Lately I have been analysing chassis from a static point of view and have noted something very odd about the DJI chassis. For the asking price of 1000$-2000$ I felt very naive at first. I then started to analyse the copter from a statics points of view and there is one point(the inclination of the arms) I need clarification on:
* Hover State
* Symmetrical Physical Structure
* All motors are at the same throttle level(This produces a force F_x)
* Sum of moments=0 (Dynamic equilibrium)
* Axis convention per figure
Problem: The inclination of the arms when maintaining static equilibrium:
To begin with to maintain static equilibrium the sum of force about the x and z-axis must be zero.
To bring my point across I will look at a symmetrical section, analysing two arms only:
The force along the X_b axis will cancel maintaining equilibrium along the X_b axis.
The problem comes in when the component of the force along the Z axis apposes the weight vector.
ie. 2(F_x cos(THETA))=mg
As apposed to a completely horizontal arm: (THETA=0)
I hope some one can provide clarification to the above as to why the inclination of the arms. Duly noted that this will have and effect of endurance.