This work concerns the manufacturing of a composite tube using RTM process. During the preforming stage, a woven braid is laid down and stacked on a mandrel so that reinforcement plies form conical shapes with a defined angle. An innovative experimental preforming procedure has been developed to respect the specific angle. The resin injection step has been studied both experimentally and numerically. In this work a focus is applied on the optimization of the mould geometry and on the way the resin is injected within the preform to prevent the appearance of defects such as displacement of plies and porosity. Different optimization steps are described in this work and a mould geometry is proposed for this specific application and the quality of the part obtained is discussed and analysed.