There are many flow problems in which the flow quantity in a short, irregular duct must be measured. A measurement technique which is fast, causes no pressure loss, and can tolerate poor flow quality is often needed. The flow through the radiator duct of a wind tunnel model is one example.Four sensors were tested for velocity response and sensitivity to duct geometry. A full-factorial experiment utilizing a modular simulation of a radiator duct was employed. Two sensors, a propeller anemometer and a long hot wire, seemed to be quite independent of velocity distribution and flow angularity.