Yes I know but doesn't sound too good by my tired ears. Best clone I ever built was the ADA Flanger with mods by a clever Canadian for almost thru zero flanging. This was achieved first I believe by the Electroharmonix Flanger Hoax, designed by a clever Dutchman with whom I had some contact a few years ago. That uses 2 x MN 3207, 2 x LM13700 for a Dome Filter and numerous opamps for static fixed phase shift networks.

Best early flanger to my ears was the EH Electric Mistress, the 2 battery version which used the SAD 1024 bucket brigade IC, now almost impossible to source in a reliably working form, Secret of its sound was the minimal filtering used.