NACA research memorandum RM (series). (National Advisory Committee for Aeronautics.) [Processed. No longer confidential.]. E55L09. Experimental investigation of 0.4 hub tip diameter ratio axial-flow compressor inlet stage at transonic inlet relative Mach numbers: 3, Effect of tip taper on over-all and blade-element performances [with list of references]: by John C. Montgomery and Frederick Glaser.