Experimental investigations of two different flat plate heat pipes (FPHP) are presented. The capillary structure is made of one or two screen mesh layers for the first FPHP and screen mesh covered grooves for the second FPHP. The heat pipes, filled with methanol, were tested in different configurations i.e. with various locations of heat sinks and heat sources, numbers and natures of the heat sinks and orientation. Water heat exchangers were first used as heat sinks to estimate the performance of the capillary structures. Experiments were also performed with aluminium radiator cooled by natural convection of air in order to show the performance of the FPHP in experimental conditions representing a practical case, typically the cooling of electronic equipments. The results show the interest of this solution for the proposed application. The method chosen to assemble this FPHP prototype with meshes is very simple and cheap. On the contrary, the performance of the heat pipe obtained with the association of grooves and meshes is not as high as one could expect. Indeed, if this capillary structure allows working in tilted unfavourable position, which is not possible with grooved heat pipe, a clear nucleate boiling limitation is observed for rather small heat fluxes.