MrChristian (Military Background)
Information relating to ducted fans might best be sought by an Airship Manufacturer. (or Blimp)
Many of these use piston engine pods with a ducted fan drive. Usually a small fan is used to enable turning to accommodate steering - low speed means a conventional rudder has little effect.
I believe Porsche engines were used by at least one .
Goodyeard might release some data - best of luck