The Bell X-1 was a better thought out project than the M.52 if the objective was just to break the sound-barrier in that the X-1 used rocket power and 'cheated' by being air-launched from a B-29. The M-52 would have had the extra problems of taking-off, climbing to altitude, and the aerodynamic problems of getting the centrifugal flow jet engine through Mach1, would it not?