Relative Airflow (RAF) = Free Stream Flow

[Ref PPL Instruction Kit Vol1 (306) – 9th Edition, V9.2 P.3]

Relative Airflow (RAF) is defined as the speed AND direction of the air movement past an aerofoil – equal in size and parallel but opposite in direction to the flight path.

[Ref 080 Principles of flight]
Relative airflow (RAF) = Free Stream Flow

– RAF due movement of acft.

RAF has 3 qualities:
  1. Direction
    It flows in a direction parallel and opposite to the direction of flight path
    (NOTE: flight path is no need to be heading)
  2. Condition
    Also, air in a region where pressure, temperature and relative velocity are unaffected by the passage of the acft through it.
  3. Magnitude
    the magnitude of RAF is TAS
#RAF #What's #relative #airflow

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