Formula: {Diameter_Main_Rotor_xi = Diameter_Main_Rotor_Head_xi + 2 × Length_Main_Blade_xi}

Description:
~ the diameter of Xi's main rotor head
Related_Formulas:
~ Diameter_Main_Rotor_Head_xi
~ Length_Main Blade_Xi
~ Length_Tail Blade_Xi
~ Xi Design / Xi's size

Analysis:
~ the design goal is to find the minimum diameter for Xi's main rotor head,
~ by which one can achieve the maximum hovering abilities

Disadvantages of too small main rotor diameter:
~ in autorotation (engine goes off...) helicopter falls down quicker

Benefits of longer main blades:
~ improved hovering

Disadvantages of longer blades:
~ heavier
~ more expensive to manufacture
~ cause more resistance with higher speeds

Disadvantages of too main rotor diameter:
~

catch ~Diameter_Main_Rotor_XCopter ~Xi!