Mart,
The offset flapping hinge gives a faster response to control inputs, whereas delta3 gives a slower softer response to control inputs.
The association between delta3 and phase angle is nowhere near as valid as the offset flapping hinge and phase angle association. However, the phase angle is the only 'adjustment' that a swashplate has.
The relationship between a rotor's
offset flapping hinge and a flight control's
phase angle is quite straight forward. The reasoning and the math are readily available in Prouty's main book etc.
Here is information on Flap Hinge Offset
Here is information on Phase Lag.
The relationship between a rotor's
delta3 and a flight control's
phase angle is quite complicated.
Frank Robinson said on PPRuNe;
"...the 18-degree delta-three angle designed into the R22 swashplate and rotor hub. This is a highly technical subject which can only be fully explained using very technical engineering terms."
You said;
So the question is: does anyone understand how "Wee-wa" works in the real world?
My posting, just above your two, is meant to be humorous, however, the response to 'wee-wa' is serious.
Here is information on Delta3 The [Sketch of Pitch Angle:] on this page should explain Robinson's use of delta3.
And, this page has more information on Delta3 and Phase Angle
Dave