In the strictest sense, a flanger has a very short delay time modulated by an LFO as a minimum. The PitchFactor can produce all kinds of "flanger-like" sounds using pitch shift. The MicroPitch, H910/H949, and HarModulator algorithms excel at this. In fact, you can get the slight pitch differences using most any mode. But you don't really get rate control over delay modulation like you would in a true flanger.
Here's a very simple, "unintentional slow flanger" sound that I like, using the H910/H949. I think that the delay differences come from the pitch processing stages (even though both are at unison and 0 ms.).
Mix: 50% (Use an EXP pedal 0%-50% as a "depth" control).
Pitch Mix: A10 + B10
Pitch A: A:1.000
Pitch B: B:1.000
Delay A: 0 ms.
Delay B: 0 ms.
Speed/Scale: NORMAL -or- MICRO
[Note: Changing this knob changes your Pitch scaling settings)]
Xnob & Ynob: 50% – moderate flange. 75% – intense.
90% – intense metallic. 100% – over-the-top runaway oscillation.
Of course, you can increase both delay times for more depth and a change in tonality. Try one Delay time slightly offset from the other [Example: Delay A: 7 ms. Delay B: 15 ms.]. Conventional wisdom puts flanging between 0-10 ms. You can go into the chorusing range with this preset [20 ms.], but I wouldn't go much past doubling [30-35 ms.]. The "bending' starts to get overwhelming, and you'll start to hear the discrete echoes in your delay lines.
In general, when I increase the average delay times in this preset [Delay A & Delay B], I tend to decrease both feedback controls [Xnob & Ynob]. Now – if you're not strictly.looking for true flanging – we can take that route by using the pitch shifters for alternative chorusing.