Theuns,
The BVM Viojett/Viofan requires a full inlet to supply air to the fan for maximum efficiency. This inlet must go from the inlet lips to the face of the fan. Larry Wolfe, Jet Hangar Hobbies, used to sell a molded Hi-Tech Inlet for his Mirage semi kit. This inlet is not seamed and could be adjusted to provide a smooth flow of air from the inlet lip to the fan face. Once adjusted it can be seamed with a strip of fiberglass tape and epoxy. You might want to check with Chris Wolfe, Larry's son, on obtaining a Hi-Tech Inlet for the Mirage or directly with: www jethangarhobbies.com. This inlet should provide an increase in static as well as dynamic thrust. Let us know how you make out.
Regards,
Art ARRO