3DR Y6 frame

APM 2.5 w/ uBlox NEO-6M GPS

RCManChild 30A SimonK ESC's

SunnySky Angel A2212-980KV Motors

9x4.7 GemFan props (10" and 11" in the mail)

A buddy and I just finished up his 3DR Y6 build and we've hit a massive roadblock that we can't seem to overcome. 

The Y6 WILL lift off but immediately start "UFOing" either to the left or the right, it differs each time we lift it off. 

The prop direction has been checked 16 million times so its not that.

We've had this issue with our old KK 1.5 "blackboards" and when this happened you needed to do a stick command to reverse the gyro for yaw.

We've seen many threads about people talking about reversing channel 4, but this isn't an RC input issue that's reversed, its the gyro being reversed and compensating the wrong direction, setting the Y6 into a uncontrollable spin.

Anyone have any ideas? Reversing gyro directions is pretty easy on the old KK board but apparently not even discussed with the APM 2.5.

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Six things to check (or re-check):

1) Motor order

2) Motor direction

3) Prop type (pusher/puller)

4) Props are right-side up

5) APM facing the right way

6) Correct code (Y6) loaded

Hi Chris! Thanks for the response! We've spent all day building this thing and the light is fading and with it is our chance to maiden this tonight. Well, I suppose it did maiden tonight, but it just spun in place.

1 though 4 - We've checked this over and over. Each individually and they're all spinning currently. Keep in mind, it does lift off just fine, we just have no yaw authority as its spinning uncontrollably. 

5 - Yep, kinda hard to mess that up but I can definitely see someone doing it.

6 - Y6 code was loaded twice. After the first time we did a full eeprom erase and factory in the CLI. 

O well, its dark already just while I was typing this so the maiden will have to wait. He's going to pull the top bay off and check his ESC's are all plugged in correctly tomorrow. Then again, the copter takes off just fine so I can't see how that could be an issue.

It really seems identical to the old KK boards. The gyro would be reversed so it would instantly try and compensate the same direction it was already spinning causing it to UFO. That's exactly what seems to be happening here. 

So I'm the aforementioned friend with the Y6. Just an update for anyone that may stumble across this thread.

The ESCs were plugged up correctly which I verified by the 'motors' command. However, I had reversed all of the motor spin directions (CCW was CW and vice-versa). Thinking this couldn't possibly make a difference since everything was just the opposite of what it was supposed to be, but consistent, I changed this last. Sure enough it took off dead stable with no yaw spin. 

Given that I started my first DIY with a tricopter, which I did the same thing with no problems, I thought it did not matter here. However, it must have been the servo compensated on the tricopter for my mistake so I never noticed a problem.

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