Abstract : The technique of obtaining thrust vector control by the injection of a liquid into the supersonic region of a rocket nozzle was studied. Liquids studied were water, Freon-12, Perchloroethylene, nitrogen tetroxide and bromine. In addition, unsymmetrical dimethylhydrazine and inhibited red fuming nitric acid were injected simultaneously to explore the effect of energy release in the nozzle exit cone with bipropellant injection. Data on the relationships of side force to injectant flow rate, the effect of axial location of the injection port, the effect of injection pressure and the effects of injectant properties are presented and discussed. (Author)