In this work, the analysis of flying buttresses as rampant arches, and by means of the classical Strength of Materials concepts, is performed. Since the elastic theory cannot be applied to masonry arches, some considerations on limit analysis of masonry arches and its boundary conditions must be exposed as well as on the equilibrium mechanism by which masonry supports bending moments. The appliance of this analysis to existing flying buttresses, allows obtaining some new conclusions on the behavior and the real role of those structures.