Quad Flips When Taking Off

[techguy]

Hi,

Please help me with this issue that I've been struggling to resolve for a while. Here's my configuration:

Frame: F450 cloned
ESCs: Skywalker 20A
Motors: F4006 950kv
Props: Gemfan 11x4.7
Board: HK Crius SE v2.0 (with 2.1 FW)
Configuration: Quad X

I have verified more than once for the following items:

1. ESCs are plugged in the right slot on the board
2. Props are rotating at the right directions
3. Gyro is correct (verified by tilting forward, to the right and read the MAG_ROLL, ACC_ROLL and GYRO_ROLL value...etc.)
4. Mag is calibrated correctly (verified in the GUI)
5. Motor oupt seems to be right (verified in the GUI)

However, when I gradually apply throttle to take off the quad tends to flip forward and it will eventually flip if I continue to increase throttle. I've read a number of posts here and on rcgroup and it seems most of the people having similar problems had their props or ESCs configured wrong, which is not my case.

I'm running out of ideas to debug and would appreciate it if someone could help. Thanks.

[mgros]

A silly idea.
you said "props are rotating at the right directions"
but, you have CW props and CCW props corectrly installed?

[techguy]

Yes, Sir. I have exactly the same props on the same motors and they used to fly well with my FF board.

[techguy]

My bad. I had D10 and D9 reversed although I swear I've checked it more than a dozen of times. Lesson learned: when in doubt, always connect your ESCs one by one then spin them up to verify they're correctly connected to the board.

Thanks.