This experimental study investigates the thermal performance of axially rotating horizontal wickless heat pipes under different operating conditions. A heat pipe is designed, constructed, and tested for the investigation. The experiments are conducted on a heat pipe rotating at speeds of 250-1500rpm, with Taylor numbers ranging from 3.0×10⁷ to 1.1×10⁹, and heat fluxes from 2090 to 16700W/m². The heat pipe is charged with water as a working fluid, filling 100% of the evaporator volume. The effect of liquid charging is also examined, varying between 5 and 55% of the heat pipe's inner volume. The results demonstrate that rotation significantly enhances the heat pipe's performance. The effective thermal conductivity of heat pipes increases by 30-40% for heat flux ranging from 2090 to 8350 W/m², and approximately 20% for higher heat fluxes as the Taylor number increases from 3.0×10⁷ to 1.1×10⁹. The best performance of the rotating heat pipe is achieved at the highest Taylor number of 1.1x10⁹ and the lowest heat flux of 2090 W/m², resulting in a remarkable 9.47-fold increase in effective thermal conductivity compared to copper. The study also identifies the optimum liquid charge for the heat pipe, which is found to be about 35% of the inner pipe volume.