DJI F450 tilts backwards on takeoff

[rayf937]

Just built my F450 and I can't get it to lift off.

Notes:

It always tips backwards, if I give it more thrust it will flip backwards

I've calibrated the GPS a few times and no change in behavior.

IMU has been calibrated.

Motors are confirmed to be in the correct position and the props are rotating correctly (This kit doesn't let me put the props on the wrong motors.)

I've moved the naza closer to the center of the copter.
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Video: https://www.youtube.com/watch?v=ct9NZBLDA0E
(If I give it more thrust it just flips all the way over.)


Pics:
http://imgur.com/a/vJOIo


Any help would be appreciated!

 

[goraplx]

Did you mount blades correctly ??

 

[OneStopRC]

Certainly the props are at fault, wrong way or your motors are turning the wrong way. Just looking at your picture, please fix that soldering and secure the wires from the Naza, them jumping around can make them break early and knocking on the Naza with mess with the sensitive sensors onboard.

 

[rayf937]

The motors are correct and the props are on the right way. With these props/motors its impossible to them on the wrong motor. Also the diagram from the first post is wrong anyway. Motors 1 and 2 should be at the front and 3 and 4 at the back.

The solder is fine and ill secure the cables when it actually gets off the ground

 

[OneStopRC]

If you are sure everything is correct, the only other thing it can be is your FC is the wrong direction, not knowing the front from the back, but seeing your battery leads exit that way, I would say your FC is backwards... ESC's outputs to the front of the Multi Rotor.

That solder joint behind the FC is not fine, it will vibrate and break off. It is your money in the air and you should do as you want with it, but my advise would be to shorten the amount of wire and keep it close to the joint as possible.

If your props are on correct, the motors are turning the right direction and you FC is on correctly... I am at a loss.

Are you taking off in GPS, ATTI or Manual mode? If GPS try in Atti or Man and see if you get the same results, if you do then it is either one of the three above.

Looking from the back of the quad, the Front Right will be Motor one which should rotate CCW
The Left front is motor two and should rotate CW
Rear Left is Motor three and should rotate CCW
Rear Right is Motor Four and should rotate CW

 

[OneStopRC]

The motors are correct and the props are on the right way. With these props/motors its impossible to them on the wrong motor.

Maybe so, but it does not stop anyone from attaching the bullet connectors in the wrong places on the ESC, swapping two bullet connectors will make the motors turn in different directions.... So I am leaning towards the FC is facing the wrong direction.

 

[rayf937]

The manual said the bullet connection postions do not matter with these motors. They have markings on the side of which way they should spin. Each one is spinning correctly. The red arms are the front of the copter. So I have the GPS unit on top facing that way, and the naza under it is also facing that way. I did have the motors the wrong way a few weeks ago. But I moved them into the correct positions since then and re calibrated everything. Even when the motors where postions incorrectly it would fall backwards.

 

[Punisher]

on the TX cali you have IMM checked put it on inteligent and see what happen from the videos Ive see it was best to leave that checked inteligent..

 

[rayf937]

IMM/ Intel didn't make a difference. Still tips backwards and flips over. Do the legs change the measurement of the Z axis? I don't think it does but I just want to make sure. It's strange because I took the motors off completely and remounted them and it still tips backwards. So it gotta be something in the naza.

 

[Punisher]

try taking the landing gear off and try to hover and see what it does (unless you already had)
when I got mine going it want to roll right but then I gave it a little snappy throttle and it self leveled out just fine... also if your on manual mode it'll tip a bit with light wind but once you put it on GPS mode it should go right up without not problem but make sure you have a GPS connection (no red light flashing)

 

[goraplx]

Please provide more pictures and another movie.

 

[rayf937]

"Please provide more pictures and another movie." -- of what?


I tried it in each mode again. I held it in my hand with manual mode on and it just feels like it wants to pull in my hand. It doesn't feel like it'll fly level. I just re calibrated the GPS and made sure the naza was blinking green. I give it throttle and push the right stick forward to compensate. No change.


GPS and manual mode do the same thing. Also now I'm getting lots of oscillation right before it starts to tip. Could something with the props be unbalanced?


These are 9443 props and E300s and 2212 motors.


**I'll try it later without the legs on it.

 

[OneStopRC]

Take off in ATTI mode and give it some throttle, if everything is fine with everything else, I see no reason it will not level off soon after take off. put it on the grass in an open area and stand well away from it.

 

[rayf937]

I tried atti mode too. If give it lots of throttle and it flips quickly. If I hold it in my hand while its level I feel it pull backwards.

 

[ChrisViperM]

To me that sounds like the channels are not connected the right way or some channels are reversed. Did you check in the assistent software that all your sticks are moving in the right direction.....???

Chris

 

[rayf937]

@chris. Everything looks good and moves correctly in the software. And they all looked like they were centered after I calibrated it.

 

[rayf937]

If I get a chance later I'll try to post a video of the copter in my hand.

 

[ChrisViperM]

Would be interesting to see what happens if you do the following:

Arm the motors and just give it enough throttle that the motors dont cut off...but not more. Then slightly push forward / backward and left/right (just a little bit) and see how your bird reacts. If everything is ok, the copter should just lean forward/backwards and left/right slightly.


Chris

 

[rayf937]

I'll try that. When its on the ground it seems to react the correct way but I can't tell since i can't seem get it to get off of the ground. So when I try to lift off I'll give it some of the right stick forward and that helps. But I'll give it more throttle and then it'll still flip. Even with the right stick all the way forward it will flip.


Could something be wrong with the naza?

 

[OneStopRC]

Also, make sure your radio has no trims on the controls, make them all center and calibrate your setup again. Radio should be setup for Acrobatic mode or Airplane mode with no mixes.