Propulsion device having unducted counter-rotating and coaxial rotors

摘要

A propulsion device including an unducted upstream propeller and a counter-rotating and coaxial downstream propeller. At least one blade of the upstream propeller is configured to generate a corotating secondary vortex for acting upstream of the downstream propeller to destabilize a blade tip vortex of the same at least one blade.

主权项

1. A propeller blade comprising:
a plurality of blade sections stacked in a radial direction over a height h between a blade root and a blade tip, each blade section extending between a leading edge and a trailing edge, and between a pressure side and a suction side; wherein the leading edge presents negative sweep at the blade root, positive sweep at the blade tip, and between the negative sweep and the positive sweep, a convex portion at a radial position zv at a distance lying in a range of 0.2×h to 0.4×h from the blade root, each blade section presenting a chord of function C(z) for which a derivative dC/dz presents a first local maximum between the blade root and the position zv, a local minimum between the position zv and a radial position zt lying at a distance in a range of 0.7×h to 0.8×h from the blade root, and a second local maximum between the position zt and the blade tip.