# The total moment when rolling

• Benyoucef Rayane

#### Benyoucef Rayane

Hey, everyone, I have a question regarding quadcopters, when the set of the arms is of configuration X, to roll we increase the velocity of the two motors on the left/right and decrease the other motors on right/left, the question is when doing so the total angular velocity is zero that means the moment of each thrust generated will be canceled out, this whole thing is confusing, I know I 'm wrong somewhere, Please any explication!

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## Answers and Replies

this whole thing is confusing
So is your post. Try separate sentences, precise description of the different situations and a clear question.

sorry, there is a typo, it is not the rolling movement actually it is yawing, so my questions are: considering the figure taken from the book " Quad Rotorcraft Control. Vision-Based Hovering and Navigation", you can find it in this link https://www.researchgate.net/publication/278745381_Quad_Rotorcraft_Control_Vision-Based_Hovering_and_Navigation
1. why the roll and pitch equations, unlike yaw equation, don't take into account the aerodynamic drag
2.since the thrust is always up and the vector from the center of mass to the applied force (Thrust) is the same whether in pitch or roll rotation, so why the negative and positive signs are different in pitch and roll equations