The effects were studied of changes in the temperature, pressure, and Reynolds number of a hot gas stream upon the required flow rates of a single liquid (water) used for film cooling different lengths of a cylindrical test section. The effects were also studied of the physical properties of water, anhydrous ammonia, ethanol, and Freon-113 on the required film coolant flow rates for a single condition of gas stream temperature, pressure, and Reynolds number. Heat flux and wall temperature distribution downstream from the liquid film were measured. A brief investigation of combined film cooling and convective cooling was conducted. Theoretical studies also were conducted to obtain relationships for predicting the convective heat transfer coefficient between a liquid film and a flowing hot gas stream, the insulation effect provided by the film coolant vapor for areas downstream from the liquid film, and the cooling requirements when external convective cooling is supplemented with internal film cooling. The resulting equations correlated the experimental data with reasonable accuracy. (Author).