Much work has been done in investigating the effects of secondary injection into a supersonic flow field for a flat plate and two-dimensional nozzle. For actual application, however, it is in the concial rocket nozzle where the most interest lies. Several variables can affect the resulting side force from secondary injection. There are: flow rate of secondary injectant, sonic or supersonic injection, location of injection port, injection pressure and angle of injection. To investigate the effect of all of these variables at the same time would be quite difficult. 9It was therefore decided to begin with only a few of these variables: flow rate of secondary injectant, location of injection port and sonic condition for the injectant. The nozzle used for the data presented in this report is shown. Each time a larger flow rate was desired for a specific location, the hole was simply drilled larger. Likewise, each time a new location was desired, the previous hole was filled and the new hole size and location was drilled. The limitations of this method are obvious. Only so many holes can be drilled safely in a nozzle of this size. Three locations were tested along with two port sizes for each location. (Author).