Equations based on aircraft speed and altitude, tank geometry, and certain parameters of the erosion process are given for the discharge from the tanks, the erosion into droplets and tbe resulting distribution on the ground of water released from a fire -bomber. A development of a previous theoretical model that displayed some weaknesses, the present model includes more realistic door-opening and discharge times and incorporates an erosion process in which the volume rate of production of droplets is dependent, not only on the area of bulk water exposed to the airstream, but also on the distance below the aircraft. Predicted solutions are matched to experimental data from tests of three aircraft, to numerically define proportionality factors used in the model. Equations are developed to estimate the width of the wetted area and to produce idealized contour patterns. The theoretical model is applicable to aircraft making drops between 75 and 110 knots at heights from 50 to 100 feet above the ground.