Characteristics of a 40 degree cone for measuring Mach number, total pressure, and flow angles at supersonic speeds

Frank J. Centolanzi
naca-tn-3967
May 1957


An experimental investigation was conducted to determine the characteristics of a 40 degree cone for use in the measurement of Mach number, total pressure, and flow angles. The cone had a total -pressure orifice at the apex and four equally spaced static-pressure orifices on the surface. Pressure measurements were taken at angles of pitch up to 26 degrees at Mach numbers of 1.72, 1.95, and 2.46 for Reynolds numbers of 3.12 and 5.41 million per foot. This instrument is capable of measuring Mach number within approximately plus-or-minus 1.0 percent and the flow angles within plus-or-minus 0.25 degrees. The total pressure can be measured within plus-or-minus 0.5 percent at a Mach number of 1.72 and within plus-or-minus 2.0 percent at a Mach number of 2.46. These flow quantities can be determined from the measured cone pressures and charts presented in this report. In general, an iterative procedure is required; however, in practice, such a procedure is necessary only for accurate determination of the Mach number and total pressure at Mach numbers near 2.5.

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