A reaction turbine intended to create an air flow, by rotation on itself, of the type including: - a lower flange and an upper flange , each having a generally annular shape, and substantially parallel to each other and perpendicular to the axis of rotation (X-X) ; - a plurality of blades disposed between the two flanges , of an arcuate shape such that: - the trailing and leading edges are inclined relative to the parallel planes of the flanges ; - the inclination of the blades , relative to the axis of rotation (X-X), varies from the leading edge to the trailing edge ; - the leading and trailing edges have respective different inclinations relative to the axis of rotation (X-X); the turbine being made by moulding, in plastic material, one of the flanges , preferably the lower flange , on the one hand, and the blades , on the other hand, being made in one single piece, characterised in that for each blade , the angle (delta) (Δ), called "trailing edge pitch" angle, formed by, on the one hand, the straight line (C) passing through the trailing edge and the leading edge , and, on the other hand, the straight line passing through the tangent (T) to the circle of displacement (D) of the trailing edge and the trailing edge , is comprised between 22.5° and 29.7°, and in that the blades are disposed angularly, seen in a diametrical plane orthogonal to the flow of air, in a distribution which is not uniform, that is to say that the angular sector separating the leading edge of a blade from the leading edge of the next blade is different from 360°/n, "n" being the number of blades, and the separation angles of two consecutive blades have a global variation between the smallest angle and the largest angle of about 30%. - a lower flange and an upper flange , each having a generally annular shape, and substantially parallel to each other and perpendicular to the axis of rotation (X-X) ; - a plurality of blades disposed between the two flanges , of an arcuate shape such that: - the trailing and leading edges are inclined relative to the parallel planes of the flanges ; - the inclination of the blades , relative to the axis of rotation (X-X), varies from the leading edge to the trailing edge ; - the leading and trailing edges have respective different inclinations relative to the axis of rotation (X-X); the turbine being made by moulding, in plastic material, one of the flanges , preferably the lower flange , on the one hand, and the blades , on the other hand, being made in one single piece, characterised in that for each blade , the angle (delta) (Δ), called "trailing edge pitch" angle, formed by, on the one hand, the straight line (C) passing through the trailing edge and the leading edge , and, on the other hand, the straight line passing through the tangent (T) to the circle of displacement (D) of the trailing edge and the trailing edge , is comprised between 22.5° and 29.7°, and in that the blades are disposed angularly, seen in a diametrical plane orthogonal to the flow of air, in a distribution which is not uniform, that is to say that the angular sector separating the leading edge of a blade from the leading edge of the next blade is different from 360°/n, "n" being the number of blades, and the separation angles of two consecutive blades have a global variation between the smallest angle and the largest angle of about 30%. <EOS>