|
Rotorcraft Flying Menu >General
Aerodynamics >Drag
> Total Drag
Total drag for a helicopter is the sum of all
three drag forces. [Figure 2-14] As airspeed increases, parasite
drag increases, while induced drag decreases. Profile drag remains
relatively constant throughout the speed range with some increase
at higher airspeeds. Combining all drag forces results in a
total drag curve. The low point on the total drag curve shows
the air-speed at which drag is minimized. This is the point
where the lift-to-drag ratio is greatest and is referred to
as L/Dmax . At this speed, the total lift capacity of the helicopter,
when compared to the total drag of the heli-copter, is most
favorable. This is important in helicopter performance.
Figure 2-14. The total drag curve represents
the combined forces of parasite, profile, and induced drag;
and is plotted against airspeed.
|
