I crashed my 350QX and had to replace the body. I was able to link the unit with no problems using the GPS mode.
However, when I advance the throttle, then unit flips over. That is, the side with the gray props pulls the unit and flips it over on the ground.
Has anyone experienced that before? Any suggestions?
Jorge Mir

you say side with the gray props. do you mean the rear

No, the gray props face the front of the unit. Where the red trap door is for inserting the batteries.
It behaves as if the red props (back of the unit) have no power and the unit flops over on the ground.

ok do you have the props set up the same as in the picture if so the red props are the front of the quad.

1) When you say, "pull," do you mean that the gray props strike the ground instead of lifting that end of the toy into the air? 2) Are all 4 motors running? 3) Do the red props turn at all? 4) Did you download and read the 350 QX online manual? It includes a great deal of information that is not included in the quick start guide that ships in the box with the 350 QX. 5) Did you mount the forward and reverse propellers correctly as specified on page 15 in the online manual? If so, their direction of rotation arrows should match the direction of rotation arrows molded into the frame right next to the number on top of each motor nacelle.

It sounds like you may have the front and back mixed up. The red trap door for the battery is the back of the 350QX - They come out of the box with red props on the front.