I don't think that'll work either. I've been testing a BVM Viper with an electric system in it. Witht he stock ducting and 3.4 inch exit nozzle and a 5 inch fan I was only getting 5.5 pounds of thrust. I whacked the nozzle off and opened it up to 4" and the thrust went up to 8 pounds +, power input went up too as the fan was partially stalled with the choked down exit...