i am making a wind tunnel in order to test aerodynamics of 1/24 scale cars. i am having two problem: 1. i am not sure what wind speed at that scale to represent 100mph. 2. i am using a fan that has an outlet wind speed of 19.4 mph. i tried to increase wind speed by decreasing the outlet speed of my tunnel from 144 square inches, to 36 square inches. but in doing this i measured the outlet velosity and it was only 9mph. what am i doing wrong? how do i increase wind speed?