The local heat transfer by forced convection from the base surface of a bluff obstacle in a variety of configurations was measured. The data are satisfactorily represented by an equation of the type hLkf=C·U∞ρfLμf2/3 The coefficient C depends upon the configuration and the location. Its value is uniformly 0.20 on the rear of a flat-plate strip at 90-deg angle of attack. It diminishes wherever any device can close the dead air space, or reduce its size.