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NACA-TN-4122
External interference effects of flow through static-pressure orifices of an NACA airspeed head at a Mach number of 3
Year: 1957
Abstract: Wind-tunnel tests have been made to determine the static-pressure error resulting from external interference effects of flow through the static-pressure orifices of an NACA airspeed head at a Mach number of 3 and 00 angle of attack.
The results indicated that the static-pressure error increased almost linearly with increase in mass flow through the orifices. At a mass-flow rate corresponding to that which would be obtained at high altitudes for an airplane in a 45° climb and for which the airspeed installation incorporates an airspeed indicator, a Mach meter, and altimeter, the error in static pressure would be about 6 percent with a corresponding error in Mach number of 3 percent. In a vertical climb with this airspeed system the error would be 8 percent in static pressure and 4 percent in Mach number. The static-pressure error of the forward set of orifices was not influenced by varying flow rates through the rear orifices. However, varying flow rates through the forward orifices caused a small effect of 1 percent or less on the static-pressure error of the rear set of orifices.
The results indicated that the static-pressure error increased almost linearly with increase in mass flow through the orifices. At a mass-flow rate corresponding to that which would be obtained at high altitudes for an airplane in a 45° climb and for which the airspeed installation incorporates an airspeed indicator, a Mach meter, and altimeter, the error in static pressure would be about 6 percent with a corresponding error in Mach number of 3 percent. In a vertical climb with this airspeed system the error would be 8 percent in static pressure and 4 percent in Mach number. The static-pressure error of the forward set of orifices was not influenced by varying flow rates through the rear orifices. However, varying flow rates through the forward orifices caused a small effect of 1 percent or less on the static-pressure error of the rear set of orifices.
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| contributor author | NASA - National Aeronautics and Space Administration (NASA) | |
| date accessioned | 2017-09-04T17:41:43Z | |
| date available | 2017-09-04T17:41:43Z | |
| date copyright | 01/01/1957 | |
| date issued | 1957 | |
| identifier other | DYONEEAAAAAAAAAA.pdf | |
| identifier uri | http://yse.yabesh.ir/std/handle/yse/164689 | |
| description abstract | Wind-tunnel tests have been made to determine the static-pressure error resulting from external interference effects of flow through the static-pressure orifices of an NACA airspeed head at a Mach number of 3 and 00 angle of attack. The results indicated that the static-pressure error increased almost linearly with increase in mass flow through the orifices. At a mass-flow rate corresponding to that which would be obtained at high altitudes for an airplane in a 45° climb and for which the airspeed installation incorporates an airspeed indicator, a Mach meter, and altimeter, the error in static pressure would be about 6 percent with a corresponding error in Mach number of 3 percent. In a vertical climb with this airspeed system the error would be 8 percent in static pressure and 4 percent in Mach number. The static-pressure error of the forward set of orifices was not influenced by varying flow rates through the rear orifices. However, varying flow rates through the forward orifices caused a small effect of 1 percent or less on the static-pressure error of the rear set of orifices. | |
| language | English | |
| title | NACA-TN-4122 | num |
| title | External interference effects of flow through static-pressure orifices of an NACA airspeed head at a Mach number of 3 | en |
| type | standard | |
| page | 13 | |
| status | Active | |
| tree | NASA - National Aeronautics and Space Administration (NASA):;1957 | |
| contenttype | fulltext |