ESC manual)
8. Once you hear the beeps, move the throttle stick all the way down (zero throttle)
9. You should here beeps depending on your ESC model
10. Turn off APM
11. Turn off Handset
12. Done

I described it in details because someone else might need this as well. If the problem persists, try to swap the ESC's so you will know if it is either ESC's fault or motors fault.

AlbEagle