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...
Did you know that military aircraft fuel tanks used to contain explosives!
Called Explosion Suppression System, Light sensitive units in the tank would indicate when eg.tracer/AA/cannon entered the tank causing a potential fire / explosion. This would trigger the tower of explosive elements...
