Station 1 Station 2 Station 3 Upper layers act to restrict flow  0° 10° 20° 30° 40° 50° 60° 70° 80° 90° 9 8 7 6 5 4 3 2 1 0  Load factor - (in Gs)  Bank angle (in degrees) Figure 2-8.  The load factor diagram allows a pilot to calculate  the amount of “G” loading exerted with various angles of bank.  2-5 Figure 2-7.  Venturi flow. Newton’s Third Law of Motion Weight into a state of motion, without it the helicopter would either  remain on the ground or at a hover. still accelerates over the curved area because the upper air  layers restrict the flow—just as the top half of the constricted  tube did. This acceleration causes decreased static pressure  above the curved portion and creates a pressure differential  caused by the variation of static and dynamic pressures. The weight of the helicopter can also be influenced by  aerodynamic loads. When you bank a helicopter while  maintaining a constant altitude, the “G” load or load factor  increases. The load factor is the actual load on the rotor  blades at any time, divided by the normal load or gross  weight (weight of the helicopter and its contents). Any time  a helicopter flies in a constant altitude curved flightpath, the  load supported by the rotor blades is greater than the total  weight of the helicopter. The tighter the curved flightpath  is, the steeper the bank is; the more rapid the flare or pullout  from a dive is, the greater the load supported by the rotor.  Therefore, the greater the load factor must be.  [Figure 2-8] Additional lift is provided by the rotor blade’s lower surface  as air striking the underside is deflected downward. According  to Newton’s Third Law of Motion, “for every action there  is an equal and opposite reaction,” the air that is deflected  downward also produces an upward (lifting) reaction.  Since air is much like water, the explanation for this source  of lift may be compared to the planing effect of skis on water.  The lift that supports the water skis (and the skier) is the force  caused by the impact pressure and the deflection of water  from the lower surfaces of the skis. To overcome this additional load factor, the helicopter must  be able to produce more lift. If excess engine power is not  available, the helicopter either descends or has to decelerate in  order to maintain the same altitude. The load factor and, hence,  Under most flying conditions, the impact pressure and the  deflection of air from the lower surface of the rotor blade  provides a comparatively small percentage of the total lift.  The majority of lift is the result of decreased pressure above  the blade, rather than the increased pressure below it.  Normally, weight is thought of as being a known, fixed value,  such as the weight of the helicopter, fuel, and occupants. To  lift the helicopter off the ground vertically, the rotor disk must  generate enough lift to overcome or offset the total weight of  the helicopter and its occupants. Newton’s First Law states:  “Every object in a state of uniform motion tends to remain  in that state of motion unless an external force is applied  to it.” In this case, the object is the helicopter whether at a  hover or on the ground and the external force applied to it  is lift, which is accomplished by increasing the pitch angle  of the main rotor blades. This action forces the helicopter 