PPRuNe Forums - View Single Post - What causes "blowback/flapback" when accelerating through transverse flow effect?
Old 10th Aug 2022, 17:28
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LRP
 
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Originally Posted by SunofAtom
I'm trying to get my head around some of the aerodynamics, and I have yet to find a good explanation of blowback.

I understand the slight right roll (CCW main rotor) when entering transverse flow effect, and the vibrations due to the uneven airflow and forces across the disc as we move through TFE. I'm not understanding why the nose wants to come up as we are getting through TFE and into ETL. I found a couple references to it being due to dissymmetry of lift becoming present and blade flapping starting to occur, but if that's the case, why would the change be so pronounced?

Thanks!
Good, practical answers to helicopter aerodynamics....Ray Prouty.
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