Current interest in developing a low cost, less complex tactical missile propulsion system that operates on readily available liquid fuels and can operate from low subsonic to a flight Mach number of 5 is driving research on pulse detonation engines. This research program involved the design, construction, and testing of a valveless Pulse Detonation Engine using a JP-10/ air mixture as the primary combustible reactants. A small JP-10/oxygen pre- detonation tube was used to initiate the detonation in the JP-10/air mixture in the engine. The engine was tested at various inlet conditions and equivalence ratios in order to determine the detonable regime of the fuel/air mixture. The original area transition from the pre-detonation tube to the main combustion tube appeared to be too extreme, so a tube was added to extend the pre- detonation tube into the throat of a shock focusing device inserted flush with the head end of the main combustion tube to promote more favorable transition conditions.