Rotorcraft Flying Menu >General Aerodynamics  > Weight

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 verti-cally, the rotor system must generate enough lift to overcome or offset the total weight of the helicopter and its occupants. This is accomplished by increasing the pitch angle of the main rotor blades.

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. Load factor is the ratio of the load sup-ported by the main rotor system to the actual weight of the helicopter and its contents. In steady-state flight, the helicopter has a load factor of one, which means the main rotor system is supporting the actual total weight of the helicopter. If you increase the bank angle to 60°, while still maintaining a constant altitude, the load fac-tor increases to two. In this case, the main rotor system has to support twice the weight of the helicopter and its contents. [Figure 2-11]

Figure 2-11. The load factor diagram allows you to calculate the amount of “G” loading exerted with various angle of bank.

Disc loading of a helicopter is the ratio of weight to the total main rotor disc area, and is determined by divid-ing the total helicopter weight by the rotor disc area, which is the area swept by the blades of a rotor. Disc area can be found by using the span of one rotor blade as the radius of a circle and then determining the area the blades encompass during a complete rotation. As the helicopter is maneuvered, disc loading changes. The higher the loading, the more power you need to maintain rotor speed.