What is resultant relative wind?

Resultant relative wind is angle airflow at the rotor blades considering rotational relative wind and induced flow.

When at a hover in a calm, no-wind condition, resultant relative wind is the combination of rotational relative wind and induced flow.  However, the movement of the helicopter and wind velocity also affect the angle of the airflow at the rotor blades.  Resultant relative wind is a factor used in determining or describing many aerodynamic factors.  Often, relative wind and resultant relative wind are used simultaneously.resultant relative windReference(s):

FAA-H-8083-21A – Helicopter Flying Handbook pg. 2-8
Principles of Helicopter Flight, 2nd Edition, pg. 47
FM 3-04.203-2007 Fundamentals of Flight pg. 1-10

Other Helicopter Aerodynamic Principles