ffording the best lift-drag ratios for the full range of velocities from rotor blade root to tip. However, the symmetrical airfoil produces less lift than a nonsymmetrical airfoil and also has relatively undesirable stall characteristics. The helicopter blade must adapt to a wide range of airspeeds and angles of attack during each revolution of the rotor. The symmetrical airfoil delivers acceptable performance under those alternating conditions. Nonsymmetrical airfoils may have a wide variety of upper and lower surface designs. The advantages of the nonsymmetrical airfoil are increased lift-drag ratios and more desirable stall characteristics
             The main rotor is the most important part because it provides lift to allow the helicopter to fly as well as lateral movements. The rotor is very strong and uses the swash plate assembly to change the blade and rotor angle of attack. The collective control can change the swash plate so both blade angles change to increase or decrease lift. The cyclic control changes the entire rotor's angle of attack to move forward, backward, left and right. The swash plate assembly has two plates, one fixed and one rotating. The fixed and rotating swash plates are connected with a set of bearings between the two plates. These bearings allow the rotating swash plate to spin on top of the fixed swash plate. The rotating swash plate rotates with the drive shaft and the rotor's blades because of the links that connect the rotating plate to the drive shaft. The pitch control rods allow the rotating swash plate to change the pitch of the rotor blades. The angle of the fixed swash plate is changed by the control rods attached to it. The fixed plate's control rods are affected by the pilot's input to
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