This thesis explains the design and testing of a water-cooled rotating detonation engine (RDE) run on hydrogen and air. The change in water temperature as it cooled the engine was used to find the steady heat rate into the containing walls of the detonation channel. The engine successfully ran four times for 20 seconds each. The steady-state heat rate was measured to be 2.5% of the propellant lower heating value (LHV) into the outer wall and 7.1% of LHV into the inner wall. Additionally, a quick-response resistance temperature detector (RTD) was used in an uncooled RDE of similar dimension to the cooled RDE to estimate the transient heat flux profile in the detonation channel. The average heat flux into the outer wall near the base of the channel was measured to be four times greater than the average heat flux over the entire cooled wall at steady-state, indicating the heat flux decreases significantly with axial distance. In addition, the large difference in heat absorption between the inner and outer cooled walls indicates that the heat flux into the inner wall is greater than that into the outer wall
