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Old 16th Dec 2008, 16:05
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bookworm
 
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Likewise, induced drag, the rearward component of the greater total lifting force would also be diagrammed with a smaller arrow, pointing aftward.
The problem, zerozero, is that you don't provide an explanation of why there is a "rearward component of the greater total lifting force" or to put it another way, of why you believe the lift vector "tilts".

The lift force does not tilt with the angle of attack to remain at 90 degrees to the chord line. The lift remains at 90 degrees to the airflow. If you choose to look at the angle of the total aerodynamic force, the vector sum of lift and drag, it will indeed be tilted back. But noting that only identifies that drag exists, it doesn't explain its origin. For an infinitely long wing, there would be no induced drag at any angle of attack.

Induced drag is the result of the the modification of the local airflow direction by the vortices that result from having a finite span. The vortices tilt the air as it approaches the wing by adding a downwash. It is this difference between the freestream and the local airflow direction that manifests itself as induced drag.
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