The method involves arranging counterweights (40, 50, 60, 70) on a set of locations. The locations are located on hub envelopes (22, 32) close to ends (22A, 22B, 32A, 32B) of the hub envelopes that are distant from planes (B-B', C-C') of a set of coaxial n...

The method involves eliminating or reducing a possible unbalance of a propulsive system (1) with front and back coaxial non streamlined contra-rotating propellers (2, 3), where the propellers comprise hubs (21, 31) concentrically surrounded by hub envelope...