module 29 with joining means 32 34 with respectively the inboard module 23 and the outboard module 33 using enlarged manufacturing moulds 47 having a common zone 13 of a length l 0 3 and an adaptive zone 15 at the beginning and or at the end of a length al 0 3 comprised preferably between the 1 15 of l 0 3 the maximum length of the intermediate module 29 being comprised between the 10 30 of the total length of the blade if the intermediate module 29 to be manufactured shall have for example a length l 3 the enlarged moulds 47 shall be arranged with said length during its manufacturing therefore suitable configured additional manufacturing moulds for said adaptive zones 15 shall be provided whether with the same transversal section than the initial transversal section of the common zone 13 or with a transversal section of variable shape the configuration of the transversal section of said adaptive zones 15 at the end of the inboard module 23 at the beginning of the outboard module 33 or at the beginning or end of the intermediate module 29 with a constant shape facilitates the manufacturing of blades of variable length but the final shape of the blade is not an aerodynamic optimal shape fig9 shows schematically an example of a mould 50 for a shell in said adaptive zones 15 with a movable template 51 the configuration of.