Well thats ok, I'm not sure my logic is completely correct but what I meant by resonant was that the natural flapping and rotational frequencies were equal, 1:1, and that the delta 3 altered the flapping frequency IE making the max flap something other than 90 degrees from where the max lifting force is applied to the blade thereby changing that 1:1 to something else, like 1:0.9 or 1:1.1. Like the cyclic offset you describe, even though the tail rotor does not have a mechanical cyclic flight control input, it does have a cyclic, differential lift input from the horizontal flow and disymmetry of lift causing flapping, and the delta 3 provides a change in phase lag, or cyclic offset(as you put it), so the max flap is other than 90 degrees from the max lifting force. I'm certainly not an expert in harmonics or waves or any kind fluid dynamics, so only describing it the best way I have understood it to be.
Anyway, I have been asking this question for a long time about the negative delta3 tail rotor and never found anyone who could give me a good answer.
I did however just find this, it's page 13 of this document:
http://www.bellhelicopter.textron.co...b/rb_mar04.pdf
But it still does not make sense to me how when a blade has positive flapping that increasing the pitch will reduce that flapping the same way as decreasing the pitch as with positive delta3. And of course while they explain very basically why it works they don't explain why they chose it over a positive delta3 tail rotor or why they chose 30 deg for the neg but 45 deg for the positive ones. And the fact that the 407 had some tail rotor accidents made me wonder even more.
