AbstractAn evaluation of Sobieczky's fictitious gas technique is presented as applied to the design of a transonic rotor. A representative transonic compressor rotor was redesigned using Sobieczky's technique in an ‘onion peel’ fashion. The design was followed by a full three‐dimensional inviscid analysis of the new rotor, to determine whether spanwise redistribution of the streamlines in the new flow would invalidate the technique by causing shocks to reappear. This analysis verified the suppression of shocks present in the initial flow field. This demonstrates that the technique can be used in practice to improve the design of transonic rotors and stators with subsonic flow at the inlet and